content: <HTML><HEAD>
  <TITLE>S-8</TITLE>
  </HEAD>
   <BODY BGCOLOR="WHITE" STYLE="line-height:Normal">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>As filed with the Securities and Exchange Commission on September&nbsp;13, 2024 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="right"><B>Registration <FONT STYLE="white-space:nowrap">No.&nbsp;333-&#8195;&#8195;&#8195;</FONT> </B></P>
  <P STYLE="font-size:4pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P> <P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P>
  <P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="margin-top:4pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>UNITED STATES </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>SECURITIES AND EXCHANGE COMMISSION </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>Washington, D.C. 20549 </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
  <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>FORM <FONT
  STYLE="white-space:nowrap">S-8</FONT></B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>REGISTRATION STATEMENT </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B><I>Under </I></B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B><I>The
  Securities Act of 1933 </I></B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:24pt; font-family:Times New Roman" ALIGN="center"><B>MBX Biosciences, Inc. </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(Exact name of registrant as specified in its charter) </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
  <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:8pt" ALIGN="center">
  
  
  <TR>
  
  <TD WIDTH="50%"></TD>
  
  <TD VALIGN="bottom" WIDTH="1%"></TD>
  <TD WIDTH="48%"></TD></TR>
  
  
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" ALIGN="center"><B>Delaware</B></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" ALIGN="center"><B><FONT STYLE="white-space:nowrap">84-1882872</FONT></B></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
  <TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(State or other jurisdiction of</B></P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>incorporation or organization)</B></P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(I.R.S. Employer</B></P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Identification No.)</B></P></TD></TR>
  </TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>MBX Biosciences, Inc. </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>11711 N. Meridian Street, Suite 300 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Carmel, Indiana 46032 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(317) <FONT STYLE="white-space:nowrap">659-0200</FONT></B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Address, including zip code and telephone number, including area code, of Registrant&#146;s principal executive offices) </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>MBX Biosciences, Inc. 2019 Stock Option and Grant Plan </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>MBX Biosciences, Inc. 2024 Stock Option and Incentive Plan </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>MBX Biosciences, Inc. 2024 Employee Stock Purchase Plan </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Full title of the plans) </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>P. Kent Hawryluk </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>President and Chief Executive Officer </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>MBX Biosciences, Inc. </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>11711 N. Meridian Street, Suite 300 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Carmel, Indiana 46032 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(317) <FONT STYLE="white-space:nowrap">659-0200</FONT></B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Name, address, including zip code, and telephone number, including area code, of agent for service) </B></P>
  <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B><I>Copies to: </I></B></P>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Mitchell S. Bloom </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Edwin
  M. O&#146;Connor </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Daniel Hughes </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Goodwin Procter LLP </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>100
  Northern Avenue </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Boston, Massachusetts 02210 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(617) <FONT STYLE="white-space:nowrap">570-1000</FONT></B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
  <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Indicate by check mark whether
  the registrant is a large accelerated filer, an accelerated filer, a <FONT STYLE="white-space:nowrap">non-accelerated</FONT> filer, a smaller reporting company, or an emerging growth company. See the definitions of &#147;large accelerated
  filer,&#148; &#147;accelerated filer,&#148; &#147;smaller reporting company,&#148; and &#147;emerging growth company&#148; in Rule <FONT STYLE="white-space:nowrap">12b-2</FONT> of the Exchange Act. </P>
  <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">
  
  
  <TR>
  
  <TD WIDTH="17%"></TD>
  
  <TD VALIGN="bottom" WIDTH="1%"></TD>
  <TD WIDTH="58%"></TD>
  
  <TD VALIGN="bottom" WIDTH="1%"></TD>
  <TD WIDTH="20%"></TD>
  
  <TD VALIGN="bottom" WIDTH="1%"></TD>
  <TD WIDTH="2%"></TD></TR>
  
  
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom">Large&nbsp;accelerated&nbsp;filer</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9744;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">Accelerated filer</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9744;</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"><FONT STYLE="white-space:nowrap">Non-accelerated&nbsp;filer</FONT></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9746;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">Smaller&nbsp;reporting&nbsp;company</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9746;</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">Emerging growth company</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9746;</TD></TR>
  </TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">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&nbsp;7(a)(2)(B) of the Securities Act.&#8194;&#9744; </P> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P>
  </DIV></Center>
  
