<SEC-DOCUMENT>0001599298-23-000090.txt : 20231016
<SEC-HEADER>0001599298-23-000090.hdr.sgml : 20231016
<ACCEPTANCE-DATETIME>20231016160825
ACCESSION NUMBER:		0001599298-23-000090
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20231013
FILED AS OF DATE:		20231016
DATE AS OF CHANGE:		20231016

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Zanganeh Mahkam
		CENTRAL INDEX KEY:			0001507650

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36866
		FILM NUMBER:		231327417

	MAIL ADDRESS:	
		STREET 1:		51 ADAM WAY
		CITY:			ATHERTON
		STATE:			CA
		ZIP:			94027

	FORMER NAME:	
		FORMER CONFORMED NAME:	Zanganeh Maky
		DATE OF NAME CHANGE:	20101210

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Summit Therapeutics Inc.
		CENTRAL INDEX KEY:			0001599298
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2882 SAND HILL ROAD
		STREET 2:		SUITE 106
		CITY:			MENLO PARK
		STATE:			CA
		ZIP:			94025
		BUSINESS PHONE:		617-514-7149

	MAIL ADDRESS:	
		STREET 1:		2882 SAND HILL ROAD
		STREET 2:		SUITE 106
		CITY:			MENLO PARK
		STATE:			CA
		ZIP:			94025

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Summit Therapeutics plc
		DATE OF NAME CHANGE:	20150219

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Summit Corp plc
		DATE OF NAME CHANGE:	20140205
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1697486896.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-10-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001599298</issuerCik>
        <issuerName>Summit Therapeutics Inc.</issuerName>
        <issuerTradingSymbol>SMMT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001507650</rptOwnerCik>
            <rptOwnerName>Zanganeh Mahkam</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SUMMIT THERAPEUTICS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2882 SAND HILL ROAD, SUITE 106</rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.68</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-10-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>11988198</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2033-10-13</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>11988198</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11988198</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The option was granted on October 13, 2023. The shares underlying the option shall vest in four equal annual installments, with the first such installment occurring on October 13, 2024. Note this does not include an additional 11,988,198 options which were granted on October 13, 2023 and are subject to the satisfaction of performance conditions based on market capitalization and revenue targets.</footnote>
        <footnote id="F2">Not applicable.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Mahkam Zanganeh</signatureName>
        <signatureDate>2023-10-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
