Quark Pharmaceuticals Development Partner Pfizer Presents In Vivo Activity of PF-04523655 at ARVO

FREMONT, Calif., May 6 /PRNewswire/ --Quark Pharmaceuticals, Inc., the world leader in clinical development of RNAi-based therapeutics, announced today that researchers from Pfizer, Inc. presented data on in vivo activity of PF-04523655 at the Association for Research in Vision and Ophthalmology (ARVO) annual meeting, being held May 2-6, 2010 in Fort Lauderdale. PF-04523655 is a chemically-modified siRNA drug candidate being co-developed by Quark and Pfizer for the treatment of wet age-related macular degeneration (wet-AMD) and diabetic macular edema (DME). PF-04523655 was designed to be resistant to nuclease degradation that can occur during normal cellular uptake processes in the eye without using a specific delivery vehicle.

Results were presented in an abstract titled "Dose-Related Gene Silencing of RTP801 with the siRNA PF-04523655 in Long Evans Rat Models of STZ Induced Diabetes and Laser Induced CNV." The study, led by Kay D. Rittenhouse, Ph.D., Head of the Translational Medicine Ophthalmology, Specialty Care Business Unit at Pfizer, demonstrated reduction of RTP801 mRNA levels in rat retina following intravitreal administration.

Daniel Zurr, Ph.D., President and Chief Executive Officer of Quark Pharmaceuticals, said, "These results on in vivo activity of PF-04523655 represent an important step forward for the field of synthetic siRNA therapeutics. Importantly, the data presented by Pfizer demonstrate that siRNAs chemically modified to improve stability are taken up by cells and elicit RNAi activity in vivo without requiring complex delivery formulations."

Dr. James Thompson, Vice President Pharmaceutical Development of Quark Pharmaceuticals said, "High concentrations of synthetic siRNA can be attained in the eye following intravitreal administration, making ocular diseases a particularly relevant therapeutic area for siRNA therapeutic development. A rise in the aging population and incidence of diabetes are contributing to the increase in wet-AMD and DME, yet many of these patients suffer from inadequate treatment from currently available therapies. Use of synthetic siRNAs represents a novel therapeutic approach to potentially address these diseases."

About the PF-04523655 (RTP801i-14) Clinical Program

PF-04523655 (RTP801i-14) is a synthetic, siRNA designed to inhibit the expression of Quark's proprietary target, RTP801. The product candidate is licensed to Pfizer on an exclusive worldwide basis.  Quark discovered the RTP801 gene using its BiFAR™ target discovery platform, which identifies clinically relevant critical genes and proteins that reverse the disease phenotype when inhibited. The Company owns a family of patents covering the RTP801 gene, its RNA and protein product sequences, specific antibodies, and gene inhibition across different pathologies.

The ongoing Phase II prospective, randomized, multi-center, dose ranging study is designed to evaluate the efficacy and safety of PF-04523655 versus laser therapy in patients with DME. Eligible patients were randomized to receive intravitreal injections of one of three dose levels of PF-04523655 or laser. Therapeutic effect is evaluated through visual acuity and retina morphological examinations conducted over a 36-month follow up period.

About Quark Pharmaceuticals, Inc.

Quark Pharmaceuticals, Inc is a leader in the discovery and development of novel RNAi therapeutics.  Quark has a fully integrated drug development platform that spans therapeutic target identification to drug development.  The Company's technology platform includes novel disease targets and siRNA structures and chemistry, providing Quark with freedom to operate in the siRNA intellectual property arena.  Quark's approach to delivery allows targeting of tissues and organs including the eye, kidney, ear, lung, spinal cord and brain.

In addition to PF-04523655, Quark's development pipeline features QPI-1002, the first systemically administered siRNA drug in human clinical trials.  QPI-1002 is being evaluated for the prevention of acute kidney injury (AKI) following major cardiovascular surgery and the prophylaxis of delayed graft function after kidney transplantation. Enrollment was successfully completed recently in Phase I studies in these indications.  For the structure of these products, Quark has obtained licenses from Silence Therapeutics and from Alnylam Pharmaceuticals.

In the first quarter of 2010, Quark initiated a Phase 1/2 study of a new synthetic siRNA, QPI-1007, as a neuroprotective agent for eye diseases.  QPI-1007 utilizes a proprietary structure developed in collaboration with BioSpring GmbH, that Quark believes provides freedom to operate in the siRNA intellectual property arena. The structure and modifications utilized in QPI-1007 preserve RNAi activity while ameliorating potential off-target and immunostimulatory effects of siRNAs.  In addition, Quark has a broad pipeline of siRNA drug candidates that have arisen from Quark's research activities.  The Company is committed to developing novel siRNA structures and expects to utilize these improvements to develop additional RNAi drug candidates based on the Company's productive R&D engine.

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

SOURCE Quark Pharmaceuticals, Inc.