Zilretta (sustained release triamcinolone acetonide) shows efficacy in phase III trial for severe osteoarthritis knee pain- Flexion Therapeutics

Flexion Therapeutics has reported that the Phase III clinical trial for its lead drug candidate Zilretta (also known as FX006, sustained release triamcinolone acetonide) met its primary endpoint at week 12, demonstrating highly significant, durable and clinically meaningful pain relief against placebo in patients with moderate to severe osteoarthritis (OA) knee pain. In addition, Zilretta achieved statistically significant analgesia against placebo at weeks 1 through 16 and patients treated with Zilretta experienced, on average, a 50 percent reduction in pain from baseline over weeks 1 through 12.

In pre-specified analyses, Zilretta achieved statistical significance against placebo in validated OA and quality of life secondary measures through week 12. In pre-specified secondary measures, compared to immediate-release triamcinolone acetonide (TCA), the most commonly injected intra-articular (IA) corticosteroid, Zilretta achieved statistical significance through 12 weeks on WOMAC A1 (pain), WOMAC B (stiffness) and WOMAC C (function) and the validated Knee injury and Osteoarthritis Outcome Score (KOOS) quality of life subscale and was numerically superior at weeks 2 through 12 on the daily pain rating scale, although it did not achieve statistical significance in that measure. The frequency of treatment-related side effects was comparable across all treatment arms in the trial. No drug-related serious adverse events were observed and no patients treated with Zilretta were discontinued from the study due to a treatment-related side effect.

Comment: Zilretta was designed using proprietary microsphere technology and is intended to provide localized and long-lasting pain relief over a period of months while minimizing systemic exposure and avoiding serious side effects common to oral therapies prescribed for OA pain. Current oral treatment options for OA knee pain include non-steroidal anti-inflammatory drugs (NSAIDS), COX II inhibitors and opioids.