Objectives: To evaluate whether prophylactic treatment with acyclovir during the first month following alemtuzumab treatment is effective in reducing the risk of herpetic infections.
Methods: CARE-MS comprised two 2-year phase 3 trials, in treatment-naïve RRMS patients (CARE-MS I) and in active RRMS patients who had experienced disease activity while on prior therapy (CARE-MS II). Patients received alemtuzumab 12 mg intravenously on 5 days at entry and on 3 days 12 months later or IFNB-1a 44 µg SC 3× weekly. After a protocol amendment in January 2009, patients received oral acyclovir 200 mg twice daily during each alemtuzumab infusion and for 28 days thereafter.
Results: During 2 years of follow up, the overall incidence of any herpetic infection was higher in the alemtuzumab 12 mg group (16.0%) than the IFNB-1a group (2.0%). The most commonly reported events in the alemtuzumab 12 mg group was oral herpes (9.2% of patients), compared with 1.5% of patients in the IFNB-1a group. During the first course of alemtuzumab 12 mg, 205/811 (25.3%) patients received prophylactic acyclovir, which reduced the incidence of herpes infections during the first month (1/205 patients; 0.5%) compared with no prophylaxis (28/606 patients; 4.6%). During the second course, 521/789 (66.0%) patients in the alemtuzumab 12 mg group received acyclovir, and the incidence of herpes infections during the first month following alemtuzumab was again lower in patients who received prophylaxis than in those who did not (4 [0.8%] vs 7 patients [2.6%], respectively).
Conclusions: Overall, these data suggest that prophylactic treatment with acyclovir for 1 month following each alemtuzumab treatment course is effective in reducing the risk of herpetic infections.