Phase III study of Zilretta in osteoarthritis of the knee published in Rheumatology and Therapy.- Flexion Therapeutics

Flexion Therapeutics announced that the results from an open-label Phase IIIb clinical trial evaluating the safety and exploratory efficacy of repeat administration of Zilretta (triamcinolone acetonide extended-release injectable suspension) in patients with osteoarthritis (OA) of the knee were published in Rheumatology and Therapy. Key topline results include the fact that repeat administration of Zilretta appeared safe and well-tolerated, with no serious adverse events or discontinuations related to Zilretta. The most commonly reported adverse events were consistent with those reported in previous clinical studies of Zilretta. X-rays conducted at baseline and Week 52 showed Zilretta had no deleterious impact on cartilage or joint structure and there were no observations of chondrolysis, osteonecrosis, insufficiency fractures or clinically significant subchondral bone changes. The median time to a second injection was 16.6 weeks, with 25.1%, 33.5%, 20.7% and 20.1% of patients receiving their second injection at Week 12, 16, 20 and 24, respectively and among those who received two injections, the magnitude and duration of clinical benefit after the first and second injections were similar with marked numeric improvements from baseline in pain scores observed when first assessed at four weeks.

The data indicate that repeat administration of Zilretta was generally safe and well-tolerated. In addition, an analysis of radiographs (X-rays) taken at baseline and Week 52 showed Zilretta had no deleterious effects on cartilage or joint structure. The data also indicate that the magnitude and duration of pain relief experienced by patients after both the first and second injections was similar to the clinical benefit of Zilretta in the pivotal Phase III trial on which the FDA approval of Zilretta was based. The repeat administration study is the first to evaluate the effect of Zilretta in patients with the most advanced radiographic knee OA (Kellgren-Lawrence grade 4), demonstrating similar benefit compared to those with less advanced disease (KL-2 and 3).

See: "Safety and Efficacy of Repeat Administration of Triamcinolone Acetonide Extended-release in Osteoarthritis of the Knee: A Phase 3b, Open-label Study" Andrew I. Spitzer et al. Rheumatol Ther (2019). https://doi.org/10.1007/s40744-019-0140-z