Bristol-Myers Squibb’s abatacept slows the progression of joint damage in patients with active rheumatoid arthritis, according to late-stage clinical trial data.

The findings come from the Phase III Aim study – a one-year 652-patient trial in which patients with active RA who had inadequately responded to treatment with methotrexate. Patients continued to receive methotrexate and were randomised to add a 30-minute intravenous infusion of either abatacept or placebo on days 1, 15, 29 and every 28 days thereafter. Abatacept-treated patients showed demonstrated an inhibition of progression based on median change from baseline in structural damage as measured by joint erosion score, joint space narrowing score, and total score compared to placebo. The rate of side effects for both study groups was similar, with the most common reports being headache. The incidence of total side effects was 87% for abatacept and 84% for placebo.

RA, which affects about 1% of the world’s population – more than 2.9 million Europeans and 2.1 million Americans – is a systemic autoimmune disease characterised by inflammation in the lining of joints, causing joint damage with chronic pain, stiffness, warmth, and swelling, and severely diminishing patients’ quality of life. Three out of four people diagnosed with RA are women.