Arrowhead Pharmaceuticals Files IND for Pivotal Phase 2/3 Study of ARO-AAT for Treatment of Alpha-1 Liver Disease

PASADENA, Calif.–(BUSINESS WIRE)–Mar. 18, 2019–
Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) today announced that it
has submitted an Investigational New Drug (IND) application to the U.S.
Food and Drug Administration (FDA) for an adaptive Phase 2/3 trial with
the potential to serve as a pivotal registrational study of ARO-AAT, the
company’s second generation subcutaneously administered RNA interference
(RNAi) therapeutic being developed as a treatment for a rare genetic
liver disease associated with alpha-1 antitrypsin deficiency (AATD).

Bruce Given, M.D., chief operating officer and head of R&D at Arrowhead,
said: “Our discussions with the FDA have been productive and helpful as
we moved through the process of determining the Phase 2/3 adaptive trial
design with appropriate surrogate endpoints. We look forward to
initiating this trial and moving closer to potentially providing
patients, physicians, and the alpha-1 community with a much-needed
therapy for alpha-1 liver disease.”

Pending regulatory review, the company intends to initiate the adaptive
design, Phase 2/3 study of ARO-AAT in patients with AATD associated
liver disease. The proposed primary objectives are to evaluate safety
and pharmacodynamic dose response, and to evaluate efficacy, defined as
an improvement in a histologic grading scale of AATD associated liver
disease, and no worsening of liver fibrosis based on Ishak score on end
of study biopsy.

Arrowhead intends to initiate the study at various sites in the U.S. in
the second quarter of 2019, followed by various international sites in
Europe, pending regulatory submission and review. The company plans to
provide additional study details following its initiation.

About Arrowhead Pharmaceuticals

Arrowhead Pharmaceuticals develops medicines that treat intractable
diseases by silencing the genes that cause them. Using a broad portfolio
of RNA chemistries and efficient modes of delivery, Arrowhead therapies
trigger the RNA interference mechanism to induce rapid, deep, and
durable knockdown of target genes. RNA interference, or RNAi, is a
mechanism present in living cells that inhibits the expression of a
specific gene, thereby affecting the production of a specific protein.
Arrowhead’s RNAi-based therapeutics leverage this natural pathway of
gene silencing.

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This news release contains forward-looking statements within the
meaning of the “safe harbor” provisions of the Private Securities
Litigation Reform Act of 1995. These statements are based upon our
current expectations and speak only as of the date hereof. Our actual
results may differ materially and adversely from those expressed in any
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uncertainties, including the safety and efficacy of our product
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timing of the receipt of future milestone and licensing fees, the future
success of our scientific studies, our ability to successfully develop
and commercialize drug candidates, the timing for starting and
completing clinical trials, rapid technological change in our markets,
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Source: Arrowhead Pharmaceuticals, Inc.

Source: Arrowhead Pharmaceuticals, Inc.

Arrowhead Pharmaceuticals, Inc.
Vince Anzalone, CFA
626-304-3400
ir@arrowheadpharma.com

Investors and Media:
LifeSci Advisors, LLC
Brian Ritchie
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