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<title>SEC FORM 
            4</title>
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<body>SEC Form 4 
   <table width="100%" border="0" cellspacing="0" cellpadding="4">
<tr>
<td width="20%" colspan="2" valign="top" align="center" class="FormName">FORM 4</td>
<td rowspan="2" width="60%" valign="middle" align="center">
<span class="FormTitle">UNITED STATES SECURITIES AND EXCHANGE COMMISSION</span><br><span class="MedSmallFormText">Washington, D.C. 20549</span><br><br><span class="FormTitle">STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP</span><br><br><span class="MedSmallFormText">Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934</span><br><span class="MedSmallFormText">or Section 30(h) of the Investment Company Act of 1940</span>
</td>
<td rowspan="2" width="20%" valign="top" align="center"><table width="100%" border="1" summary="OMB Approval Status Box">
<tr><td class="FormTextC">OMB APPROVAL</td></tr>
<tr><td><table width="100%" border="0" summary="OMB Interior Box">
<tr>
<td class="SmallFormText" colspan="3">OMB Number:</td>
<td class="SmallFormTextR">3235-0287</td>
</tr>
<tr><td class="SmallFormText" colspan="4">Estimated average burden</td></tr>
<tr>
<td class="SmallFormText" colspan="3">hours per response:</td>
<td class="SmallFormTextR">0.5</td>
</tr>
</table></td></tr>
</table></td>
</tr>
<tr valign="middle">
<td><table width="100%" border="1" cellpadding="0" cellspacing="0"><tr><td>  </td></tr></table></td>
<td class="SmallFormText">Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. 
         <i>See</i>

