Patients with juvenile idiopathic arthritis (JIA) who take biologic therapies have a higher rate of serious or opportunistic infections, a new study shows.

The study reporting that finding, “High rate of serious infection in juvenile idiopathic arthritis patients under biologic therapy in a real-life setting,” was published in the journal Modern Rheumatology.

Although the exact risk of infection in people taking biologic or non-biologic drugs has not been established so far, studies have suggested that the risk is higher for biologic drugs. These, different from non-biologic therapies, are produced in a living system (a micro-organism, plant or animal cells).

JIA itself also has been associated with an increased risk for infections.

Now, a research team assessed the rate of serious/opportunistic infections and possible risk factors in JIA patients in a single biologic therapy center in a real-life setting in Brazil.

The study included 107 JIA patients, with a mean age of 14.6 years, 71 percent of whom were female. The time patients had been on biologic therapy ranged from 0.15 to 11.5 years.

Researchers found that serious infections requiring either hospitalization or intravenous therapy occurred  35 times in 27 patients. None of the patients died from infections. Herpes Zoster, a type of virus, caused opportunistic infections in four patients; other opportunistic infections included tuberculosis and systemic mycosis.

Rates of serious/opportunistic infections in patients receiving each of the therapies was measured through the number of infections per 100 patient-years. Patient-years (py) are calculated by adding up the period of time each patient in the treated group took the drug.

Serious/opportunistic infection rates were 14.8/100 py for Actemra, 10.9/100 py for Humira, 10.6 per 100 py for Enbrel, and 2.6/100 py for Orencia. Only one patient in the Remicade group had an infection.

By comparing the group of 27 patients who experienced infections with the 80 patients who did not, the team found that patients with systemic JIA (arthritis throughout the body), who had begun biologic therapy at younger ages, or who typically had suffered from infections before receiving biologic therapy, were more likely to develop infections.

“In conclusion, this single center study demonstrated a high rate of serious infections in JIA patients under biologic therapy in a real-life setting, except for ABA [Orencia]. Systemic-onset JIA, lower age at biologic therapy start and history of previous serious infections were important risk factors for these complications,” the team wrote.