GlaxoSmithKline (GSK) and Genmab has announced positive primary efficacy data (evaluated at 24 Weeks) to be presented at EULAR 2007, the Annual European Congress of rheumatology from a phase II study of ofatumumab in patients with rheumatoid arthritis (RA). Ofatumumab is being co-developed under a worldwide agreement between GlaxoSmithKline and Genmab.

A total of 225 patients with active RA who have previously failed one or more disease-modifying anti-rheumatic drugs (DMARDs) were enrolled into this double-blind placebo controlled study to evaluate the safety and efficacy of ofatumumab. Patients within the study were randomised into one of four treatment groups (300 mg, 700 mg or 1000 mg ofatumumab or placebo) and assessed based on their American College of Rheumatology (ACR) and EULAR responses at 24 weeks. Continuation of current stable doses of methotrexate and low dose corticosteroids were permitted.

In the intention-to-treat study population, comprising 224 patients, ACR20 was achieved by 46 per cent of all patients receiving ofatumumab, ACR50 achieved by 24 per cent and ACR70 achieved by 6 per cent of ofatumumab patients compared to 15 per cent 5 per cent and 0 per cent in the placebo group.

The data also showed that ofatumumab appeared well tolerated, with no increased frequency of serious infections. Approximately half of the adverse events occurred on infusion days (51%) with the most frequently reported being mild or moderate (CTC grade 1-2 events), including throat irritation, dyspnoea and rash.

"These results represent another positive milestone in the development of ofatumumab. They will enable us to progress development in the rheumatoid arthritis (RA) indication and help bring this potentially important treatment to patients suffering from this often painful and debilitating condition," commented Dr Rouan, vice president, research and development, GlaxoSmithKline.

"The level of response of patients in the study illustrates the potential of ofatumumab in the treatment of RA and we hope to see similar results in the phase III study being planned for later this year," said Lisa N Drakeman, Ph.D., chief executive officer of Genmab.