<SEC-DOCUMENT>0001070081-19-000010.txt : 20190109
<SEC-HEADER>0001070081-19-000010.hdr.sgml : 20190109
<ACCEPTANCE-DATETIME>20190109171125
ACCESSION NUMBER:		0001070081-19-000010
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20190107
FILED AS OF DATE:		20190109
DATE AS OF CHANGE:		20190109

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Utter Christine Marie
		CENTRAL INDEX KEY:			0001707685

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35969
		FILM NUMBER:		19518758

	MAIL ADDRESS:	
		STREET 1:		C/O PTC THERAPEUTICS, INC.
		STREET 2:		100 CORPORATE COURT
		CITY:			SOUTH PLAINFIELD
		STATE:			NJ
		ZIP:			07080

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PTC THERAPEUTICS, INC.
		CENTRAL INDEX KEY:			0001070081
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				043416587
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		100 CORPORATE COURT
		CITY:			SOUTH PLAINFIELD
		STATE:			NJ
		ZIP:			07080-2449
		BUSINESS PHONE:		9082227000

	MAIL ADDRESS:	
		STREET 1:		100 CORPORATE COURT
		CITY:			SOUTH PLAINFIELD
		STATE:			NJ
		ZIP:			07080-2449

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PTC THERAPEUTICS INC
		DATE OF NAME CHANGE:	19980909
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_154707186908284.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-01-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001070081</issuerCik>
        <issuerName>PTC THERAPEUTICS, INC.</issuerName>
        <issuerTradingSymbol>PTCT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001707685</rptOwnerCik>
            <rptOwnerName>Utter Christine Marie</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PTC THERAPEUTICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>100 CORPORATE COURT</rptOwnerStreet2>
            <rptOwnerCity>SOUTH PLAINFIELD</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07080</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Principal Financial Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2019-01-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>297</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>34.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7446</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares automatically sold pursuant to an irrevocable sell to cover election to satisfy tax withholding obligations in connection with the vesting of 975 RSUs from a January 3, 2017 grant of 3,900 RSUs.</footnote>
        <footnote id="F2">Includes 715 shares of common stock acquired under the Issuer's employee stock purchase plan for the period ending June 30, 2018 and 368 shares of common stock acquired under the Issuer's employee stock purchase plan for the period ending December 31, 2018.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Avraham S. Adler, attorney-in-fact</signatureName>
        <signatureDate>2019-01-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
