UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 Form 10-Q (Mark One) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2019 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 0-19125 Ionis Pharmaceuticals, Inc. (Exact name of Registrant as specified in its charter) Delaware 33-0336973 (IRS Employer Identification No ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ___________ to ___________ Commission file number 0-19125 Ionis Pharmaceuticals, Inc. (Exact name of Registrant as specified in its charter) Delaware 33-0336973 (State or other ju ...