The global, randomized, two-year, Phase 3 pivotal studies compared treatment with Lemtrada to Rebif (subcutaneous interferon beta-1a; EMD Serono) 44 mcg in patients with relapsing-remitting MS who were either new to treatment (CARE-MS I) or who had relapsed while on prior therapy (CARE-MS II). More than 90% of the patients who participated in these Phase 3 trials enrolled in the extension study. Patients who originally received Lemtrada were eligible to receive additional treatment in the extension study if they experienced at least one relapse or at least two new or enlarging brain or spinal lesions.
Analysis of the first year of the extension study demonstrated that relapse rates and sustained accumulation of disability remained low among patients who had previously received Lemtrada in either of the Phase 3 CARE-MS I and CARE-MS II studies. In these pivotal studies, Lemtrada was given as two annual courses, at the start of the study and 12 months later. More than 80% of patients did not receive further treatment with Lemtrada during the first year of the extension study. Patients who took Rebif in the pivotal study phase and crossed over to receive Lemtrada in the extension phase received Lemtrada once daily for five days and then once daily for three days one year later.
Interim results from the first year of the extension study for patients who previously received Lemtrada in the two-year studies demonstrated that more than half of patients (67% in CARE-MS I and 55% in CARE-MS II) who received Lemtrada in the pivotal trials and enrolled in the extension study were still relapse-free through the first year of the extension study. In the first year of the extension phase, the annualized relapse rate for patients who received Lemtrada in the pivotal trials was 0.24 and 0.25, comparable to the annualized relapse rate for those patients in CARE MS I and CARE-MS II, respectively. In the extension phase, 72.4% of patients in CARE MS I and 70% in CARE MS II had improved or stable disability as measured by EDSS. More than 80% of patients treated with Lemtrada in the pivotal studies did not receive a third course of treatment within a year of entering the extension study.
Alemtuzumab is a monoclonal antibody that selectively targets CD52, a protein abundant on T and B cells. Treatment with alemtuzumab results in the depletion of circulating T and B cells thought to be responsible for the damaging inflammatory process in MS. Alemtuzumab has minimal impact on other immune cells.
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