Relief of pain associated with spasticity in adult patients after treatment with onabotulinumtoxinA: Post hoc observational results from the ASPIRE study.

Background: Pain is often observed in patients with spasticity, but little is known about the relationship between pain and spasticity and the effectiveness of treating pain with botulinum toxins in these patients.

Objective: To explore onabotulinumtoxinA (onabotA) use and pain relief in patients with spasticity with pain at baseline.

Design: Subanalysis of a 2-year multicenter, prospective, observational study (ASPIRE [Adult Spasticity International Registry], NCT01930786).

Setting: Fifty-four international clinical sites.

Participants: Adults with spasticity (N = 494) and pain at baseline (Numeric Pain Rating Scale [NPRS]>0) across multiple etiologies and age groups.

Intervention: OnabotA administered at clinician's discretion.

Main outcomes: OnabotA use, pain measured with the NPRS and Disability Assessment Scale (DAS), patient- and physician-reported satisfaction, and safety.

Results: Of 730 patients who received ≥1 onabotA dose in ASPIRE, 494 (68%) had baseline pain (mean age, 54 years; stroke, 56%; naïve to onabotA, 38%; NPRS ≥5, 65%). Average onabotA dose per treatment session (Tx) ranged from 345 to 463 U. Pain reduction from baseline was observed across all Tx; mean NPRS decreased from 5.4 to 2.6 at Tx8, model estimated mean NPRS was significantly reduced after each Tx (Tx1-7, p ≤ .001; Tx8, p ≤ .005), and a high proportion achieved clinically meaningful pain reductions across Tx1-4 (mean NPRS decreased by ≥30% for 49%-59%, by ≥50% for 40%-49%, and by ≥70% for 24%-34% of patients). Relief of pain was supported by significant improvements from baseline on the DAS pain subscale across most Tx with most patients/physicians being satisfied with onabotA treatment. Overall, 15 patients (3%) reported 17 treatment-related adverse events (TRAEs), and 2 patients (0.4%) reported 3 serious TRAEs.

Conclusion: In patients with spasticity experiencing pain, long-term onabotA treatment demonstrated consistent clinically meaningful reductions in pain, reduced pain disability on DAS, and high patient and physician satisfaction with no new safety signals identified, regardless of prior onabotA treatment or age groups.