Phase 3 Trial of One-Shot Low Back Pain Injection Completes Patient Treatment

Australian biotechnology company Mesoblast announced this week that its Phase 3 trial of rexlemestrocel-L, an experimental treatment for chronic low back pain, has completed treating all participants. The trial was expanded from an originally planned 300 people to 350 after investigators asked to include more of their patients.

Half of the participants received a single intra-discal injection of the active therapeutic, while the other half received a sham, or control, injection. The trial's primary goal is to measure how much pain participants report after 12 months, while secondary measures include physical function, quality of life, and whether patients could stop taking pain medication.

Rexlemestrocel-L is derived from human bone marrow and designed as an off-the-shelf injection intended to regenerate worn spinal discs, shifting the treatment approach from managing pain to attempting to rebuild the tissue behind it. Participants in the trial had experienced chronic low back pain for less than five years due to degenerative disc disease, the leading cause of back pain; an estimated 20% of US adults show disc degeneration by age 65.

"Completing treatment of 350 patients in our pivotal low back pain trial is a momentous milestone for the company as we now count down to the 12-month read-out for what we hope will be the basis of our first blockbuster product," said Mesoblast chief executive Silviu Itescu. The treatment already holds Regenerative Medicine Advanced Therapy designation from the US Food and Drug Administration for this use, meaning it could be prioritized for approval if the trial meets its goals. Results are expected by mid-2027, once all participants complete their 12-month evaluation.