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<title>Document</title></head><body><div id="id72c89f0081d4f67af70c9f5da05afb6_30"></div><div style="height:72pt;width:100%;"><div><font><br></font></div></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">As filed with the Securities and Exchange Commission on June 10, 2020</font></div><div style="text-align:right;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Registration No.</font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:115%;">  </font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">333-</font></div><div style="text-align:center;margin-bottom:6pt;"><table style="margin-left:auto;margin-right:auto;border-collapse:collapse;text-align:left;text-indent:0pt;display:inline-table;width:99.358%;"><tr><td style="width:1.0%;"></td><td style="width:18.000%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:18.000%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:18.000%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:18.000%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:18.000%;"></td><td style="width:1.0%;"></td></tr><tr><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;border-bottom:3pt double #000;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;border-bottom:3pt double #000;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;border-bottom:3pt double #000;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;border-bottom:3pt double #000;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;border-bottom:3pt double #000;padding-left:1pt;padding-right:1pt;"></td></tr></table></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:115%;">UNITED STATES</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:115%;">SECURITIES AND EXCHANGE COMMISSION</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:14pt;font-weight:700;line-height:115%;">Washington, D.C.  20549</font></div><div><font><br></font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:115%;">FORM S-8</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:115%;">REGISTRATION STATEMENT</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:115%;">UNDER</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:115%;">THE SECURITIES ACT OF 1933</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:115%;">____________________________________________</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:115%;">X4 Pharmaceuticals, Inc.</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">(Exact name of registrant as specified in its charter)</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">___________________________________________</font></div><div><table style="margin-left:auto;margin-right:auto;border-collapse:collapse;text-align:left;text-indent:0pt;display:inline-table;width:98.076%;"><tr><td style="width:1.0%;"></td><td style="width:35.908%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:37.052%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:21.040%;"></td><td style="width:1.0%;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Delaware</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">27-3181608</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">(State or other jurisdiction of<br>incorporation or organization)</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">(I.R.S. Employer<br>Identification No.)</font></td></tr><tr><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="6" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">955 Massachusetts Avenue, 4th Floor</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Cambridge, Massachusetts</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">02139</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">(Address of Principal Executive Offices)</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">(Zip Code)</font></td></tr></table></div><div style="text-align:center;"><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">X4 Pharmaceuticals, Inc. Amended and Restated 2017 Equity Incentive Plan</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">(Full title of the plan)</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Paula Ragan, Ph.D.</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">President and Chief Executive Officer</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">X4 Pharmaceuticals, Inc.</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">955 Massachusetts Avenue, 4th Floor</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Cambridge, Massachusetts 02139</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">(857) 529-8300</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">(Name, address and telephone number, including area code, of agent for service)</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">___________________________</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:115%;">Copy to&#58;</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Daniel I. Goldberg</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Richard C. Segal</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Courtney T. Thorne </font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Cooley LLP </font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">55 Hudson Yards</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">New York, NY 10001-2157</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">(212) 479-6000</font></div><div><font><br></font></div><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:115%;">Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company.  See the definitions of &#8220;large accelerated filer,&#8221; &#8220;accelerated filer,&#8221; &#8220;smaller reporting company&#8221; and &#8220;emerging growth company&#8221; in Rule 12b-2 of the Exchange </font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Act.</font></div><div><table style="margin-left:auto;margin-right:auto;border-collapse:collapse;text-align:left;text-indent:0pt;display:inline-table;width:100.000%;"><tr><td style="width:1.0%;"></td><td style="width:24.207%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:16.448%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:41.923%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:9.422%;"></td><td style="width:1.0%;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Large accelerated filer</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">&#9744;</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Accelerated filer</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">&#9746;</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Non-accelerated filer</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">&#9744;</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Smaller reporting company</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">&#9746;</font></td></tr><tr><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Emerging growth company</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">&#9746;</font></td></tr></table></div><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:115%;">If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.  &#9746;</font></div><div><font><br></font></div><div style="position:relative;width:100%;height:72pt;"><div style="position:absolute;bottom:0;width:100%;"><div><font><br></font></div></div></div><div id="id72c89f0081d4f67af70c9f5da05afb6_55"></div><hr style="page-break-after:always"><div style="height:72pt;width:100%;"><div><font><br></font></div></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:400;line-height:115%;">________________________________</font></div><div style="text-align:center;"><font><br></font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">CALCULATION OF REGISTRATION FEE</font></div><div style="text-align:center;"><table style="margin-left:auto;margin-right:auto;border-collapse:collapse;text-align:left;text-indent:0pt;display:inline-table;width:97.115%;"><tr><td style="width:1.0%;"></td><td style="width:33.478%;"></td><td style="width:1.0%;"></td><td style="width:0.1%;"></td><td style="width:0.955%;"></td><td style="width:0.1%;"></td><td style="width:1.0%;"></td><td style="width:13.346%;"></td><td style="width:1.0%;"></td><td style="width:0.1%;"></td><td style="width:0.460%;"></td><td style="width:0.1%;"></td><td style="width:1.0%;"></td><td style="width:13.346%;"></td><td style="width:1.0%;"></td><td style="width:0.1%;"></td><td style="width:0.460%;"></td><td style="width:0.1%;"></td><td style="width:1.0%;"></td><td style="width:13.346%;"></td><td style="width:1.0%;"></td><td style="width:0.1%;"></td><td style="width:0.460%;"></td><td style="width:0.1%;"></td><td style="width:1.0%;"></td><td style="width:13.349%;"></td><td style="width:1.0%;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"><font style="font-size:9pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Title of<br>securities to be registered</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:700;line-height:115%;">Amount</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:700;line-height:115%;">to be</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:700;line-height:115%;">registered </font><sup style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.85pt;font-weight:700;line-height:115%;vertical-align:top;">(1)</sup></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:700;line-height:115%;">Proposed maximum offering price</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:700;line-height:115%;">per share </font><sup style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.85pt;font-weight:400;line-height:115%;vertical-align:top;">(2)</sup></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:700;line-height:115%;">Proposed</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:700;line-height:115%;">maximum aggregate</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:700;line-height:115%;">offering price </font><sup style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.85pt;font-weight:400;line-height:115%;vertical-align:top;">(2)</sup></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"><font style="font-size:9pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Amount of registration fee</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:middle;border-top:1pt solid #000000;border-bottom:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:115%;">Common Stock, $0.001 par value per share</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;border-top:1pt solid #000000;border-bottom:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><font style="font-size:9pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">474,465 shares</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;border-top:1pt solid #000000;border-bottom:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><font style="font-size:10pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">$8.83</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;border-top:1pt solid #000000;border-bottom:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><font style="font-size:10pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">$4,189,525.95</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;border-top:1pt solid #000000;border-bottom:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><font style="font-size:10pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">$543.80</font></td></tr></table></div><div style="text-align:center;"><font><br></font></div><div style="text-indent:-27pt;padding-left:36pt;"><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">(1)    </font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:115%;">  </font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Pursuant to Rule 416 of the Securities Act of 1933, as amended (the &#8220;</font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:115%;">Securities Act</font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#8221;), this Registration Statement shall also cover any additional shares of the Registrant&#8217;s common stock, par value $0.001 per share (the &#8220;</font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:115%;">Common Stock</font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#8221;), that become issuable under the X4 Pharmaceuticals, Inc. Amended and Restated 2017 Equity Incentive Plan (as amended from time to time, the &#8220;</font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:115%;">2017 Plan</font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#8221;) by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without receipt of consideration that increases the number of the Registrant&#8217;s outstanding shares of Common Stock.</font></div><div style="text-indent:-27pt;padding-left:36pt;"><font><br></font></div><div style="text-indent:-27pt;padding-left:36pt;"><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">(2)      This calculation is made solely for the purpose of determining the registration fee pursuant to the provisions of Rule 457(c) and (h) under the Securities Act. The offering price per share and the aggregate offering price for shares reserved for future grant or issuance under the Plans are based on the average of the high and low sale prices per share of the Common Stock as reported on The Nasdaq Capital Market as of a date (June 5, 2020) within five business days prior to filing this Registration Statement.