SAN ANTONIO — Etanercept and infliximab do not appear to reduce responses to pneumococcal vaccination—but methotrexate treatment does, suggest the findings of a prospective trial conducted in Sweden.
Whenever possible, “rheumatoid arthritis patients should be vaccinated before starting methotrexate,” the lead investigator, Meliha Crnkic, M.D., advised at the annual meeting of the American College of Rheumatology.
Dr. Crnkic of Lund University Hospital and colleagues found that 50% of 62 rheumatoid arthritis patients receiving either etanercept or infliximab monotherapy had adequate responses to vaccination, defined as a twofold or better increase in immunoglobulin G antibody (23F and 6B) titers 4–6 weeks after vaccination.
By comparison, the response rate was 32% in 50 patients being treated with one of the biologics combined with methotrexate; 14% of the 37 patients receiving methotrexate monotherapy responded adequately. The difference between the response of the patients on biologic monotherapy and methotrexate monotherapy was statistically significant.
Among 47 healthy volunteers, 38% responded to vaccination. The difference in response rates between these controls and the patients on biologic monotherapy was not statistically significant. However, the healthy controls were slightly older as a group than the patients on the biologic agents alone, and, among the controls, age was shown to be factor in response, with the younger patients responding better, Dr. Crnkic noted.
Age did not appear to be a factor in response rates among patients taking the biologics, nor was gender, drug dosage, nor concurrent low-dose corticosteroid treatment.
It's not clear why the patients on combination treatment had a better response than the patients on methotrexate alone.
The study is the first prospective trial to investigate whether pneumococcal vaccination response is affected by treatment with a biologic agent. Previous reports had suggested that the agents did not cause a problem, Dr. Crnkic said.