Form 4 Filing for Arrowhead Pharmaceuticals, Inc.

This filing details a series of stock sales by Christopher Richard Anzalone, the Chief Executive Officer and a Director of Arrowhead Pharmaceuticals, Inc. The transactions occurred on December 19 and December 22, 2025. A total of 25,031 shares of common stock were sold. These sales were conducted under a 10b5-1 trading plan. The sales on December 19 involved 3,979 shares at a weighted average price of $66.67, 8,147 shares at a weighted average price of $68.01, and 1,319 shares at a weighted average price of $68.48. On December 22, 10,012 shares were sold at a weighted average price of $68.33, and an additional 2,574 shares were sold at a weighted average price of $68.85. The reported prices are weighted averages, with specific ranges provided in the footnotes. Following these transactions, the post-transaction share ownership for Mr. Anzalone is reported as 3,805,926 shares, which includes shares underlying RSUs that may still be subject to vesting conditions.