<SEC-DOCUMENT>0000874015-21-000033.txt : 20210120
<SEC-HEADER>0000874015-21-000033.hdr.sgml : 20210120
<ACCEPTANCE-DATETIME>20210120190055
ACCESSION NUMBER:		0000874015-21-000033
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210115
FILED AS OF DATE:		20210120
DATE AS OF CHANGE:		20210120

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			O'NEIL PATRICK R.
		CENTRAL INDEX KEY:			0001564926

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19125
		FILM NUMBER:		21539973

	MAIL ADDRESS:	
		STREET 1:		C/O ISIS PHARMACEUTICALS, INC.
		STREET 2:		2855 GAZELLE COURT
		CITY:			CARLSBAD
		STATE:			CA
		ZIP:			92010

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IONIS PHARMACEUTICALS INC
		CENTRAL INDEX KEY:			0000874015
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				330336973
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2855 GAZELLE COURT
		CITY:			CARLSBAD
		STATE:			CA
		ZIP:			92010
		BUSINESS PHONE:		7609319200

	MAIL ADDRESS:	
		STREET 1:		2855 GAZELLE COURT
		CITY:			CARLSBAD
		STATE:			CA
		ZIP:			92010

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ISIS PHARMACEUTICALS INC
		DATE OF NAME CHANGE:	19930328
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
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    <periodOfReport>2021-01-15</periodOfReport>

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        <issuerName>IONIS PHARMACEUTICALS INC</issuerName>
        <issuerTradingSymbol>IONS</issuerTradingSymbol>
    </issuer>

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            <rptOwnerCik>0001564926</rptOwnerCik>
            <rptOwnerName>O'NEIL PATRICK R.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O IONIS PHARMACEUTICALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2855 GAZELLE CT.</rptOwnerStreet2>
            <rptOwnerCity>CARLSBAD,</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92010</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP &amp; General Counsel</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
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                <sharesOwnedFollowingTransaction>
                    <value>32253</value>
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    <footnotes>
        <footnote id="F1">Acquired pursuant to vesting and release of shares in accordance with Restricted Stock Unit awards.</footnote>
        <footnote id="F2">Shares withheld to cover the required tax withholding obligations pursuant to the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan.</footnote>
        <footnote id="F3">Grant to reporting person of Restricted Stock Units under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan.</footnote>
        <footnote id="F4">Each Restricted Stock Unit represents a contingent right to receive one share of Ionis common stock, or its equivalent cash value.</footnote>
        <footnote id="F5">Restricted Stock Units vest in four equal monthly installments.  Upon vesting, the Restricted Stock Units will be paid out in whole shares of Ionis common stock or cash as may be determined by Ionis.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/Patrick R. O'Neil</signatureName>
        <signatureDate>2021-01-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
