Ariad Initiates Phase II Clinical Trial of AP23573

Ariad Pharmaceuticals has initiated enrollment of patients with prostate cancer who have become refractory to standard hormone therapy in a multicenter Phase II clinical trial of its novel mTOR inhibitor, AP23573, as a single agent.

Prostate cancer is the most common cancer diagnosis in men other than skin cancer. Progression to hormone-refractory disease is associated with a very poor prognosis, and current therapeutic options are severely limited.

This non-randomized study will evaluate the clinical benefit of AP23573 in well-characterized prostate cancer patients. Up to 35 patients will be enrolled in the trial at several centers in the U.S. AP23573 will be administered intravenously using a weekly dosing regimen. Patients will be followed for at least nine months after enrollment but may continue on AP23573 until disease progression occurs. Data on multiple mTOR-pathway biomarkers will be obtained to help identify patients who are most likely to benefit from treatment with AP23573.

The small-molecule drug starves cancer cells and shrinks tumors by inhibiting the critical cell-signaling protein, mTOR, which regulates the response of tumor cells to nutrients and growth factors, and controls tumor blood supply and angiogenesis through effects on vascular endothelial growth factor in tumor and endothelial cells. AP23573 also blocks the proliferation and migration of vascular smooth muscle cells, the primary cause of narrowing and reblockage of injured arteries, and is an analog of sirolimus, another mTOR inhibitor that has been approved for use in drug-eluting stents.