Mesoblast Limited (NASDAQ: MESO) has announced that the U.S. Food and Drug Administration (FDA) has provided constructive feedback related to the company’s prospective Biologics License Application (BLA) for rexlemestrocel-L, its investigational allogeneic cell therapy aimed at treating chronic discogenic low back pain (CLBP). This development comes after the FDA conducted a Type B meeting review of clinical data from Mesoblast’s initial randomized controlled Phase 3 trial, designated MSB-DR003.
The Phase 3 trial MSB-DR003 evaluated the efficacy of rexlemestrocel-L in lowering patient-reported pain levels and assessed its impact on opioid consumption over an extended period—up to three years—following a one-time administration of the therapy. Mesoblast has positioned this therapy for FDA approval specifically based on the 12-month pain reduction outcomes.
FDA Recognition of Rexlemestrocel-L's Therapeutic Impact
In reviewing data comparing rexlemestrocel-L to placebo, the FDA recognized that the treatment demonstrated a favorable effect on reducing pain intensity. The regulatory body confirmed that a meaningful decline in pain experienced by patients receiving the active therapy versus those receiving placebo at 12 months post-treatment could substantiate the product’s efficacy profile.
Furthermore, the FDA indicated that solid evidence showcasing opioid reduction—derived from at least one well-controlled clinical trial—may be incorporated into the Clinical Studies section of the product’s official labeling upon approval. This presents an opportunity for Mesoblast to highlight both pain management and opioid use benefits in their application.
Ongoing Clinical Trials and Regulatory Designations
Mesoblast is actively enrolling patients in a second randomized controlled Phase 3 trial known as MSB-DR004, which has surpassed 50% enrollment toward its 300-patient recruitment target. Completion of enrollment is anticipated within the next quarter, reinforcing Mesoblast’s commitment to generating comprehensive data for regulatory evaluation.
Additionally, rexlemestrocel-L has been granted Regenerative Medicine Advanced Therapy (RMAT) designation by the FDA specifically for the treatment of chronic discogenic low back pain. This designation is intended to expedite the development and review process for promising regenerative therapies addressing serious conditions.
Addressing Opioid Reduction Goals Through Novel Therapy
Mesoblast’s Chief Executive Officer, Silviu Itescu, commented on the therapy's potential impact, stating that rexlemestrocel-L offers a potent option for managing chronic inflammatory back pain. He emphasized the therapy’s possible role in supporting public health objectives related to reducing or eliminating opioid dependency among patients.
This focus is particularly relevant given that discogenic back pain constitutes approximately half of prescription opioid usage in the United States. Reducing reliance on opioids remains a critical goal in managing chronic pain safely and effectively.
Phase 3 Trial Data Supporting Opioid Cessation
Insights from Mesoblast’s initial Phase 3 trial involving 404 patients—including 168 individuals using opioids at baseline—revealed notable opioid cessation benefits associated with rexlemestrocel-L treatment. Specifically, over a 36-month period, patients receiving a single intra-discal injection of rexlemestrocel-L combined with hyaluronic acid demonstrated a more than threefold increase in the number of individuals discontinuing opioid use compared to saline-injected control subjects. This difference was statistically significant with a p-value of 0.008.
Additional Regulatory Pursuits
In parallel with its chronic pain program, Mesoblast is pursuing accelerated approval from the FDA for rexlemestrocel-L, marketed as Revascor, for a separate indication focusing on ischemic heart failure with reduced ejection fraction (HFrEF) and inflammation.
Market Response
At the time of this report, Mesoblast’s shares traded at $16.85, reflecting a decline of 3.41% on the day. This movement follows the announcement of FDA feedback and ongoing clinical developments.