Pilot study of minocycline in relapsing-remitting multiple sclerosis

Background: Current multiple sclerosis (MS) treatment is only partially effective and not all patients respond well. The goal in this study was to evaluate minocycline for its safety, tolerability, and MRI impact as a potential therapy over 36 months after a three month run-in in ten relapsing-remitting (RR) MS patients. Methods: Clinical assessments were at three month intervals until six months, then at six month intervals. Three Tesla MRI was performed monthly during the run-in and first six months of treatment, then at 12, 24, and 36 months. Results: Treatment was safe and well tolerated. Annualized relapse rate was 1.2 during the run-in and 0.25 during treatment. The proportion of active scans was lower during the first six months of treatment (5.6%, p<0.001) and during the extension (8.7%, p= 0.002) than during the run-in (47.5%). Consistent with these outcomes, mean T2 lesion volume remained stable over three years and percent brain volume change was reduced during year three (-0.37%) of minocycline treatment. Conclusions: This trial is limited by small sample and no control group but suggests that minocycline is safe and potentially beneficial in RRMS. This supports further investigation of its efficacy.