  
  <p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
  <HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Part I </B></P>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="10%" VALIGN="top" ALIGN="left"><B>Item&#8201;1.</B></TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left"><B>Plan Information. </B></P></TD></TR></TABLE>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The documents containing the information specified in this Item 1 will be sent or given to participants as specified by Rule 428(b)(1) under the Securities Act
  of 1933, as amended (the &#147;Securities Act&#148;). In accordance with the rules and regulations of the U.S. Securities and Exchange Commission (the &#147;Commission&#148;) and the instructions to Form <FONT STYLE="white-space:nowrap">S-8,</FONT>
  such documents are not being filed with the Commission either as part of this Registration Statement on Form <FONT STYLE="white-space:nowrap">S-8</FONT> (this &#147;Registration Statement&#148;) or as prospectuses or prospectus supplements pursuant
  to Rule 424 under the Securities Act. </P> <P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="10%" VALIGN="top" ALIGN="left"><B>Item&#8201;2.</B></TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left"><B>Registrant Information and Employee Plan Annual Information. </B></P></TD></TR></TABLE>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The documents containing the information specified in this Item 2 will be sent or given to participants as specified by Rule 428(b)(1) under the Securities
  Act. In accordance with the rules and regulations of the Commission and the instructions to Form <FONT STYLE="white-space:nowrap">S-8,</FONT> such documents are not being filed with the Commission either as part of this Registration Statement or as
  prospectuses or prospectus supplements pursuant to Rule 424 under the Securities Act. </P> <P STYLE="margin-top:24pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Part II </B></P>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>INFORMATION REQUIRED IN THE REGISTRATION STATEMENT </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="10%" VALIGN="top" ALIGN="left"><B>Item&#8201;3.</B></TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left"><B>Incorporation of Documents by Reference. </B></P></TD></TR></TABLE>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The registrant hereby incorporates by reference into this Registration Statement the following documents filed with the Commission: </P>
  <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="4%" VALIGN="top" ALIGN="left">(a)</TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left">The <A HREF="http://www.sec.gov/Archives/edgar/data/1776111/000119312524215436/d790774ds1a.htm">Amendment No.&nbsp;2</A> to the registrant&#146;s Registration Statement on Form <FONT STYLE="white-space:nowrap">S-1</FONT> filed with the Commission on September&nbsp;9, 2024 (File No.&nbsp;333- 281764), which contains the registrant&#146;s audited financial
  statements for the latest fiscal year for which such statements have been filed; and </P></TD></TR></TABLE> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="4%" VALIGN="top" ALIGN="left">(b)</TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left">The description of the registrant&#146;s common stock, par value $0.0001 per share (the &#147;Common
  Stock&#148;) contained in the registrant&#146;s Registration Statement on <A HREF="http://www.sec.gov/Archives/edgar/data/1776111/000119312524216643/d891647d8a12b.htm">Form <FONT STYLE="white-space:nowrap">8-A</FONT></A> (File No.&nbsp;001-42272),
  filed by the registrant with the Commission under Section&nbsp;12(b) of the Securities Exchange Act of 1934, as amended (the &#147;Exchange Act&#148;), on September&nbsp;10, 2024, including any amendments or reports filed for the purpose of updating
  such description. </P></TD></TR></TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">All documents that the registrant subsequently files pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange
  Act prior to the filing of a post-effective amendment to this Registration Statement which indicates that all of the shares of Common Stock offered have been sold or which deregisters all of such shares then remaining unsold, shall be deemed to be
  incorporated by reference in this Registration Statement and to be a part hereof from the date of the filing of such documents. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Any statement contained
  in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be
  incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement. </P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Under no circumstances will any information filed under current items 2.02 or 7.01 of Form <FONT STYLE="white-space:nowrap">8-K</FONT> be deemed incorporated
  herein by reference unless such Form <FONT STYLE="white-space:nowrap">8-K</FONT> expressly provides to the contrary. </P>
  </DIV></Center>
  
  
  <p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
  <HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
  