</font></div><div style="text-indent:-27pt;padding-left:36pt;"><font><br></font></div><div style="padding-left:36pt;"><font><br></font></div><div><font><br></font></div><div style="text-align:center;"><font><br></font></div><div style="text-align:center;"><font><br></font></div><div id="id72c89f0081d4f67af70c9f5da05afb6_60"></div><div><font><br></font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">INCORPORATION OF DOCUMENTS BY REFERENCE</font></div><div><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">This Registration Statement on Form S-8 is being filed for the purpose of increasing the number of securities of the same class as other securities for which a Registration Statement on Form S-8 of the Registrant relating to the same employee benefit plans is effective. Accordingly, this Registration Statement incorporates by reference the contents of (i) the Registration Statement on Form S-8 (File No. 333-221622) filed with the Securities and Exchange Commission (&#8220;</font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:115%;">SEC</font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#8221;) on </font><font style="background-color:#ffffff;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312517345721/d493744ds8.htm" style="background-color:#ffffff;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;">November 16, 2017</a></font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;"> relating to the 2017 Plan and certain other of the Registrant&#8217;s employee benefit plans&#59; (ii) the Registration Statement on Form S-8 (File No. 333-223539) filed with the SEC on </font><font style="background-color:#ffffff;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312518076441/d535539ds8.htm" style="background-color:#ffffff;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;">March 9, 2018 </a></font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">relating to the 2017 Plan&#59; (iii) the Registration Statement on Form S-8 (File No. 333-230181) filed with the SEC on </font><font style="background-color:#ffffff;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312519070143/d715399ds8.htm" style="background-color:#ffffff;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;">March 11, 2019</a></font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;"> relating to the 2017 Plan and certain other of the Registrant&#8217;s benefit plans&#59; and (iv) the Registration Statement on Form S-8 (File No. 333-237164) filed with the SEC on </font><font style="background-color:#ffffff;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312520072921/d884915ds8.htm" style="background-color:#ffffff;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;">Marc</a><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312520072921/d884915ds8.htm" style="background-color:#ffffff;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;">h 13, 2020</a></font><font style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;"> relating to the 2017 Plan and certain other of the Registrant&#8217;s employee benefit plans, in each case except for Item 8, Exhibits, with respect to which the Exhibit Index below is incorporated herein by reference.</font></div><div><font><br></font></div><div style="position:relative;width:100%;height:72pt;"><div style="position:absolute;bottom:0;width:100%;"><div><font><br></font></div></div></div><hr style="page-break-after:always"><div style="height:72pt;width:100%;"><div><font><br></font></div></div><div><font><br></font></div><div id="id72c89f0081d4f67af70c9f5da05afb6_65"></div><div style="text-align:center;-sec-extract:summary;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">PART II</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">INFORMATION REQUIRED IN THE REGISTRATION STATEMENT</font></div><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">Item 8. Exhibits</font></div><div style="text-align:center;"><font><br></font></div><div><table style="margin-left:auto;margin-right:auto;border-collapse:collapse;text-align:left;text-indent:0pt;display:inline-table;width:98.557%;"><tr><td style="width:1.0%;"></td><td style="width:6.292%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:39.463%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:7.593%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:14.747%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:10.357%;"></td><td style="width:1.0%;"></td><td style="width:1.0%;"></td><td style="width:9.548%;"></td><td style="width:1.0%;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Exhibit Number</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Exhibit Description</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Filed Herewith</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Incorporated Reference herein from Form or Schedule</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Filing Date</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:middle;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">SEC File&#47;Reg. Number</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">4.1.1</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312517348213/d495338dex31.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Restated Certificate of Incorporation of the Registrant, filed with the Secretary of State of the State of Delaware on November 20, 2017</a></font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;border-top:1pt solid #000000;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;border-top:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">8-K<br>(Exhibit 3.1)</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">11&#47;20&#47;2017</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000000;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">001-38295</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">4.1.2</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312519073465/d702482dex31.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Certificate of Amendment (Reverse Stock Split) to the Restated Certificate of Incorporation of the Registrant, filed with the Secretary of State of the State of Delaware on March 13, 2019</a></font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">8-K<br>(Exhibit 3.1)</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">03&#47;13&#47;2019</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">001-38295</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">4.1.3</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312519073465/d702482dex32.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Certificate of Amendment (Name Change) to the Restated Certificate of Incorporation of the Registrant, filed with the Secretary of State of the State of Delaware on March 13, 2019</a></font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">8-K<br>(Exhibit 3.2)</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">03&#47;13&#47;2019</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">001-38295</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">4.2</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312517348213/d495338dex32.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Amended and Restated By-laws of the Registrant</a></font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">8-K<br>(Exhibit 3.2)</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">11&#47;20&#47;2017</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">001-38295</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">4.3</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312519073465/d702482dex41.