Quark Pharmaceuticals Presented At ARVO Data Showing That PF-04523655 Enters Retinal...

Quark Pharmaceuticals Presented At ARVO Data Showing That PF-04523655 Enters
Retinal Cells And Elicits Its Pharmacologic Effect Via Target Gene Knock-Down
Without Activating TLR3

FREMONT, Calif., May 11 /PRNewswire/ -- 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.
Quark Pharmaceuticals, Inc. The Ruth Group (investors / media)
Juliana Friedmann Sara Ephraim / Janine McCargo
+972 89 30 5111 (646) 536-7004 / 7033
jfriedman@quarkpharma.com sephraim@theruthgroup.com
jmccargo@theruthgroup.com

SOURCE Quark Pharmaceuticals, Inc.

Juliana Friedmann of Quark Pharmaceuticals, Inc., +972-89-30-5111,
jfriedman@quarkpharma.com; or Investors, Sara Ephraim, +1-646-536-7004,
sephraim@theruthgroup.com, or Media, Janine McCargo, +1-646-536-7033,
jmccargo@theruthgroup.com, both of The Ruth Group