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="10%" VALIGN="top" ALIGN="left"><B>Item&#8201;4.</B></TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left"><B>Description of Securities. </B></P></TD></TR></TABLE>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Not applicable. </P> <P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="10%" VALIGN="top" ALIGN="left"><B>Item&#8201;5.</B></TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left"><B>Interests of Named Experts and Counsel. </B></P></TD></TR></TABLE>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Not applicable. </P> <P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="10%" VALIGN="top" ALIGN="left"><B>Item&#8201;6.</B></TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left"><B>Indemnification of Directors and Officers. </B></P></TD></TR></TABLE>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Section&nbsp;145 of the Delaware General Corporation Law (the &#147;DGCL&#148;) authorizes a corporation to indemnify its directors and officers against
  liabilities arising out of actions, suits and proceedings to which they are made or threatened to be made a party by reason of the fact that they have served or are currently serving as a director or officer to a corporation. The indemnity may cover
  expenses (including attorneys&#146; fees) judgments, fines and amounts paid in settlement actually and reasonably incurred by the director or officer in connection with any such action, suit or proceeding. Section&nbsp;145 permits corporations to
  pay expenses (including attorneys&#146; fees) incurred by directors and officers in advance of the final disposition of such action, suit or proceeding. In addition, Section&nbsp;145 provides that a corporation has the power to purchase and maintain
  insurance on behalf of its directors and officers against any liability asserted against them and incurred by them in their capacity as a director or officer, or arising out of their status as such, whether or not the corporation would have the
  power to indemnify the director or officer against such liability under Section&nbsp;145. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The registrant has adopted provisions in its Fourth Amended and
  Restated Certificate of Incorporation (&#147;Charter&#148;) and Amended and Restated Bylaws (&#147;Bylaws&#148;), each to be effective upon the closing of the registrant&#146;s initial public offering, that limit or eliminate the personal liability
  of the registrant&#146;s directors and officers to the fullest extent permitted by the DGCL, as it now exists or may in the future be amended. Consequently, the registrant&#146;s directors and officers will not be personally liable to the registrant
  or its stockholders for monetary damages or a breach of fiduciary duty in their capacities and directors and officers, except for liability: </P> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="5%">&nbsp;</TD>
  <TD WIDTH="3%" VALIGN="top" ALIGN="left">&#149;</TD>
  <TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
  <TD ALIGN="left" VALIGN="top"> <P ALIGN="left" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">for any breach of a director or officer&#146;s duty of loyalty to the registrant or its stockholders;
  </P></TD></TR></TABLE> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="5%">&nbsp;</TD>
  <TD WIDTH="3%" VALIGN="top" ALIGN="left">&#149;</TD>
  <TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
  <TD ALIGN="left" VALIGN="top"> <P ALIGN="left" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law;
  </P></TD></TR></TABLE> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="5%">&nbsp;</TD>
  <TD WIDTH="3%" VALIGN="top" ALIGN="left">&#149;</TD>
  <TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
  <TD ALIGN="left" VALIGN="top"> <P ALIGN="left" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">for any transaction from which the director or officer derived an improper personal benefit;
  </P></TD></TR></TABLE> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="5%">&nbsp;</TD>
  <TD WIDTH="3%" VALIGN="top" ALIGN="left">&#149;</TD>
  <TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
  <TD ALIGN="left" VALIGN="top"> <P ALIGN="left" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">arising under Section&nbsp;174 of the DGCL for directors; and </P></TD></TR></TABLE>
  <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="5%">&nbsp;</TD>
  <TD WIDTH="3%" VALIGN="top" ALIGN="left">&#149;</TD>
  <TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
  <TD ALIGN="left" VALIGN="top"> <P ALIGN="left" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">arising from any claim brought or in the right of the registrant for officers. </P></TD></TR></TABLE>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">These limitations of liability do not alter director and officer liability under the federal securities laws and do not affect the availability of equitable
  remedies such as an injunction or rescission. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">In addition, the Bylaws provide that: </P>
  <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="5%">&nbsp;</TD>
  <TD WIDTH="3%" VALIGN="top" ALIGN="left">&#149;</TD>
  <TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
  <TD ALIGN="left" VALIGN="top"> <P ALIGN="left" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">the registrant will indemnify its directors, officers and, in the discretion of its board of directors, certain
  employees to the fullest extent permitted by the DGCL, as it now exists or may in the future be amended; and </P></TD></TR></TABLE> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="5%">&nbsp;</TD>
  <TD WIDTH="3%" VALIGN="top" ALIGN="left">&#149;</TD>
  <TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
  <TD ALIGN="left" VALIGN="top"> <P ALIGN="left" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">the registrant will advance reasonable expenses, including attorneys&#146; fees, to its directors and, at the
  discretion of its board of directors, to officers and certain employees, in connection with legal proceedings relating to their service for or on behalf of the registrant, subject to limited exceptions. </P></TD></TR></TABLE>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The registrant has entered into indemnification agreements with each of its directors and officers. These agreements provide that the registrant will
  indemnify each of its directors, officers and, at times, their affiliates to the fullest extent permitted by the DGCL. The registrant will advance expenses, including attorneys&#146; fees (but excluding judgments, fines and settlement amounts), to
  each indemnified director, officer or affiliate in connection with any proceeding in which indemnification is available and the registrant will indemnify its directors and officers for any action or proceeding arising out of that person&#146;s
  services as a director or officer brought on behalf of the registrant </P>
  </DIV></Center>
  
  
  <p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
  <HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">
  or in furtherance of the registrant&#146;s rights. Additionally, certain of the registrant&#146;s directors or officers may have certain rights to indemnification, advancement of expenses or
  insurance provided by their affiliates or other third parties, which indemnification relates to and might apply to the same proceedings arising out of such director&#146;s or officer&#146;s services as a director referenced herein. Nonetheless, the
  registrant has agreed in the indemnification agreements that its obligations to those same directors or officers are primary and any obligation of such affiliates or other third parties to advance expenses or to provide indemnification for the
  expenses or liabilities incurred by those directors are secondary. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The registrant also maintains general liability insurance which covers certain
  liabilities of its directors and officers arising out of claims based on acts or omissions in their capacities as directors or officers, including liabilities under the Securities Act. </P>
  <P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="10%" VALIGN="top" ALIGN="left"><B>Item&#8201;7.</B></TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left"><B>Exemption from Registration Claimed. </B></P></TD></TR></TABLE>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Not applicable. </P>
  </DIV></Center>
  