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Form of Common Stock Certificate</a></font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">8-K<br>(Exhibit 4.1)</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">03&#47;13&#47;2019</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">001-38295</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">5.1</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="x4-sx8x51opinionjune2020.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Opinion of Cooley LLP with respect to the legality of the securities being registered</a></font></div></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">X</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">23.1</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="xfor_6102020xs-8xconsent.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Consent of PricewaterhouseCoopers LLP, independent registered public accounting firm to X4 Pharmaceuticals, Inc. </a></font></div></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">X</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">23.2</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="x4-sx8x51opinionjune2020.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Consent of Cooley LLP (included in Exhibit 5.1)</a></font></div></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">X</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">24.1</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="#id72c89f0081d4f67af70c9f5da05afb6_70" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;">Power of Attorney to file future amendments (set forth on the signature page of this Registration Statement)</a></font></div></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">X</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">99.1</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="xfor_06102020xamendedandre.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Amended and Restated 2017 Equity Incentive Plan</a></font></div></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">X</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"></font></font></td><td colspan="3" style="background-color:#ffffff;text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"></font></font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"></font></font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">99.2</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312517315505/d427310dex108.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Form of Incentive Stock Option Agreement under the Amended and Restated 2017 Equity Incentive Plan</a></font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"></font></font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">S-1  <br>(Exhibit 10.8)</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:#ffffff;text-align:right;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">10&#47;20&#47;2017</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">001-38295</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">99.3</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312517315505/d427310dex109.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Form of Nonstatutory Stock Option Agreement under the Amended and Restated 2017 Equity Incentive Plan</a></font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"></font></font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">S-1  <br>(Exhibit 10.9)</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:#ffffff;text-align:right;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">10&#47;20&#47;2017</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">001-38295</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">99.4</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312518334447/d663229dex106.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Form of Restricted Stock Agreement under the Amended and Restated 2017 Equity Incentive Plan</a></font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"></font></font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">8-K <br>(Exhibit 10.6)</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:#ffffff;text-align:right;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">11&#47;27&#47;2018</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">001-38295</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">99.5</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="http://www.sec.gov/Archives/edgar/data/1501697/000119312519176532/d765457dex105.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Form of Restricted Stock Unit Agreement under the Amended and Restated 2017 Equity Incentive Plan</a></font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);"></font></font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">8-K <br>(Exhibit 10.5)</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:#ffffff;text-align:right;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">06&#47;19&#47;2019</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">001-38295</font></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">99.6</font></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;"><a href="x4-2017planxformofperforma.htm" style="background-color:rgb(255,255,255, 0.0);color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:115%;text-decoration: underline;-sec-extract:exhibit;">Form of Performance-Based Restricted Stock Unit Agreement under the Amended and Restated 2017 Equity Incentive Plan</a></font></div></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:center;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:8pt;font-weight:400;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">X</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr></table></div><div style="text-align:center;"><font><br></font></div><div style="position:relative;width:100%;height:72pt;"><div style="position:absolute;bottom:0;width:100%;"><div><font><br></font></div></div></div><hr style="page-break-after:always"><div style="height:72pt;width:100%;"><div><font><br></font></div></div><div style="text-align:center;"><font><br></font></div><div id="id72c89f0081d4f67af70c9f5da05afb6_70"></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">SIGNATURES</font></div><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cambridge, Commonwealth of Massachusetts, on June 10, 2020.</font></div><div style="text-indent:288pt;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">X4 PHARMACEUTICALS, INC.</font></div><div style="text-indent:288pt;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">By&#58; </font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration: underline;"> &#47;s&#47; Paula Ragan, Ph.D </font></div><div style="text-indent:306pt;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Paula Ragan, Ph.D.