ARWR

EX-99.1

2 arwr-202608048kex991.htm

EX-99.1

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EXHIBIT 99.1

PRESS RELEASE

August 4, 2026

Arrowhead Pharmaceuticals Reports Fiscal 2026 Third Quarter Results

Conference Call and Webcast Today, August 4, 2026 at 4:30 p.m. ET

PASADENA, Calif., August 4, 2026 — Arrowhead Pharmaceuticals, Inc. (NASDAQ: ARWR) today announced financial results for its fiscal 2026 third quarter ended June 30, 2026. The Company is hosting a conference call today, August 4, 2026, at 4:30 p.m. ET to discuss the results.

“The recent period for Arrowhead included transformational events that support continued growth,” said Christopher Anzalone, Ph.D., President and CEO at Arrowhead Pharmaceuticals. “We recently announced topline results from the SHASTA-3 and SHASTA-4 studies supporting our continued belief that plozasiran is a best-in-class molecule for patients with a spectrum of triglyceride disorders. Based on these promising results, we acquired a priority review voucher (PRV) that potentially accelerates the process of bringing this important new medicine to patients. On the commercial front, REDEMPLO continued to demonstrate growing momentum and penetration with physicians and patients with familial chylomicronemia syndrome. Lastly, we made strong progress across our broad pipeline of RNAi therapeutic candidates at various stages of development, expanding the opportunity to help patients in diverse disease areas.”

Key REDEMPLO® Commercial Events

•U.S. REDEMPLO launch continued to build momentum during the quarter. Key progress included:

◦REDEMPLO prescription volume roughly doubled during the fiscal third quarter.

◦More than 400 unique practitioners have now prescribed REDEMPLO, with the specialty mix led by preventive cardiology and endocrinology.

◦REDEMPLO now has favorable policies in place for the most significant U.S. payers and overall coverage is progressing at a fast trajectory.

•Announced marketing authorizations of REDEMPLO in two new territories:

◦The European Commission (EC) formally granted marketing authorization for REDEMPLO as an adjunct to diet to reduce triglyceride levels in adult patients with FCS. REDEMPLO is the first and only siRNA medicine authorized by the EC for adults with FCS, diagnosed either by the presence of clinical criteria or genetic testing.

◦The Australian Therapeutic Goods Administration (TGA) approved REDEMPLO, as an adjunct to diet to reduce triglyceride levels for adult patients with FCS in Australia.

Key R&D Events

•Announced topline results for the global Phase 3 SHASTA-3 and SHASTA-4 clinical studies of plozasiran in patients with severe hypertriglyceridemia (sHTG). Detailed results will be presented as a HOT LINE Late Breaker at the European Society of Cardiology (ESC) Congress on August 30, 2026.

◦SHASTA-3 and SHASTA-4 successfully met the primary endpoint of triglyceride reduction versus placebo and met all prespecified secondary endpoints in both studies.

◦Deep, durable, and consistent median triglyceride reductions of 79% and 81% from baseline were observed in SHASTA-3 and SHASTA-4, respectively.

◦Statistically significant 78% reduction in acute pancreatitis (AP) events versus placebo was observed across the entire sHTG study population, with an unprecedented 100% event reduction in patients with triglycerides above 880 mg/dL and a prior medical history of AP, widely considered to be at the highest risk for AP.

◦Continued and consistent safety and tolerability profile was demonstrated with no new safety signals and a favorable liver safety profile.

•Announced that the Company completed enrollment in the global Phase 3 YOSEMITE clinical trial of zodasiran, the Company’s investigational RNA interference (RNAi) therapeutic being developed as a potential treatment for homozygous familial hypercholesterolemia (HoFH), a rare genetic condition that leads to severely elevated low-density lipoprotein cholesterol (LDL-C) and early-onset cardiovascular disease.

◦The Company anticipates that YOSEMITE will be completed in mid-2027 and, pending successful clinical results, intends to seek regulatory approval in multiple geographies thereafter.

◦YOSEMITE was initially designed to enroll 60 participants with HoFH; however, strong global patient and physician interest led to an increase in target enrollment to 70 patients.

•Presented interim results at the European Association for the Study of the Liver Congress (EASL 2026) from a Phase 1/2a clinical trial of ARO-INHBE, the company’s investigational RNA interference (RNAi) therapeutic being developed as a potential treatment for obesity and metabolic dysfunction-associated steatohepatitis (MASH).

◦The interim data demonstrate that ARO-INHBE treatment led to clinically meaningful reductions in liver fat as a monotherapy and in combination with low-dose tirzepatide, a GLP-1/GIP receptor co-agonist, in adults with obesity.

•Reported new positive plozasiran clinical data in two oral presentations at the 94th European Ath

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arwr-202602050000879407FALSE00008794072026-02-052026-02-05

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(D) OF

THE SECURITIES EXCHANGE ACT OF 1934

February 5, 2026 Date of Report (Date of earliest event reported)

Arrowhead Pharmaceuticals, Inc. (Exact name of registrant as specified in its charter)

Delaware001-3804246-0408024 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Employer Identification No.)

177 E. Colorado Blvd, Suite 700, Pasadena, CA 91105 (Address of principal executive offices, including Zip Code) (626) 304-3400 (Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐Pre-commencement communications pursuant to Rule 13e-4 (c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act: Title of each class Trading Symbol(s) Name of each exchange on which registered Common Stock, par value $0.001 per share ARWR The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 Results of Operations and Financial Condition On February 5, 2026, Arrowhead Pharmaceuticals, Inc. announced and commented on its fiscal 2026 financial results for the period ended December 31, 2025. A copy of the press release is furnished herewith as Exhibit 99.1. In accordance with General Instruction B.2 of Form 8-K, the information in this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, whether made before or after the date hereof, except as expressly set forth by specific reference in such filing to this Current Report on Form 8-K.

Item 9.01. Financial Statements and Exhibits. (d) Exhibits

Exhibit No.Description

99.1Press Release, dated February 5, 2026.

104Cover Page Interactive Data File (the cover page tags are embedded within the Inline XBRL document).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. Date: February 5, 2026

ARROWHEAD PHARMACEUTICALS, INC.

By:/s/ Daniel Apel Daniel Apel Chief Financial Officer