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   <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 March&nbsp;6, 2025 </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>CytomX Therapeutics, 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">
  
  
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  <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">27-3521219</FONT></B></TD></TR>
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  <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&nbsp;or&nbsp;other&nbsp;jurisdiction&nbsp;of</B></P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>incorporation&nbsp;or&nbsp;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.&nbsp;Employer</B></P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Identification&nbsp;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>151 Oyster Point Blvd. </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Suite 400 </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>South San
  Francisco, CA 94080 </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Address of Principal Executive Offices) (Zip Code) </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>CytomX Therapeutics, Inc. 2015 Equity Incentive 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 Plan) </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>Sean A.
  McCarthy, D.Phil. </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>CytomX Therapeutics, Inc. </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>151 Oyster Point Blvd., Suite 400 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>South San Francisco, CA 94080 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(650) <FONT STYLE="white-space:nowrap">515-3185</FONT> </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Name and address of agent for service) </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(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>Mark
  V. Roeder, Esq. </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Latham&nbsp;&amp; Watkins LLP </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>140 Scott Drive </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Menlo
  Park, California 94025 </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(650) <FONT STYLE="white-space:nowrap">328-4600</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; text-indent:4%; 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, 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">
  
  
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  <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&nbsp;filer</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9746;</TD></TR>
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  <TD VALIGN="bottom">Non-accelerated filer</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9744;</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>
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  <TD VALIGN="bottom">&nbsp;</TD>
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  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">Emerging&nbsp;growth&nbsp;company</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9744;</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 comply 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: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>Proposed sale
  to take place as soon after the effective date of the </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>registration statement as awards under the plans are exercised and/or vest.
  </B></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>
  
  
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   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>EXPLANATORY NOTE </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">This Registration Statement on Form <FONT STYLE="white-space:nowrap">S-8</FONT> is being filed for the purpose of registering an additional
  3,203,996 shares of the Registrant&#146;s common stock issuable under the following employee benefit plans for which Registration Statements of the Registrant on Form <FONT STYLE="white-space:nowrap">S-8</FONT> (File Nos. <FONT
  STYLE="white-space:nowrap">333-207694,</FONT> <FONT STYLE="white-space:nowrap">333-209992,</FONT> <FONT STYLE="white-space:nowrap">333-215795,</FONT> <FONT STYLE="white-space:nowrap">333-223491,</FONT>
  <FONT STYLE="white-space:nowrap">333-229916,</FONT> <FONT STYLE="white-space:nowrap">333-236711,</FONT> <FONT STYLE="white-space:nowrap">333-253452,</FONT> <FONT STYLE="white-space:nowrap">333-255832,</FONT>
  <FONT STYLE="white-space:nowrap">333-263321,</FONT> <FONT STYLE="white-space:nowrap">333-270869</FONT> and <FONT STYLE="white-space:nowrap">333-277819)</FONT> are effective: the CytomX Therapeutics, Inc. 2015 Equity Incentive Plan, as a result of
  the operation of an automatic annual increase provision therein, which added 3,203,996 shares of common stock. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>INCORPORATION BY
  REFERENCE OF CONTENTS OF REGISTRATION STATEMENT ON FORM <FONT STYLE="white-space:nowrap">S-8</FONT> </B></P> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Pursuant to Instruction E of Form
  <FONT STYLE="white-space:nowrap">S-8,</FONT> the contents of the Registration Statements on Form <FONT STYLE="white-space:nowrap">S-8</FONT> filed with the Securities and Exchange Commission on <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312515360038/d205218ds8.htm">October
