FDA Grants Regenerative Medicine Advanced Therapy (Rmat) Designation for Rexlemestrocel-L in Chronic Low Back Pain

On Feb 9, 2023

Mesoblast Limited announced that the United States Food and Drug Administration’s (FDA) Office of Tissues and Advanced Therapies (OTAT) has granted Regenerative Medicine Advanced Therapy (RMAT) designation for rexlemestrocel-L in the treatment of chronic low back pain (CLBP) associated with disc degeneration, in combination with hyaluronic acid (HA) as delivery agent for injection into the lumbar disc.

RMAT designations aim to expedite the development of regenerative medicine therapies intended to treat, modify, reverse, or cure a serious or life-threatening disease or condition where preliminary clinical evidence indicates that the drug has the potential to address unmet medical needs for the disease or condition. An RMAT designation for rexlemestrocel-L 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).

There is a significant need for a safe, effective, and durable opioid-sparing treatment in patients with CLBP associated with degenerative disc disease. Data from the completed 404-patient randomized, blinded placebo-controlled Phase 3 trial of rexlemestrocel-L combined with HA formed the basis for FDA’s determination that Mesoblast’s allogeneic cell therapy has the potential to address unmet medical needs for patients suffering from CLBP due to disc degeneration. Results from the trial showed that:

A single injection of rexlemestrocel-L+HA into the lumbar disc resulted in significant reduction in pain compared with saline control at 12 and 24 months across all subjects (n=404).
- The reduction in low back pain observed in all subjects was substantially enhanced in the pre-specified population with CLBP of shorter duration than the median of 68 months for the study (n=194).
- Significant improvement in function and quality of life measures were observed in subjects with a shorter duration of CLBP at baseline.
- Pain reduction through 36 months was seen in the subset of patients using opioids at baseline (n=168) with the rexlemestrocel-L+HA group having substantially greater reduction at all time points compared with saline controls.
- Among patients on opioids at baseline, despite instructions to maintain existing therapies throughout the trial, at 36 months 28% who received rexlemestrocel-L + HA were not taking an opioid compared with 8% of saline treated controls.

“We are pleased to receive RMAT designation for our cellular therapy to treat CLBP due to disc degeneration” said Mesoblast Chief Executive Silviu Itescu. “We look forward to working closely with FDA to efficiently generate the additional data needed to support marketing approval of rexlemestrocel-L for the treatment of this serious and debilitating condition.”