Basis of Presentation

6 Months Ended

Jun. 30, 2017

We prepared the unaudited interim condensed consolidated financial statements for the three and six months ended June 30, 2017 and 2016 on the same basis as the audited financial statements for the year ended December 31, 2016. We included all normal recurring adjustments in the financial statements, which we considered necessary for a fair presentation of our financial position at such dates and our operating results and cash flows for those periods. Results for the interim periods are not necessarily indicative of the results for the entire year. For more complete financial information, these financial statements, and notes thereto, should be read in conjunction with the audited financial statements for the year ended December 31, 2016 included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission, or SEC.

In the condensed consolidated financial statements we included the accounts of Ionis Pharmaceuticals, Inc. and the consolidated results of our subsidiary, Akcea Therapeutics, Inc., which we formed in December 2014. In July 2017, Akcea completed an initial public offering, or IPO, and therefore beginning in July 2017, we no longer own 100 percent of Akcea. As of July 19, 2017, the closing of the IPO, we retained a 68 percent ownership of Akcea. Refer to Note 8, Subsequent Events, for further information related to Akcea’s IPO. Unless the context requires otherwise, “Ionis”, “Company,” “we,” “our,” and “us” refers to Ionis Pharmaceuticals, Inc. and its majority owned subsidiary, Akcea Therapeutics, Inc.