Arrowhead Provides Update on IND for ARC-520 Phase 2b Study

PASADENA, Calif.–(BUSINESS WIRE)–

Arrowhead Research Corporation (NASDAQ: ARWR), a biopharmaceutical

company developing targeted RNAi therapeutics, today announced that the

U.S. Food and Drug Administration (FDA) verbally informed the Company in

a preliminary call of a partial clinical hold, under which the Company

is cleared to begin a modified multiple-dose study of ARC-520 in

patients with chronic hepatitis B infection. The FDA requested that the

Company start the multiple-dose study at 1 mg/kg of ARC-520 rather than

the proposed parallel study design of 2 and 4 mg/kg, and requested

additional information be provided to the agency. The additional

information includes a final study report from the single-dose Phase 2a

study in patients who received 1-4 mg/kg ARC-520, which is ongoing and

has not reported any serious adverse events or evidence of end organ

toxicity to date. The FDA also requested a final study report from an

ongoing multiple-dose non-clinical study, which has shown ARC-520 to be

well tolerated with no evidence of end organ toxicity to date. The FDA

committed to provide the Company with a letter detailing its thoughts

and requests within 30 days. The ongoing Phase 2a study continues as

planned, and the Company expects to file with Asian and European

agencies to begin additional Phase 2b studies in coming weeks.

“Over the next 30 days, Arrowhead will begin preparations for the

multiple-dose Phase 2b study,” said Arrowhead President and CEO, Dr.

Christopher Anzalone. “We will work closely with the FDA throughout this

process while we continue to seek approval to proceed with other planned

studies in Asia and Europe.”

About ARC-520

Arrowhead’s RNAi-based candidate ARC-520 is being investigated in the

treatment of chronic HBV infection. The small interfering RNAs (siRNAs)

in ARC-520 intervene at the mRNA level, upstream of the reverse

transcription process where current standard of care nucleotide and

nucleoside analogues act. Arrowhead is investigating ARC-520

specifically, to determine if it can be used to achieve a functional

cure, which is an immune clearant state characterized by hepatitis B

s-antigen negative serum with or without sero-conversion. Arrowhead has

completed a Phase 1 single ascending dose study in normal volunteers and

the company is conducting a single dose Phase 2a study in chronic HBV

patients. Approximately 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.

About Arrowhead Research Corporation

Arrowhead Research Corporation is a biopharmaceutical company developing

targeted RNAi therapeutics. The company is leveraging its proprietary

Dynamic Polyconjugate™ delivery platform to develop targeted drugs based

on the RNA interference mechanism that efficiently silences

disease-causing genes. Arrowhead’s pipeline includes ARC-520 for chronic

hepatitis B virus, ARC-AAT for liver disease associated with Alpha-1

antitrypsin deficiency, and partner-based programs in obesity and

oncology.

For more information please visit http://www.arrowheadresearch.com,

or follow us on Twitter @ArrowRes.

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please visit http://ir.arrowheadresearch.com/alerts.cfm.

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 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, actions of the U.S. Food and Drug Administration (FDA) and

similar global regulatory bodies, rapid technological change in our

markets, and the enforcement of our intellectual property rights.

Arrowhead Research Corporation’s 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 Research Corporation

Arrowhead Research Corporation
Vince Anzalone, CFA, 626-304-3400
ir@arrowres.com
or
Investor

Relations:
The Trout Group
Lauren Glaser, 646-378-2972
ir@arrowres.com
or
Media:
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Martina Schwarzkopf, Ph.D., 212-845-4292
martina.schwarzkopf@russopartnersllc.com

Source: Arrowhead Research Corporation

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