Low-dose ketamine infusion for the treatment of multiple sclerosis fatigue (INKLING-MS): Study protocol for a randomized, double-blind, active placebo-controlled phase II trial

Background: Fatigue is one of the most common symptoms of people with Multiple Sclerosis (MS). However, currently-used medications for the treatment of fatigue probably do not work better than a placebo. In a pilot trial, we showed that one infusion of low-dose ketamine significantly improved fatigue severity measured four weeks after the infusion. Methods: The proposed study is a single-center, phase II, randomized, double-blind, parallel-group, active-placebo-controlled trial of intravenous low-dose ketamine in patients with MS fatigue. Participants will be randomized 1:1:1 into three groups: receiving either one or two infusions of ketamine (0.5 mg/kg over 40 min) or zero to one infusion of the active placebo (midazolam, 0.05 mg/kg over 40 min). Eligibility criteria include adult patients diagnosed with MS based on the latest criteria, complaining of fatigue as one of the main symptoms, and having a screening MFIS score higher than a pre-specified threshold. Results: One hundred and ten participants will be randomized over 30 months at Johns Hopkins MS Center. Complete enrollment is expected by mid-2025. The study's primary outcome will be the MFIS score at the end of week 4, comparing two-thirds of the participants who received ketamine with one-third who received midazolam. The secondary and exploratory outcomes (measured four weeks after the second infusion) will show how long the effects of a single infusion last and if two infusions of ketamine are better than one in improving MS fatigue. Conclusion: This study can show whether intervening in the glutamatergic pathways would improves MS fatigue.