Mesoblast (ASX:MSB) Announces Key FDA Meeting for Opioid Cessation Drug Rexlemestrocel-L

Mesoblast Limited (ASX: MSB, NASDAQ: MESO) has reached a key regulatory point, securing a scheduled Mesoblast FDA Rexlemestrocel-L Meeting for early December 2025. The discussion will focus on data from its opioid cessation treatment programme. This development aligns with recent FDA guidance that underscores the need for non-opioid treatments for chronic pain, placing Mesoblast in a position to address the ongoing opioid crisis in the United States.

This ASX announcement follows the release of Mesoblast’s Phase 3 clinical trial data. The results indicated that patients who received a single intra-discal injection of rexlemestrocel-L showed 3-fold higher rates of complete opioid cessation by 36 months when compared to control groups, with a statistical significance of p=0.008. The upcoming December meeting is a critical event for the company’s regulatory strategy and commercial future.

Why Does the Mesoblast FDA Rexlemestrocel-L Meeting Matter for Investors?

The healthcare industry is under considerable pressure to find solutions to the opioid epidemic. Chronic low back pain is a major contributor, accounting for approximately 50% of prescription opioid use in the United States. Mesoblast’s cellular therapy is designed to address this unmet medical need with a single-injection treatment that targets both pain reduction and opioid dependency.

Chief Executive Silviu Itescu stated: “FDA has emphasised 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.”

The company’s initial randomised controlled Phase 3 trial involved 404 patients, with 168 patients using opioids at the study’s start. The results show compelling efficacy in a patient group that represents a large segment of America’s opioid-dependent chronic pain sufferers. Furthermore, the September 2025 FDA Guidance to Industry on the Development of Non-Opioid Agents for the Treatment of Chronic Pain establishes a favourable regulatory climate for this therapeutic approach.

Key Clinical Trial Metrics

How Does Rexlemestrocel-L Address Chronic Back Pain?

Mesoblast’s rexlemestrocel-L is a second-generation allogeneic stromal cell product. It combines STRO3-immunoselected mesenchymal stromal cells with hyaluronic acid, which acts as a delivery agent. This cellular therapy is aimed at degenerative disc disease and functions by releasing anti-inflammatory factors that counter various parts of the immune system’s inflammatory response.

The treatment works by addressing chronic low back pain directly at its source through an injection into the affected lumbar disc. This method is fundamentally different from traditional pain management strategies, which typically focus on symptom control rather than the underlying inflammatory causes.

Treatment Characteristics:

• Industrial-scale manufacturing to ensure consistent product quality.
• Cryopreserved, off-the-shelf availability for immediate patient access.
• A single treatment protocol, which may reduce the burden on the healthcare system.
• Targets inflammatory processes associated with degenerative disc disease.

Back pain is the primary cause of disability in Americans under 45, with an annual prevalence of 10-30% in the adult population. Its link to degenerative disc disease affects over 7 million people in the United States, indicating a substantial market for effective treatments.

What Regulatory Advantages Does Mesoblast Have?

The FDA has granted rexlemestrocel-L a Regenerative Medicine Advanced Therapy (RMAT) designation for the treatment of chronic low back pain. This status offers notable regulatory benefits, including all the advantages of Breakthrough and Fast Track designations. The upcoming Mesoblast FDA Rexlemestrocel-L Meeting will concentrate specifically on the opioid reduction and cessation data.

RMAT Benefits Include:

• Eligibility for rolling review of Biologics License Application (BLA) submissions.
• Qualification for priority review, with a standard 6-month timeline.
• More frequent communication and meetings with the FDA.
• An expedited approval pathway for treatments addressing unmet medical needs.

Critically, the FDA has already agreed on the design of Mesoblast’s 300-patient confirmatory Phase 3 trial and the 12-month pain reduction endpoint as an approvable indication. This regulatory alignment lowers development risk and presents a clearer path to market.

What Are the Commercial Prospects for Rexlemestrocel-L?

Mesoblast’s confirmatory Phase 3 trial is currently recruiting 300 patients across 40 sites in the United States, with enrolment expected to conclude in the next quarter. The company is aiming for FDA approval based on a reduction in chronic low back pain over 12 months, an endpoint that was met in its first Phase 3 trial.

The commercial opportunity extends beyond the US market. Mesoblast has partnerships in Japan, Europe, and China, which could provide global market access. With a market capitalisation of approximately $3.09 billion and 1,246,754,403 shares on issue, the company has substantial backing from investors.

Market Positioning Factors:

• A potential first-mover advantage as the first FDA-approved cellular therapy for chronic low back pain.
• Intellectual property protection through over 1,000 granted patents extending to at least 2044.
• Scalable manufacturing with industrial-scale, cryopreserved production.
• A platform technology applicable to multiple inflammatory conditions.

How Will This FDA Meeting Impact Development Timelines?

The December 2025 Mesoblast FDA Rexlemestrocel-L Meeting is a key event for the company’s regulatory and commercial plans. The focus on opioid reduction data aligns with current healthcare policy priorities.

Meeting Significance:

• Offers potential regulatory validation of opioid cessation as a therapeutic endpoint.
• Provides clarification on the commercial pathway for dual pain relief and opioid reduction claims.
• May accelerate development timelines through enhanced FDA collaboration.

Key Investment Catalysts Ahead

What Makes Mesoblast’s Technology Platform Unique?

Beyond the rexlemestrocel-L programme, Mesoblast operates a cellular therapy platform that addresses multiple inflammatory conditions. The company’s proprietary mesenchymal lineage cell therapy technology is designed to respond to severe inflammation by releasing anti-inflammatory factors that modulate immune system responses.

The platform’s versatility is demonstrated across several therapeutic areas:

• Steroid-refractory acute graft versus host disease (Ryoncil, already FDA-approved).
• Heart failure applications currently under development.
• Biologic-resistant inflammatory bowel disease in clinical testing.

This diversification provides multiple potential revenue streams and reduces the company’s reliance on a single therapeutic candidate. The upcoming meeting with the FDA is a critical step in advancing its lead product for chronic back pain and opioid cessation, representing a major catalyst for investors following the company’s progress.

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