Describe the design of a phase 2 study (NCT05642442) of a once-daily, extended-release formulation of suvecaltamide to treat moderate to severe residual Parkinson’s disease tremor (PDT).

This double-blind, placebo-controlled, flexible-dosing, parallel-group, multicenter study will enroll participants with PD (aged 40−85 years) with inadequately controlled tremor despite optimized treatment with PD medications. Participants will be randomized 1:1 to placebo or suvecaltamide, stratified by baseline TETRAS composite score (>17 or ≤17). In a 5-week titration period, participants will receive suvecaltamide 5 mg/day for 1−2 weeks, increasing to 10 mg/day for 1 week, then increasing by 10 mg/day once weekly up to 30 mg/day to optimize efficacy and tolerability. A 12-week maintenance period follows. The primary endpoint is change from baseline at week 17 on a TETRAS composite score. Additional endpoints assess PD symptoms, clinician and participant global impressions, embarrassment/quality of life due to tremor, and safety and tolerability.

Target enrollment is 160 participants (128 evaluable) with 80% power to detect a 3-point change from baseline to week 17 on the primary endpoint between suvecaltamide and placebo (common σ=6.0, 2-sided α=0.05). Enrollment is ongoing.

The phase 2 proof-of-concept study for the efficacy of suvecaltamide to treat the functional impact of PDT represents the first large clinical study informing the use of TETRAS to assess tremor in this population.