This study aims to see if a treatment called **rexlemestrocel-L combined with HA (hyaluronic acid)** can reduce **chronic low back pain** in patients. Chronic low back pain means having pain in your lower back that doesn't go away for a long time. This study will check if this treatment helps with pain 12 months after it's given and if it is safe. The treatment involves an injection into the back.

To join, you need to have had back pain for at least six months, and it should be pretty bad. You also should have tried other treatments for at least three months without success. You cannot join if you have had certain types of back surgery, have other medical problems like osteoporosis, or if you have had certain injections recently.

• This study lasts for 12 months with regular check-ins.
• Participants will receive a single injection.
• Some people will get a placebo, which is not the actual treatment, to compare results.