Pacira BioSciences bought Flexion Therapeutics for $8.5 per share. The company will pay up to $8 more per share, contingent on reaching Zilretta's sales targets and approval of two candidates in Phase 1 clinical trials. Zilretta was approved by the FDA in 2017 as a non-opioid pain reliever for osteoarthritis of the knee and is Flexion's primary drug of choice.