A Study to Compare Five Different Treatment Regimens of CNTX-4975 for Participants With Chronic, Moderate-to-Severe Osteoarthritis Pain

Key Inclusion Criteria:

- Male or female subjects between 40 and 95 years of age (inclusive)

- Confirmation of osteoarthritis (OA) of the knee: radiography of both knees using
standard standing films (scored by the investigator) or using the fixed flexion
method, taken during the Screening Visit of CNTX-4975i-OA-301 or CNTX-4975i-OA-304.

- Confirmation of OA of the index knee: American College of Rheumatology (ACR)
diagnostic criteria

- For subjects for monoarticular knee injection, the index knee must have moderate to
severe pain at screening associated with OA, which must be stable for a minimum of 6
months prior to Screening, as assessed by the investigator.

- Body mass index ≤45 kg/m^2.

Key Exclusion Criteria:

- Joint replacement surgery of the index knee at any time, or open surgery of the index
knee in the past 24 months. Joint replacement of the contralateral knee is permitted
for subjects who will not receive an injection in the contralateral (natural) knee.

- Prior arthroscopic surgery of the index knee within 6 months of Screening.

- Any painful conditions of the index knee due to joint disease other than OA. Radicular
or referred pain involving the index knee or from joint disease other than OA
involving the index knee, such as, but not restricted to chondromalacia patellae,
inflammatory disease, metabolic diseases, gout/pseudogout, hemochromatosis,
acromegaly, etc.

- Periarticular pain from any cause, including referred pain, bursitis, tendonitis, soft
tissue tenderness, or subacute/acute pain from injury.

- Other chronic pain anywhere in the body that requires the use of chronic analgesic
medications, including, but not limited to, local painful areas, myofascial pain
syndromes, fibromyalgia, genetic, metabolic abnormalities, hematologic, or neuropathic
pain.