Two MS Drug Studies Yield Divergent Clinical Findings

The researchers found that the two-year risk of relapse for patients who had received glatiramer acetate was 5.3%, compared with a rate of 13.5% in those who had received interferon beta-1b. The two-year risk of relapse for those who had taken glatiramer acetate was 5.2%, versus a rate of 10% among those who used interferon beta-1a IM. The two-year risk of relapse was 5.9% in those who had used glatiramer acetate, compared with 10.9% in those who had taken interferon beta-1a SC.

“In this recent comparison of immunomodulators for MS, the two-year risk of relapse was significantly lower for glatiramer acetate than for any of the three interferon beta drugs,” stated Dr. Johnson, Professor Emeritus of Neurology, University of Maryland, and Program Director of the Maryland Center for MS in Baltimore. “Nationwide outcomes came from treating physicians’ personal treatment decisions, free of drug company–sponsored studies or programs.”

In an interview with Neurology Reviews, Dr. Johnson said, “[Our] data show that in the broad population of patients across the US, glatiramer acetate works better than any of the interferons and is less costly, but it doesn’t work in every patient. We’re just now beginning to figure out which patients respond to which drugs.

“My recommendation,” advised Dr. Johnson, “is to start with glatiramer acetate, and if the patients do well, and probably around 60% of them will do well, then that’s the drug of choice. But for those patients who seem to respond poorly, we now have other choices.

“There are several problems with interferons that don’t occur with glatiramer acetate,” he continued. “Depending on the interferon, as many as a third of patients may develop neutralizing antibodies, in which case the drug is no longer effective. Rare patients develop liver toxicity and have to be taken off the interferon. So there are some indications for wanting to take patients off interferon. But if they’re doing well, there is no reason to do that. Interferons have been tested long enough [for clinicians] to know that they are effective but not as effective as glatiramer acetate, and they have more problems and more side effects.”

Dr. Johnson pointed out that it is important to differentiate between efficacy and effectiveness when interpreting his study’s results. Efficacy is the finding from a [specific] population of patients like we define in clinical trials, and in those situations the drugs were probably more or less equal,” he said. “However, in effectiveness, which is the broad category of patients in the US population with any disease, the effectiveness may not be the same as efficacy, and that’s why these findings are coming out the way they are.”