Mesoblast Limited announced that the U.S. Food & Drug Administration has scheduled a meeting in early December to discuss the company's data on opioid reduction and cessation from its first Phase 3 study of rexlemestrocel-L in patients with chronic low back pain. The meeting comes as the FDA emphasizes the importance of developing non-opioid treatments for chronic pain conditions.
Significant Opioid Cessation Results
In Mesoblast's first randomized controlled Phase 3 trial involving 404 patients, 168 of whom were taking opioids at baseline, the results demonstrated compelling efficacy for opioid cessation. Patients treated with a single intra-discal injection of rexlemestrocel-L combined with hyaluronic acid were more than 3-fold more likely to cease use of all opioids by 36 months compared with saline-treated controls (p=0.008).
"FDA has emphasized the importance of developing non opioid treatments for chronic pain, and we look forward to discussing plans for rexlemestrocel-L as an agent that may result in both amelioration of CLBP as well as opioid reduction or cessation," said Mesoblast Chief Executive Silviu Itescu.
Addressing the Opioid Crisis
The timing of this FDA meeting aligns with the agency's September 2025 guidance to industry on development of non-opioid agents for treatment of chronic pain. Chronic low back pain represents a significant contributor to the opioid epidemic, accounting for approximately 50% of prescription opioid usage in the United States. The condition affects over 7 million people in the US alone and is the leading cause of disability in Americans under 45 years.
Back pain has an annual prevalence of 10-30% in the general US adult population, with chronic low back pain caused by inflammation and degenerative disc disease representing a serious condition associated with impaired quality of life, severe limitations in daily activities, reduced work capacity, and negative mental health impacts.
Regulatory Pathway and Current Development
Rexlemestrocel-L has received Regenerative Medicine Advanced Therapy (RMAT) designation for treatment of chronic low back pain due to degenerative disc disease. This 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.
The FDA has previously agreed on the design of Mesoblast's 300-patient randomized, placebo-controlled confirmatory Phase 3 trial, including the 12-month primary endpoint of pain reduction as an approvable indication. This endpoint was successfully met in the company's first Phase 3 trial. Key secondary measures include improvement in quality of life and function.
Confirmatory Trial Progress
Mesoblast is actively recruiting for its confirmatory Phase 3 trial across 40 sites in the US, with enrollment expected to be completed in the coming quarter. The trial evaluates the company's second generation allogeneic, STRO3-immunoselected, and industrially manufactured stromal cell product candidate rexlemestrocel-L in combination with hyaluronic acid as a delivery agent for injection into the lumbar disc.
The study focuses on patients with chronic low back pain due to inflammatory degenerative disc disease of less than five years duration. A particular emphasis is placed on treatment of patients currently on opioids, given that discogenic back pain accounts for approximately half of prescription opioid usage in the United States.
Company Background
Mesoblast is a world leader in developing allogeneic cellular medicines for severe and life-threatening inflammatory conditions. The company's therapies respond to severe inflammation by releasing anti-inflammatory factors that counter and modulate multiple effector arms of the immune system, resulting in significant reduction of the damaging inflammatory process.
The company's Ryoncil (remestemcel-L-rknd) for treatment of steroid-refractory acute graft versus host disease in pediatric patients 2 months and older represents the first FDA-approved mesenchymal stromal cell therapy. Mesoblast maintains a strong intellectual property portfolio with over 1,000 granted patents or patent applications covering mesenchymal stromal cell compositions, manufacturing methods, and indications, providing commercial protection extending through at least 2044 in major markets.
