Mesoblast (ASX:MSB) will meet with the U.S. Food and Drug Administration (FDA) next month to discuss new data showing significant reductions in opioid use among patients treated with its investigational cell therapy rexlemestrocel-L for chronic low back pain (CLBP).
The meeting follows results from the company’s first Phase 3 clinical trial (MSB-DR003), which involved 404 patients, including 168 who were taking opioids at baseline. In that study, patients receiving a single intra-discal injection of rexlemestrocel-L with hyaluronic acid (HA) were more than three times as likely to completely stop using opioids after 36 months compared with those receiving saline treatment (p = 0.008).
Mesoblast said the data align with the FDA’s new guidance encouraging the development of non-opioid therapies for chronic pain, issued in September 2025 amid escalating concern over the U.S. opioid crisis.
Chief Executive Silviu Itescu said the company looks forward to engaging with the agency. “The FDA has emphasised the importance of developing non-opioid treatments for chronic pain,” he said. “We look forward to discussing our plans for rexlemestrocel-L as an agent that may achieve both pain reduction and opioid cessation.”
Rexlemestrocel-L, which has received Regenerative Medicine Advanced Therapy (RMAT) designation from the FDA, is being developed for the treatment of degenerative disc disease, a significant cause of chronic pain and one of the leading drivers of long-term prescription opioid use.
Mesoblast is currently recruiting patients for a 300-patient confirmatory Phase 3 trial at 40 U.S. sites, with enrolment expected to be completed in the coming quarter. The FDA has agreed that the primary endpoint of pain reduction over 12 months would be considered an approvable indication. Secondary endpoints include improvements in quality of life, function, and opioid use.
Back pain is the leading cause of disability among Americans under 45, affecting an estimated 7 million people with CLBP due to degenerative disc disease. The condition accounts for roughly half of all prescription opioid use in the United States.
Mesoblast’s platform is based on allogeneic, off-the-shelf mesenchymal stromal cell therapies that modulate inflammation and immune responses. Its first approved product, Ryoncil (remestemcel-L), is authorised in the U.S. for steroid-refractory acute graft-versus-host disease in paediatric patients, while its next-generation candidate rexlemestrocel-L is in late-stage development for both heart failure and chronic low back pain.
“There is a major unmet need for safe and effective treatments that not only relieve pain but help patients discontinue opioids,” Dr Itescu said. “Our goal is to make rexlemestrocel-L the first regenerative medicine therapy that addresses both.”