Ionis Pharmaceuticals, Inc. (NASDAQ: IONS) is filing the following information with the Securities and Exchange Commission for the purpose of updating certain aspects of its publicly disclosed information regarding SPINRAZA.

On April 25, 2017 Biogen, Inc. provided an update regarding the commercial launch for SPINRAZA. As part of the update, Biogen reported first quarter 2017 revenues for SPINRAZA of $47 million.

FORWARD-LOOKING STATEMENT

This report includes forward-looking statements regarding Ionis’ strategic relationship with Biogen and the development, activity, therapeutic potential, safety and commercialization of SPINRAZA. Any statement describing Ionis’ goals, expectations, financial or other projections, intentions or beliefs is a forward-looking statement and should be considered an at-risk statement. Such statements are subject to certain risks and uncertainties, particularly those inherent in the process of discovering, developing and commercializing drugs that are safe and effective for use as human therapeutics, and in the endeavor of building a business around such drugs. Ionis’ forward-looking statements also involve assumptions that, if they never materialize or prove correct, could cause its results to differ materially from those expressed or implied by such forward-looking statements. Although Ionis’ forward-looking statements reflect the good faith judgment of its management, these statements are based only on facts and factors currently known by Ionis. As a result, you are cautioned not to rely on these forward-looking statements. These and other risks concerning Ionis’ programs are described in additional detail in Ionis’ annual report on Form 10-K for the year ended December 31, 2016, which is on file with the SEC. Copies of this document are available from the Company.

In this report, unless the context requires otherwise, “Ionis,” “Company,” “we,” “our,” and “us” refers to Ionis Pharmaceuticals and its subsidiaries.

Ionis Pharmaceuticals™ is a trademark of Ionis Pharmaceuticals, Inc. SPINRAZA™ is a trademark of Biogen.

About IONIS PHARMACEUTICALS, INC. (NASDAQ:IONS)

Ionis Pharmaceuticals, Inc., formerly Isis Pharmaceuticals, Inc., is engaged in discovering and developing ribonucleic acid-targeted (RNA-targeted) therapeutics. The Company operates through two segments: Ionis Core and Akcea Therapeutics. The Company’s Ionis Core segment is developing a drug discovery platform. The Company’s Akcea Therapeutics segment consists of the operations of its subsidiary, Akcea Therapeutics, Inc., which develops and commercializes drugs for cardiometabolic disorders. The Company is developing transformational drugs, which include nusinersen, IONIS-TTR and volanesorsen that are designed to treat patients with orphan diseases. In addition to its Phase III programs, the Company has a pipeline of drugs in Phase II development, which includes IONIS-FXI and IONIS-APO(a)-L. Its Phase II pipeline includes drugs to treat patients with severe and rare diseases, viral infections, ocular diseases, metabolic disorders and cardiovascular diseases.

IONIS PHARMACEUTICALS, INC. (NASDAQ:IONS) Recent Trading Information

IONIS PHARMACEUTICALS, INC. (NASDAQ:IONS) closed its last trading session 00.00 at 45.74 with 1,617,704 shares trading hands.