MedImmune, Inc (GAITHERSBURG, Maryland), wholly owned by AstraZeneca plc and Medarex, Inc (PRINCETON, New Jersey), a biopharmaceutical company focused on fully human antibody-based therapeutics, announced that MedImmune has initiated enrollment in a phase IIa trial with a human monoclonal antibody (MEDI-545) targeting interferonα in patients with lupus. The study is designed to assess the safety and tolerability of multiple subcutaneous dose schedules of the antibody versus placebo in adult patients with moderate-to-severe, active lupus despite standard of care.

The randomized, double-blind, placebo-controlled, parallel-dose trial will also assess the effects of the agent on disease activity in lupus patients. The study is expected to enroll 80 patients and will be conducted at about 20 sites throughout the US, many of which are currently recruiting. The estimated final data collection date for primary outcome measure is January 2009. The estimated study completion date is April 2010.

Published data indicate that levels of interferonα are elevated in many patients with active lupus 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 the multiple elevated interferonα subtypes seen in the serum of lupus patients. Data from an earlier reported placebo-controlled phase I study suggested therapeutic activity with single doses of MEDI-545 in patients with lupus.

MEDI-545 is a fully human antibody generated by Medarex's UltiMAb Human Antibody Development System^®. Medarex will receive a milestone payment of an undisclosed amount. In November 2004, MedImmune entered into collaboration with Medarex to focus on two specific antibodies, one of which is now known as MEDI-545. 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 codevelop the products in return for the opportunity to copromote and to receive a share of the commercial profits in the US. In all other cases, Medarex will be entitled to receive milestone payments and royalties.