  <U></U>&nbsp;30, 2015</A> (File No.&nbsp;333-207694), <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312516495280/d155038ds8.htm">March<U></U>&nbsp;7, 2016</A> (File <FONT STYLE="white-space:nowrap">No.&nbsp;
  333-209992),</FONT> <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312517022008/d294863ds8.htm">January<U></U>&nbsp;27, 2017</A> (File <FONT STYLE="white-space:nowrap">No.&nbsp;
  333-215795),</FONT> <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312518073612/d545328ds8.htm">March<U></U>&nbsp;7, 2018</A> (File <FONT STYLE="white-space:nowrap">No.&nbsp;
  333-223491),</FONT> <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312519054171/d701915ds8.htm">February<U></U>&nbsp;27, 2019</A> (File <FONT STYLE="white-space:nowrap">No.&nbsp;
  333-229916),</FONT> <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312520052872/d893269ds8.htm">February<U></U>&nbsp;27, 2020</A> (File <FONT STYLE="white-space:nowrap">No.&nbsp;
  333-236711),</FONT> <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312521054696/d134950ds8.htm">February<U></U>&nbsp;24, 2021</A> (File <FONT STYLE="white-space:nowrap">No.&nbsp;
  333-253452),</FONT> <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312521153339/d924558ds8.htm">May<U></U>&nbsp;6, 2021</A> (File <FONT STYLE="white-space:nowrap">No.&nbsp;
  333-255832),</FONT> <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312522066309/d239385ds8.htm">March<U></U>&nbsp;4, 2022</A> (File <FONT STYLE="white-space:nowrap">No.&nbsp;
  333-263321),</FONT> <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312523080477/d492639ds8.htm">March<U></U>&nbsp;
  27, 2023</A> <FONT STYLE="white-space:nowrap">(333-270869)</FONT> and <A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312524064845/d760313ds8.htm">March<U></U>&nbsp;11, 2024</A> <FONT STYLE="white-space:nowrap">(333-277819)</FONT> are
  incorporated by reference herein; except for Item 8 which is being updated by this Registration Statement. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Item&#8201;8. Exhibits </B></P>
  <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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  <TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><B>Filed<BR>Herewith</B></TD>
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  <TD VALIGN="bottom" NOWRAP> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman"><B>Exhibit</B></P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; border-bottom:1.00pt solid #000000; display:table-cell; font-size:8pt; font-family:Times New Roman; "><B>Number</B></P></TD>
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  <TD VALIGN="bottom" COLSPAN="2" ALIGN="center"><B>Date</B></TD>
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  <TD VALIGN="top" NOWRAP>&#8199;&#8199;4.1</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312524141699/d816353dex31.htm">Amended and Restated Certificate of Incorporation. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right"><FONT STYLE="white-space:nowrap">8-K</FONT></TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
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  <TD VALIGN="bottom" ALIGN="right">5/17/2024</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
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  <TD VALIGN="bottom" ALIGN="right">3.1</TD>
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  <TD VALIGN="top" NOWRAP>&#8199;&#8199;4.2</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312524075211/d803852dex31.htm">Amended and Restated Bylaws. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right"><FONT STYLE="white-space:nowrap">8-K</FONT></TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">3/22/2024</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">3.1</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;&#8199;4.3</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312515329662/d948537dex41.htm">Form of Common Stock Certificate.</A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right"><FONT STYLE="white-space:nowrap">S-1/A</FONT></TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">9/28/2015</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">4.1</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;&#8199;4.4</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000156459017022252/ctmx-ex44_91.htm">Registration Rights Agreement dated as of September<U></U>&nbsp;29, 2017 by and between CytomX Therapeutics, Inc. and Amgen, Inc.</A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right"><FONT STYLE="white-space:nowrap">10-Q</FONT></TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">11/7/2017</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">4.4</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;&#8199;5.1</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d897389dex51.htm">Opinion of Latham&nbsp;&amp; Watkins&nbsp;LLP. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">X</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;23.1</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d897389dex231.htm">Consent of independent registered public accounting firm. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">X</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;23.2</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d897389dex51.htm">Consent of Latham&nbsp;&amp; Watkins&nbsp;LLP (included in Exhibit&nbsp;5.1). </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">X</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;24.1</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d897389ds8.htm#sig">Power of Attorney. Reference is made to the signature page to the Registration Statement. