Mesoblast Limited has reached a critical juncture in its development timeline, completing patient treatment in the MSB-DR004 Phase 3 trial for chronic low back pain associated with degenerative disc disease. The company enrolled and treated 350 patients with either rexlemestrocel-L, its investigational allogeneic cellular medicine, or sham injection, surpassing the original 300-patient target due to strong demand from trial investigators seeking to include their patients in the program.
This milestone matters significantly because the trial is now sufficiently powered to demonstrate the treatment benefit of rexlemestrocel-L compared to controls. The primary endpoint will confirm whether the drug can maintain the durable pain reduction at 12 months that was observed in the earlier Phase 2 MSB-DR003 trial. If successful, this would establish the foundation for a regulatory filing in a major therapeutic area where unmet medical need remains profound despite decades of treatment options.
The market opportunity underlying this trial is substantial. Chronic low back pain caused by degenerative disc disease affects over 7 million people in the United States alone and is the leading cause of disability for Americans under 45 years old. The company has estimated potential peak year revenues exceeding US$10 billion even assuming only single-digit market penetration. This projection reflects both the prevalence of the condition and the current limitations of available treatments, which range from physical therapy to opioid dependency and surgical intervention.
Rexlemestrocel-L holds Regenerative Medicine Advanced Therapy designation from the FDA, which provides eligibility for priority review once a biologics license application is filed. This regulatory pathway potentially shortens the review timeline compared to standard approval processes, an important advantage in a space where patients are actively seeking alternatives to chronic opioid use. A secondary endpoint in the trial will specifically measure reduction in opioid consumption, given that discogenic back pain accounts for approximately 50 percent of opioid prescriptions in the United States.
Top-line results from the trial are expected in mid-2027 once the last enrolled patient completes 12 months of follow-up assessment. The coming months will provide incremental clarity through any interim safety reviews or regulatory communications that might be disclosed. Success of this trial could position rexlemestrocel-L as the company’s first blockbuster product, fundamentally reshaping Mesoblast’s commercial profile and valuation. This announcement has been flagged as price sensitive material by the ASX.
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About Mesoblast Limited (ASX: MSB)
Mesoblast Limited is a biotechnology company headquartered in Melbourne, Australia, specializing in the development of allogeneic cellular medicines derived from adult stem cells. The company focuses on treating severe and life-threatening inflammatory conditions, with a pipeline spanning cardiovascular diseases, spine orthopedic disorders, and immune-mediated conditions. It is a world leader in the development of off-the-shelf cellular medicine therapies for these therapeutic areas.
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