The primary objective is to demonstrate that the auto-injector(AI) is suitable to be used to administer fasinumab at home by patients or their caregivers, as measured by collecting 12 weeks of actual-use data on the technical performance of the device.

The secondary objectives of the study are:

• To evaluate the successful injection of fasinumab by patients or their caregivers using the AI in an unsupervised setting
• To evaluate patient/caregiver satisfaction with the AI for fasinumab injection in an unsupervised setting
• To evaluate exposure in serum for fasinumab administered by patients or their caregivers using an AI in an unsupervised setting, or fasinumab administered by study staff using a PFS that has been used in the phase 3 program
• To characterize the safety, tolerability, and immunogenicity of fasinumab administered by patients or their caregivers using an AI in an unsupervised setting, or fasinumab administered by study staff using a PFS that has been used in the phase 3 program

Key Inclusion Criteria:

1. A clinical diagnosis of Osteoarthritis (OA) of the knee or hip based on the American College of Rheumatology criteria with radiologic evidence of OA (K-L score ≥2 for the index joint) at the screening visit
2. Moderate-to-severe pain in the index joint defined as a WOMAC average pain subscale score of ≥4 at both the screening and randomization visits
3. Willing to discontinue current pain medications and to adhere to study requirements for rescue treatments
4. A history of at least 12 weeks of analgesic use for pain due to OA of the knee or hip
5. History of regular use of analgesic medications for OA pain (defined as an average of 4 days per week over the 4 weeks prior to the screening visit), including NSAIDs, selective cyclooxygenase 2 inhibitors, opioids, paracetamol/acetaminophen, or combinations thereof

Key Exclusion Criteria:

1. History or presence at the screening visit of non-OA inflammatory joint disease (eg,rheumatoid arthritis, lupus erythematosus, psoriatic arthritis, pseudo-gout, gout, spondyloarthropathy, polymyalgia rheumatica, joint infections within the past 5 years), Paget's disease of the spine, pelvis or femur, neuropathic disorders, multiple sclerosis, fibromyalgia, tumors or infections of the spinal cord, or renal osteodystrophy
2. History or presence on imaging of arthropathy (osteonecrosis, subchondral insufficiency fracture, rapidly progressive OA type 1 or type 2), stress fracture, recent stress fracture, neuropathic joint arthropathy, hip dislocation (prosthetic hip dislocation is eligible), knee dislocation (patella dislocation is eligible), congenital hip dysplasia with degenerative joint disease, extensive subchondral cysts, evidence of bone fragmentation of collapse, or primary metastatic tumor with the exception of chondromas or pathologic fractures during the screening period
3. Trauma to the index joint within 3 months prior to the screening visit
4. Signs or symptoms of carpal tunnel syndrome within 6 months of screening
5. Patient is not a candidate for MRI

Note: Other protocol defined Inclusion/Exclusion criteria apply.

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing

Individual de-identified participant data will be made available once the indication has been approved by a regulatory body, if there is participant consent and there is not a reasonable likelihood of participant re-identification

Qualified researchers may request access to anonymized patient level data or aggregate study data when Regeneron has received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc) for the product and indication, has the legal authority to share the data, and has made the study results publicly available (eg, scientific publication, scientific conference, clinical trial registry).