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">X</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;99.1(a)#</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000119312515338434/d948537dex105.htm">CytomX Therapeutics, Inc. 2015 Equity Incentive Plan. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right"><FONT STYLE="white-space:nowrap">S-1/A</FONT></TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">10/6/2015</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">10.5</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;99.1(b)#</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000156459015010977/ctmx-ex104_591.htm">Form of Option Award Notice under the CytomX Therapeutics, Inc. 2015 Equity Incentive Plan. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right"><FONT STYLE="white-space:nowrap">10-Q</FONT></TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">11/23/2015</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">10.4</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;99.1(c)#</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000156459015010977/ctmx-ex105_592.htm">Form of Early Exercise Option Award Notice under the CytomX Therapeutics, Inc. 2015 Equity Incentive Plan. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right"><FONT STYLE="white-space:nowrap">10-Q</FONT></TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">11/23/2015</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">10.5</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>&#8199;99.1(d)#</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1501989/000095017022002519/ctmx-ex10_3.htm">Form of 2015 Plan Restricted Share Unit Award Grant Notice and Agreement </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right"><FONT STYLE="white-space:nowrap">10-K</FONT></TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">3/1/2022</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">10.3</TD>
  <TD NOWRAP VALIGN="bottom">(d)&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></TD>
  <TD HEIGHT="8" COLSPAN="4"></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;</TD>
  <TD VALIGN="top"><A HREF="d897389dexfilingfees.htm">Filing Fee Table </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="right">X</TD>
  <TD NOWRAP VALIGN="bottom">&nbsp;</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="4%" 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">Indicates management contract or compensatory plan. </P></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><A NAME="sig"></A>SIGNATURES </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:9%; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the Securities Act of 1933, as amended, 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 South San Francisco,
  California, on this 6th day of March, 2025. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><DIV ALIGN="right">
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="40%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt">
  
  
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  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" COLSPAN="3"><B>CytomX Therapeutics, 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="top">By:</TD>
  <TD VALIGN="bottom" STYLE=" BORDER-BOTTOM:1px solid #000000">&nbsp;</TD>
  <TD VALIGN="top" STYLE="BORDER-BOTTOM:1px solid #000000">/s/ Sean A. McCarthy</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">Sean A. McCarthy, D.Phil.</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">Chief Executive Officer</TD></TR>
  </TABLE></DIV> <P STYLE="margin-top:24pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>POWER OF ATTORNEY </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:9%; font-size:10pt; font-family:Times New Roman">KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below does hereby constitute and appoint Sean A. McCarthy and
  Lloyd A. Rowland, and each of them, with full power of substitution and full power to act without the other, his or her true and lawful <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorney-in-fact</FONT></FONT> and agent to act
  for him or her in his or her 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 this registration statement, with all exhibits thereto,
  and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorneys-in-fact</FONT></FONT> and agents, and each of them, full power
  and authority to do and perform each and every act and thing requisite and necessary to be done in order to effectuate the same as fully, to all intents and purposes, as they or he or she might or could do in person, hereby ratifying and confirming
  all that said <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorneys-in-fact</FONT></FONT> and agents, or any of them, may lawfully do or cause to be done by virtue hereof. </P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:9%; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons
  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">
  
  
