Real-World Evaluation of Botulinum Toxin A in Focal Peripheral Neuropathic Pain: Longitudinal Outcomes.

[BACKGROUND] Neuropathic pain (NP) is frequently resistant to conventional treatments. Botulinum toxin type A (BT-A) is a recommended option for focal peripheral NP, but the dynamics of its effect in real-life conditions remain poorly characterized.

[OBJECTIVE] To assess BT-A efficacy in a real-world study of patients with focal peripheral NP, over a 1-year follow-up period.

[METHODS] In this prospective, observational study, adult patients with chronic focal peripheral NP refractory to standard therapies were treated with BT-A in two French pain centers. Injections were individualized and administered at approximately 3-month intervals. The primary outcome was the patient-reported percentage of improvement since the first injection, assessed at each follow-up visit (Cycles 2-5). Secondary outcomes included the Patient Global Impression of Change (PGIC), average pain intensity over the previous 8 days, and exploratory analysis of response trajectories distinguishing early (≥ 30% improvement at Cycle 3) from late responders.

[RESULTS] Eighty-two patients received ≥ 2 BT-A cycles. Mean self-reported improvement increased from 30.7% at Cycle 2 to 51.0% at Cycle 5 (p < 0.001). PGIC and pain intensity also showed significant improvements. Among 59 patients evaluable at Cycle 3, 66% were early responders; late responders showed significant benefit after the third injection. BT-A was well tolerated: 63.6% reported end-of-dose effects, and 25.8% experienced only mild, transient adverse events.

[CONCLUSION] This real-life study over 1 year suggests that BT-A provides progressive and sustained benefit in focal peripheral NP, supporting continued treatment beyond two cycles.