Quark Pharmaceuticals Presents Data on Synthetic siRNAs for Prevention of Ocular and Inner Ear Sensory Cell Damage

FREMONT, Calif., - 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, "siRNA Therapeutics for Prevention of Ocular and Inner Ear Sensory Cells Death," at the DxRx Summit: Nucleic Acid Diagnostics & Therapeutics. The event was held May 12-13, 2009 in Boston, MA.

Dr. Feinstein presented data demonstrating that synthetic, chemically-modified 19-bp siRNAs, including PF 04523655 currently being studied by partners Pfizer and Quark in patients with diabetic macular edema (DME) and age-related macular degeneration (AMD), enter cells in the retina of the eye and exert their therapeutic effects while avoiding non-specific activation of the toll-like receptor 3 (TLR3) - the effect reported for other synthetic siRNAs. Similar data for QPI-1007, Quark's proprietary siRNA composition, were also reported. QPI-1007 was demonstrated to confer effective ocular neuroprotection and is currently in late-stage IND-enabling studies.

In addition to studies in the eye, Dr. Feinstein also reported results demonstrating effective delivery of synthetic siRNAs to the inner ear, which resulted in protection of hearing epithelium from ototoxic and noise-induced damage. These studies were performed in collaboration with Prof. Jayakrishna Ambati, University of Kentucky College of Medicine, Lexington, KY; Prof. Ann Logan, University of Birmingham, UK; Prof. Adriana Di Polo, University of Montreal; and Prof. Richard Salvi, SUNY University at Buffalo.

Daniel Zurr, Ph.D., President and Chief Executive Officer, said, "Results from the studies presented at DxRx demonstrate our successful track record in discovering and advancing industry-leading siRNA product candidates. Our strong position in the RNAi landscape has been validated by our ability to secure co-development agreements with major pharmaceutical partners, including Pfizer, to advance our siRNA product candidates further towards commercialization."

Dr. Feinstein added, "Our synthetic, chemically modified siRNA product candidates have been designed to elicit pharmacologic effects through target gene-knock down while avoiding potentially harmful off-target effects reported for other synthetic siRNAs. These results support our capabilities to discover and develop siRNA product candidates with greater specificity and reduced side effects."

Quark Pharmaceuticals Presented At ARVO Data Showing That PF-04523655 Enters Retinal Cells And Elicits Its Pharmacologic Effect Via Target Gene Knock-

FREMONT, Calif., - 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."