Biologic drugs have revolutionized the way rheumatoid arthritis (RA) is treated since the first one was approved by the U.S. Food and Drug Administration in 1998. Today, nine biologics are approved for RA on the market, which raises a very important question: Is one better than another? Head-to-head trials, comparing one biologic to another, are starting to provide some answers. Three such studies were recently published or presented. 

In RA, the immune system, which is designed to protect us, becomes overactive, causing the body to attack its own joint tissue. Different biologic drugs work on different components (or pathways) of the immune system. Five biologics block tumor necrosis factor (TNF) – a cytokine (protein) involved in the inflammatory process. Other biologics target interleukin-6 (IL-6) or interleukin-1 (IL-1), or B cells or T cells (types of white blood cells).

In one trial, examining abatacept (Orencia) and adalimumab (Humira), researchers report that although the two medications work in different ways, they were equally effective targeting the pain and inflammation of 646 RA patients also taking methotrexate. The results of the study were presented at the American College of Rheumatology’s annual meeting in November and were published online in Arthritis & Rheumatism, also in November.

Abatacept blocks the stimulation of T cells, which help regulate the immune response. Adalimumab is a TNF inhibitor. Nearly 65 percent of patients taking abatacept achieved at least a 20 percent improvement after a year, compared with 63.4 percent who received adalimumab. Bristol-Myers Squibb, the maker of abatacept, funded this study, but researchers say they used the recommended doses of both drugs and there was no intravenous loading dose of abatacept.

“We were not at all surprised to see abatacept achieve the same results as [adalimumab]. The speed of response of abatacept, however, was a surprise. At week 52, the two drugs were equivalent clinically,” explains the study’s first author Michael Weinblatt, MD, professor of medicine at Harvard Medical School and co-director of clinical rheumatology at Brigham and Women’s Hospital, both in Boston. “This gives patients validation that there are other pathways that work.”

A second study, published in the December issue of Arthritis & Rheumatism, compared adalimumab with another TNF inhibitor, etanercept (Enbrel), in 407 RA participants who had not previously tried a TNF inhibitor. The study found that patients in both groups had virtually the same response in the long term to the two medications.