Arrowhead Presents Data on Potential RNAi Candidate Targeting Factor 12 Mediated Angioedemic and Thromboembolic Diseases

PASADENA, Calif.–(BUSINESS WIRE)–

Arrowhead Research Corporation (NASDAQ: ARWR), a biopharmaceutical

company developing targeted RNAi therapeutics, today presented data at

IBC’s 17th Annual TIDES Conference in San Diego on the

preclinical development of an RNAi therapeutic as a potential treatment

for factor 12 (F12) mediated angioedemic and thromboembolic diseases.

The presentation included data from in vitro screenings, in vivo

evaluations, a disease model, and a multiple dose study in nonhuman

primates. These data support advancement of ARC-F12 as a potential new

candidate in Arrowhead’s growing pipeline of RNAi-based therapeutics

enabled by the company’s Dynamic Polyconjugate (DPC) delivery platform.

A copy of the presentation may be viewed on the Events and Presentations

section of the company’s website at http://ir.arrowheadresearch.com/events.cfm.

“We see factor 12 as an extremely attractive target to add to our

pipeline. There is clear unmet need in thrombosis and angioedema and the

biology of factor 12 as part of the coagulation cascade and the

kinin-kallikrein system suggest that its reduction through RNAi may

present opportunities in both disease areas,” said Christopher Anzalone,

Ph.D., president and chief executive officer. “We will be conducting

additional studies in relevant disease models shortly to provide us with

further data to decide on the advancement of ARC-F12 as a clinical

candidate and initiation of IND enabling studies.”

David Lewis, Ph.D., chief scientific officer, presented initial data

from wild type mice, showing that various RNAi triggers selected from in

vitro screening sets and co-administered with DPCs achieved significant

and sustained knockdown of F12 levels of greater than 99% at nadir for

most triggers. Strategic incorporation of various modifications to the

most potent RNAi trigger increased the depth and duration of F12

knockdown activity as shown in dose response studies. In a study in

mice, these modified triggers exhibited a dose-dependent increase in F12

knockdown. A single intravenous dose of 0.5 mg/kg reduced F12 by greater

than 80%. When the dose was increased to 2 mg/kg, the reduction

increased to greater than 95% at nadir, with greater than 70% knockdown

observed at the one month time point. The lead RNAi trigger was also

highly active in multiple dose nonhuman primate studies. With four

intravenous doses of 2 mg/kg given once every four weeks, approximately

90% F12 knockdown was achieved after the first dose with even greater

knockdown following subsequent doses. Knockdown was also highly durable

with greater than 80% reduction maintained between monthly doses. The

combination of RNAi trigger and DPC appeared to be generally

well-tolerated and no drug-related changes in toxicity markers were

observed as measured by clinical chemistry and hematologic parameters.

Dr. Lewis also presented data from a relevant disease model on the lead

RNAi trigger and DPC combination. In this mouse model, thromboembolism

is induced by exposure of carotid artery to ferric chloride. The time to

blood flow occlusion is then measured as a clinically relevant indicator

of physiological response to F12 knockdown. Animals were treated with

saline or the lead RNAi trigger and DPC combination 15 days prior to

ferric chloride challenge. Treated animals showed approximately 99%

knockdown in serum F12 levels at Day 15 relative to baseline, while

animals receiving saline showed no reduction. A dramatic increase in

occlusion times as a measure of the inhibition of thrombus formation was

observed in treated mice.

Arrowhead believes that ARC-F12 may present opportunities to target

multiple diseases, including in thrombosis. The company is currently

planning to investigate ARC-F12 in hereditary angioedema (HAE) as the

first target indication. HAE is a rare genetic disorder with a

prevalence of approximately 1/5,000-1/10,000 that is most commonly

caused by mutations in the complement factor 1 esterase inhibitor gene

(C1INH). Patients with HAE can experience recurrent and dangerous acute

inflammatory attacks in multiple tissues, with attacks of laryngeal

edema being particularly serious and potentially fatal. Current

treatments seek to reduce the severity, duration, and frequency of acute

HAE attacks, but frequent intravenous dosing of 1-3 times weekly is

required and many patients do not respond adequately. Arrowhead believes

the novel mechanism of ARC-F12 may fill an unmet need for patients and

physicians who desire long term prophylaxis and may view intravenous

dosing every 4-6 weeks as a significant advance.

The company is currently planning additional evaluation of ARC-F12 in

relevant HAE disease models including C1INH knockout animals and

captopril-induced vascular leak, among potential other studies to

support advancement of ARC-F12 into IND enabling studies.

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 and ARC-AAT for liver disease associated with Alpha-1

antitrypsin deficiency.

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

or follow us on Twitter @ArrowRes.

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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

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, challenges to the validity of our intellectual property rights,

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:
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Todd James
646-378-2926
ir@arrowres.com
or
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Source: Arrowhead Research Corporation

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