Company: ARWR
Filing Date: 2025-12-11
Form Type: S-3ASR
Source: 0001193125-25-314755
Chunk: 28

Company: ARROWHEAD PHARMACEUTICALS, INC.
Filing Date: 2025-12-11
Form: S-3ASR
Chunk 28
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, before making an investment decision. You should also read and consider the information in the documents to which we have referred you in the sections entitled
“Where You Can Find More Information” and “Incorporation of Certain Information by Reference” in this prospectus supplement and in the accompanying prospectus.

S-1

In this prospectus supplement, “Arrowhead,” the “Company,”
“we,” “us,” and “our” and similar terms refer to Arrowhead Pharmaceuticals, Inc. and its subsidiaries, unless the context indicates otherwise. References to our “common stock” refer to the common
stock, par value $0.001 per share, of Arrowhead Pharmaceuticals, Inc.

All references in this prospectus supplement to our financial
statements include, unless the context indicates otherwise, the related notes.

The industry and market data and other statistical
information contained in this prospectus supplement, the accompanying prospectus and the documents we incorporate by reference herein and therein are based on management’s own estimates, independent publications, government publications,
reports by market research firms or other published independent sources, and, in each case, are believed by management to be reasonable estimates. Although we believe these sources are reliable, we have not independently verified the information.

This prospectus supplement and the accompanying prospectus contain references to our trademarks and to trademarks belonging to other
entities. Solely for convenience, trademarks and trade names referred to in this prospectus supplement and the accompanying prospectus, including logos, artwork and other visual displays, may appear without the or TM symbols, but such references are not intended to indicate, in any way, that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto. We do
not intend our use or display of other companies’ trademarks or trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

S-2

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying prospectus and the information incorporated by reference herein and therein contain or
incorporate forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). These forward-looking statements reflect
management’s beliefs and assumptions. In addition, these forward-looking statements reflect management’s current views with respect to future events or our financial performance, and involve certain known and unknown risks, uncertainties
and other factors, including those