A Prospective, Multicenter, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy and Safety of a Single Injection of Rexlemestrocel-L Alone or Combined With Hyaluronic Acid (HA) in Subjects With Chronic Low Back Pain

• Male and female participants 18 years of age and older

• If female of childbearing potential, participant is non-pregnant, non-nursing, and agrees to use highly effective methods of contraception for a minimum of 24 months post-treatment

• Signed informed consent and country-appropriate privacy forms indicating participant is willing to undergo treatment and willing to be available for each examination scheduled over the study duration

• Have documented diagnosis of moderate radiographic degeneration of an intervertebral disc from L1 to S1, with a disc suspected of causing chronic low back pain (CLBP) associated with moderate radiographic degeneration at a lumbar disc is defined as the following (participant must meet all of the listed conditions):

‣ Chronic low back pain for at least 6 months

⁃ Have failed 6 months of conservative back pain care. (Conservative treatment regimens may include any or all of the following: initial rest, medications \[e.g., anti-inflammatory, analgesics, narcotics/opioids, muscle relaxants\], massage, acupuncture, chiropractic manipulations, activity modification, home-directed lumbar exercise program, and non-invasive pain control treatments or procedures)

⁃ Have at a minimum undergone supervised physical therapy, such as daily walking routines, therapeutic exercises, and back education programs specifically for the treatment of low back pain and taken a pain medication for back pain (e.g. non-steroidal anti-inflammatory drug (NSAID) and/or opioid medication).

⁃ Change from normal disc morphology of the index disc as defined by radiographic evaluation by the core imaging evaluation provider. Radiographs must show all of the following:

• A modified Pfirrmann score of 3, 4, 5 or 6 on magnetic resonance imaging (MRI) at the index disc

• Modic Grade II changes or less on MRI at the index disc

• With or without contained disc protrusion at the index disc on MRI

• e. Low back pain of at least 40mm and not more than 90mm of 100mm on low back pain visual analogue scale (VAS) (average pain over 24 hours)

• f. Leg pain ≤20mm in both legs on a 100mm VAS scale

• g. Oswestry disability index (ODI) score of at least 30 and no more than 90 on a 100 point scale.