</font></div><div style="text-indent:306pt;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:115%;">President and Chief Executive Officer</font></div><div style="text-indent:306pt;"><font><br></font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%;">SIGNATURES AND POWER OF ATTORNEY</font></div><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">We, the undersigned officers and directors of X4 Pharmaceuticals, Inc., hereby severally constitute and appoint Paula Ragan, Ph.D.</font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:400;line-height:115%;"> </font><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">and Adam S. Mostafa, and each of them singly (with full power to each of them to act alone), our true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution in each of them for him or her and in his or her name, place and stead, and in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement on Form S-8 of X4 Pharmaceuticals, Inc., and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite or necessary to be done in and about the premises, as full to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them or their or his or her substitute or substitutes may lawfully do or cause to be done by virtue hereof.</font></div><div><font><br></font></div><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.</font></div><div><table style="margin-left:auto;margin-right:auto;border-collapse:collapse;text-align:left;text-indent:0pt;display:inline-table;width:96.955%;"><tr><td style="width:1.0%;"></td><td style="width:30.231%;"></td><td style="width:1.0%;"></td><td style="width:0.1%;"></td><td style="width:1.122%;"></td><td style="width:0.1%;"></td><td style="width:1.0%;"></td><td style="width:48.413%;"></td><td style="width:1.0%;"></td><td style="width:0.1%;"></td><td style="width:0.461%;"></td><td style="width:0.1%;"></td><td style="width:1.0%;"></td><td style="width:13.373%;"></td><td style="width:1.0%;"></td></tr><tr><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><font style="font-size:10pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Signature</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-bottom:1pt solid #000;padding-left:1pt;padding-right:1pt;"><font style="font-size:10pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Title</font></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-bottom:1pt solid #000;padding-left:1pt;padding-right:1pt;"><font style="font-size:10pt;font-weight:700;font-family:'Times New Roman',sans-serif;color:#000000;background-color:rgb(255,255,255, 0.0);">Date</font></td></tr><tr><td colspan="3" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;border-top:1pt solid #000;padding-left:1pt;padding-right:1pt;"></td><td colspan="6" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="6" style="height:3pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#47;s&#47; Paula Ragan</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" rowspan="2" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">President, Chief Executive Officer and Director</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">(principal executive officer)</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">June 10, 2020</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Paula Ragan, Ph.D.</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#47;s&#47; Adam S. Mostafa</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" rowspan="2" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Chief Financial Officer and Treasurer</font></div><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">(principal financial officer and principal accounting officer)</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">June 10, 2020</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Adam S. Mostafa</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#47;s&#47; Michael S. Wyzga</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" rowspan="2" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Chairman of the Board of Directors</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">June 10, 2020</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Michael S. Wyzga</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#47;s&#47; William E. Aliski</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" rowspan="2" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Director</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">June 10, 2020</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">William E. Aliski</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#47;s&#47; Gary J. Bridger</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" rowspan="2" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Director</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">June 10, 2020</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Gary J. Bridger, Ph.D.</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#47;s&#47; David McGirr</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" rowspan="2" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Director</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">June 10, 2020</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">David McGirr, M.B.A.</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#47;s&#47;  Ren&#233; Russo</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" rowspan="2" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Director</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">June 10, 2020</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Ren&#233; Russo, Pharm.D.</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr><tr><td colspan="3" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="6" style="height:12pt;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">&#47;s&#47; Murray W. Stewart, M.D.</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" rowspan="2" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Director</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;padding-left:1pt;padding-right:1pt;"><div style="text-align:center;"><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">June 10, 2020</font></div></td></tr><tr><td colspan="3" style="padding-top:2px;padding-bottom:2px;background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:top;border-top:1pt solid #000;padding-left:1pt;padding-right:1pt;"><div><font style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;">Murray W. Stewart, M.D.</font></div></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="display:none;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td><td colspan="3" style="background-color:rgb(255,255,255, 0.0);text-align:left;vertical-align:bottom;padding-left:1pt;padding-right:1pt;"></td></tr></table></div><div style="position:relative;width:100%;height:72pt;"><div style="position:absolute;bottom:0;width:100%;"><div><font><br></font></div></div></div></body></html>
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Document
As filed with the Securities and Exchange Commission on June 10, 2020
Registration No.