  
  <p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
  <HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
  
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="10%" VALIGN="top" ALIGN="left"><B>Item&#8201;8.</B></TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left"><B>Exhibits. </B></P></TD></TR></TABLE> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">
  
  
  <TR>
  
  <TD></TD>
  
  <TD VALIGN="bottom" WIDTH="5%"></TD>
  <TD WIDTH="92%"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
  <TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><B>Exhibit<BR>Number</B></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Exhibit table</B></P></TD></TR>
  
  
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;4.1</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top">Form of Fourth Amended and Restated Certificate of Incorporation (Incorporated by reference to <A HREF="http://www.sec.gov/Archives/edgar/data/1776111/000119312524211217/d790774dex32.htm">Exhibit 3.2</A> to the registrant&#146;s
  Registration Statement on Form <FONT STYLE="white-space:nowrap">S-1,</FONT> as amended (File <FONT STYLE="white-space:nowrap">No.&nbsp;333-281764)).</FONT></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;4.2</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top">Form of Amended and Restated Bylaws (Incorporated by reference to <A HREF="http://www.sec.gov/Archives/edgar/data/1776111/000119312524211217/d790774dex34.htm">Exhibit 3.4</A> to the registrant&#146;s Registration Statement on Form <FONT
  STYLE="white-space:nowrap">S-1,</FONT> as amended (File <FONT STYLE="white-space:nowrap">No.&nbsp;333-281764)).</FONT></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;4.3</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top">Second Amended and Restated Investors&#146; Rights Agreement among the Registrant and certain of its stockholders, dated August&nbsp;
  2, 2024 (Incorporated by reference to <A HREF="http://www.sec.gov/Archives/edgar/data/1776111/000119312524206227/d790774dex41.htm">Exhibit 4.1</A> to the registrant&#146;s Registration Statement on Form <FONT STYLE="white-space:nowrap">S-1,</FONT> as
  amended (File <FONT STYLE="white-space:nowrap">No.&nbsp;333-281764)).</FONT></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;4.4</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top">Form of Common Stock Certificate (Incorporated by reference to <A HREF="http://www.sec.gov/Archives/edgar/data/1776111/000119312524206227/d790774dex42.htm">Exhibit 4.2</A> to the registrant&#146;s Registration Statement on Form <FONT
  STYLE="white-space:nowrap">S-1,</FONT> as amended (File <FONT STYLE="white-space:nowrap">No.&nbsp;333-281764)).</FONT></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;5.1*</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d829867dex51.htm">Opinion of Goodwin Procter LLP. </A></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>23.1*</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d829867dex231.htm">Consent of Ernst&nbsp;&amp; Young LLP, Independent Registered Public Accounting Firm. </A></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>23.2*</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d829867dex51.htm">Consent of Goodwin Procter LLP (included in Exhibit 5.1). </A></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>24.1*</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d829867ds8.htm#sig">Power of Attorney (included on signature page). </A></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>99.1</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top">MBX Biosciences, Inc. 2019 Stock Option and Grant Plan, as amended, and forms of award agreements thereunder (Incorporated by reference to <A HREF="http://www.sec.gov/Archives/edgar/data/1776111/000119312524206227/d790774dex101.htm">Exhibit
   10.1</A> to the registrant&#146;s Registration Statement on Form <FONT STYLE="white-space:nowrap">S-1,</FONT> as amended (File <FONT STYLE="white-space:nowrap">No.&nbsp;333-281764)).</FONT></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>99.2</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top">MBX Biosciences, Inc. 2024 Stock Option and Incentive Plan and forms of award agreements thereunder (Incorporated by reference to <A HREF="http://www.sec.gov/Archives/edgar/data/1776111/000119312524211217/d790774dex102.htm">Exhibit 10.2</A> to the registrant&#146;s Registration Statement on Form <FONT STYLE="white-space:nowrap">S-1,</FONT> as amended (File <FONT STYLE="white-space:nowrap">No.&nbsp;333-281764)).</FONT></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>99.3</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top">MBX Biosciences, Inc. 2024 Employee Stock Purchase Plan (Incorporated by reference to <A HREF="http://www.sec.gov/Archives/edgar/data/1776111/000119312524211217/d790774dex103.htm">Exhibit 10.3</A> to the registrant&#146;s
  Registration Statement on Form <FONT STYLE="white-space:nowrap">S-1,</FONT> as amended (File No.&nbsp;333<B>&#150;</B>281764<B>)).</B></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>107*</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d829867dexfilingfees.htm">Fee table. </A></TD></TR>
  </TABLE> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="2%" VALIGN="top" ALIGN="left">*</TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left">Filed herewith. </P></TD></TR></TABLE> <P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="10%" VALIGN="top" ALIGN="left"><B>Item&#8201;9.</B></TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left"><B>Undertakings. </B></P></TD></TR></TABLE>
  <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(a) The registrant hereby undertakes: </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(1) To file, during any
  period in which offers or sales are being made, a post-effective amendment to this Registration Statement: </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(i) To include any prospectus required by
  Section&nbsp;10(a)(3) of the Securities Act. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(ii) To reflect in the prospectus any facts or events arising after the effective date of the Registration
  Statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the Registration Statement. Notwithstanding the foregoing, any increase or
  decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of
  prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the &#147;Calculation of Registration
  Fee&#148; table in the Registration Statement. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(iii) To include any material information with respect to the plan of distribution not previously
  disclosed in the Registration Statement or any material change to such information in the registration statement. </P>
  </DIV></Center>
  
