FDA clears regulatory path for Mesoblast’s back pain cell therapy

Mesoblast shares were in focus Monday after the company announced positive formal feedback from the U.S. Food and Drug Administration (FDA) regarding its allogeneic cell therapy, rexlemestrocel-L.

The regulator’s guidance provides a definitive framework for a Biologics License Application (BLA) in the treatment of chronic discogenic low back pain (CLBP), a condition affecting millions with few non-surgical options.

Following a Type B meeting, the FDA acknowledged that results from the first Phase 3 trial (MSB-DR003) showed pain-intensity outcomes that "favor" rexlemestrocel-L over placebo.

Crucially, the agency confirmed that a clinically meaningful reduction in pain at the 12-month mark is an acceptable primary endpoint to support the product's efficacy for approval.

The agency also opened the door for a significant commercial differentiator: opioid stewardship.

The FDA indicated that if a second "adequate and well-controlled" trial demonstrates robust results, data regarding the reduction or cessation of opioid use could be included in the product's official labeling.

In previous analyses, patients treated with the cell therapy showed a three-fold higher rate of opioid cessation compared to controls at 36 months.

"Rexlemestrocel-L could offer a powerful solution for management of chronic inflammatory back pain with the added potential to contribute to the administration’s goals of opioid reduction," said Mesoblast CEO Silviu Itescu.

The company is now racing to complete its confirmatory Phase 3 study, MSB-DR004.

The trial is currently more than 50% enrolled across 40 U.S. sites, with Mesoblast aiming to reach its 300-patient enrollment target within the next three months.

As a recipient of the FDA’s Regenerative Medicine Advanced Therapy (RMAT) designation, the program is eligible for rolling review, which could allow the company to submit portions of its BLA as they are completed.