To gain FDA approval for Lemtrada (alemtuzumab), Genzyme carried out two large Phase III clinical studies to investigate its safety and effectiveness.1,2 The drug development program included almost 1,500 patients with relapsing MS. In those two studies, treatment with Lemtrada was compared to treatment with a different medication for relapsing MS: Rebif (high-dose subcutaneous interferon beta-1a), which is marketed jointly by EMD Serono and Pfizer. While Lemtrada is administered via IV over the course of several days once a year (for two years), Rebif is an injectable medication that is self-administered three times per week.
The first study, called CARE-MS I, included patients with relapsing MS who had never received any kind of previous treatment for their condition. CARE-MS II was a second study that included patients who had relapsed while receiving some other previous therapy for MS. In both studies, patients received treatment with either Lemtrada or Rebif over the course of two years. To determine the effectiveness of the treatment regimens, investigators looked at three different factors:
- Patients’ average annual relapse rates
- Proportions of patients who experienced disability progression
- Percentages of patients who were still relapse-free at the end of the study
In the CARE-MS I study, Lemtrada-treated patients experienced a relative reduction in their average relapse rate of about 50% over the two years. Patients in the Lemtrada treatment group for the CARE-MS II study experienced a similar relative reduction in their average relapse rate – about 55%.
In both studies, patients who were treated with Lemtrada had significantly lower average rates of relapse than patients treated with Rebif. These results show that Lemtrada is more effective than Rebif in reducing patients’ relapse rate over the course of the two-year study.
The proportion of Lemtrada-treated patients whose disability had progressed by the end of the CARE-MS I study was about 13%. In the CARE-MS II study, a lower proportion of patients (8%) in the Lemtrada group had disability progression. In the group treated with Rebif, 21% of patients in the CARE-MS I study and 11% of patients in the CARE-MS II study had experienced disability progression by the end of the second year.
When disability progression for the Lemtrada group is compared to the group treated with Rebif, patients in the Lemtrada group overall had lower proportions of patients with disability progression than in the Rebif group, in both studies. However, this difference was only statistically significant in the CARE-MS II study. These results indicate that Lemtrada is at least as effective in slowing down disability progression as Rebif in patients who have never received treatment for their MS. For patients who have relapsed while receiving other types of MS medication in the past, Lemtrada is demonstrated to be more effective than Rebif.
At the end of the CARE-MS I study, 65% of patients who were treated with Lemtrada remained completely relapse-free (versus 47% of the patients treated with Rebif). Of the Lemtrada-treated patients in the CARE-MS II study, 78% of patients were relapse-free at the end of the second year. In the Rebif treatment group, 59% of patients were similarly without relapse. In both studies, treatment with Lemtrada was demonstrated to be more effective than Rebif in helping patients to remain completely relapse-free during the two-year study period.