Clinical Program Leverages Quark’s RNAi Technology


Fremont, California, July 30, 2008 – Quark Pharmaceuticals, Inc., a development-stage pharmaceutical company discovering and developing novel RNA interference (RNAi)-based therapeutics, today announced that its partner, Pfizer Inc, initiated patient dosing in a Phase II trial evaluating PF-4523655 (RTP801i-14) in patients with diabetic macular edema (DME). PF-4523655 is a novel siRNA drug candidate being co-developed by Quark and Pfizer. As part of the companies’ Global Licensing Agreement, the successful commencement of the trial triggers a milestone payment to Quark from Pfizer, a small percentage of which is payable by Quark to Silence Therapeutics and Alnylam as technology license milestone payments.

The Phase II prospective, randomized, dose-ranging study is evaluating the safety and efficacy of PF-4523655 versus laser therapy in 160 DME patients at multiple centers worldwide. PF-4523655 was designed to inhibit Quark’s proprietary target RTP801, a gene involved in abnormal blood vessel development and leakage in the eye. Under the companies’ Global Licensing Agreement, Pfizer has exclusive development rights to siRNA-mediated therapies that inhibit RTP801 for ophthalmic and non-ophthalmic indications, while Quark is eligible for development and sales based milestone payments.

Elena Feinstein, Chief Scientific Officer of Quark, commented, “By targeting the RTP801 gene, PF-4523655 is differentiated from other therapeutics for the same ophthalmic indications. While many competitors target VEGF and its receptors, PF-4523655 inhibits abnormal blood vessel growth and leakage independently of the VEGF pathway, reduces inflammation and suppresses apoptosis. Therefore, PF-4523655 is a siRNA therapeutic candidate with the potential to be efficacious when used as a monotherapy and in combination with existing VEGF-based therapies.”

Shai Erlich, Chief Development Officer of Quark, commented, “The progression of PF-4523655 into Phase II further supports our integrated RNAi approach that leverages our internal BiFAR target discovery platform. In addition, Pfizer’s interest demonstrates the viability of RTP801 as a potential target for ophthalmic indications. We look forward to continuing our relationship with Pfizer throughout later stages of clinical development and intend to fully collaborate towards the potential commercialization of PF-4523655 in diabetic macular edema, age-related macular degeneration, and other ophthalmic indications covered in our agreement.”

Dario Paggiarino, Executive Director Clinical Development of Pfizer Inc, stated, “Our collaboration with Quark is a prime example of Pfizer’s commitment to the research and development of innovative therapies with the potential to preserve sight and improve patient outcomes in ophthalmology. This research is important because not all patients with retinal disease benefit from currently available treatments.”

Results from a Phase I/II trial completed by Quark on Pfizer’s behalf showed that PF-4523655 was safe and well tolerated in patients with wet age-related macular degeneration (wet-AMD) who failed to respond to currently approved therapies. Based on data from this trial, Pfizer decided to pursue a Phase II trial in DME. In addition, Quark and Pfizer are considering an additional Phase II study of PF-4523655 in patients with wet-AMD.

About the PF-4523655 (RTP801i-14) Clinical Program

PF-4523655 (RTP801i-14) is a synthetic, siRNA molecule 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 RTP801 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 Phase II prospective, randomized, multi-center, dose ranging study is designed to evaluate the efficacy and safety of PF-04523655 versus laser therapy in 160 patients with DME. Eligible patients will be randomized to receive intravitreal injections of one of three dose levels of PF-04523655 or laser. Therapeutic effect will be 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 development-stage pharmaceutical company engaged in discovering and developing novel therapeutic RNAi drug candidates. 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 that the Company believes provide Quark with freedom to operate in the siRNA intellectual property arena, as well as the ability to deliver siRNA locally and systemically to organs including the eye, ear, kidney, lung, spinal cord and bone marrow.

PF-4523655 (RTP801i-14), currently in Phase II clinical trials, is a synthetic, chemically modified, siRNA molecule to inhibit the expression of the gene RTP801. In addition, Quark’s current clinical pipeline includes AKIi-5, developed by Quark for the prevention of acute kidney injury (AKI) following major cardiac surgery, currently in Phase I/IIa clinical trials via systemic delivery. Based on publicly available information, Quark believes this was the first siRNA delivered systemically in a human clinical trial. The Company has structure related technology licenses from Silence Therapeutics and from Alnylam.

In addition, Quark has a broad pipeline of siRNA drug candidates based a novel structure developed internally. The Company expects to utilize the structure to develop additional RNAi drug candidates without in-licensing any structure-related technology patents. 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