Flexion Therapeutics is an American pharmaceutical company based in Burlington, Massachusetts that is developing reformulated sustained release versions of existing drugs that are intended to be injected into the joint to treat osteoarthritis.
It was founded around 2007 by two former Eli Lilly & Co. executives and went public in 2014.
In November 2016 the FDA accepted Flexion's New Drug Application for FX006, a sustained-release formulation of triamcinolone acetonide (a corticosteroid), branded "Zilretta". In March 2017 FiercePharma reported that Flexion was in discussions with Sanofi about a possible acquisition, valued at the time at around $1 billion.
Flexion had been developing FX007, a selective small-molecule TrkA inhibitor that it had licensed from AstraZeneca, for osteoarthritis. As of March 2017 Flexion had terminated development. Flexion had also terminated development of FX005, a P38 mitogen-activated protein kinase inhibitor, by that time.