Basis of Presentation

We prepared the unaudited interim condensed consolidated financial statements for the three months ended March 31, 2018 and 2017 on the same basis as the audited financial statements for the year ended December 31, 2017. 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, 2017 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 majority-owned subsidiary, Akcea Therapeutics, Inc., which we formed in December 2014. In July 2017, Akcea completed an initial public offering, or IPO. As of July 19, 2017, the closing of the IPO, and at March 31, 2018, we owned approximately 68 percent of Akcea.

In April 2018, we received 8 million shares of Akcea’s stock for the license of TEGSEDI (inotersen) and AKCEA-TTR-L_Rx to Akcea and purchased an additional 10.7 million shares of Akcea’s stock for $200 million, increasing our ownership percentage to approximately 75 percent. We will reflect this increase in our ownership percentage in the second quarter of 2018. Refer to the noncontrolling interest in Akcea section in Note 2, Significant Accounting Policies, for further information related to our accounting for our investment in Akcea. Unless the context requires otherwise, “Ionis”, “Company,” “we,” “our,” and “us” refers to Ionis Pharmaceuticals, Inc. and its majority owned subsidiary, Akcea Therapeutics, Inc.