This two-part study will be conducted in male and female patients, 30 - 80 years of age with painful OA of the index knee with Kellgren-Lawrence (K-L) Grade 2, 3 or 4.~Part 1 - SAD Phase: Up to three ascending doses of FX201 (low dose, mid dose and high dose) will be tested in cohorts of 5-8 patients. Each patient will only receive one injection of FX201. A maximum of 24 patients will be enrolled (range 15 to 24).~When a minimum of 4 weeks have elapsed since the last patient of the current cohort has been treated, all safety data will be collected and reviewed by an independent Data Monitoring Committee (DMC). After evaluating cohort safety data, the DMC will evaluate continuing the trial and initiating treatment in the next dosing cohort as well as expanding enrollment in dose level(s).~Part 2 - Expansion Phase: After the DMC has met to review safety data from each Cohort and has recommended expanding dose level(s), enrollment slots for dose levels reviewed by the DMC will be opened. A maximum of 105 patients [up to an additional 35 patients per dose level (up to 20 FX201 alone and up to 15 FX201 with IA methylprednisolone 40 mg/mL pre-treatment)].
This two-part study will be conducted in male and female patients, 30 - 80 years of age with painful OA of the index knee with Kellgren-Lawrence (K-L) Grade 2, 3 or 4.~Part 1 - Single Ascending Dose (SAD) Phase: Up to three ascending doses of FX201 will be tested in cohorts of 5-8 patients. Each patient will only receive one injection of FX201. An independent Data Monitoring Committee (DMC) will review safety and guide the conduct of the study.~Part 2 - Expansion Phase: Up to an additional 35 patients will be enrolled at each dose level reviewed by the DMC. Each patient will only receive one injection of FX201.