Fremont, CA – May 11, 2009 – Quark Pharmaceuticals, Inc., a development-stage pharmaceutical company discovering and developing novel RNA interference (RNAi)-based therapeutics, today announced that Elena Feinstein, M.D., Ph.D., Chief Scientific Officer, presented a study titled, “PF-04523655 (REDD14NP), an siRNA Compound Targeting RTP801, Penetrates Retinal Cells Producing Target Gene Knockdown and Avoiding TLR3 Activation,” at the Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting, taking place from May 3-7, 2009, in Fort Lauderdale, Florida. PF-04523655 is currently being studied by partners Pfizer and Quark in patients with diabetic macular edema (DME) and age-related macular degeneration (AMD).

The study presented at ARVO was performed in collaboration with Dr. Jayakrishna Ambati at the Department of Ophthalmology and Visual Sciences, University of Kentucky College of Medicine, Lexington, KY. The objective of the study was to determine whether PF-04523655, a synthetic chemically modified 19-bp siRNA, enters cells in the retina leading to downregulation of its target gene while avoiding activation of Toll Like Receptor 3 (TLR3). Previous studies from Dr. Ambati’s laboratory have shown that unmodified 21-mer siRNA molecules exhibit antiangiogenic effects by inadvertently activating TLR3 rather than down-regulating expression of their target genes. Results obtained in vivo and in vitro indicated that PF-04523655 does enter cells in the retina and elicits its pharmacologic effect via target gene knock-down without activating TLR3.

Daniel Zurr, Ph.D., President and Chief Executive Officer, said, “We believe that the results presented at ARVO continue to substantiate our leadership in siRNA therapeutics, in particular Quark’s ability to develop highly specific siRNA products and advance them through the clinic toward commercialization. Quark’s ability to establish collaborations with major pharmaceutical companies like Pfizer to co-develop PF-04523655 in DME, wet-AMD, and other potential ocular indications provides further credibility to our siRNA technology capabilities.”

Jayakrishna Ambati M.D., Professor and Vice Chair, Department of Ophthalmology & Visual Sciences, University of Kentucky, member of Quark’s Medical Advisory Board, and one of the authors on the study, stated, “My laboratory’s research has shown that many siRNAs suppress neovascularization regardless of their sequences or targets and can have dangerous off target effects. For that reason, I’m gratified to see this research, suggesting that Quark is seeing success in developing siRNA compounds that are effective.”

About Quark Pharmaceuticals, Inc.
Quark Pharmaceuticals, Inc. is a development-stage pharmaceutical company engaged in discovering and developing novel RNAi-based therapeutics. Quark has a fully integrated drug development platform that spans therapeutic target identification to drug development. Quark’s RNAi technology includes novel siRNA structures and chemistry providing Quark with freedom to operate in the siRNA intellectual property arena, as well as the ability for non-invasive delivery of siRNA to other target tissues including the eye, ear, lung, spinal cord and brain.

PF-04523655 (RTP801i-14), currently in Phase II clinical trials, is a synthetic, chemically modified siRNA designed to inhibit the expression of the gene RTP801 discovered by Quark through the gene discovery platform BiFAR. PF-04523655 is licensed to Pfizer. In addition, Quark’s current clinical pipeline includes QPI-1002, the first systemically administered siRNA drug in human clinical trials, developed by Quark for the prevention of acute kidney injury (AKI) following major cardiac surgery and of delayed graft function in kidney transplantation. For the structure of these products Quark has licenses from Silence Therapeutics and from Alnylam Pharmaceuticals.

QPI-1007, a siRNA that utilizes a proprietary structure developed by Quark, is being evaluated in advanced IND-enabling preclinical studies as a neuroprotective agent for eye diseases. In addition, Quark has a broad pipeline of siRNA drug candidates based on novel structures developed internally. The Company expects to utilize the structures to develop additional RNAi drug candidates.

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