Quark Pharmaceuticals Inc. Presented Positive Preclinical Results of Systemic RNAi Compound for Acute Renal Failure (ARF)

FREMONT, Calif., Aug. 2 /PRNewswire/ -- Quark Pharmaceuticals, Inc., a clinical-stage biopharmaceutical company focused on discovering and developing novel RNA interference-based therapeutics, announced today the presentation of positive results from preclinical efficacy studies for its proprietary systemically-administered, siRNA compound, AKIi-5, in acute renal failure (ARF).

In the study, rats treated with a single bolus injection of rat AKIi-5, Quark’s proprietary siRNA compound targeting the p53 gene, were significantly protected from ischemia/reperfusion-induced acute kidney injury. The compound was most efficacious when administered within a well-determined time window of 2-4 hours post injury. The study also proved that AKIi-5 has a favorable drug disposition (PK) profile, with short local exposure predominantly to the kidney-exhibiting rapid clearance of the drug post-administration. Quark’s preclinical studies to date also indicate that AKIi-5 has a favorable safety profile, with a therapeutic index (toxic dose/effective dose) in rats greater than 250.

Elena Feinstein, M.D., Ph.D., the Company’s Chief Scientific Officer, presented the results of the preclinical efficacy studies in a poster session at the Beyond Genome 2007 conference in San Francisco, CA. Quark’s poster presentation was based on unpublished data. The studies were performed in collaboration with Bruce A. Molitoris, M.D., Director of the Division of Nephrology and Professor of Medicine at Indiana University School of Medicine, and lead academic investigator in the Quark program.

Daniel Zurr, CEO of Quark, commented, “Our pharmacokinetic, distribution, and toxicity studies indicate that siRNA-mediated, temporary inhibition of p53 by our systemically administered drug, AKIi-5, is a safe and efficient way to treat and prevent acute kidney injury caused by ischemia-reperfusion. Our drug could potentially offer a lifesaving treatment for this severe disease, which exhibits high rates of morbidity and mortality and represents a very serious unmet medical need. We have an open IND for AKIi-5 and expect to initiate a Phase I trial for the prevention of ARF through the systemic delivery of AKIi- 5 in patients undergoing major cardiac surgery. Based on publicly available information, we believe that this will be the first human clinical trial involving the systemic delivery of siRNA.”

About AKIi-5

AKIi-5 is a synthetic, chemically modified siRNA molecule designed to temporarily inhibit the expression of p53, a gene which plays a significant role in ARF by inducing tubular cell death (apoptosis) in response to injury. AKIi-5 is based on Quark’s proprietary, patented concept of temporary and reversible inhibition, for therapeutic purposes, of the expression of the transcription factor human p53, which is associated with DNA repair and apoptosis. Using RNA interference technology to temporarily inhibit p53 in acute settings such as acute kidney injury, apoptosis is delayed thereby allowing natural repair mechanisms to restore normal DNA and cellular integrity. The AKIi-5 molecule was designed and patented by Quark. The Company has licenses for AtuRNAi(TM) technology from Silence Therapeutics and additional RNAi intellectual property from Alnylam.

About Acute Renal Failure (ARF)

ARF is a syndrome characterized by a rapid decline of kidney function leading to death in a high percentage of cases. Major cardiac surgery is one of the many causes of ARF. During cardiac bypass surgery, lack of oxygen caused by reduced local blood flow to the kidneys, followed by rapid reintroduction of oxygen, or reperfusion, to the kidneys upon removal of the patient from cardiopulmonary bypass, initiates a chain of events that can lead to ARF. Currently, there are no approved drug therapies that effectively prevent or treat ARF.

About Quark Pharmaceuticals, Inc.

Quark Pharmaceuticals is a clinical-stage biopharmaceutical company focused on discovering and developing novel therapeutics based on its proprietary gene discovery science and technology, with an initial focus on drug candidates that work through the recently discovered natural mechanism in the cell known as RNA interference, or RNAi, for the treatment of diseases associated with oxidative stress. Quark believes that its proprietary target gene discovery platform, BiFAR(TM), combined with its ability to design and successfully deliver synthetic molecules of the new class of RNAi therapeutics known as small-interfering RNA, or siRNA, to specific organs in the body, enables the Company to rapidly develop drug candidates. Quark has two internally discovered and developed lead candidates: RTP801i-14 in Phase 1 clinical trial for the treatment of wet age-related macular degeneration, and AKIi-5 for the prevention of acute renal failure. The Company has licensed siRNA drug candidates designed to inhibit Quark’s proprietary target gene RTP801, including RTP801i-14, to Pfizer on an exclusive worldwide basis. Quark has, in addition, a product candidate portfolio of RNAi therapeutics based on novel targets and therapeutic concepts discovered using BiFAR(TM) and designed for the treatment of oxidative stress associated diseases of the inner ear, lungs and additional organs of the body.

Quark is headquartered in Fremont, California and operates research and development facilities in Boulder, Colorado and Ness-Ziona, Israel. Additional information is available on the Company website at www.quarkpharma.com.

Forward-looking statement

Various statements in this release concerning the Company’s future expectations, plans and prospects, including its intention to publicly offer shares of its common stock, constitute forward-looking statements for the purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, including risks related to fluctuations in our stock price, as well as those risks more fully discussed in the “Certain Factors That May Affect Future Results” section of the Company’s most recent Quarterly Report on Form 10-Q on file with the Securities and Exchange Commission. In addition, any forward- looking statements represent the Company’s views only as of today and should not be relied upon as representing its views as of any subsequent date. The Company does not assume any obligation to update any forward-looking statements.

Quark Pharmaceuticals, Inc The Ruth Group Gavin Samuels Stephanie Carrington / Elizabeth SVP, Business Development Scott (investors) (646) 502-7488 (646) 536-7017 / 7014 scarrington@theruthgroup.comescott@theruthgroup.com Janine McCargo (media) (646) 536-7033 jmccargo@theruthgroup.com

Quark Pharmaceuticals, Inc.

CONTACT: Gavin Samuels, SVP, Business Development, Quark Pharmaceuticals,Inc., +1-646-502-7488; Stephanie Carrington +1-646-536-7017,scarrington@theruthgroup.com, or Investors, Elizabeth Scott,+1-646-536-7014, escott@theruthgroup.com, or Media, Janine McCargo,+1-646-536-7033, jmccargo@theruthgroup.com, all of The Ruth Group, forQuark Pharmaceuticals

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