Flexion Therapeutics announces publication of independent data review of pain relief by Zilretta in the Journal Drugs

Flexion Therapeutics, Inc. announced an independent evaluation of clinical data for Zilretta (triamcinolone acetonide extended-release injectable suspension), conducted by Adis Drug Review, was published in the journal Drugs(Vol 79 (4) pp 455–462). The evidence-based evaluation concluded that Zilretta provided effective pain relief, while being generally well-tolerated as demonstrated in clinical studies, and it expands the treatment options for osteoarthritis (OA) knee pain. Adis Drug Review provides an independent analysis of data on new or established treatments, across all therapeutic areas, to determine clinical potential.

The assessment of Zilretta included data from six clinical trials conducted over the past seven years, which evaluated 1,347 patients, 613 of whom were treated with Zilretta.

The Adis Drug Evaluation found : Treatment with a single injection of Zilretta provided significant pain relief in patients with OA knee pain relative to placebo with respect to average daily pain (ADP) scoring in clinical trials and provided a similar level of pain relief to that of a single injection of triamcinolone acetonide crystalline suspension (TAcs). In the Phase III trial, patients who received Zilretta reported improvements in pain, stiffness, and physical function compared with TAcs and placebo in pre-specified exploratory endpoints, which utilized the OA-specific Western Ontario and McMaster Universities Arthritis Index. Furthermore, they also reported improvements compared with TAcs and placebo on the Knee Injury and OA Outcome Score Quality of Life assessment.

Zilretta had a similar tolerability profile to those seen with TAcs and placebo. Zilretta was generally well-tolerated with most adverse events (AEs) being of mild to moderate severity, and no radiographic evidence of rapidly progressing OA was observed over the 24-week study period in the Phase III trial. Patients with type 2 diabetes receiving Zilretta in the Phase II trial experienced a significantly smaller (p = 0.045) change in blood glucose elevation compared with those receiving TAcs and a negligible impact on their glycemic control. Results from the single-arm Phase IIIb trial showed that the tolerability of repeat administration of Zilretta was consistent with that seen in the single administration Phase III trial. An analysis of radiographs (X-rays) taken at baseline and Week 52 showed no evidence of deleterious effects on cartilage or other aspects of joint structure with the repeat administration. Data suggest that a repeat administration of Zilretta may be similarly efficacious to an initial injection without further increasing the risk for AEs.

The most frequent AE in patients who received two injections of Zilretta was arthralgia in any joint (joint pain without swelling), including two treatment-related arthralgia cases after the first injection and no treatment-related cases following the second injection.

Comment: A randomized, double-blind, placebo-controlled Phase III trial evaluating the safety and efficacy of Zilretta in patients with hip OA is currently enrolling. The study is expected to complete in 2020.