EXELIXIS INC

Dana T. Aftab, our Executive Vice President, Discovery and Translational Research, and Chief Scientific Officer, an officer for purposes of Section 16 of the Exchange Act, entered into a pre-arranged stock trading plan on May 25, 2023, which was subsequently modified on February 27, 2024. As modified, Dr. Aftab’s trading plan provides for the sale of up to 194,656 shares of our common stock (including shares obtained from the exercise of vested stock options covered by the trading plan) between May 30, 2024 and September 30, 2025. This trading plan is intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act and Exelixis’ policies regarding transactions in Exelixis securities.

Jeffrey J. Hessekiel, our Executive Vice President, General Counsel and Secretary, an officer for purposes of Section 16 of the Exchange Act, entered into a pre-arranged stock trading plan on February 28, 2024. Mr. Hessekiel’s trading plan provides for the sale of up to 200,000 shares of our common stock (including shares obtained from the exercise of vested stock options covered by the trading plan) between May 29, 2024 and December 31, 2024. This trading plan is intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act and Exelixis’ policies regarding transactions in Exelixis securities.

Jack L Wyszomierski, a member of our Board of Directors, entered into a pre-arranged stock trading plan on February 12, 2024. Mr. Wyszomierski’s trading plan provides for the sale of up to 19,973 shares of our common stock (including shares obtained from the exercise of vested stock options covered by the trading plan) between May 13, 2024 and June 12, 2024. This trading plan is intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act and Exelixis’ policies regarding transactions in Exelixis securities.

During the three months ended March 31, 2024, no other directors or Section 16 officers of the Company adopted, modified or terminated any “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408 of Regulation S-K.