This is a multi-center, randomized, double-blind, and placebo-controlled phase 3 study evaluating the safety and efficacy of HP-5000 in subjects with OA pain of the knees. The study will consist of up to a 28-day Screening Phase that will include a Washout Period of current prescription and over the counter (OTC) analgesics; a 12-week Double-blind Treatment Phase, and a 1-week safety Follow-up Phase.