<SEC-DOCUMENT>0001104659-21-074444.txt : 20210528
<SEC-HEADER>0001104659-21-074444.hdr.sgml : 20210528
<ACCEPTANCE-DATETIME>20210528203039
ACCESSION NUMBER:		0001104659-21-074444
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210526
FILED AS OF DATE:		20210528
DATE AS OF CHANGE:		20210528

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Mirabelli Christopher
		CENTRAL INDEX KEY:			0001262326

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37990
		FILM NUMBER:		21982497

	MAIL ADDRESS:	
		STREET 1:		55 CAMBRIDGE PARKWAY
		STREET 2:		SUITE 301
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142

	FORMER NAME:	
		FORMER CONFORMED NAME:	MIRAELLI CHRISTOPHER
		DATE OF NAME CHANGE:	20030904

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LEAP THERAPEUTICS, INC.
		CENTRAL INDEX KEY:			0001509745
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				274412575
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		47 THORNDIKE STREET
		STREET 2:		SUITE B1-1
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
		BUSINESS PHONE:		617 252 4343

	MAIL ADDRESS:	
		STREET 1:		47 THORNDIKE STREET
		STREET 2:		SUITE B1-1
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Dekkun Corp
		DATE OF NAME CHANGE:	20110107
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>tm2117938-1_4seq1.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-05-26</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001509745</issuerCik>
        <issuerName>LEAP THERAPEUTICS, INC.</issuerName>
        <issuerTradingSymbol>LPTX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001262326</rptOwnerCik>
            <rptOwnerName>Mirabelli Christopher</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O LEAP THERAPEUTICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>47 THORNDIKE STREET SUITE B1-1</rptOwnerStreet2>
            <rptOwnerCity>CAMBRIDGE</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02141</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.62</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2021-05-26</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2031-05-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>30000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Option was granted pursuant to Leap's 2016 Equity Incentive Plan and shall vest and become exercisable in a series of 36 equal monthly installments until the Option is fully vested, with the first such monthly installment vesting on the one month anniversary of May 26, 2021, the Vesting Start Date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Douglas E. Onsi, as Attorney-in-Fact for Christopher Mirabelli</signatureName>
        <signatureDate>2021-05-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
