Abstract
OBJECTIVE: To develop combined therapies for amyotrophic lateral sclerosis (ALS), we investigated the long-term safety of ultra-high-dose methylcobalamin (50-mg intramuscular, twice weekly) in patients with advanced ALS. METHODS: As an open-label extension of a multicenter, randomized, double-blind, placebo-controlled phase 2/3 study, patients were enrolled and administered methylcobalamin 50 mg intramuscularly twice weekly for up to 52 weeks. RESULTS: In total, 144 patients (mean age, 62.1 years; 61.1 % male) were included, and the overall disease duration was 53.2 ± 17.9 months, with 85.4 % of patients having an ALS severity stage ≥3. The incidence of adverse events was 94.4 %, and adverse drug reactions occurred in 3.5 % of patients, which included proteinuria (2.1 %) and single cases of supraventricular arrhythmia, increased blood urea, and hypertension (0.7 % each). None led to discontinuation or death. The survival rate at 52 weeks was 85.7 %, and as shown for the following patient subgroups: by ALS severity (stage 1-2, 100 %; 3, 85.3 %; 4, 82.8 %; 5, 82.0 %) and by presence of tracheostomy (with, 88.8 %; without, 84.1 %). The median change in the ALS functional rating scale total score from baseline to 52 weeks was -1.0. CONCLUSION: There were no particular safety issues as reported in the phase 2/3 study and no clear deterioration in survival rate or physical function when ultra-high-dose methylcobalamin was administered intramuscularly in patients with advanced ALS. This regimen could be a candidate for initial therapy with further add-on to overcome ALS in the future.