333-
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C.  20549
FORM S-8
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933
____________________________________________
X4 Pharmaceuticals, Inc.
(Exact name of registrant as specified in its charter)
___________________________________________
Delaware
27-3181608
(State or other jurisdiction of
incorporation or organization)
(I.R.S. Employer
Identification No.)
955 Massachusetts Avenue, 4th Floor
Cambridge, Massachusetts
02139
(Address of Principal Executive Offices)
(Zip Code)
X4 Pharmaceuticals, Inc. Amended and Restated 2017 Equity Incentive Plan
(Full title of the plan)
Paula Ragan, Ph.D.
President and Chief Executive Officer
X4 Pharmaceuticals, Inc.
955 Massachusetts Avenue, 4th Floor
Cambridge, Massachusetts 02139
(857) 529-8300
(Name, address and telephone number, including area code, of agent for service)
___________________________
Copy to:
Daniel I. Goldberg
Richard C. Segal
Courtney T. Thorne
Cooley LLP
55 Hudson Yards
New York, NY 10001-2157
(212) 479-6000
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company.  See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange
Act.
Large accelerated filer
☐
Accelerated filer
☒
Non-accelerated filer
☐
Smaller reporting company
☒
Emerging growth company
☒
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.  ☒
________________________________
CALCULATION OF REGISTRATION FEE
Title of
securities to be registered
Amount
to be
registered
(1)
Proposed maximum offering price
per share
(2)
Proposed
maximum aggregate
offering price
(2)
Amount of registration fee
Common Stock, $0.001 par value per share
474,465 shares
$8.83
$4,189,525.95
$543.80
(1)
Pursuant to Rule 416 of the Securities Act of 1933, as amended (the "
Securities Act
"), this Registration Statement shall also cover any additional shares of the Registrant's common stock, par value $0.001 per share (the "
Common Stock
"), that become issuable under the X4 Pharmaceuticals, Inc. Amended and Restated 2017 Equity Incentive Plan (as amended from time to time, the "
2017 Plan
") by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without receipt of consideration that increases the number of the Registrant's outstanding shares of Common Stock.
(2)      This calculation is made solely for the purpose of determining the registration fee pursuant to the provisions of Rule 457(c) and (h) under the Securities Act. The offering price per share and the aggregate offering price for shares reserved for future grant or issuance under the Plans are based on the average of the high and low sale prices per share of the Common Stock as reported on The Nasdaq Capital Market as of a date (June 5, 2020) within five business days prior to filing this Registration Statement.
INCORPORATION OF DOCUMENTS BY REFERENCE
This Registration Statement on Form S-8 is being filed for the purpose of increasing the number of securities of the same class as other securities for which a Registration Statement on Form S-8 of the Registrant relating to the same employee benefit plans is effective. Accordingly, this Registration Statement incorporates by reference the contents of (i) the Registration Statement on Form S-8 (File No. 333-221622) filed with the Securities and Exchange Commission ("
SEC
") on
November 16, 2017
relating to the 2017 Plan and certain other of the Registrant's employee benefit plans; (ii) the Registration Statement on Form S-8 (File No. 333-223539) filed with the SEC on
March 9, 2018
relating to the 2017 Plan; (iii) the Registration Statement on Form S-8 (File No. 333-230181) filed with the SEC on
March 11, 2019
relating to the 2017 Plan and certain other of the Registrant's benefit plans; and (iv) the Registration Statement on Form S-8 (File No. 333-237164) filed with the SEC on
Marc
h 13, 2020
relating to the 2017 Plan and certain other of the Registrant's employee benefit plans, in each case except for Item 8, Exhibits, with respect to which the Exhibit Index below is incorporated herein by reference.
