Flexion Reports Positive Topline Results from Phase 2a Trial with FX006

Flexion Therapeutics, Inc.

today announced positive topline clinical trial results from a Phase 2a synovial fluid PK study of FX006, which demonstrated, for the first time, that a single intra-articular (IA) injection of FX006 can provide therapeutic concentrations of drug in joint fluid for at least 12 weeks. FX006 is Flexion's novel, non-opioid, sustained-release, IA formulation of TCA. It is designed to provide prolonged pain relief for the treatment of osteoarthritis (OA) of the knee, while potentially avoiding untoward systemic effects associated with immediate-release steroids. These FX006 data represent a six-fold increase in the duration of joint residency compared with immediate-release TCA, which is the current standard of care injectable therapy. It is also noteworthy that a prior PK study of FX006 demonstrated that the peak plasma concentration in the hours following injection was decreased 40-fold relative to immediate-release TCA, a decrease that may meaningfully reduce adverse systemic side effects. Neil Bodick, M.D., Ph.D., Flexion Therapeutics Chief Medical Officer, said, "The pharmacokinetic data from this Phase 2a clinical trial underpin the differentiation of FX006 from the current standard of care. They are consistent with the efficacy observed in our initial Phase 2b dose-ranging clinical trial, where a single dose of FX006 produced a meaningful prolongation and amplification of pain relief compared to immediate-release TCA. Importantly, the results from this trial will inform the design of our planned repeat-dose clinical study of safety and tolerability in patients with OA." In this multi-center, open-label study of 50 patients with OA of the knee, researchers assigned patients sequentially to one of five groups that received a single IA injection of either 10 or 40 mg of FX006 or 40 mg of immediate-release TCA. Synovial fluid concentrations of drug were measured at 12 weeks in all dose groups and also at 16 and 20 weeks in the FX006 40 mg dose group. At 12 weeks both the FX006 10 mg and 40 mg dose groups had therapeutic concentrations of drug in synovial fluid. In contrast, the 40 mg immediate-release TCA dose group had concentrations of drug that were below the lower limit of quantitation. The FX006 40 mg dose group also demonstrated readily measurable concentrations of drug at 16 weeks, which fell to below the lower limit of quantitation at 20 weeks.