The objectives of this study were to characterize the local extent and duration of exposure of TA from FX006 and TCA IR, characterize the systemic PK of FX006 and TCA IR, and assess the safety and general tolerability of a single 5 mL IA injection of 32 mg FX006 relative to 40 mg of TCA IR in patients with OA of the knee.

This study employed an open-label, single administration design and was conducted in male and female patients ≥40 years of age with OA of the knee.

Patients were enrolled sequentially with at least 10 patients per cohort as follows:

Cohort A: FX006 32 mg, Final Visit at Week 20 Cohort B: FX006 32 mg, Final Visit at Week 16 Cohort C: FX006 32 mg, Final Visit at Week 12 Cohort D: FX006 32 mg, Final Visit at Week 6 Cohort E: FX006 32 mg, Final Visit at Week 1 Cohort F: TCA IR 40 mg, Final Visit Week 6

Each patient was screened to confirm eligibility and assigned to a cohort on Day 1/baseline. Each patient was evaluated for safety during his/her participation in the study at 6, 12, 16, or 20 weeks following a single IA injection depending on the assigned Cohort, and plasma and synovial fluid was collected for drug concentration measurements.

Safety and tolerability was assessed by physical examinations, index knee examinations, vital signs, clinical laboratory evaluations, and adverse events (AEs).

No efficacy assessments were employed in this study.

Inclusion Criteria:

• Written consent to participate in the study
• Willingness and ability to comply with the study procedures and visit schedules and ability to follow verbal and written instructions
• Symptoms associated with OA of the knee for ≥ 6 months prior to Screening (patient reported is acceptable)
• Currently meets American College of Rheumatology (ACR) Criteria (clinical and radiological) for OA
• Index knee pain for >15 days over the last month (as reported by the patient)
• Body mass index (BMI) ≤ 40 kg/m2
• Ambulatory and in good general health

Exclusion Criteria:

• Fibromyalgia, Reiter's syndrome, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, or arthritis associated with inflammatory bowel disease
• History of infection in the index knee joint
• Clinical signs and symptoms of active knee infection or crystal disease of the index knee within 1 month of Screening
• Presence of surgical hardware or other foreign body in the index knee
• Unstable joint within 12 months of Screening
• IA corticosteroid (investigational or marketed) in any joint within 6 months of Screening
• IA hyaluronic acid (investigational or marketed) in the index knee within 6 months of Screening
• Intravenous or Intramuscular corticosteroids (investigational or marketed) within 3 months of Screening
• Oral corticosteroids (investigational or marketed) within 1 month of Screening
• Inhaled, intranasal or topical corticosteroids (investigational or marketed) within 2 weeks of Screening
• Any other IA investigational drug/biologic use within 6 months of Screening or 5 half-lives (whichever is longer)
• Prior use of FX006
• Women of child-bearing potential not using effective contraception or who are pregnant or nursing

Adverse Events were collected following IA administration on Baseline/Day 1 up to 20 weeks.

Subsequent to completion of clinical studies extensive testing was performed to assess the actual FX006 dose delivered. It was determined that the FX006 delivered dose to the patient from an FX006 40 mg vial is 32 mg.