Botulinum neurotoxin A for treatment of pain in lower extremity ulcers: an exploratory study.

Objective: Pain in patients with leg ulcers is common and there is a need for effective treatments. The analgesic effects of botulinum neurotoxin A (BTX-A) have been well-documented and this exploratory study primarily investigated its analgesic effect in patients with leg ulcers.

Method: In this prospective, investigator-initiated, open-label, clinical trial, patients with leg and foot ulcers dominated by neuropathic wound pain were enrolled consecutively and treated with perilesional injections of BTX-A on day 0 (D0). The patients were followed-up on D21, D60 and D90.

Results: A total of 10 patients with leg and foot ulcers were enrolled in this study (≥30mm on a visual analogue scale (VAS) for pain from 0-100mm)-seven with venous leg ulcers and three with inflammatory ulcers. After starting treatment with BTX-A, pain was reduced by ≥20mm on the VAS at D21 (pre-defined endpoint) in seven (70%) patients (p<0.05). Neuropathic pain scores (Douleur Neuropathique 4 questionnaire) were significantly (p<0.05) reduced at all follow-up visits, while wellbeing scores (World Health Organization-5) increased significantly (p<0.05) after BTX-A injection. Percentage reduction of wound area was significant from D60 onwards. The wound fluid levels of interleukin-1β and the neuropeptide calcitonin gene-related peptide resembled the wound healing course. BTX-A was well-tolerated with no drug-related severe adverse events.

Conclusion: The findings of this study demonstrated that BTX-A holds potential for wound pain management and justify the need for more rigorous clinical investigations.