X0306 4 2018-03-16 0 0000879407 ARROWHEAD PHARMACEUTICALS, INC. ARWR 0001423029 Anzalone Christopher Richard 225 S. LAKE AVENUE SUITE 1050 PASADENA CA 91101 1 1 0 0 Chief Executive Officer Common Stock 2018-03-16 4 S 0 26000 7.40 D 1968789 D Open market sale pursuant to a 10b5-1 trading plan adopted by the Reporting Person in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended. The sale was made to generate proceeds to cover the tax liability incident to the vesting of restricted stock units. The price reported on Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $7.40 to $7.41, inclusive. The reporting person undertakes to provide to Arrowhead Pharmaceuticals, Inc., any security holder of Arrowhead Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote of this Form 4. Includes a total of 1,186,000 shares underlying restricted stock units that may be earned based on the achievement of certain performance goals. If the performance goals are not met within the required time periods, the awards will be forfeited in part or in whole. /s/ Chris Anzalone 2018-03-16