  
  <p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
  <HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><I>Provided, however</I>, that paragraphs (a)(1)(i) and (a)(1)(ii) herein do not apply if the information
  required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section&nbsp;13 or Section&nbsp;15(d) of the Exchange Act (15 U.S.C. 78m or
  78o(d)) that are incorporated by reference in the Registration Statement. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(2) That, for the purpose of determining any liability under the Securities
  Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. </P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the
  offering. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(b) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the
  registrant&#146;s annual report pursuant to Section&nbsp;13(a) or Section&nbsp;15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan&#146;s annual report pursuant to Section&nbsp;15(d) of the Exchange Act) that is
  incorporated by reference in the Registration Statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide
  offering thereof. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(c) Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling
  persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore,
  unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of
  any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling
  precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue. </P>
  </DIV></Center>
  
  
  <p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
  <HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B><A NAME="sig"></A>SIGNATURES </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the Securities Act, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements
  for filing on Form <FONT STYLE="white-space:nowrap">S-8</FONT> and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Carmel, Indiana, on this 13th day of September,
  2024. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="40%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt">
  
  
  <TR>
  
  <TD WIDTH="7%"></TD>
  
  <TD VALIGN="bottom" WIDTH="1%"></TD>
  <TD WIDTH="92%"></TD></TR>
  
  
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" COLSPAN="3"><B>MBX Biosciences, Inc.</B></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom">By:</TD>
  <TD VALIGN="bottom" STYLE=" BORDER-BOTTOM:1px solid #000000">&nbsp;</TD>
  <TD VALIGN="bottom" STYLE="BORDER-BOTTOM:1px solid #000000">/s/ P. Kent Hawryluk</TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">Name: P. Kent Hawryluk</TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">Title: President and Chief Executive Officer</TD></TR>
  </TABLE>
  </DIV></Center>
  
  
  <p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
  <HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>POWER OF ATTORNEY AND SIGNATURES </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">KNOW ALL BY THESE PRESENT, that each individual whose signature appears below hereby constitutes and appoints each of P. Kent Hawryluk and Rick Bartram, as
  such person&#146;s true and lawful <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorney-in-fact</FONT></FONT> and agent with full power of substitution and resubstitution, for such person in such person&#146;s name, place and
  stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto, and all documents in connection therewith, with the Commission
  granting unto each said <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorney-in-fact</FONT></FONT> and agent full power and authority to do and perform each and every act and thing requisite and necessary to be done in and
  about the premises, as fully to all intents and purposes as such person might or could do in person, hereby ratifying and confirming all that any said <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorney-in-fact</FONT></FONT>
  and agent, or any substitute or substitutes of any of them, may lawfully do or cause to be done by virtue hereof. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the
  Securities Act, this Registration Statement has been signed by the following person in the capacities and on the date indicated. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt">
  
  
  <TR>
  
  <TD WIDTH="38%"></TD>
  
  <TD VALIGN="bottom"></TD>
  <TD WIDTH="44%"></TD>
  
  <TD VALIGN="bottom" WIDTH="1%"></TD>
  <TD WIDTH="16%"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
  <TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>NAME</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>TITLE</B></P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>DATE</B></P></TD></TR>
  
  
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ P. Kent Hawryluk</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">P. Kent Hawryluk</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">President, Chief Executive Officer and Director</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">(Principal Executive Officer)</P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">September&nbsp;13, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Rick Bartram</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Rick Bartram</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Chief Financial Officer</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">(Principal Financial Officer and Principal Accounting Officer)</P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">September&nbsp;13, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Tiba Aynechi</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Tiba Aynechi</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">September&nbsp;13, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ James M. Cornelius</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">James M. Cornelius</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">September&nbsp;13, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Carl L. Gordon</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Carl L. Gordon</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">September&nbsp;13, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Patrick Heron</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Patrick Heron</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">September&nbsp;13, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Edward T. Mathers</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Edward T. Mathers</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">September&nbsp;13, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Ora Pescovitz</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Ora Pescovitz</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">September&nbsp;13, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Steven Ryder</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Steven Ryder</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">September&nbsp;13, 2024</TD></TR>
  </TABLE>
  </DIV></Center>
  
