<SEC-DOCUMENT>0001959173-25-007516.txt : 20251204
<SEC-HEADER>0001959173-25-007516.hdr.sgml : 20251204
<ACCEPTANCE-DATETIME>20251204161832
ACCESSION NUMBER:		0001959173-25-007516
CONFORMED SUBMISSION TYPE:	144
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20251204
DATE AS OF CHANGE:		20251204

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Sensei Biotherapeutics, Inc.
		CENTRAL INDEX KEY:			0001829802
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	001-39980
		FILM NUMBER:		251549594

	BUSINESS ADDRESS:	
		STREET 1:		1405 RESEARCH BLVD, SUITE 125
		CITY:			ROCKVILLE
		STATE:			MD
		ZIP:			20850
		BUSINESS PHONE:		(240) 243-8000

	MAIL ADDRESS:	
		STREET 1:		1405 RESEARCH BLVD, SUITE 125
		CITY:			ROCKVILLE
		STATE:			MD
		ZIP:			20850

REPORTING-OWNER:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Cambrian BioPharma Inc
		CENTRAL INDEX KEY:			0001797409
		ORGANIZATION NAME:           	
		EIN:				842985609
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144

	BUSINESS ADDRESS:	
		STREET 1:		228 PARK AVENUE S.
		STREET 2:		#66643
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10003
		BUSINESS PHONE:		(516) 962-3186

	MAIL ADDRESS:	
		STREET 1:		228 PARK AVENUE S.
		STREET 2:		#66643
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10003

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Cambrian BioPharma Inc.
		DATE OF NAME CHANGE:	20191219
</SEC-HEADER>
<DOCUMENT>
<TYPE>144
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
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      <issuerCik>0001829802</issuerCik>
      <issuerName>Sensei Biotherapeutics, Inc.</issuerName>
      <secFileNumber>001-39980</secFileNumber>
      <issuerAddress>
        <com:street1>1405 RESEARCH BLVD, SUITE 125</com:street1>
        <com:city>ROCKVILLE</com:city>
        <com:stateOrCountry>MD</com:stateOrCountry>
        <com:zipCode>20850</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>(240) 243-8000</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Cambrian BioPharma Inc</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>10% Stockholder</relationshipToIssuer>
      </relationshipsToIssuer>
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    <securitiesInformation>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>Fidelity Brokerage Services LLC</name>
        <address>
          <com:street1>245 Summer Street</com:street1>
          <com:city>Boston</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>02110</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>5844</noOfUnitsSold>
      <aggregateMarketValue>50901.00</aggregateMarketValue>
      <noOfUnitsOutstanding>1261290</noOfUnitsOutstanding>
      <approxSaleDate>12/04/2025</approxSaleDate>
      <securitiesExchangeName>NASDAQ</securitiesExchangeName>
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    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>04/07/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
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      <amountOfSecuritiesAcquired>100</amountOfSecuritiesAcquired>
      <paymentDate>04/07/2021</paymentDate>
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    <securitiesToBeSold>
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      <paymentDate>04/01/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
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    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/30/2021</acquiredDate>
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      <paymentDate>03/30/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
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      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
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      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>187</amountOfSecuritiesAcquired>
      <paymentDate>03/24/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
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      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
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      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>475</amountOfSecuritiesAcquired>
      <paymentDate>03/23/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/22/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>109</amountOfSecuritiesAcquired>
      <paymentDate>03/22/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/18/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>41</amountOfSecuritiesAcquired>
      <paymentDate>03/18/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/08/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>50</amountOfSecuritiesAcquired>
      <paymentDate>03/08/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/05/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>400</amountOfSecuritiesAcquired>
      <paymentDate>03/05/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/04/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>100</amountOfSecuritiesAcquired>
      <paymentDate>03/04/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/03/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>150</amountOfSecuritiesAcquired>
      <paymentDate>03/03/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
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      <acquiredDate>03/02/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>150</amountOfSecuritiesAcquired>
      <paymentDate>03/02/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>02/26/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>250</amountOfSecuritiesAcquired>
      <paymentDate>02/26/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
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      <acquiredDate>02/25/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>600</amountOfSecuritiesAcquired>
      <paymentDate>02/25/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
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      <acquiredDate>02/24/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>950</amountOfSecuritiesAcquired>
      <paymentDate>02/24/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>02/23/2021</acquiredDate>
      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>1015</amountOfSecuritiesAcquired>
      <paymentDate>02/23/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
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      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>490</amountOfSecuritiesAcquired>
      <paymentDate>02/22/2021</paymentDate>
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    </securitiesToBeSold>
    <securitiesToBeSold>
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      <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>N/A</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
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      <paymentDate>02/19/2021</paymentDate>
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    <securitiesToBeSold>
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      <paymentDate>02/18/2021</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <noticeSignature>
      <noticeDate>12/04/2025</noticeDate>
      <signature>/s/ Cristina Garcia, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Cambrian BioPharma Inc</signature>
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