         Instruction 1(b).</td>
</tr>
<tr valign="middle">
<td><table width="100%" border="1" cellpadding="0" cellspacing="0"><tr><td>  </td></tr></table></td>
<td class="SmallFormText">Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10. </td>
</tr>
</table>
<table width="100%" border="1" cellspacing="0" cellpadding="4">
<tr>
<td rowspan="4" width="35%" valign="top">
<span class="MedSmallFormText">1. Name and Address of Reporting Person<sup>*</sup></span><table border="0" width="100%"><tr><td><a href="/cgi-bin/browse-edgar?action=getcompany&amp;CIK=0001714023">Reine Allan</a></td></tr></table>
<hr width="98%">
<table border="0" width="100%"><tr>
<td width="33%" class="MedSmallFormText">(Last)</td>
<td width="33%" class="MedSmallFormText">(First)</td>
<td width="33%" class="MedSmallFormText">(Middle)</td>
</tr></table>
<table border="0" width="100%">
<tr><td><span class="FormData">C/O PRIME MEDICINE, INC.</span></td></tr>
<tr><td><span class="FormData">60 FIRST STREET</span></td></tr>
</table>
<hr width="98%">
<span class="MedSmallFormText">(Street)</span><table border="0" width="100%"><tr>
<td width="33%"><span class="FormData">CAMBRIDGE</span></td>
<td width="33%"><span class="FormData">MA</span></td>
<td width="33%"><span class="FormData">02141</span></td>
</tr></table>
<hr width="98%">
<table border="0" width="100%"><tr>
<td width="33%" class="MedSmallFormText">(City)</td>
<td width="33%" class="MedSmallFormText">(State)</td>
<td width="33%" class="MedSmallFormText">(Zip)</td>
</tr></table>
</td>
<td width="35%" valign="top">
<span class="MedSmallFormText">2. Issuer Name <b>and</b> Ticker or Trading Symbol
      </span><br><a href="/cgi-bin/browse-edgar?action=getcompany&amp;CIK=0001894562">Prime Medicine, Inc.</a>
     [ <span class="FormData">PRME</span> ]
   </td>
<td rowspan="2" valign="top">
<span class="MedSmallFormText">5. Relationship of Reporting Person(s) to Issuer
      </span><br><span class="MedSmallFormText">(Check all applicable)</span><table border="0" width="100%">
<tr>
<td width="15%" align="center"><span class="FormData">X</span></td>
<td width="35%" class="MedSmallFormText">Director</td>
<td width="15%" align="center"></td>
<td width="35%" class="MedSmallFormText">10% Owner</td>
</tr>
<tr>
<td align="center"><span class="FormData">X</span></td>
<td class="MedSmallFormText">Officer (give title below)</td>
<td align="center"></td>
<td class="MedSmallFormText">Other (specify below)</td>
</tr>
<tr>
<td width="15%" align="center"></td>
<td width="35%" align="left" style="color: blue">Chief Executive Officer</td>
<td width="15%" align="center"></td>
<td width="35%" align="left" style="color: blue"></td>
</tr>
</table>
</td>
</tr>
<tr><td valign="top">
<span class="MedSmallFormText">3. Date of Earliest Transaction
         (Month/Day/Year)</span><br><span class="FormData">08/01/2025</span>
</td></tr>
<tr>
<td valign="top">
<span class="MedSmallFormText">4. If Amendment, Date of Original Filed
         (Month/Day/Year)</span><br>
</td>
<td valign="top">
<span class="MedSmallFormText">6. Individual or Joint/Group Filing (Check Applicable Line)
      </span><table border="0" width="100%">
<tr>
<td width="15%" align="center"><span class="FormData">X</span></td>
<td width="85%" class="MedSmallFormText">Form filed by One Reporting Person</td>
</tr>
<tr>
<td width="15%" align="center"></td>
<td width="85%" class="MedSmallFormText">Form filed by More than One Reporting Person</td>
</tr>
</table>
</td>
</tr>
</table>
<table width="100%" border="1" cellspacing="0" cellpadding="4"><thead>
<tr><th width="100%" valign="top" colspan="11" align="center" class="FormTextC"><b>Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned</b></th></tr>
<tr>
<th width="36%" valign="top" rowspan="2" align="left" class="MedSmallFormText">1. Title of Security (Instr. 
      3)
   </th>
<th width="6%" valign="top" rowspan="2" align="left" class="SmallFormText">2. Transaction Date
      (Month/Day/Year)</th>
<th width="5%" valign="top" rowspan="2" align="left" class="SmallFormText">2A. Deemed Execution Date, if any
      (Month/Day/Year)</th>
<th width="7%" valign="top" colspan="2" align="left" class="SmallFormText">3. Transaction Code (Instr. 
      8)
   </th>
<th width="19%" valign="top" colspan="3" align="left" class="SmallFormText">4. Securities Acquired (A) or Disposed Of (D) (Instr. 
      3, 4 and 5)
   </th>
<th width="11%" valign="top" rowspan="2" align="left" class="SmallFormText">5. 
      Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 
      3 and 4)
   </th>
<th width="9%" valign="top" rowspan="2" align="left" class="SmallFormText">6. Ownership Form: Direct (D) or Indirect (I) (Instr. 
      4)
   </th>
<th width="8%" valign="top" rowspan="2" align="left" class="SmallFormText">7. Nature of Indirect Beneficial Ownership (Instr. 
      4)
   </th>
</tr>
<tr>
<th width="4%" align="center" class="SmallFormText">Code</th>
<th width="3%" align="center" class="SmallFormText">V</th>
<th width="8%" align="center" class="SmallFormText">Amount</th>
<th width="5%" align="center" class="SmallFormText">(A) or (D)</th>
<th width="6%" align="center" class="SmallFormText">Price</th>
</tr>
</thead></table>
<table width="100%" border="1" cellspacing="0" cellpadding="4">
<thead>
<tr><th width="100%" valign="top" colspan="16" align="center" class="FormTextC">
<b>Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned</b><br><b>(e.g., puts, calls, warrants, options, convertible securities)</b>
</th></tr>
<tr>
<th width="13%" valign="top" rowspan="2" align="left" class="SmallFormText">1. Title of Derivative Security (Instr. 
      3)
   </th>
<th width="5%" valign="top" rowspan="2" align="left" class="SmallFormText">2. Conversion or Exercise Price of Derivative Security
   </th>
<th width="5%" valign="top" rowspan="2" align="left" class="SmallFormText">3. Transaction Date
      (Month/Day/Year)</th>
<th width="5%" valign="top" rowspan="2" align="left" class="SmallFormText">3A. Deemed Execution Date, if any
      (Month/Day/Year)</th>
<th width="9%" valign="top" colspan="2" align="left" class="SmallFormText">4. Transaction Code (Instr. 
      8)
   </th>
<th width="10%" valign="top" colspan="2" align="left" class="SmallFormText">5. 
      Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 
      3, 4 and 5)
   </th>
<th width="9%" valign="top" colspan="2" align="left" class="SmallFormText">6. Date Exercisable and Expiration Date 
      (Month/Day/Year)</th>
<th width="17%" valign="top" colspan="2" align="left" class="SmallFormText">7. Title and Amount of Securities Underlying Derivative Security (Instr. 
      3 and 4)
   </th>
<th width="6%" valign="top" rowspan="2" align="left" class="SmallFormText">8. Price of Derivative Security (Instr. 
      5)
   </th>
<th width="6%" valign="top" rowspan="2" align="left" class="SmallFormText">9. 
      Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 
      4)
   </th>
<th width="6%" valign="top" rowspan="2" align="left" class="SmallFormText">10. Ownership Form: Direct (D) or Indirect (I) (Instr. 
      4)
   </th>
<th width="7%" valign="top" rowspan="2" align="left" class="SmallFormText">11. Nature of Indirect Beneficial Ownership (Instr. 
      4)
   </th>
</tr>
<tr>
<th width="4%" valign="bottom" align="center" class="SmallFormText">Code</th>
<th width="4%" valign="bottom" align="center" class="SmallFormText">V</th>
<th width="5%" valign="bottom" align="center" class="SmallFormText">(A)</th>
<th width="5%" valign="bottom" align="center" class="SmallFormText">(D)</th>
<th width="5%" valign="bottom" align="center" class="SmallFormText">Date Exercisable</th>
<th width="4%" valign="bottom" align="center" class="SmallFormText">Expiration Date</th>
<th width="10%" valign="bottom" align="center" class="SmallFormText">Title</th>
<th width="7%" valign="bottom" align="center" class="SmallFormText">Amount or Number of Shares</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left"><span class="SmallFormData">Stock Option (right to buy)</span></td>
<td align="center">
<span class="SmallFormText">$</span><span class="SmallFormData">6.8</span>
</td>
<td align="center"><span class="SmallFormData">08/01/2025</span></td>
<td align="center"></td>
<td align="center">
<span class="SmallFormData">D</span><span class="FootnoteData"><sup>(1)</sup></span>
</td>
<td align="center"></td>
<td align="center"></td>
<td align="center"><span class="SmallFormData">850,000</span></td>
<td align="center">
<span class="SmallFormData">
                
