Some biologic drugs may be safer than others according to a new systematic review by Cochrane researchers. Biologics are a broad class of drugs based on biological molecules. The drugs are used to reduce inflammation in diseases such as rheumatoid arthritis and inflammatory bowel disease.
Although the effectiveness of biologics is now well established, it is thought that some may have rare but serious side effects related to their immune-suppressing activities. Links have been made to increased risk of infections, reactivation of tuberculosis (TB), cancer and congestive heart failure.
The review is based on data from 163 studies focused on nine different biologics used to treat arthritis and other conditions. A total of 50,010 patients took part in the studies. Adverse events and TB reactivation were more likely among those taking biologics compared to controls. Serious side effects, lymphoma and congestive heart failure were no more likely. When compared to each other, two drugs, adalimumab and infliximab, caused more adverse events, whereas abatacept and anakinra were associated with fewer serious adverse events. Taking certolizumab pegol was more likely to result in a serious infection compared to several other biologics.
The researchers say the results should be treated cautiously. "The data provides some guidance for clinicians and patients as regards the safety of different biologic drugs, but we should remember that these are not head-to-head trials." said lead researcher Jasvinder Singh of the Birmingham VA Medical Center in Birmingham, Alabama. "There is still an urgent need for more research into the safety of these drugs, and in particular their comparative safety."
Some adverse events were so rare that it was difficult to establish whether or not they were linked to the drugs. "Biologics did not seem to increase the likelihood of congestive heart failure or cancer compared to placebos, but there were few cases in total, so we can't be very confident about these results," said Singh. "The studies we looked at did show a few more people suffering from tuberculosis with biologics, but again total numbers were low."