MedImmune, Inc, of Gaithersburg, Maryland, and Medarex, Inc, of Princeton, New Jersey, announced that patient dosing has begun in a phase I clinical trial to evaluate the safety and tolerability of MEDI-545  (formerly MDX-1103) in patients diagnosed with mild systemic lupus erythematosus (SLE). A fully human monoclonal antibody targeting interferon-alpha, MEDI-545 is generated by Medarex's UltiMAb Human Antibody Development System®. This first-in-humans study is a randomized, double-blind, placebo-controlled, dose-escalation trial involving a single intravenous dose of the anti-interferon-alpha antibody in patients who have mild SLE with lupus rash or skin lesions. Forty-five individuals will be enrolled at approximately 20 centers in North America.

Published data indicate that interferon-alpha levels are elevated in many patients with active SLE and other autoimmune disorders, and may be associated with disease activity. Preclinical data from animal models suggest that MEDI-545 may suppress the abnormal immune activity associated with lupus by binding to multiple interferon-alpha subtypes seen in the serum of lupus patients.

In November 2004, MedImmune and Medarex entered into a collaboration agreement to develop and commercialize antibodies for the treatment of autoimmune diseases. The two antibodies currently being developed, MEDI-545 and MEDI-546 (formerly MDX-1333), are believed to target the interferon-alpha and the type 1 interferon receptor, respectively. Experimental data shows that the type 1 interferon receptor may also be involved with lupus disease activity.

Under the terms of the agreement, MedImmune is responsible for all ongoing clinical development activities. Prior to the beginning of pivotal studies, Medarex may elect to co-develop the products in return for the opportunity to co-promote and receive a share of the commercial profits in the US. In all other cases, Medarex will be entitled to receive milestone payments and royalties.

— A Techman