Mesoblast’s Rexlemestrocel-L Shows Clinically Meaningful 12-Month Pain Relief, FDA Confirms

FDA Feedback Highlights Rexlemestrocel-L’s Promise

Mesoblast Limited has taken a significant step forward in its quest to bring rexlemestrocel-L, an allogeneic cell therapy, to patients suffering from chronic discogenic low back pain (CLBP). The U.S. Food and Drug Administration (FDA) has acknowledged that the therapy demonstrates a clinically meaningful reduction in pain intensity at 12 months compared to placebo, based on data from Mesoblast’s first Phase 3 trial (MSB-DR003). This recognition supports the product’s efficacy and strengthens the case for regulatory approval.

Importantly, the FDA also confirmed that the robust opioid reduction observed in the trial could be reflected in the product’s clinical labelling. Given the ongoing opioid crisis in the United States, this potential benefit adds a compelling dimension to rexlemestrocel-L’s therapeutic profile.

Ongoing Phase 3 Trial and Regulatory Pathway

Mesoblast is actively recruiting for its second Phase 3 trial (MSB-DR004), which is more than halfway to its 300-patient target across 40 U.S. sites. This confirmatory study follows the FDA-agreed design and primary endpoint of pain reduction at 12 months, aiming to solidify the therapy’s clinical benefits. Secondary outcomes include improvements in quality of life and functional capacity, critical factors for patients debilitated by CLBP.

The therapy’s designation as a Regenerative Medicine Advanced Therapy (RMAT) by the FDA offers Mesoblast advantages such as rolling review and priority consideration, potentially accelerating the approval process. This status reflects the FDA’s recognition of rexlemestrocel-L’s innovative approach and unmet medical need.

Addressing a Major Public Health Challenge

Chronic low back pain, particularly when linked to degenerative disc disease, affects millions in the U.S. and is a leading cause of disability among adults under 45. It also accounts for roughly half of prescription opioid use in the country, underscoring the urgent need for effective non-opioid treatments.

Mesoblast’s therapy, which combines stromal cells with hyaluronic acid for targeted injection into the lumbar disc, aims to reduce inflammation and pain, potentially enabling patients to reduce or cease opioid use. The first Phase 3 trial showed that patients receiving rexlemestrocel-L were more than three times as likely to stop opioid use by 36 months compared to controls, a finding that resonates strongly amid the opioid epidemic.

Looking Ahead

While the FDA’s feedback is encouraging, final approval will depend on the successful completion of the ongoing trial and subsequent regulatory review. Mesoblast’s ability to translate these clinical benefits into market access and reimbursement will be critical to the therapy’s commercial success and its impact on public health.

With a strong intellectual property portfolio extending to 2044 and established manufacturing capabilities, Mesoblast is well positioned to advance rexlemestrocel-L. Investors and observers will be watching closely as the company moves toward potential FDA submission and eventual market launch.