<SEC-DOCUMENT>0001070081-20-000097.txt : 20200507
<SEC-HEADER>0001070081-20-000097.hdr.sgml : 20200507
<ACCEPTANCE-DATETIME>20200507154446
ACCESSION NUMBER:		0001070081-20-000097
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200505
FILED AS OF DATE:		20200507
DATE AS OF CHANGE:		20200507

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Peltz Stuart Walter
		CENTRAL INDEX KEY:			0001578962

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35969
		FILM NUMBER:		20856101

	MAIL ADDRESS:	
		STREET 1:		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_158888066893504.xml
<DESCRIPTION>FORM 4
<TEXT>
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    <periodOfReport>2020-05-05</periodOfReport>

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

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            <rptOwnerName>Peltz Stuart Walter</rptOwnerName>
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            <rptOwnerStreet1>C/O PTC THERAPEUTICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>100 CORPORATE COURT</rptOwnerStreet2>
            <rptOwnerCity>SOUTH PLAINFIELD</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07080</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
            <otherText></otherText>
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            <expirationDate>
                <value>2021-04-27</value>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
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                <underlyingSecurityShares>
                    <value>541.0</value>
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                    <value>541</value>
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                    <value>D</value>
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                <value>218.4</value>
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            <expirationDate>
                <value>2022-01-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
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                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>416.0</value>
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            <postTransactionAmounts>
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                    <value>416</value>
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                <sharesOwnedFollowingTransaction>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
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                <underlyingSecurityShares>
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                <value>Stock Option (Right To Buy)</value>
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            <expirationDate>
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                    <value>265000</value>
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                    <value>D</value>
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                <value>2029-01-21</value>
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                    <value>Common Stock</value>
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                <underlyingSecurityShares>
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                    <value>55000</value>
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                <directOrIndirectOwnership>
                    <value>D</value>
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            <securityTitle>
                <value>Stock Option (Right To Buy)</value>
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                <value>51.16</value>
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            <expirationDate>
                <value>2030-01-28</value>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
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                <underlyingSecurityShares>
                    <value>192500.0</value>
                </underlyingSecurityShares>
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                <sharesOwnedFollowingTransaction>
                    <value>192500</value>
                </sharesOwnedFollowingTransaction>
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    <footnotes>
        <footnote id="F1">This transaction was effected pursuant to a written Rule 10b5-1 plan adopted by the Reporting Person on March 5, 2020.</footnote>
        <footnote id="F2">This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $50.00 to $50.99 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.</footnote>
        <footnote id="F3">This price represents the weighted average price of sale transactions that were executed in multiple trades at prices ranging from $51.00 to $51.07 per share. The Reporting Person hereby undertakes, upon request by the SEC staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.</footnote>
        <footnote id="F4">This option was granted on May 15, 2013 and vests over four years, with 25% of the shares underlying the option vested on May 15, 2014 and an additional 2.083% of the original number of shares underlying the option vesting monthly thereafter beginning on June 15, 2014.</footnote>
        <footnote id="F5">Currently exercisable.</footnote>
        <footnote id="F6">This option was granted on January 3, 2017, and vests over four years, with 25% of the shares underlying the option vesting on January 3, 2018, and an additional 6.25% of the original number of shares underlying the option vesting at the end of each successive three-month period thereafter, beginning on April 3, 2018.</footnote>
        <footnote id="F7">This option was granted on January 3, 2018, and vests over four years, with 25% of the shares underlying the option vesting on January 3, 2019, and an additional 6.25% of the original number of shares underlying the option vesting at the end of each successive three-month period thereafter, beginning on April 3, 2019.</footnote>
        <footnote id="F8">This option was granted on January 22, 2019 and vests over four years, with 25% of the shares underlying the option vesting on January 22, 2020, and an additional 6.25% of the original number of shares underlying the option vesting at the end of each successive three-month period thereafter, beginning April 22, 2020.</footnote>
        <footnote id="F9">This option was granted on January 22, 2019 and vests over four years, with 50% of the shares underlying the option vesting on January 22, 2022, and the remaining 50% of the original number of shares underlying the option vesting on January 22, 2023.</footnote>
        <footnote id="F10">This option was granted on January 29, 2020 and vests over four years, with 25% of the shares underlying the option vesting on January 29, 2021, and an additional 6.25% of the original number of shares underlying the option vesting at the end of each successive three-month period thereafter, beginning April 29, 2021.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Avraham S. Adler, attorney-in-fact</signatureName>
        <signatureDate>2020-05-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
