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<p style="text-align:center;margin-bottom:0pt;margin-top:4pt;text-indent:0%;font-weight:bold;font-size:18pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">UNITED STATES</p>
<p style="text-align:center;margin-bottom:0pt;margin-top:4pt;text-indent:0%;font-weight:bold;font-size:18pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">SECURITIES AND EXCHANGE COMMISSION </p>
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<p style="text-align:center;margin-bottom:0pt;margin-top:12pt;text-indent:0%;font-weight:bold;font-size:18pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">FORM 8-K </p>
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<p style="text-align:center;margin-bottom:0pt;margin-top:12pt;text-indent:0%;font-weight:bold;font-size:14pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">CURRENT REPORT </p>
<p style="text-align:center;margin-bottom:0pt;margin-top:12pt;text-indent:0%;font-weight:bold;font-size:12pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">Pursuant to Section&#160;13 or 15(d) of </p>
<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-weight:bold;font-size:12pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">the Securities Exchange Act of 1934 </p>
<p style="text-align:center;margin-bottom:0pt;margin-top:12pt;text-indent:0%;font-weight:bold;font-size:12pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">Date of Report (Date of earliest event reported): February 26, 2015 </p>
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<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-weight:bold;font-size:24pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">Atara Biotherapeutics, Inc. </p>
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<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;font-family:Times New Roman;font-size:10pt;font-style:normal;text-transform:none;font-variant: normal;">46-0920988</p></td>
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<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;font-size:8pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">(Commission<br>File Number)</p></td>
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<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;font-size:8pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">(IRS Employer Identification No.)</p></td>
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<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;font-size:10pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">701 Gateway Boulevard, Suite 200</p>
<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;font-size:10pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">South San Francisco, CA </p></td>
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<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;font-family:Times New Roman;font-size:10pt;font-style:normal;text-transform:none;font-variant: normal;">94080</p></td>
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<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;font-size:8pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">(Zip Code)</p></td>
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<p style="text-align:center;margin-bottom:0pt;margin-top:12pt;text-indent:0%;font-weight:bold;font-size:10pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">Registrant&#8217;s Telephone Number, Including Area Code: (650) 278-8930 </p>
<p style="text-align:center;margin-bottom:0pt;margin-top:12pt;text-indent:0%;font-weight:bold;font-size:10pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">Not Applicable </p>
<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-weight:bold;font-size:8pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">(Former Name or Former Address, if Changed Since Last Report) </p>
<p style="margin-top:6pt;text-align:center;border-bottom:Solid 1pt;padding-bottom:1pt;margin-bottom:0pt;margin-left:40%;margin-right:40%;text-indent:0%;font-size:6pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">&#160;</p>
<p style="margin-bottom:0pt;margin-top:12pt;text-indent:0%;font-size:10pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instructions A.2. below): </p>
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<p style="margin-bottom:0pt;margin-top:12pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;font-family:Times New Roman;font-size:10pt;">Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) </p></td></tr></table></div>
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<p style="margin-bottom:0pt;margin-top:12pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;font-family:Times New Roman;font-size:10pt;">Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) </p></td></tr></table></div>
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<p style="margin-bottom:0pt;margin-top:12pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;font-family:Times New Roman;font-size:10pt;">Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) </p></td></tr></table></div>
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<p style="margin-bottom:0pt;margin-top:12pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;font-family:Times New Roman;font-size:10pt;">Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) </p></td></tr></table></div>
<p style="margin-top:8pt;text-align:center;border-top:Solid 1pt;padding-top:1pt;line-height:1pt;margin-bottom:0pt;border-top:Solid 0.75pt #000000;padding-top:0pt;text-indent:0%;font-size:4pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">&#160;</p>
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<p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-family:Times New Roman;font-size:10pt;">&nbsp;</p>
<p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-family:Times New Roman;font-size:10pt;">&nbsp;</p>
<p style="margin-bottom:0pt;margin-top:18pt;text-indent:0%;font-weight:bold;;font-size:10pt;">&nbsp;</p>
<p style="margin-top:12pt;margin-bottom:0pt;text-indent:0%;font-size:12pt;font-family:Times New Roman;">&nbsp;</p>

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<p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-weight:bold;font-size:10pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">Item&#160;2.02 Results of Operations and Financial Condition. </p>
