Vion Pharmaceuticals Inc has initiated a new Phase 1 trial of Triapine in combination with cytarabine (Ara-C) in patients with advanced leukemia. Enrollment of patients began at the University of Texas M.D. Anderson Cancer Center's Department of Leukemia under the direction of Dr. Francis Giles, Chief of Experimental Therapeutics.

Cytarabine is a cytotoxic drug that is used alone and in combination for treatment of leukemia. In preclinical studies, Vion has demonstrated that the combination of Triapine and cytarabine produces greater killing of cancer cells than either agent alone.

Dr. Mario Sznol, Vice President, Clinical Affairs, stated, "This study builds on the results of our Phase 1 trials of Triapine as a single agent in leukemia, and our preclinical work combining Triapine with cytarabine. It will provide important additional evidence of the role that Triapine can play in the treatment of leukemia." He added, "We are pleased to be working once again with the M.D. Anderson Cancer Center, one of the premier cancer treatment hospitals in the U.S."

Dr. Giles stated, "This study is an important step towards determining the role of Triapine within combination cytotoxic drug regimens - such regimens are the cornerstone of current anti-leukemia therapy."

Vion has two ongoing Phase 2 clinical trials of Triapine as a single agent in head and neck and prostate cancer. Vion is also planning to study Triapine in combination with gemcitabine in Phase 2 trials in non-small cell lung and pancreatic cancer. In Phase 1 trials, Triapine was well-tolerated and evidence of anti-tumor activity was observed in several malignancies.

Triapine is designed to be a potent inhibitor of ribonucleotide reductase, an enzyme important for DNA synthesis.