Mesoblast Limited (Nasdaq:MESO; ASX:MSB), global leader in allogeneic cellular medicines for inflammatory diseases,  announced that it has achieved its target of at least 300 patients treated in the MSB-DR004 pivotal Phase 3 randomized controlled trial of rexlemestrocel-L for chronic low back pain (CLBP) associated with degenerative disc disease. The trial aims to confirm the durable pain reduction from a single intra-discal injection of rexlemestrocel-L seen in the earlier MSB-DR003 trial.

Silviu Itescu, Chief Executive of Mesoblast, said: “Completing our target of treating at least 300 patients in the placebo-controlled pivotal back pain trial ensures the trial is well powered for success. Commercial manufacturing is proceeding in parallel so that we can file for approval as soon as possible after trial results readout.”

CLBP caused by inflammation and degenerative disc disease is a serious condition with a prevalence of over 7 million people in the U.S. alone. The indication is a potential blockbuster for Mesoblast with potential peak year revenue of >US$10 billion with single digit market penetration.

The trial's primary endpoint is powered to show a significant difference in reduction of low back pain at 12 months between rexlemestrocel-L and sham controls. Secondary endpoints include improvements in function, quality of life, and cessation of pain medication, including opioids.

Rexlemestrocel-L has Regenerative Medicine Advanced Therapy (RMAT) designation from the United States Food and Drug Administration (FDA) for treatment of CLBP due to degenerative disc disease providing eligibility for priority review once the Biologics License Application (BLA) has been filed. Top-line results are expected in mid-CY2027 after the last treated patient has completed 12 months follow-up.

Rexlemestrocel-L for Chronic Low Back Pain associated with Degenerative Disc Disease
The 300-patient randomized controlled confirmatory Phase 3 trial of Mesoblast’s second generation allogeneic, STRO3-immunoselected, and industrially manufactured stromal cell product candidate rexlemestrocel-L in combination with hyaluronic acid (HA) as delivery agent for injection into the lumbar disc is actively enrolling in patients with chronic low back pain (CLBP) due to inflammatory degenerative disc disease (DDD) of less than five years duration at multiple sites across the U.S.

FDA has previously agreed on the design of this 300-patient randomized, placebo-controlled confirmatory Phase 3 trial, and the 12-month primary endpoint of pain reduction as an approvable indication. This endpoint was successfully met in Mesoblast’s first Phase 3 trial. Key secondary measures include improvement in quality of life and function.

A particular focus is on treatment of patients on opioids, since discogenic back pain accounts for approximately 50% of prescription opioid usage in the U.S. Significant pain reduction and opioid cessation were observed in Mesoblast’s first Phase 3 trial.

FDA has designated rexlemestrocel-L a Regenerative Medicine Advanced Therapy (RMAT) for the treatment of chronic low back pain. RMAT designation provides all the benefits of Breakthrough and Fast Track designations, including rolling review and eligibility for priority review on filing of a Biologics License Application (BLA).