  </BODY></HTML>
metadata_documents: [{"type": "S-8", "sequence": "1", "filename": "d829867ds8.htm", "description": "S-8", "secsgml_size_bytes": 57983}]
metadata_filer: {"company-data": {"conformed-name": "MBX Biosciences, Inc.", "cik": "0001776111", "assigned-sic": "2834", "organization-name": "03 Life Sciences", "irs-number": "000000000", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-282106", "film-number": "241298092"}, "business-address": {"street1": "12406 HORESHAM STREET", "city": "CARMEL", "state": "IN", "zip": "46032", "phone": "3179893100"}, "mail-address": {"street1": "12406 HORESHAM STREET", "city": "CARMEL", "state": "IN", "zip": "46032"}}
text: S-8
  As filed with the Securities and Exchange Commission on September 13, 2024
  Registration
  No. 333-
  UNITED STATES
  SECURITIES AND EXCHANGE COMMISSION
  Washington, D.C. 20549
  FORM
  S-8
  REGISTRATION STATEMENT
  Under
  The
  Securities Act of 1933
  MBX Biosciences, Inc.
  (Exact name of registrant as specified in its charter)
  Delaware
  84-1882872
  (State or other jurisdiction of
  incorporation or organization)
  (I.R.S. Employer
  Identification No.)
  MBX Biosciences, Inc.
  11711 N. Meridian Street, Suite 300
  Carmel, Indiana 46032
  (317)
  659-0200
  (Address, including zip code and telephone number, including area code, of Registrant's principal executive offices)
  MBX Biosciences, Inc. 2019 Stock Option and Grant Plan
  MBX Biosciences, Inc. 2024 Stock Option and Incentive Plan
  MBX Biosciences, Inc. 2024 Employee Stock Purchase Plan
  (Full title of the plans)
  P. Kent Hawryluk
  President and Chief Executive Officer
  MBX Biosciences, Inc.
  11711 N. Meridian Street, Suite 300
  Carmel, Indiana 46032
  (317)
  659-0200
  (Name, address, including zip code, and telephone number, including area code, of agent for service)
  Copies to:
  Mitchell S. Bloom
  Edwin
  M. O'Connor
  Daniel Hughes
  Goodwin Procter LLP
  100
  Northern Avenue
  Boston, Massachusetts 02210
  (617)
  570-1000
  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. ☐
  Part I
  INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
  Item 1.
  Plan Information.
  The documents containing the information specified in this Item 1 will be sent or given to participants as specified by Rule 428(b)(1) under the Securities Act
  of 1933, as amended (the "Securities Act"). In accordance with the rules and regulations of the U.S. Securities and Exchange Commission (the "Commission") and the instructions to Form
  S-8,
  such documents are not being filed with the Commission either as part of this Registration Statement on Form
  S-8
  (this "Registration Statement") or as prospectuses or prospectus supplements pursuant
  to Rule 424 under the Securities Act.
  Item 2.
  Registrant Information and Employee Plan Annual Information.
  The documents containing the information specified in this Item 2 will be sent or given to participants as specified by Rule 428(b)(1) under the Securities
  Act. In accordance with the rules and regulations of the Commission and the instructions to Form
  S-8,
  such documents are not being filed with the Commission either as part of this Registration Statement or as
  prospectuses or prospectus supplements pursuant to Rule 424 under the Securities Act.
  Part II
  INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  Item 3.
  Incorporation of Documents by Reference.
  The registrant hereby incorporates by reference into this Registration Statement the following documents filed with the Commission:
  (a)
  The
  Amendment No. 2
  to the registrant's Registration Statement on Form
  S-1
  filed with the Commission on September 9, 2024 (File No. 333- 281764), which contains the registrant's audited financial
  statements for the latest fiscal year for which such statements have been filed; and
  (b)
  The description of the registrant's common stock, par value $0.0001 per share (the "Common
  Stock") contained in the registrant's Registration Statement on
  Form
  8-A
  (File No. 001-42272),
  filed by the registrant with the Commission under Section 12(b) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), on September 10, 2024, including any amendments or reports filed for the purpose of updating
  such description.
  All documents that the registrant subsequently files pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange
  Act prior to the filing of a post-effective amendment to this Registration Statement which indicates that all of the shares of Common Stock offered have been sold or which deregisters all of such shares then remaining unsold, shall be deemed to be
  incorporated by reference in this Registration Statement and to be a part hereof from the date of the filing of such documents.
  Any statement contained
  in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be
  incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.
  Under no circumstances will any information filed under current items 2.02 or 7.01 of Form
  8-K
  be deemed incorporated
  herein by reference unless such Form
  8-K
  expressly provides to the contrary.
  Item 4.
  Description of Securities.
  Not applicable.
  Item 5.
  Interests of Named Experts and Counsel.
  Not applicable.
  Item 6.
  Indemnification of Directors and Officers.
  Section 145 of the Delaware General Corporation Law (the "DGCL") authorizes a corporation to indemnify its directors and officers against