PART II
INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
Item 8. Exhibits
Exhibit Number
Exhibit Description
Filed Herewith
Incorporated Reference herein from Form or Schedule
Filing Date
SEC File/Reg. Number
4.1.1
Restated Certificate of Incorporation of the Registrant, filed with the Secretary of State of the State of Delaware on November 20, 2017
8-K
(Exhibit 3.1)
11/20/2017
001-38295
4.1.2
Certificate of Amendment (Reverse Stock Split) to the Restated Certificate of Incorporation of the Registrant, filed with the Secretary of State of the State of Delaware on March 13, 2019
8-K
(Exhibit 3.1)
03/13/2019
001-38295
4.1.3
Certificate of Amendment (Name Change) to the Restated Certificate of Incorporation of the Registrant, filed with the Secretary of State of the State of Delaware on March 13, 2019
8-K
(Exhibit 3.2)
03/13/2019
001-38295
4.2
Amended and Restated By-laws of the Registrant
8-K
(Exhibit 3.2)
11/20/2017
001-38295
4.3
Form of Common Stock Certificate
8-K
(Exhibit 4.1)
03/13/2019
001-38295
5.1
Opinion of Cooley LLP with respect to the legality of the securities being registered
X
23.1
Consent of PricewaterhouseCoopers LLP, independent registered public accounting firm to X4 Pharmaceuticals, Inc.
X
23.2
Consent of Cooley LLP (included in Exhibit 5.1)
X
24.1
Power of Attorney to file future amendments (set forth on the signature page of this Registration Statement)
X
99.1
Amended and Restated 2017 Equity Incentive Plan
X
99.2
Form of Incentive Stock Option Agreement under the Amended and Restated 2017 Equity Incentive Plan
S-1
(Exhibit 10.8)
10/20/2017
001-38295
99.3
Form of Nonstatutory Stock Option Agreement under the Amended and Restated 2017 Equity Incentive Plan
S-1
(Exhibit 10.9)
10/20/2017
001-38295
99.4
Form of Restricted Stock Agreement under the Amended and Restated 2017 Equity Incentive Plan
8-K
(Exhibit 10.6)
11/27/2018
001-38295
99.5
Form of Restricted Stock Unit Agreement under the Amended and Restated 2017 Equity Incentive Plan
8-K
(Exhibit 10.5)
06/19/2019
001-38295
99.6
Form of Performance-Based Restricted Stock Unit Agreement under the Amended and Restated 2017 Equity Incentive Plan
X
SIGNATURES
Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cambridge, Commonwealth of Massachusetts, on June 10, 2020.
X4 PHARMACEUTICALS, INC.
By:
/s/ Paula Ragan, Ph.D
Paula Ragan, Ph.D.
President and Chief Executive Officer
SIGNATURES AND POWER OF ATTORNEY
We, the undersigned officers and directors of X4 Pharmaceuticals, Inc., hereby severally constitute and appoint Paula Ragan, Ph.D.
and Adam S. Mostafa, and each of them singly (with full power to each of them to act alone), our true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution in each of them for him or her and in his or her name, place and stead, and in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement on Form S-8 of X4 Pharmaceuticals, Inc., and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite or necessary to be done in and about the premises, as full to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them or their or his or her substitute or substitutes may lawfully do or cause to be done by virtue hereof.
Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.
Signature
Title
Date
/s/ Paula Ragan
President, Chief Executive Officer and Director
(principal executive officer)
June 10, 2020
Paula Ragan, Ph.D.
/s/ Adam S. Mostafa
Chief Financial Officer and Treasurer
(principal financial officer and principal accounting officer)
June 10, 2020
Adam S. Mostafa
/s/ Michael S. Wyzga
Chairman of the Board of Directors
June 10, 2020
Michael S. Wyzga
/s/ William E. Aliski
Director
June 10, 2020
William E. Aliski
/s/ Gary J. Bridger
Director
June 10, 2020
Gary J. Bridger, Ph.D.
/s/ David McGirr
Director
June 10, 2020
David McGirr, M.B.A.
/s/  René Russo
Director
June 10, 2020
René Russo, Pharm.D.
/s/ Murray W. Stewart, M.D.
Director
June 10, 2020
Murray W. Stewart, M.D.