Cylene Pharmaceuticals Initiates Phase I Clinical Trial for CX-3543, a First-in-Class Agent for Multiple Cancers

San Diego, CA - July 19, 2005

Cylene Pharmaceuticals, an oncology drug discovery and development company, today announced that it has initiated a Phase I clinical trial for CX-3543, its lead candidate for the treatment of multiple cancers. CX-3543 is a first-in-class small molecule with a novel mechanism of action that selectively induces cancer cell death. The clinical trial is being conducted at the Cancer Therapy and Research Center in San Antonio, Texas and at the Mayo Clinic in Scottsdale, Arizona.

The clinical trial is currently open for enrollment and is designed to enroll approximately 36 patients with solid tumors or lymphomas. The objectives of the trial are to determine the safety and tolerability of CX-3543, to characterize its pharmacokinetic profile, to define dose-limiting toxicities and the maximum-tolerated dose, and to select the appropriate dose for Phase II trials.

"We're very gratified to advance CX-3543 into clinical trials," said William G. Rice, Ph.D., President and CEO of Cylene. "The novel mechanism of this compound engenders the potential for treating many types of cancers, and CX-3543 has shown very favorable safety and efficacy profiles during preclinical testing. Our world-class development team, led by Daniel Von Hoff, M.D. and John K.C. Lim, Pharm.D., along with our supportive investors, position us to rapidly advance CX-3543 while elevating other small molecule agents in our pipeline toward the clinic."

"Preclinical findings with CX-3543 revealed target selectivity at the molecular level and excellent drug-like properties," said Cylene co-founder Daniel D. Von Hoff, M.D. "It has demonstrated a favorable in vivo safety profile, as well as compelling anti-tumor activity in xenograft models of colorectal, pancreatic, and prostate cancers. I look forward to the molecule advancing through the clinic."

About CX-3543
CX-3543 is a proprietary small molecule designed to selectively interact with quadruplex nucleic acid structures and induce apoptotic cell death in cancer cells. Preclinical studies with CX-3543 have demonstrated favorable pharmacokinetic properties, potent in vivo efficacy in murine xenograft models with a broad safety window, as well as practical formulation, stability and drug manufacturing properties. CX-3543 represents a first-in-class quadruplex-interactive small molecule to enter the clinic with the potential to affect a broad range of cancers.

About Cylene Pharmaceuticals, Inc.
Cylene Pharmaceuticals, Inc. is a privately held pharmaceutical company dedicated to the discovery, development and commercialization of first-in-class small molecule drugs to treat life-threatening cancers. Cylene's product pipeline is led by CX-3543, a quadruplex-interactive agent in Phase 1 clinical trials. CX-3543 and other molecules in the pipeline originate from the company's proprietary drug discovery platform. More information can be found at www.cylenepharma.com.