Medarex Inc announced the initiation of a multi-dose, dose-escalation phase II clinical trial of MDX-070, a fully human antibody to prostate specific membrane antigen (PSMA), for patients with hormone refractory prostate cancer.

The phase II clinical trial is expected to enrol up to 30 patients with prostate cancer. Patients are expected to receive four bi-weekly doses of 1, 5 or 10 mg/kg of MDX-070 and will be assessed for tumour response based on objective tumour response and decrease in prostate specific antigen (PSA) serum levels.

In the single-dose phase I clinical study in 18 patients with metastatic prostate cancer, the antibody was well tolerated, and no serious drug-related adverse events were reported.

In addition to developing MDX-070 as a potential single antibody therapeutic agent, Medarex has expanded its MDX-070 programme to include a second-generation toxin conjugate programme, currently in preclinical development.

"We believe that PSMA is an attractive cancer target for potential antibody therapeutics like MDX-070," said Donald L. Drakeman, president and CEO of Medarex. "We have been encouraged by the preclinical and early clinical data and expect to rapidly develop this program for patients in need," he added.

MDX-070 is a fully human antibody that targets PSMA, a cell surface marker that is preferentially expressed on malignant prostate tissues and also on blood vessels in other tumours. Preclinical studies conducted by Medarex suggest that MDX-070 may effectively target and eliminate live prostate tumour cells through immunological pathways that prevent cancer cell proliferation or induce elimination of cancer cells.

According to the American Cancer Society, other than skin cancer, prostate cancer is the most common type of cancer found in American men and is the second leading cause of cancer deaths in men, exceeded only by lung cancer.

Medarex is a biopharmaceutical company focused on the discovery and development of therapeutics to treat life-threatening and debilitating diseases.