February 20, 2014 | News | MS Treatments

Aubagio: new side effects reported

A U.S. health information company has reported that Aubagio (teriflunomide) may be associated with some adverse effects that are not listed on the product label. The data were obtained by AdverseEvents (adverseevents.com), Santa Rosa, California, through a Freedom of Information Act request for an update of the FDA’s Adverse Event Reporting System.

Aubagio was approved as an MS treatment in the U.S. in September 2012. In 2013, there were 1,792 case reports in the FDA database. New adverse effects in the new report included muscle weakness, muscle spasms, memory impairment, urinary tract infection, kidney stones, vertigo (dizziness) and skin discolouration.

Following approval of a new medication, it’s not uncommon for new side effects to emerge as more people are exposed to the drug. However, it should be noted that adverse effects can occur during treatment that may be unrelated to the medication, and it’s very difficult to establish cause-and-effect. For example, muscle weakness, spasms and memory impairment are also symptoms of MS.

In Canada, Aubagio was approved just a few months ago and adverse-effects data are not yet available from Health Canada’s MedEffect database.

In clinical trials, Aubagio was generally well tolerated by people. In the phase III TEMSO study, the rate of serious adverse effects with the two doses of teriflunomide (14.1-15.9%) was similar to what was seen with placebo (12.8%) (O’Connor and colleagues. N Engl J Med 2011;365:1293-1303). About 10-11% of people stopped taking Aubagio because of side effects, compared to 8% who stopped the placebo because of side effects. This rate of stopping treatment is quite low for a clinical trial, suggesting that the level and severity of adverse effects are acceptable.

The Aubagio product label does caution about a risk of liver damage, so periodic blood tests are needed. The drug has known effects on the kidneys, so doctors also need to look for changes in kidney function during treatment. Some people may also experience skin changes, nerve tingling or pain (e.g. in both hands or both feet; this can include carpal tunnel syndrome), and blood pressure changes.

Aubagio stays in the system for a long time (about 8 months and up to two years in some) after you stop taking it so the drug needs to be actively eliminated from the body in some situations. Women (and men) planning a pregnancy, some people thinking about switching to another therapy and those with significant side effects will need to undergo the elimination regimen (taking activated charcoal or cholestyramine for 11 days). Aubagio may cause birth defects, so pregnant women should avoid exposure to the drug.

AdverseEvents speculated that the FDA may issue an alert to advise people about these potential side effects. The significance of this new information hasn’t been established yet and more analyses will be needed. But the report underscores the importance of being on the lookout for adverse effects with any medication (including non-prescription and alternative medicines), and reporting them promptly to a doctor, MS nurse or pharmacist.

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