Arrowhead Pharmaceuticals Doses First Patient with Hepatitis B in Multiple Ascending Dose Portion of Phase 1/2 Study of ARC-521

PASADENA, Calif.–(BUSINESS WIRE)–

Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) today announced that it

has dosed the first patient in the multiple ascending dose (MAD) portion

of its ongoing Phase 1/2 study of ARC-521, the company’s second

RNAi-based investigational medicine for the treatment of chronic

hepatitis B virus (HBV) infection. To date 24 healthy volunteers have

been treated in the study, and the drug safety committee (DSC) approved

initiation of the MAD after a planned review of safety data from cohort

3 of the healthy volunteer portion of the study. The MAD is designed to

evaluate the safety, tolerability, and antiviral activity of single and

multiple doses of ARC-521 in patients with chronic HBV.

Bruce Given, M.D., chief operating officer and head of R&D at Arrowhead

said, “The innovative design for the first-in-man study of ARC-521 is

intended to get to multiple dose data in patients rapidly. Arrowhead’s

development staff and the experienced investigators working on the study

are operating at best-in-class speeds, enabling us to begin the MAD

portion of the study just three months into the clinical program. This

study may have multiple readouts, including single dose safety data in

healthy volunteers and single and multiple dose safety and antiviral

activity data in HBV patients. These readouts should happen

progressively, potentially starting during the first quarter of 2017.”

The MAD portion of the ARC-521 study (ARC5211001) is a multicenter,

sequential, multiple dose, open label study in patients with chronic

HBV. Up to 24 chronic HBV patients (8 patients per dose level) that are

negative for Hepatitis B e-antigen (HBeAg) at screening will enroll

sequentially into up to 3 dose levels (2 mg/kg, 4 mg/kg, 6 mg/kg) to

receive 3 monthly doses of open label ARC-521.

About ARC-521

Arrowhead’s ARC-521 is being investigated for its potential to produce

functional cures in patients with chronic hepatitis B virus (HBV)

infection. ARC-521 intervenes upstream of the reverse transcription

process where current standard-of-care nucleotide and nucleoside analogs

act, and is designed to silence the production of all HBV gene products.

The small interfering RNAs (siRNAs) in ARC-521 engage the body’s normal

cellular RNAi machinery and direct specific cleavage of HBV RNA

transcripts, thereby reducing the levels of HBV proteins and the RNA

template used to produce viral DNA. Designed to complement ARC-520,

ARC-521 is a second generation HBV candidate that targets HBV mRNA

transcripts from both cccDNA and integrated DNA and is expected to be

most suitable for those patients who tend to have lower levels of viral

cccDNA. Arrowhead is investigating ARC-521 specifically to determine if

significantly reducing circulating and non-circulating viral proteins

and RNA will allow for re-constitution of an effective host immune

response and ultimately HBsAg seroclearance resulting in functional

cure. As many as 350-400 million people worldwide are chronically

infected with the hepatitis B virus, which can lead to cirrhosis of the

liver and is responsible for 80% of primary liver cancers globally.

Arrowhead is conducting a Phase 1/2 single and multiple dose study in

healthy volunteers and HBV patients.

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. The company’s pipeline includes ARC-520 and ARC-521 for

chronic hepatitis B virus infection, ARC-AAT for liver disease

associated with alpha-1 antitrypsin deficiency, ARC-F12 for hereditary

angioedema and thromboembolic disorders, ARC-LPA for cardiovascular

disease, and ARC-HIF2 for renal cell carcinoma.

For more information please visit www.arrowheadpharma.com,

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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 our ability to finance our operations, the

future success of our scientific studies, our ability to successfully

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revise forward-looking statements to reflect new events or circumstances.

DYNAMIC POLYCONJUGATES is a trademark of Arrowhead

Pharmaceuticals, Inc.

Source: Arrowhead Pharmaceuticals, Inc.

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

Relations:
The Trout Group
Chad Rubin, 646-378-2947
ir@arrowheadpharma.com
or
Media:
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Source: Arrowhead Pharmaceuticals Inc.

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