Usefulness of Mirogabalin in Central Neuropathic Pain After Stroke: Post Hoc Analysis of a Phase 3 Study by Stroke Type and Location.

Introduction: Central post-stroke pain (CPSP) is a common type of central neuropathic pain (CNeP) that can occur following the onset of stroke. The oral gabapentinoid mirogabalin besylate (mirogabalin) is a selective αδ ligand that is effective for the treatment of CNeP, including CPSP. However, it is unknown whether the analgesic effect of mirogabalin on CPSP varies in patients with different background factors.

Methods: This was a post hoc subgroup analysis of a multinational, open-label, long-term phase 3 study of mirogabalin for the treatment of CNeP conducted between March 2019 and December 2020. Data from patients with CPSP were stratified by type of stroke (ischemic or hemorrhagic), stroke location (thalamus, putamen, brainstem, or other), presence/absence of motor weakness, median time since stroke (≥ 59 or < 59 months), and median duration of CPSP (≥ 55.5 or < 55.5 months). Efficacy was assessed with the short-form McGill Pain Questionnaire (SF-MPQ), and treatment-emergent adverse events (TEAEs) and adverse drug reactions (ADRs) were recorded.

Results: This subanalysis included all 94 patients with CPSP from the phase 3 study; all were Japanese, and the mean age was 65.3 years. The least squares mean change [95% confidence interval] in SF-MPQ visual analog scale (VAS) score from baseline at week 52 (last observation carried forward) was - 17.0 [- 22.1, - 11.9] mm. Among the subgroups, least squares mean changes in SF-MPQ VAS scores were not different. Most TEAEs were mild or moderate; severe TEAEs occurred in six patients (6.4%). Somnolence (25.5%), peripheral edema (13.8%), dizziness (11.7%), and weight gain (6.4%) were the most common ADRs, and the types and frequencies of ADRs were similar among subgroups.

Conclusion: Mirogabalin was generally effective and well tolerated in patients with CPSP, regardless of background factors such as stroke type or location, presence/absence of motor weakness, time since stroke, and duration of CPSP.

Trial Registration: Trial registration number NCT03901352.