More studies needed to compare the efficacy of different biologic drugs for RA, say researchers

More studies that directly compare the effectiveness of different biologic drugs for rheumatoid arthritis (RA) are needed, say Cochrane Researchers. The researchers reviewed all previous Cochrane Systematic Reviews assessing the effectiveness of biologic disease-modifying drugs for treatment of RA and found that although all were very effective, there was little data on direct comparisons between the drugs that could help doctors decide which to prescribe.

RA is an autoimmune disease that affects up to 1 in 100 people in Western countries. Patients experience chronic pain and inflammation as a result of the body's own immune system attacking the lining of the joints. In recent years, biologic disease-modifying anti-rheumatic drugs (DMARDs) have been introduced that can help to modify this irregular immune response and improve symptoms of the disease. Although these drugs may have fewer side effects than traditional DMARDs such as methotrexate, they are more expensive.

The six previous reviews considered by the researchers used two measures to make indirect comparisons between different biologic drugs. The first was doctor or patient assessment of symptoms including the number of swollen joints. For adalimumab, etanercept and rituximab, an increase of at least 40% was seen in the number of people experiencing improved symptoms, when the drugs were compared to placebos. Anakinra was the least effective at just 6% improvement compared to placebos. The second measure was the number of people who dropped out of studies due to adverse effects. Less than 10% dropped out in most cases, however, etanercept, abatacept and infliximab seemed to be responsible for the fewest withdrawals, showing little difference to the numbers dropping out when taking placebos.

"Doctors are faced with a difficult dilemma when choosing biologics to prescribe to RA patients. Although anakinra seemed less effective in the trials we looked at, we did not have any data from direct comparisons between different drugs," says lead researcher Jasvinder Singh, who is based at the Minneapolis Veterans Affairs Medical Center in Minneapolis in the US.

"We believe that direct head-to-head comparisons of biologic drugs in patients suffering from RA are needed. These trials should examine efficacy and safety at different stages and severity levels of the disease, as well as prior treatment with other drugs."