<p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-weight:bold;;font-size:10pt;">&nbsp;</p>
<p style="margin-bottom:0pt;margin-top:0pt;text-indent:6.67%;font-size:10pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">On February 26, 2015, Atara Biotherapeutics, Inc. (&#8220;Atara&#8221;) announced certain financial results for the fourth quarter and full year ended December 31, 2014.&nbsp;&nbsp;A copy of Atara&#8217;s press release, titled &#8220;Atara Biotherapeutics Announces Fourth Quarter and Full Year 2014 Operating Results,&#8221; is furnished as Exhibit 99.1 hereto. </p>
<p style="margin-top:8pt;margin-bottom:0pt;text-indent:0%;font-family:Times New Roman;font-size:10pt;">&nbsp;</p>
<p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-weight:bold;;font-size:10pt;">&nbsp;</p>
<p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-weight:bold;font-size:10pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">Item&#160;9.01 Financial Statements and Exhibits. </p>
<p style="margin-bottom:0pt;margin-top:6pt;text-indent:0%;font-size:10pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">(d)&nbsp;&nbsp;<font style="font-style:italic;">Exhibits</font></p>
<p style="margin-bottom:0pt;margin-top:6pt;text-indent:4.54%;font-size:10pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">99.1<font style="margin-left:36pt;">Press Release, dated February 26, 2015, titled &#8220;</font>Atara Biotherapeutics Announces Fourth Quarter and Full Year 2014 Operating Results.&#8221;</p>
<p style="margin-bottom:0pt;margin-top:18pt;text-indent:0%;font-size:10pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">The information in this report, including the exhibit hereto, is being furnished and shall not be deemed &#8220;filed&#8221; for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of Section 11 and 12(a)(2) of the Securities Act of 1933, as amended.&nbsp;&nbsp;The information in this report and the attached Exhibit 99.1 shall not be incorporated by reference into any filing with the U.S. Securities and Exchange Commission, whether made before or after the date hereof, except as shall be expressly set forth by specific reference in such filing.</p>
<p style="margin-top:12pt;margin-bottom:0pt;text-indent:0%;font-size:12pt;font-family:Times New Roman;">&nbsp;</p>

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<p style="text-align:center;margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-weight:bold;font-size:10pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">SIGNATURES </p>
<p style="margin-bottom:0pt;margin-top:12pt;text-indent:4.54%;font-size:10pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. </p>
<p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-size:12pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">&#160;</p>
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<p style="margin-top:0pt;margin-bottom:0pt;margin-left:0pt;;text-indent:0pt;;text-align:left;font-size:8pt;font-weight:normal;font-style:normal;font-family:Times New Roman;text-transform:none;font-variant: normal;">&#160;</p></td>
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<p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;text-align:left;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">/s/ John F. McGrath, Jr.</p></td>
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<p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;text-align:left;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">John F. McGrath, Jr.</p></td>
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<p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;text-align:left;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Chief Financial Officer</p></td>
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<p style="margin-bottom:0pt;margin-top:12pt;text-indent:0%;font-size:10pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Date:&nbsp;&nbsp; February 26, 2015 </p>
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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d) of
the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): February 26, 2015
Atara Biotherapeutics, Inc.
(Exact name of Registrant as Specified in Its Charter)
Delaware
001-36548
46-0920988
(State or Other Jurisdiction
of Incorporation)
(Commission
File Number)
(IRS Employer Identification No.)
701 Gateway Boulevard, Suite 200
South San Francisco, CA
94080
(Address of Principal Executive Offices)
(Zip Code)
Registrant's Telephone Number, Including Area Code: (650) 278-8930
Not Applicable
(Former Name or Former Address, if Changed Since Last Report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instructions A.2. below):
¨
Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
¨
Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
¨
Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
¨
Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
Item 2.02 Results of Operations and Financial Condition.
On February 26, 2015, Atara Biotherapeutics, Inc. ("Atara") announced certain financial results for the fourth quarter and full year ended December 31, 2014.  A copy of Atara's press release, titled "Atara Biotherapeutics Announces Fourth Quarter and Full Year 2014 Operating Results," is furnished as Exhibit 99.1 hereto.
Item 9.01 Financial Statements and Exhibits.
(d)
Exhibits
99.1
Press Release, dated February 26, 2015, titled "
Atara Biotherapeutics Announces Fourth Quarter and Full Year 2014 Operating Results."
The information in this report, including the exhibit hereto, is being furnished and shall not be deemed "filed" for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of Section 11 and 12(a)(2) of the Securities Act of 1933, as amended.  The information in this report and the attached Exhibit 99.1 shall not be incorporated by reference into any filing with the U.S. Securities and Exchange Commission, whether made before or after the date hereof, except as shall be expressly set forth by specific reference in such filing.
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.
Atara Biotherapeutics, Inc.
(Registrant)
By:
/s/ John F. McGrath, Jr.
John F. McGrath, Jr.
Chief Financial Officer
Date:   February 26, 2015
Exhibit Index
Exhibit No.
Description
99.1
Press Release, dated February 26, 2015, titled "Atara Biotherapeutics Announces Fourth Quarter and Full Year 2014 Operating Results."