            </span><span class="FootnoteData"><sup>(2)</sup></span>
</td>
<td align="center"><span class="SmallFormData">01/17/2034</span></td>
<td align="center"><span class="SmallFormData">Common Stock</span></td>
<td align="center"><span class="FormData">850,000</span></td>
<td align="center"><span class="FootnoteData"><sup>(1)</sup></span></td>
<td align="center"><span class="SmallFormData">0</span></td>
<td align="center"><span class="SmallFormData">D</span></td>
<td align="left"></td>
</tr>
<tr>
<td align="left"><span class="SmallFormData">Stock Option (right to buy)</span></td>
<td align="center">
<span class="SmallFormText">$</span><span class="SmallFormData">4.04</span>
</td>
<td align="center"><span class="SmallFormData">08/01/2025</span></td>
<td align="center"></td>
<td align="center">
<span class="SmallFormData">A</span><span class="FootnoteData"><sup>(1)</sup></span>
</td>
<td align="center"></td>
<td align="center"><span class="SmallFormData">850,000</span></td>
<td align="center"></td>
<td align="center">
<span class="SmallFormData">
                
            </span><span class="FootnoteData"><sup>(2)</sup></span>
</td>
<td align="center"><span class="SmallFormData">01/17/2034</span></td>
<td align="center"><span class="SmallFormData">Common Stock</span></td>
<td align="center"><span class="FormData">850,000</span></td>
<td align="center"><span class="FootnoteData"><sup>(1)</sup></span></td>
<td align="center"><span class="SmallFormData">850,000</span></td>
<td align="center"><span class="SmallFormData">D</span></td>
<td align="left"></td>
</tr>
</tbody>
</table>
<table border="0" width="100%">
<tr><td class="MedSmallFormText"><b>Explanation of Responses:</b></td></tr>
<tr><td class="FootnoteData">1. Effective as of August 1, 2025 (the "Repricing Date"), the Issuer's stockholders approved a one-time repricing of certain outstanding stock options (the "Repriced Options") granted under the Issuer's 2019 Stock Option and Grant Plan, as amended (the "2019 Plan") and/or the 2022 Stock Option and Incentive Plan (the "2022 Plan" and, together with the 2019 Plan, the "Plans"), which reduced the per share exercise price of each Repriced Option to $4.04, representing the closing price of the Issuer's common stock on The Nasdaq Global Market on the Repricing Date (the "Option Repricing"). Except as modified by the Option Repricing, all other terms and conditions of the Repriced Options, including, without limitation, any provisions with respect to vesting and term of the Repriced Options, remain in full force and effect.</td></tr>
<tr><td class="FootnoteData">2. This stock option award was issued pursuant to the 2019 Plan and/or the 2022 Plan, as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.</td></tr>
<tr><td class="FormText"><b>Remarks:</b></td></tr>
<tr><td class="FootnoteData"></td></tr>
</table>
<table width="100%" border="0">
<tr>
<td width="60%"></td>
<td width="20%"><u><span class="FormData">/s/ Ryan Brown, attorney-in-fact</span></u></td>
<td width="20%"><u><span class="FormData">08/05/2025</span></u></td>
</tr>
<tr>
<td></td>
<td class="MedSmallFormText">** Signature of Reporting Person</td>
<td class="MedSmallFormText">Date</td>
</tr>
<tr><td colspan="3" class="MedSmallFormText">Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.</td></tr>
<tr><td colspan="3" class="MedSmallFormText">* If the form is filed by more than one reporting person, 
                  <i>see</i>

                  Instruction 
                  4

                  (b)(v).</td></tr>
<tr><td colspan="3" class="MedSmallFormText">** Intentional misstatements or omissions of facts constitute Federal Criminal Violations 
                  <i>See</i>

                  18 U.S.C. 1001 and 15 U.S.C. 78ff(a).</td></tr>
<tr><td colspan="3" class="MedSmallFormText">Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, 
                  <i>see</i>

                  Instruction 6 for procedure.</td></tr>
<tr><td colspan="3" class="MedSmallFormText"><b>Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.</b></td></tr>
</table>
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