Disclosures: Randall M. Stevens, MD: Centrexion Therapeutics Corp (Products/Services: Yes) (Employment, Stockholder/Ownership Interest (excluding diversified mutual funds))

Objective : Evaluate joint cooling/administration procedures for CNTX-4975 (capsaicin) intra-articular injection.

Design: Phase 3, open-label, 8-week trial (NCT03661996).

Setting : Multicenter.

Participants : Subjects (40–95 years, Kellgren-Lawrence grade 1–4, body mass index ≤45 kg/m2) with stable, moderate-to-severe osteoarthritis knee pain after ≥2 failed therapies.

Interventions: Unilateral/bilateral CNTX-4975 1 mg intra-articular injections as determined by osteoarthritis pain/joint replacement status, randomized by site to circumferential ice-water wrap (Group 1) or circumferential gel-pack wrap joint cooling with varying cooling schedules/injection techniques (Groups 2–5).

Main Outcome Measures: Primary outcome measure assessed circulating ice-water wrap cooling versus other cooling variations as acceptable treatment regimens (day 1) using a combined sum of 1) procedural pain (0 [none] to 4 [severe]) 30 minutes post–CNTX-4975 injection; 2) subject satisfaction (SS) with joint cooling/administration procedures; and 3) investigator satisfaction (IS) with procedures. SS and IS were measured on a 7-point scale (1, completely dissatisfied; 7, completely satisfied); pain was reverse scored and normalized (1, severe; 7, none) for equal weighting of composite score. Geometric mean ratio (GMR) with 95% confidence intervals (CIs) were constructed for each regimen versus control (analysis of covariance); lower 95% CI >0.7 was considered clinically acceptable.

Results: The intent-to-treat population comprised 848 subjects (Groups 1–5: N=162, 179, 175, 160, 172). Group 1–5 mean (standard deviation) composite scores were: 17.23 (2.660); 18.23 (2.023); 16.81 (2.891); 17.57 (3.049); 16.43 (3.138). All CNTX-4975 procedures tested were clinically acceptable, with evaluated cold gel-based wraps at least as effective as the circulating ice-water wrap; GMR (standard error [95% CI]) vs Group 1 control: Group 2, 1.06 (1.022 [1.02, 1.11]); Group 3, 0.96 (1.022 [0.92, 1.00]); Group 4, 1.01 (1.022 [0.97, 1.06]); Group 5, 0.93 (1.022 [0.89, 0.97]).

Conclusions: All CNTX-4975 intra-articular cooling and administration regimens for moderate-to-severe knee osteoarthritis pain were clinically acceptable.

Funding: Centrexion Therapeutics Corp.

Level of Evidence: Level I

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/comparison-of-5-treatment-regimens-for-cntx-4975-capsaicin-intra-articular-injection-in-subjects-with-moderate-to-severe-osteoarthritis-knee-pain-results-from-the-victory-3-study/