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  <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>Signature</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/ Sean A. McCarthy</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Sean A. McCarthy, D.Phil</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&nbsp;Executive&nbsp;Officer&nbsp;and&nbsp;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"><I>(Principal Executive Officer)</I></P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">March&nbsp;6, 2025</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/ Christopher W. Ogden</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Christopher W. Ogden</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"><I>(Principal Accounting Officer)</I></P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" NOWRAP ALIGN="center">March&nbsp;6, 2025</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/ Matthew P. Young</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Matthew P. Young</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">March&nbsp;6, 2025</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/ Alan Ashworth</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Alan Ashworth, Ph.D. FRS</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">March&nbsp;6, 2025</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 R. Meyers</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">James R. Meyers</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">March&nbsp;6, 2025</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/ Elaine V. Jones</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Elaine V. Jones, Ph.D.</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">March&nbsp;6, 2025</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/ Halley E. Gilbert</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Halley E. Gilbert</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">March&nbsp;6, 2025</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/ Mani Mohindru, Ph.D.</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Mani Mohindru, Ph.D.</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">March&nbsp;6, 2025</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/ Zhen Su, M.D.</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Zhen Su, M.D.</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">March&nbsp;6, 2025</TD></TR>
  </TABLE>
  </DIV></Center>
  
  </BODY></HTML>
metadata_documents: [{"type": "S-8", "sequence": "1", "filename": "d897389ds8.htm", "description": "S-8", "secsgml_size_bytes": 46218}]
metadata_filer: {"company-data": {"conformed-name": "CytomX Therapeutics, Inc.", "cik": "0001501989", "assigned-sic": "2834", "organization-name": "03 Life Sciences", "irs-number": "273521219", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-285594", "film-number": "25715221"}, "business-address": {"street1": "151 OYSTER POINT BLVD.", "street2": "SUITE 400", "city": "SOUTH SAN FRANCISCO", "state": "CA", "zip": "94080", "phone": "650.515.3185"}, "mail-address": {"street1": "151 OYSTER POINT BLVD.", "street2": "SUITE 400", "city": "SOUTH SAN FRANCISCO", "state": "CA", "zip": "94080"}}
text: S-8
  As filed with the Securities and Exchange Commission on March 6, 2025
  Registration
  No. 333-
  UNITED STATES
  SECURITIES AND EXCHANGE COMMISSION
  Washington, D.C. 20549
  FORM
  S-8
  REGISTRATION STATEMENT
  UNDER
  THE
  SECURITIES ACT OF 1933
  CytomX Therapeutics, Inc.
  (Exact name of Registrant as specified in its charter)
  Delaware
  27-3521219
  (State or other jurisdiction of
  incorporation or organization)
  (I.R.S. Employer
  Identification No.)
  151 Oyster Point Blvd.
  Suite 400
  South San
  Francisco, CA 94080
  (Address of Principal Executive Offices) (Zip Code)
  CytomX Therapeutics, Inc. 2015 Equity Incentive Plan
  (Full Title of the Plan)
  Sean A.
  McCarthy, D.Phil.
  President and Chief Executive Officer
  CytomX Therapeutics, Inc.
  151 Oyster Point Blvd., Suite 400
  South San Francisco, CA 94080
  (650)
  515-3185
  (Name and address of agent for service)
  (Telephone number, including area code, of agent for service)
  Copies to:
  Mark
  V. Roeder, Esq.
  Latham & Watkins LLP
  140 Scott Drive
  Menlo
  Park, California 94025
  (650)
  328-4600
  Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a
  non-accelerated
  filer, 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 comply with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐
  Proposed sale
  to take place as soon after the effective date of the
  registration statement as awards under the plans are exercised and/or vest.
  EXPLANATORY NOTE
  This Registration Statement on Form
  S-8
  is being filed for the purpose of registering an additional
  3,203,996 shares of the Registrant's common stock issuable under the following employee benefit plans for which Registration Statements of the Registrant on Form
  S-8
  (File Nos.
  333-207694,
  333-209992,
  333-215795,
  333-223491,
  333-229916,
  333-236711,
  333-253452,
  333-255832,
  333-263321,
  333-270869
  and
  333-277819)
  are effective: the CytomX Therapeutics, Inc. 2015 Equity Incentive Plan, as a result of
  the operation of an automatic annual increase provision therein, which added 3,203,996 shares of common stock.
  INCORPORATION BY
  REFERENCE OF CONTENTS OF REGISTRATION STATEMENT ON FORM
  S-8
  Pursuant to Instruction E of Form
  S-8,
  the contents of the Registration Statements on Form
  S-8
  filed with the Securities and Exchange Commission on
  October
  30, 2015
  (File No. 333-207694),
  March
  7, 2016
  (File
  No. 
  333-209992),
  January
  27, 2017
  (File
  No. 
  333-215795),
  March
  7, 2018
  (File
  No. 
  333-223491),
  February
  27, 2019
  (File
  No. 
  333-229916),
  February
  27, 2020
  (File
  No. 
  333-236711),
  February
  24, 2021
  (File
  No. 
  333-253452),
  May
  6, 2021
  (File
  No. 
  333-255832),
  March
  4, 2022
  (File
  No. 