  liabilities arising out of actions, suits and proceedings to which they are made or threatened to be made a party by reason of the fact that they have served or are currently serving as a director or officer to a corporation. The indemnity may cover
  expenses (including attorneys' fees) judgments, fines and amounts paid in settlement actually and reasonably incurred by the director or officer in connection with any such action, suit or proceeding. Section 145 permits corporations to
  pay expenses (including attorneys' fees) incurred by directors and officers in advance of the final disposition of such action, suit or proceeding. In addition, Section 145 provides that a corporation has the power to purchase and maintain
  insurance on behalf of its directors and officers against any liability asserted against them and incurred by them in their capacity as a director or officer, or arising out of their status as such, whether or not the corporation would have the
  power to indemnify the director or officer against such liability under Section 145.
  The registrant has adopted provisions in its Fourth Amended and
  Restated Certificate of Incorporation ("Charter") and Amended and Restated Bylaws ("Bylaws"), each to be effective upon the closing of the registrant's initial public offering, that limit or eliminate the personal liability
  of the registrant's directors and officers to the fullest extent permitted by the DGCL, as it now exists or may in the future be amended. Consequently, the registrant's directors and officers will not be personally liable to the registrant
  or its stockholders for monetary damages or a breach of fiduciary duty in their capacities and directors and officers, except for liability:
  •
  for any breach of a director or officer's duty of loyalty to the registrant or its stockholders;
  •
  for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law;
  •
  for any transaction from which the director or officer derived an improper personal benefit;
  •
  arising under Section 174 of the DGCL for directors; and
  •
  arising from any claim brought or in the right of the registrant for officers.
  These limitations of liability do not alter director and officer liability under the federal securities laws and do not affect the availability of equitable
  remedies such as an injunction or rescission.
  In addition, the Bylaws provide that:
  •
  the registrant will indemnify its directors, officers and, in the discretion of its board of directors, certain
  employees to the fullest extent permitted by the DGCL, as it now exists or may in the future be amended; and
  •
  the registrant will advance reasonable expenses, including attorneys' fees, to its directors and, at the
  discretion of its board of directors, to officers and certain employees, in connection with legal proceedings relating to their service for or on behalf of the registrant, subject to limited exceptions.
  The registrant has entered into indemnification agreements with each of its directors and officers. These agreements provide that the registrant will
  indemnify each of its directors, officers and, at times, their affiliates to the fullest extent permitted by the DGCL. The registrant will advance expenses, including attorneys' fees (but excluding judgments, fines and settlement amounts), to
  each indemnified director, officer or affiliate in connection with any proceeding in which indemnification is available and the registrant will indemnify its directors and officers for any action or proceeding arising out of that person's
  services as a director or officer brought on behalf of the registrant
  or in furtherance of the registrant's rights. Additionally, certain of the registrant's directors or officers may have certain rights to indemnification, advancement of expenses or
  insurance provided by their affiliates or other third parties, which indemnification relates to and might apply to the same proceedings arising out of such director's or officer's services as a director referenced herein. Nonetheless, the
  registrant has agreed in the indemnification agreements that its obligations to those same directors or officers are primary and any obligation of such affiliates or other third parties to advance expenses or to provide indemnification for the
  expenses or liabilities incurred by those directors are secondary.
  The registrant also maintains general liability insurance which covers certain
  liabilities of its directors and officers arising out of claims based on acts or omissions in their capacities as directors or officers, including liabilities under the Securities Act.
  Item 7.
  Exemption from Registration Claimed.
  Not applicable.
  Item 8.
  Exhibits.
  Exhibit
  Number
  Exhibit table
  4.1
  Form of Fourth Amended and Restated Certificate of Incorporation (Incorporated by reference to
  Exhibit 3.2
  to the registrant's
  Registration Statement on Form
  S-1,
  as amended (File
  No. 333-281764)).
  4.2
  Form of Amended and Restated Bylaws (Incorporated by reference to
  Exhibit 3.4
  to the registrant's Registration Statement on Form
  S-1,
  as amended (File
  No. 333-281764)).
  4.3
  Second Amended and Restated Investors' Rights Agreement among the Registrant and certain of its stockholders, dated August 
  2, 2024 (Incorporated by reference to
  Exhibit 4.1
  to the registrant's Registration Statement on Form
  S-1,
  as
  amended (File
