Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose: Morton’s neuroma (MN) is a painful condition of the third intermetatarsal space caused by distal common digital nerve compression. CNTX-4975, a highly purified, synthetic trans-capsaicin, targets the transient receptor potential vanilloid 1, producing analgesia via reversible desensitization of end terminals of primary afferent pain fibers. A prior double-blind randomized trial demonstrated efficacy of CNTX-4975 100 µg injected into the area surrounding the neuroma.* This phase 1b, open-label trial further evaluated dosing, safety (including sensory and motor examination), tolerability, efficacy, and duration of pain relief following injection of CNTX-4975.
Methods: Subjects with painful MN indicated their level of pain at baseline and up to 6 months following a single injection of CNTX-4975 200 µg or 600 µg using the Numeric Pain Rating Scale (NPRS; 0 [none]–10 [severe]). Clinically meaningful pain reduction was defined as ≥30% pain decrease versus baseline.
Results: Eleven subjects were enrolled (200 µg, n=5; 600 µg, n=6). The mean (SD) baseline pain score with walking was 5.7 (1.3). A substantial reduction in pain with walking was evident as early as 1 week in both dose groups (−3.0, 200 µg; −2.9, 600 µg). The mean (SD) change in pain with walking score at 8 weeks was −3.0 (3.8) in the 200-µg group and −4.3 (2.4) in the 600-µg group. At 6 months (only the 600-µg group was followed), the change in pain score was −3.8 (3.1). None of the subjects had a decrease in sensory or motor function compared with baseline. All 11 subjects reported procedure pain as tolerable.
Conclusion: A single injection of CNTX-4975 200 µg and 600 µg for MN provided a rapid and prolonged duration of clinically meaningful pain reduction with acceptable tolerability and safety. This study provides a basis for further randomized trials at these dose levels. *Campbell, et al, Pain, 2016.
To cite this abstract in AMA style:Hanson P, Gottlieb I, Kelly M, Campbell J, Allen R, Stevens R. Cntx-4975 (Trans-Capsaicin) Injection Provides Clinically Meaningful Pain Reduction in Subjects with Painful Intermetatarsal Neuroma (Morton’s Neuroma): An Open-Label, Ascending-Dose Study [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/cntx-4975-trans-capsaicin-injection-provides-clinically-meaningful-pain-reduction-in-subjects-with-painful-intermetatarsal-neuroma-mortons-neuroma-an-open-label-ascending-dose-study/. Accessed January 24, 2022.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/cntx-4975-trans-capsaicin-injection-provides-clinically-meaningful-pain-reduction-in-subjects-with-painful-intermetatarsal-neuroma-mortons-neuroma-an-open-label-ascending-dose-study/