X0202 SCHEDULE 13G/A 0000902664-24-006530 0001633313 XXXXXXXX LIVE 3 Common Stock, par value $0.001 per share 06/30/2026 0000879407 Arrowhead Pharmaceuticals, Inc. 04280A100 177 E COLORADO BLVD SUITE 700 PASADENA CA 91105 Rule 13d-1(b) Avoro Capital Advisors LLC b DE 13823383.00 0.00 13823383.00 0.00 13823383.00 N 9.64 IA OO Includes 2,467,828 shares of Common Stock (as defined in Item 2(a)) issuable upon exercise of warrants. Behzad Aghazadeh b X1 13823383.00 0.00 13823383.00 0.00 13823383.00 N 9.64 HC IN Includes 2,467,828 shares of Common Stock issuable upon exercise of warrants. Arrowhead Pharmaceuticals, Inc. 177 E. Colorado Blvd, Suite 700, Pasadena, CA 91105 This statement is filed by: (i) Avoro Capital Advisors LLC, a Delaware limited liability company ("Avoro"), which provides investment advisory and management services and has acquired the shares of common stock, par value $0.001 per share ("Common Stock") and the shares of Common Stock underlying warrants of Arrowhead Pharmaceuticals, Inc., a Delaware corporation (the "Company"), solely for investment purposes on behalf of Avoro Life Sciences Fund LLC, a Delaware limited liability company, and (ii) Behzad Aghazadeh ("Dr. Aghazadeh," and together with Avoro, the "Reporting Persons"), who serves as the portfolio manager and controlling person of Avoro. The filing of this statement should not be construed as an admission that any Reporting Person is, for purposes of Section 13 of the Act, the beneficial owner of the securities reported herein. The address of the business office of each of the Reporting Persons is 110 Greene Street, Suite 800, New York, NY 10012. Avoro is a Delaware limited liability company. Dr. Aghazadeh is a United States citizen. N IA HC The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The percentage set forth in this Schedule 13G is calculated based upon an aggregate of 140,857,021 shares of Common Stock outstanding as of May 1, 2026 as reported in the Company's Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2026, filed with the Securities and Exchange Commission on May 7, 2026, and assumes the exercise of warrants reported herein. 9.64% The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference. Y N See Item 2(a). Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11. Avoro Capital Advisors LLC /s/ Scott Epstein 08/14/2026 Behzad Aghazadeh /s/ Behzad Aghazadeh 08/14/2026