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

Objective: Present outcomes of bilateral knee injections of CNTX-4975, a long-acting non-opioid analgesic.

Design: Open-label study.

Setting: Knee osteoarthritis.

Participants: 15 subjects with bilateral moderate to severe knee osteoarthritis pain.

Interventions: Intra-articular lidocaine 2% (15 mL) given 3–30 minutes before a single CNTX-4975 1.0 mg intra-articular injection into each knee (left knee, then right), with 7 (±2) days between injections.

Main Outcome Measures: Pain with walking over past 24 hours: Numeric Pain Rating Scale (NPRS, 0–10; 0=no pain, 10=worst pain imaginable) at baseline (NPRS 4–9) and 6 weeks, each knee. Change in pain, each knee: Patient Global Impression of Change (PGIC; 7-point scale, very much improved to very much worse). Injection site issues and adverse events (AEs) were recorded.

Results: Baseline post-injection averaged NPRS scores across both knees ranged from 4 to 8. Mean pain with walking score decreased from 6.0 (baseline) to 1.5 (day 42; P<.00001, two-tailed, paired t-test). 10 of 15 subjects reported pain level ≤2, 6 of whom reported no pain in either knee 6 weeks post-injection. A similar pattern of improvement was evident with PGIC: in 26 of 30 recordings (15 subjects, both knees), subjects described pain 6 weeks post-injection as much or very much improved. No subject reported pain unchanged or worse. Treatment-emergent AEs (TEAEs) reported day of injection: nausea (n=3), headache (n=2), vasovagal attack, dizziness, elevated blood pressure, and tachycardia (n=1 each), all reported mild; 2 (vasovagal attack, 1 report of nausea) deemed possibly related to treatment. TEAEs reported after day of injection: insect bite (n=2), hay fever, vasovagal attack, back pain, acid reflux (esophageal), allergic conjunctivitis, and bruise (n=1 each), all mild and deemed unlikely/not related to study treatment.

Conclusions: Pain reduction following bilateral intra-articular CNTX-4975 1.0 mg injections into osteoarthritic knees was clinically and statistically significant at 6 weeks.

Level of Evidence: Level I

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/bilateral-intra-articular-injection-of-cntx-4975-for-management-of-painful-osteoarthritis-of-the-knee-results-at-6-weeks-from-an-open-label-trial/