  No. 333-281764)).
  4.4
  Form of Common Stock Certificate (Incorporated by reference to
  Exhibit 4.2
  to the registrant's Registration Statement on Form
  S-1,
  as amended (File
  No. 333-281764)).
  5.1*
  Opinion of Goodwin Procter LLP.
  23.1*
  Consent of Ernst & Young LLP, Independent Registered Public Accounting Firm.
  23.2*
  Consent of Goodwin Procter LLP (included in Exhibit 5.1).
  24.1*
  Power of Attorney (included on signature page).
  99.1
  MBX Biosciences, Inc. 2019 Stock Option and Grant Plan, as amended, and forms of award agreements thereunder (Incorporated by reference to
  Exhibit
   10.1
  to the registrant's Registration Statement on Form
  S-1,
  as amended (File
  No. 333-281764)).
  99.2
  MBX Biosciences, Inc. 2024 Stock Option and Incentive Plan and forms of award agreements thereunder (Incorporated by reference to
  Exhibit 10.2
  to the registrant's Registration Statement on Form
  S-1,
  as amended (File
  No. 333-281764)).
  99.3
  MBX Biosciences, Inc. 2024 Employee Stock Purchase Plan (Incorporated by reference to
  Exhibit 10.3
  to the registrant's
  Registration Statement on Form
  S-1,
  as amended (File No. 333
  –
  281764
  )).
  107*
  Fee table.
  *
  Filed herewith.
  Item 9.
  Undertakings.
  (a) The registrant hereby undertakes:
  (1) To file, during any
  period in which offers or sales are being made, a post-effective amendment to this Registration Statement:
  (i) To include any prospectus required by
  Section 10(a)(3) of the Securities Act.
  (ii) To reflect in the prospectus any facts or events arising after the effective date of the Registration
  Statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the Registration Statement. Notwithstanding the foregoing, any increase or
  decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of
  prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the "Calculation of Registration
  Fee" table in the Registration Statement.
  (iii) To include any material information with respect to the plan of distribution not previously
  disclosed in the Registration Statement or any material change to such information in the registration statement.
  Provided, however
  , that paragraphs (a)(1)(i) and (a)(1)(ii) herein do not apply if the information
  required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Exchange Act (15 U.S.C. 78m or
  78o(d)) that are incorporated by reference in the Registration Statement.
  (2) That, for the purpose of determining any liability under the Securities
  Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.
  (3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the
  offering.
  (b) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the
  registrant's annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is
  incorporated by reference in the Registration Statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide
  offering thereof.
  (c) Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling
  persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore,
  unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of
  any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling
  precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.
  SIGNATURES
  Pursuant to the requirements of the Securities Act, 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 Carmel, Indiana, on this 13th day of September,
  2024.
  MBX Biosciences, Inc.
  By:
  /s/ P. Kent Hawryluk
  Name: P. Kent Hawryluk
  Title: President and Chief Executive Officer
  POWER OF ATTORNEY AND SIGNATURES
  KNOW ALL BY THESE PRESENT, that each individual whose signature appears below hereby constitutes and appoints each of P. Kent Hawryluk and Rick Bartram, as
  such person's true and lawful
  attorney-in-fact
  and agent with full power of substitution and resubstitution, for such person in such person's name, place and
  stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto, and all documents in connection therewith, with the Commission
  granting unto each said
  attorney-in-fact
  and agent full power and authority to do and perform each and every act and thing requisite and necessary to be done in and
  about the premises, as fully to all intents and purposes as such person might or could do in person, hereby ratifying and confirming all that any said
  attorney-in-fact
  and agent, or any substitute or substitutes of any of them, may lawfully do or cause to be done by virtue hereof.
  Pursuant to the requirements of the
  Securities Act, this Registration Statement has been signed by the following person in the capacities and on the date indicated.
  NAME
  TITLE
  DATE
  /s/ P. Kent Hawryluk
  P. Kent Hawryluk
  President, Chief Executive Officer and Director
  (Principal Executive Officer)
  September 13, 2024
  /s/ Rick Bartram
  Rick Bartram
  Chief Financial Officer
  (Principal Financial Officer and Principal Accounting Officer)
  September 13, 2024
  /s/ Tiba Aynechi
  Tiba Aynechi
  Director
  September 13, 2024
  /s/ James M. Cornelius
  James M. Cornelius
  Director
  September 13, 2024
  /s/ Carl L. Gordon
  Carl L. Gordon
  Director
  September 13, 2024
  /s/ Patrick Heron
  Patrick Heron
  Director
  September 13, 2024
  /s/ Edward T. Mathers
  Edward T. Mathers
  Director
  September 13, 2024
  /s/ Ora Pescovitz
  Ora Pescovitz
  Director
  September 13, 2024
  /s/ Steven Ryder
  Steven Ryder
  Director
  September 13, 2024