Sunesis Pharmaceuticals, Inc. announced that the United States Patent and Trademark Office (USPTO) has granted US Patent No. 7,829,577, claiming the company's pharmaceutical compositions of lead drug candidate vosaroxin. This patent is scheduled to expire on March 14, 2025, and could be eligible for patent term extension beyond this date. Corresponding patent applications are pending in major markets throughout the world including Europe, Japan, Australia and Canada.

"This patent is an important new addition to our intellectual property estate, as it covers the formulation currently used in our clinical trials," stated Daniel Swisher, chief executive officer of Sunesis. "Vosaroxin's extended patent life to 2025 increases not only the value of our AML franchise but also provides sufficient time for lifecycle evaluation of vosaroxin in other indications. We are pursuing a sophisticated and deliberate strategy to extend exclusive coverage in the vosaroxin patent estate beyond 2025. In addition to our granted patents, we have filed patent applications covering additional formulations, combination uses, dosing, manufacturing processes and composition of matter claims. We look forward to the successful prosecution of these patent applications in multiple territories around the world."

Vosaroxin is a first-in-class anticancer quinolone derivative, or AQD, a class of compounds that has not been used previously for the treatment of cancer. Vosaroxin both intercalates DNA and inhibits topoisomerase II, resulting in replication-dependent, site-selective DNA damage, G2 arrest and apoptosis. Vosaroxin is currently being evaluated in a fully enrolled single agent Phase 2 clinical trial (known as the REVEAL-1 trial) in previously untreated elderly AML patients and in a fully enrolled phase 2 clinical trial combining vosaroxin with cytarabine for the treatment of patients with relapsed/refractory AML. A phase 2 single agent clinical trial in platinum-resistant ovarian cancer has also been completed. Sunesis plans to initiate the VALOR trial, a multinational, randomized, double-blind, placebo-controlled, pivotal phase 3 clinical trial of vosaroxin in combination with cytarabine in a relapsed/refractory AML patient population, in the fourth quarter of this year.

Sunesis is a biopharmaceutical company focused on the development and commercialization of new oncology therapeutics for the treatment of solid and haematologic cancers.