Onconova announces three presentations on Estybon- (ON 01910.Na) at ASH 2010

Results with Estybon (ON 01910.Na) in Patients with myelodysplastic syndromes; ON 013105 cyclin D1 inhibitor active in models of mantle cell lymphoma

Onconova Therapeutics announces its late-stage anticancer agent, Estybon- (ON 01910.Na), will be featured in three presentations at the 52nd American Society of Hematology (ASH) Annual Meeting in Orlando, FL, December 4-7, 2010.

Principal investigators at four centers, Dr. Lewis Silverman (Mount Sinai Medical Center), Dr. Azra Raza (Columbia University Medical Center), Dr. Elaine Sloand (NHLBI), and Dr. Peter Greenberg (Stanford University Medical Center) report that in 48 higher risk patients with MDS or AML (who failed or became resistant to previous drug treatments), when treated with ON 01910.Na showed increases in overall survival, which correlated with bone marrow blast responses. The most dramatic improvement in overall survival was seen in 19 patients who also showed either bone marrow complete response (CR) or initial >50% decrease in blast cells (Abstract #3998). Dr. Greenberg's team reports encouraging efficacy and drug tolerance results in a Phase II trial with patients who had all failed the standard hypomethylating agent treatments (Abstract #4010). Dr. Silverman and colleagues have observed 50% responders in a Phase I study (Abstract #2944).

Estybon- (ON 01910.Na) is a small molecule, targeted therapeutic with a broad spectrum of activity. It has been tested in patients with solid tumors, myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) at major centers in the U.S. and abroad. MDS and AML are blood disorders widely recognized as difficult to manage, with limited therapeutic options for patients, especially those with drug-resistant disease. The presentations will describe the latest results on activity and safety of Estybon- (ON 01910.Na) in MDS and AML patients treated in on-going Phase I and Phase II clinical trials.

These studies are a part of comprehensive evaluation of the safety and activity of Estybon- (ON 01910.Na). To date, nearly 300 cancer patients have been treated in Phase I and Phase II trials, including more than 70 patients with MDS or AML. These studies have lead to a multi-site Phase III pivotal trial under a Special Protocol Assessment (SPA) from the U.S. FDA. This trial is being supported by an award from the Therapeutics Acceleration Program (TAP) of the Leukemia and Lymphoma Society (LLS).

"We continue to make meaningful progress in our MDS program, and information to be presented at the ASH meeting reflects the breadth of data becoming available for ON 01910.Na in MDS patients," said Francois Wilhelm, MD, PhD, Senior Vice President and Chief Medical Officer of Onconova. "We are committed to the rapid development of this promising agent for MDS patients by conducting a multi-site trial in the United States and France," Dr. Wilhelm added.

Another presentation will highlight the mechanism of action and activity in nonclinical models of mantle cell lymphoma (MCL) of ON 013105, a novel Onconova agent directed to controlling Cyclin D1 in cancer cells (Abstract #771). ON 013105 alone or in combination with rituximab induced dramatic reduction of MCL tumor volumes in mouse xenograft models, suggesting that ON 013105 alone or in combination may be a potent therapeutic agent against MCL. ON 013105 is currently in Phase I clinical safety studies in lymphoma patients.