Mesoblast Limited has received a Biologics License Application (BLA) filing number from the U.S. Food and Drug Administration (FDA) and has requested a modular review of its application for rexlemestrocel-L. The therapy is intended for the prevention of life-threatening gastrointestinal bleeding due to right ventricular dysfunction in end-stage heart failure patients with a left ventricular assist device (LVAD). This regulatory step is significant for patients with high mortality and irreversible morbidity associated with orphan rare diseases.

The FDA recently provided additional guidance regarding regulatory flexibility for products addressing rare diseases. The new draft guidance, titled ‘Demonstrating Substantial Evidence of Effectiveness for Human Drug and Biological Products’, emphasizes a flexible approach to substantial evidence of effectiveness. This follows a May guidance titled ‘Chemistry, Manufacturing, and Controls Flexibilities for Developing Human Cellular and Gene Therapy Products for a Biologics License Application.’

Rexlemestrocel-L has received Orphan Drug Designation for the prevention of life-threatening major mucosal bleeding events. It also holds Regenerative Medicine Advanced Therapy (RMAT) designation for this patient population, which provides eligibility for rolling and priority reviews of the BLA. Mesoblast Chief Executive Dr. Silviu Itescu stated that the company looks forward to working closely with the FDA to make the therapy available for end-stage heart failure patients on mechanical devices who are at high risk of life-threatening gastrointestinal bleeding.

The investigational therapy is an allogeneic preparation of immunoselected and culture-expanded mesenchymal precursor cells (MPC). It is being developed as an immunomodulatory therapy to address inflammation in the heart and circulation across the spectrum of heart failure and reduced ejection fraction (HFrEF) patients. The goal is to reduce the rate of major cardiac events and complications.

Rexlemestrocel-L has been trialled in two large placebo-controlled randomized studies in patients with chronic heart failure (CHF). These include a 565-patient trial in New York Heart Association (NYHA) class II/III HFrEF patients and a 159-patient trial in end-stage HFrEF patients implanted with an LVAD. The therapy has FDA RMAT and Orphan Drug designations for patients with end-stage HFrEF implanted with an LVAD.

Chronic heart failure affects approximately 6.5 million people in the United States and 26 million people globally. The mortality rate approaches 50% at 5 years as patients progress beyond NYHA early class II disease. Every year in the United States, over 100,000 patients progress to end-stage HFrEF, with a one-year mortality as high as 50%. In these patients, more than 2,500 life-prolonging LVADs are implanted in the US annually.

Mesoblast Limited has drawn down US$50 million from a five-year facility provided by existing shareholder and director Dr. Gregory George. The transaction, announced on June 24, 2026, strengthens the company's balance sheet by retiring higher cost debt and optimizing its capital structure. Mesoblast reported cash reserves of US$122 million as of March 30, 2026, positioning it to invest in commercial operations and its growth pipeline.

The new credit-line features a fixed interest rate of 8.00% per annum, a substantial reduction from prior facilities. It includes a five-year interest-only period from the initial draw and is secured solely by the Temcell royalty. The facility can be repaid at any time without incurring early prepayment, make-whole, or exit fees.

Key Facility Details

Mesoblast Chief Executive Silviu Itescu stated that the favorable long-term facility eliminates short-term high-cost debt. He noted that the facility does not encumber any material assets or intellectual property, enabling unrestricted entry into strategic partnerships or licensing transactions. The company intends to use the funds to retire the NovaQuest Capital Management LLC debt facility, thereby eliminating short-term debt obligations.