  333-263321),
  March
  27, 2023
  (333-270869)
  and
  March
  11, 2024
  (333-277819)
  are
  incorporated by reference herein; except for Item 8 which is being updated by this Registration Statement.
  Item 8. Exhibits
  Incorporated by Reference
  Filed
  Herewith
  Exhibit
  Number
  Exhibit Description
  Form
  Date
  Number
  4.1
  Amended and Restated Certificate of Incorporation.
  8-K
  5/17/2024
  3.1
  4.2
  Amended and Restated Bylaws.
  8-K
  3/22/2024
  3.1
  4.3
  Form of Common Stock Certificate.
  S-1/A
  9/28/2015
  4.1
  4.4
  Registration Rights Agreement dated as of September
  29, 2017 by and between CytomX Therapeutics, Inc. and Amgen, Inc.
  10-Q
  11/7/2017
  4.4
  5.1
  Opinion of Latham & Watkins LLP.
  X
  23.1
  Consent of independent registered public accounting firm.
  X
  23.2
  Consent of Latham & Watkins LLP (included in Exhibit 5.1).
  X
  24.1
  Power of Attorney. Reference is made to the signature page to the Registration Statement.
  X
  99.1(a)#
  CytomX Therapeutics, Inc. 2015 Equity Incentive Plan.
  S-1/A
  10/6/2015
  10.5
  99.1(b)#
  Form of Option Award Notice under the CytomX Therapeutics, Inc. 2015 Equity Incentive Plan.
  10-Q
  11/23/2015
  10.4
  99.1(c)#
  Form of Early Exercise Option Award Notice under the CytomX Therapeutics, Inc. 2015 Equity Incentive Plan.
  10-Q
  11/23/2015
  10.5
  99.1(d)#
  Form of 2015 Plan Restricted Share Unit Award Grant Notice and Agreement
  10-K
  3/1/2022
  10.3
  (d)
  107
  Filing Fee Table
  X
  #
  Indicates management contract or compensatory plan.
  SIGNATURES
  Pursuant to the requirements of the Securities Act of 1933, as amended, 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 South San Francisco,
  California, on this 6th day of March, 2025.
  CytomX Therapeutics, Inc.
  By:
  /s/ Sean A. McCarthy
  Sean A. McCarthy, D.Phil.
  Chief Executive Officer
  POWER OF ATTORNEY
  KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below does hereby constitute and appoint Sean A. McCarthy and
  Lloyd A. Rowland, and each of them, with full power of substitution and full power to act without the other, his or her true and lawful
  attorney-in-fact
  and agent to act
  for him or her in his or her 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 this registration statement, with all exhibits thereto,
  and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said
  attorneys-in-fact
  and agents, and each of them, full power
  and authority to do and perform each and every act and thing requisite and necessary to be done in order to effectuate the same as fully, to all intents and purposes, as they or he or she might or could do in person, hereby ratifying and confirming
  all that said
  attorneys-in-fact
  and agents, or any of them, may lawfully do or cause to be done by virtue hereof.
  Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons
  in the capacities and on the date indicated.
  Signature
  Title
  Date
  /s/ Sean A. McCarthy
  Sean A. McCarthy, D.Phil
  Chief Executive Officer and Director
  (Principal Executive Officer)
  March 6, 2025
  /s/ Christopher W. Ogden
  Christopher W. Ogden
  Chief Financial Officer
  (Principal Accounting Officer)
  March 6, 2025
  /s/ Matthew P. Young
  Matthew P. Young
  Director
  March 6, 2025
  /s/ Alan Ashworth
  Alan Ashworth, Ph.D. FRS
  Director
  March 6, 2025
  /s/ James R. Meyers
  James R. Meyers
  Director
  March 6, 2025
  /s/ Elaine V. Jones
  Elaine V. Jones, Ph.D.
  Director
  March 6, 2025
  /s/ Halley E. Gilbert
  Halley E. Gilbert
  Director
  March 6, 2025
  /s/ Mani Mohindru, Ph.D.
  Mani Mohindru, Ph.D.
  Director
  March 6, 2025
  /s/ Zhen Su, M.D.
  Zhen Su, M.D.
  Director
  March 6, 2025