A placebo controlled, randomized clinical trial of galcanezumab for vestibular migraine: The INVESTMENT study

OBJECTIVE: To study if galcanezumab is effective for vestibular migraine (VM). BACKGROUND: There are currently no placebo-controlled trials showing that treatment is effective for VM. Therefore, we performed the first placebo controlled, randomized clinical trial of a calcitonin gene-related peptide-targeted monoclonal antibody for VM. METHODS: This was a single site, prospective, double-blind placebo controlled randomized clinical trial. Key inclusion criteria were as follows: participants aged 18-75 years with a diagnosis of VM or probable VM per Barany Society criteria. The primary outcome was change in VM-PATHI (Vestibular Migraine Patient Assessment Tool and Handicap Inventory) score, and secondary outcomes included change in DHI (Dizziness Handicap Inventory) score, and count of definite dizzy days (DDDs). Participants were randomized 1:1 to 3 months of treatment with galcanezumab or placebo via subcutaneous injection with a pre-filled syringe, 240 mg the first month, and 120 mg for the second and third months. RESULTS: Forty participants were randomized, and 38 participants were in the modified intent to treat analysis. VM-PATHI score was reduced 5.1 points (95% confidence interval [CI] -13.0 to 2.7) for placebo (N = 21), and 14.8 points (95% CI -23.0 to -6.5) for galcanezumab (N = 17), a difference of -9.6 (95% CI -20.7 to 1.5, p = 0.044). DHI dropped 8.3 points in the placebo arm (95% CI -15.0 to 1.6), and 22.0 points in the galcanezumab arm (95% CI -31.9 to -12.1), a difference of -13.7 (95% CI -20.4 to -8.5, p = 0.018). The count of DDDs per month dropped from 18 days (standard deviation [SD] 7.6) in the baseline month to 12.5 days (SD 11.2) in month 4 for those in the placebo arm, and from 17.9 days (SD 7.9) in the baseline month to 6.6 days (SD 7.3) in month 4 for those in the galcanezumab arm, a difference of -5.7 days (95% CI -10.7 to -0.7, p = 0.026). No serious adverse events were observed. CONCLUSIONS: In this pilot study, galcanezumab was effective in treating VM.