“They are quite similar, which is kind of what we expected. It’s nice now that we are getting head-to-head studies, which we didn’t have before,” says Donald Miller PharmD, professor and chair of the Pharmacy Practice Department at North Dakota State University in Fargo. Miller was not involved in the study.

Miller notes that among study participants taking adalimumab, the effectiveness of the drug depended a great deal on the presence of anti-adalimumab antibodies. Antibodies are the immune system’s response to molecules the body views as foreign invaders. Participants without antibodies to adalimumab responded the best to the drug, while those who developed anti-adalimumab antibodies responded the worst.

“Adalimumab is what we call a humanized monoclonal antibody, so it’s supposed to be something the body would not recognize as foreign. But as it turns out, our bodies can make antibodies to adalimumab and that can be a limiting factor in the response,” Miller explains. “So what the study is showing is that if you start making antibodies to adalimumab, you won’t get a good response.”

A third study, presented at the European League Against Rheumatism’s annual meeting earlier this year, compared tocilizumab (Actemra), which blocks the production of interleukin-6, to adalimumab. It found that among 325 patients, tocilizumab was more effective at reducing swollen joints and pain than adalimumab. After six months, 40 percent of those taking tocilizumab achieved remission compared with 11 percent of patients getting adalimumab. Abbott, which makes adalimumab, questioned the results of this study, saying that patients were given the minimum dose of adalimumab and the maximum dose of tocilizumab.

Miller says that ultimately, these studies mean this is a reassuring time for RA patients, because researchers are developing a better understanding of the biologics on the market. “We probably know a little more about the anti-TNFs, but there is still a lot to learn about how to choose the right drug for the right patient,” he says. “It’s kind of a guessing game right now. It would be nice if there was some way to figure out why patients respond or don’t respond to individual drugs.”

Dr. Weinblatt believes patients can also take comfort in knowing that this type of clinical trial – comparing one therapy to another, particularly in patients on background methotrexate – is likely to become the norm. “These are expensive molecules. They have demonstrated efficacy in stand-alone studies, and I think the clinician needs to know, when offering patients a choice, what the data is comparing one drug to another,” he explains.

Experts also hope that these kinds of studies will allow them to personalize medicine one day – that is, look at a patient’s blood work and, based on that, be able to tell what medication will work best.

“I think the bottom-line message to patients is the rheumatology community is very interested in studying one drug versus another to determine if they are comparable,” says Dr. Weinblatt. “And that all of these studies should incorporate additional analysis to see if there are any predictors to response or lack of response.”