AMSTERDAM—Results of a head-to-head comparison of alemtuzumab and interferon beta-1a have shown that 78% of patients with relapsing-remitting MS treated with alemtuzumab remained relapse-free for two years, compared with 58% of patients taking interferon beta-1a. Findings from the phase 3 CARE-MS I trial were reported at the ECTRIMS/ACTRIMS 5th Joint Triennial Congress.
The CARE-MS I trial compared alemtuzumab (12 mg/d IV for five days with a second 3-day IV administration one year later) to treatment with interferon beta-1a (44 mcg SC injection 3 times per week) in 581 patients with relapsing-remitting MS who had had no previous MS treatment except steroids.
Additional findings include other secondary endpoints that suggest positive outcomes with alemtuzumab. Improvement in the Multiple Sclerosis Functional Composite (MSFC) score was observed in alemtuzumab-treated patients compared with interferon beta-1a–treated patients (0.12 versus 0.05, mean change from baseline at year 2). Reduction in T2-hyperintense lesion volume with alemtuzumab compared to interferon beta-1a was -9.3 versus -6.5 (median percent change at year 2). Statistically significant improvement was observed for alemtuzumab versus interferon beta-1a in the percentage of patients with new enlarging T2-hyperintense lesions (49% versus 58%), with new gadolinium-enhancing lesions (15% versus 27%), and with new T1-hypointense lesions (24% versus 31%). Alemtuzumab-treated patients also experienced less change in brain parenchymal fraction compared to interferon beta-1a (-0.87 versus -1.49, median change from baseline).
Common adverse events associated with alemtuzumab in the CARE-MS I trial were infusion-associated reactions that were mild to moderate. The incidence of infection was increased, with the most common infections involving the upper respiratory and urinary tract and oral herpes. Infections were mild to moderate and none were life-threatening or fatal.
Serious adverse events were similar between both groups (18.4% for alemtuzumab and 14.4% for interferon beta-1a). Just over 18% of alemtuzumab-treated patients developed an autoimmune thyroid-related adverse event, and 0.8% developed immune thrombocytopenia during the two-year study period. Cases of autoimmunity were detected and managed using conventional therapies.