Medarex Inc. has initiated the phase II clinical development programme of MDX-1100, a fully human monoclonal antibody that targets CXCL10 (also known as IP-10), in ulcerative colitis (UC) and rheumatoid arthritis (RA).

MDX-1100 could potentially treat UC and RA by suppressing the inflammatory process characteristic of these diseases.

"Based on positive safety data in phase I studies, we have initiated patient enrolment in phase II studies that are designed to establish proof-of-concept," said Geoffrey M Nichol, M.B.Ch.B., senior vice president of product development at Medarex. "We are optimistic about the broad potential of MDX-1100 to address a range of inflammatory diseases".

Patients in the phase II randomized, double-blind, placebo-controlled, multi-centre study in UC will be administered MDX-1100 at 10 mg/kg or placebo every 2 weeks for a total of 4 doses. All patients will have active UC and will continue standard UC therapy during the trial. The trial is expected to enrol 106 patients at multiple sites internationally. The primary endpoint of the study is the response rate at 8 weeks. Clinical response is based on the Mayo score, a composite endpoint that assesses stool frequency and the amount of bloody stool per day as recorded in a patient diary, physician global assessment and the assessment of colon mucosal inflammation ascertained by endoscopy.

Patients in the phase II randomized, double-blind, placebo-controlled, multi-center study in RA will be administered MDX-1100 at 10 mg/kg or placebo every 2 weeks for a total of 6 doses. All patients will have active RA while on methotrexate. The trial is expected to enrol 70 patients at multiple sites in Europe. The primary endpoint of the study is the ACR20 response, a composite endpoint that indicates a 20 per cent improvement in RA signs and symptoms, at 12 weeks.

MDX-1100 is a fully human antibody that targets CXCL10 (also known as IP-10), a chemokine expressed in association with multiple inflammatory disease indications such as rheumatoid arthritis, inflammatory bowel disease and multiple sclerosis.