Cylene Pharmaceuticals Initiates Phase II Clinical Trial of Quarfloxin (CX-3543) in Patients with Carcinoid/Neuroendocrine Tumors

- December 15, 2008

Cylene Pharmaceuticals today announced the initiation of a Phase II clinical trial of quarfloxin (CX-3543) in patients with carcinoid/neuroendocrine tumors (C/NET), which are malignant cancers arising from neural crest cells.

"Quarfloxin (CX-3543) is a small molecule that disrupts a protein:rDNA complex that forms in the abnormal nucleoli of cancer cells, thereby selectively inducing apoptotic cell death in cancers," said Dr. William Rice, President and Chief Executive Officer of Cylene Pharmaceuticals. "Many commercialized cancer therapeutics act on or through the nucleolus, but quarfloxin is the first agent designed to directly target a key function within the nucleolus. Quarfloxin has been well tolerated in humans and has demonstrated signs of biological benefit for patients with C/NET in Phase I clinical trials. Moreover, biodistribution studies revealed that quarfloxin accumulates in the tissues in which C/NET arise. "

In this open-label Phase II trial, quarfloxin will be administered to patients with low or intermediate grade C/NET, including those receiving concomitant treatment with a stable dose of octreotide. This multicentered study will include an assessment of improvements in patients' symptoms and biochemical markers, in addition to RECIST tumor response measurements. The first patient was enrolled and treated at Front Range Cancer Specialists in Fort Collins, CO under the care of Robert Marschke Jr. M.D. This study is expected to enroll up to 25 patients at several leading cancer centers.

"The initiation of this Phase II trial with quarfloxin is a major milestone for Cylene, but more importantly, we hope that quarfloxin will be an effective treatment for cancer patients with limited therapeutic alternatives," added Dr. Daniel Von Hoff, Cylene's Co-Founder and Vice President, Medical Affairs. "Quarfloxin has demonstrated potent in vivo efficacy against a broad range of tumors and a considerable therapeutic window in preclinical antitumor models, and has a unique profile of concentrating in neural crest tissues. For these reasons, we are enthusiastic about offering a Phase II clinical trial for patients with carcinoid/neuroendocrine tumors."

About Quarfloxin (CX-3543), a Nucleolus Targeting Agent (NTA)
Quarfloxin is a ground-breaking small-molecule targeted cancer therapeutic derived from the validated fluoroquinolone class of drugs. Rationally designed to selectively inhibit ribosomal RNA (rRNA) biogenesis in cancer cells, quarfloxin disrupts the interaction between the Nucleolin protein and a G-quadruplex DNA structure in the ribosomal DNA (rDNA) template, a critical interaction for rRNA biogenesis and one that is amplified in cancer cells. As a result, quarfloxin selectively induces apoptotic cell death in cancers. Many commercialized cancer therapeutics act indirectly on rRNA Biogenesis through upstream modulators, but quarfloxin is the first agent to directly target this cancer-specific aberrant cell function.

About Cylene Pharmaceuticals, Inc.
Cylene Pharmaceuticals is a biotech pharmaceutical company dedicated to the discovery, development and commercialization of targeted small-molecule drugs to treat life-threatening cancers. Cylene has created a diverse portfolio of product candidates, including novel inhibitors of cancer-linked serine/threonine kinases, as well as innovative Nucleolus Targeting Agents (NTAs) that target the abnormal nucleolus functions of cancer cells and selectively kill cancer cells. More information can be found at www.cylenepharma.com.

Cylene cautions you that statements included in this press release that are not a description of historical facts, including implied statements relating to future outcomes of clinical trials, may be forward-looking statements that are subject to risks and uncertainties. Actual results may differ materially from those set forth in this release due to the risks and uncertainties inherent in Cylene's business including, without limitation, risks related to difficulties or delays in, testing, obtaining regulatory approval for, producing and marketing its products; unexpected adverse side effects or inadequate therapeutic efficacy of its products that could delay or prevent product development or commercialization, the scope and validity of patent protection for its products; competition from other pharmaceutical or biotechnology companies; and its ability to obtain additional financing to support its operations. All forward-looking statements are qualified in their entirety by this cautionary statement and Cylene undertakes no obligation to revise or update this news release to reflect events or circumstances after the date hereof.