Phase 3 Trial of Alemtuzumab for Multiple Sclerosis Yields Promising Results

A Phase 3 trial of the investigational multiple sclerosis (MS) drug alemtuzumab (Lemtrada) met both of its co-primary endpoints: reduction of relapse rate and reduction of sustained accumulation of disability. The results were announced earlier this month by Genzyme, which is developing the medication in collaboration with Bayer HealthCare.

The CARE-MS II trial included 840 patients with relapse-remitting MS, all of whom had experienced at least two relapses in the previous two years, at least one relapse in the previous year, and at least one relapse while on a prior therapy. The participants received either intravenous alemtuzumab 12 mg daily for five days and again for three days one year later or interferon beta-1a (Rebif) 44 mcg three times per week via injection for the entire two-year duration of the study.

Over the two years, participants who received alemtuzumab had a 49% reduction in relapse rate and a 42% reduction in risk of sustained accumulation of disability compared with those who received interferon beta-1a. These results come on top of the previously completed CARE-MS I trial, in which alemtuzumab produced a statistically significant reduction in relapse rate compared with interferon beta-1a in relapsing-remitting MS patients who had not received prior treatment. According to preliminary research, alemtuzumab works by depleting the T- and B-cells thought to be potentially responsible for cellular damage in MS.

In the current trial, infections were common in both groups, though they were more common in the alemtuzumab group. The most common infections in the alemtuzumab group included upper respiratory and urinary tract infections, sinusitis and herpes simplex infections. Approximately 16% of patients receiving alemtuzumab developed an autoimmune thyroid-related adverse event and approximately 1% developed immune thrombocytopenia.

Alemtuzumab has been granted fast track designation by the FDA and is eligible for priority review. According to a Genzyme press release announcing the results of the CARE-MS II trial, the company is on track to submit the drug for review by US and European regulatory authorities in the first quarter of 2012.