Teriflunomide (AUBAGIO). Multiple sclerosis: just a metabolite of leflunomide

In mid-2014, subcutaneous or intramuscular interferon beta injection is the standard disease-modifying treatment for patients with relapsing-remitting multiple sclerosis, in the absence of a better alternative. Teriflunomide, the main active metabolite of leflunomide, has been approved as an oral treatment in this setting. Both substances have immunosuppressive effects. Clinical evaluation of teriflunomide is based on a comparative trial versus interferon beta-1a in 324 patients and on two placebo-controlled trials in a total of about 2300 patients lasting 1 to 2 years. In these trials, oral teriflunomide at a dose of 14 mg per day led to a statistically significant decrease in the average annual number of relapses compared to placebo, but teriflunomide may be less effective than interferon beta. No impact on the progression of disability has been shown during less than 2 years of follow-up. The burdensome adverse effect profile of teriflunomide is similar to that of leflunomide and includes hepatotoxicity, infections, leukopenia, arterial hypertension, peripheral neuropathy and alopecia. The long half-life of teriflunomide (about 19 days) complicates the management of its adverse effects and multiple drug interactions, and has important implications for patients wishing to have children. Teriflunomide is teratogenic in animals and should not be used by pregnant women. Fetal toxicity via semen cannot be ruled out. In practice, the adverse effects of teriflunomide in multiple sclerosis are disproportionate to its efficacy. It is better to choose interferon beta, despite its limitations.