Osteoarthritis Knee Pain Relief Study of 0.25% 920-CGS-200

This is a study of a over-the-counter, capsaicin-based (0.25%) topical analgesic for management of osteoarthritis knee pain meeting the US Food and Drug Administration's (FDAs) Tentative Final Monograph (TFM) guidance for "External Analgesic Drug Products For Over-the-Counter Human Use," published in the Federal Register on February 8, 1983 (final proposed 21 CFR 348). Subjects meeting the inclusion criteria and not meeting the exclusion criteria were randomized into one of four groups: once daily treatment with active product, once daily treatment with product vehicle (no capsaicin), twice daily treatment with active product, and twice daily treatment with product vehicle (no capsaicin), all for 7 consecutive days of treatment. The twice daily treatments were spaced approximately 12 hours apart. Both knees received study drug treatment but only one knee per subject was assigned as the "study knee". Osteoarthritis knee pain was assessed by the 100 mm visual analog scale and the response criterion was a 50% or greater reduction in osteoarthritis knee pain from baseline. Baseline was defined as the visual analog scale recorded not more than 30 minutes before the first study drug application (on Study Day 1). For subjects in the once daily (QD) groups the osteoarthritis knee pain assessments were at 12 hrs after the initial application (during Study Day 1) and 24 hours (Study Day 2) after the initial application and then once in the morning on Study Days 3 - 28. For subjects in the twice daily (BID) groups the osteoarthritis knee pain assessments were at 12 hrs after the initial application (during Study Day 1) and 24 hours(Study Day 2) after the initial application and then once in the morning and once 12 hours later on Study Days 3 - 28. Tolerability data were also collected as reported burning-stinging pain, erythema and pruritus at the site of application.