Arrowhead Completes Dosing in Phase 1 Study of ARO-AAT for Treatment of Alpha-1 Liver Disease

PASADENA, Calif.–(BUSINESS WIRE)–Aug. 31, 2018–
Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) today announced that it
has completed dosing of a Phase 1 clinical 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. Arrowhead
intends to submit a late-breaking abstract with initial clinical data on
ARO-AAT to the Liver Meeting®, the Annual Meeting of the
American Association for the Study of Liver Disease (AASLD), being held
in November 2018.

AROAAT1001 (NCT03362242)
is a Phase 1 single- and multiple-ascending dose study to evaluate the
safety, tolerability, pharmacokinetics, and effect of ARO-AAT on serum
alpha-1 antitrypsin levels in healthy adult volunteers. The study
includes 7 cohorts in which subjects receive placebo, a single dose of
ARO-AAT, or three monthly doses of ARO-AAT at doses of 35 (single dose
only), 100, 200, or 300 mg. Additional cohorts were planned at a dose of
400 mg, but were deemed unnecessary based on observed activity at lower
doses.

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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Safe Harbor Statement under the Private Securities Litigation Reform
Act:

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
forward-looking statements as a result of various factors and
uncertainties, including the safety and efficacy of our product
candidates, the duration and impact of regulatory delays in our clinical
programs, our ability to finance our operations, the future success of
our scientific studies, our ability to successfully develop drug
candidates, the timing for starting and completing clinical trials,
rapid technological change in our markets, and the enforcement of our
intellectual property rights. Our most recent Annual Report on Form 10-K
and subsequent Quarterly Reports on Form 10-Q discuss some of the
important risk factors that may affect our business, results of
operations and financial condition. We assume no obligation to update or
revise forward-looking statements to reflect new events or circumstances.

Source: Arrowhead Pharmaceuticals, Inc.

Source: Arrowhead Pharmaceuticals Inc.

Arrowhead Pharmaceuticals, Inc.
Vince Anzalone, 626-304-3400
CFA
ir@arrowheadpharma.com
or
Investors
and Media:
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