Mesoblast Receives IND Clearance From FDA to Directly Proceed to Registrational Trial for Approval of Ryoncil in Duchenne Muscular Dystrophy - CORRECTION

Working with Parent Project Muscular Dystrophy and the Duchenne Registry on patient identification and trial awareness efforts 

~15,000 children are living with DMD in the U.S.

NEW YORK, April 10, 2026 -- Mesoblast Limited (Nasdaq:MESO; ASX:MSB), global leader in allogeneic cellular medicines for inflammatory diseases, today announced that the United States Food and Drug Administration (FDA) has granted Investigational New Drug (IND) clearance to directly proceed for a registrational clinical trial evaluating Ryoncil

(remestemcel-L-rknd) in Duchenne muscular dystrophy (DMD), which affects approximately 15,000 children in the U.S.

Ryoncil

is the first mesenchymal stromal cell (MSC) product approved by FDA, and the only product approved for children under age 12 with steroid-refractory acute graft-versus-host disease (SR-aGvHD) . This new registrational trial builds on Ryoncil’s proven safety in children, evidence of efficacy in DMD preclinical models, and FDA-approved manufacturing process. Leveraging Ryoncil's anti-inflammatory mechanism of action in SR-aGvHD, Mesoblast aims to reduce the inflammatory cascade characteristic of DMD, preserve muscle function, and slow disease progression.

The trial will randomize 76 patients aged 5 to 9 years to either Ryoncil

(7 infusions of 2 x 10 cells/kg over 9 months) or placebo, on top of standard of care. The trial’s primary endpoint will be time-to-stand at nine months, a validated FDA endpoint for approval. To help support successful execution of this study, Mesoblast has contracted with Parent Project Muscular Dystrophy (PPMD) and the Duchenne Registry to support patient identification and trial awareness.

“This study represents an important step forward in potentially addressing the inflammatory component of DMD, a major driver of disease progression,” said Aravindhan Veerapandiyan, MD, Director of the Comprehensive Neuromuscular Program at Arkansas Children’s Hospital, and Principal Investigator of the study. “By leveraging the anti-inflammatory effects of Ryoncil, we aim to intervene at a stage where muscle tissue may still be preserved, potentially altering the trajectory of the disease.”

“We are very pleased to have received clearance to proceed directly to a registrational study for DMD based on our preclinical data in DMD animal models and our extensive safety data in children with SR-aGvHD. Our experience with Ryoncil suggests that we may have a unique approach to help with this devastating disease in children,” said Silviu Itescu, Chief Executive of Mesoblast

This press release is a correction to version dated April 7, 2026, which was not intended to imply any endorsement by PPMD.

About Duchenne Muscular Dystrophy (DMD)
Duchenne Muscular Dystrophy (DMD) is a X-linked genetic disorder characterized by progressive muscle degeneration affecting the skeletal, respiratory, and cardiac muscles. It is caused by the absence of functional dystrophin, a key structural protein in muscle cells. DMD affects approximately 15,000 individuals in the United States and primarily impacts boys. Over time, deterioration of the muscle leads to loss of ambulation, respiratory failure and cardiomyopathy ultimately leading to death by the third decade.

About Parent Project Muscular Dystrophy
Duchenne is a genetic disorder that slowly robs people of their muscle strength. Parent Project Muscular Dystrophy (PPMD) fights every single battle necessary to end Duchenne.

We demand optimal care standards and ensure every family has access to expert healthcare providers, cutting edge treatments, and a community of support. We invest deeply in treatments for this generation of Duchenne patients and in research that will benefit future generations. Our advocacy efforts have secured hundreds of millions of dollars in funding and won eight FDA approvals.

Everything we do—and everything we have done since our founding in 1994—helps those with Duchenne live longer, stronger lives. We will not rest until we end Duchenne for every single person affected by the disease. Join our fight against Duchenne.

About Mesoblast
Mesoblast (the Company) is a world leader in developing allogeneic (off-the-shelf) cellular medicines for the treatment of severe and life-threatening inflammatory conditions. The therapies from the Company’s proprietary mesenchymal lineage cell therapy technology platform 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.

Mesoblast’s Ryoncil

(remestemcel-L-rknd) for the treatment of steroid-refractory acute graft versus host disease (SR-aGvHD) in pediatric patients 2 months and older is the first FDA-approved mesenchymal stromal cell (MSC) therapy. Please see the full Prescribing Information at .

Mesoblast is committed to developing additional cell therapies for distinct indications based on its remestemcel-L and rexlemestrocel-L allogeneic stromal cell technology platforms. Ryoncil

is being developed for additional inflammatory diseases including SR-aGvHD in adults and biologic-resistant inflammatory bowel disease. Rexlemestrocel-L is being developed for heart failure and chronic low back pain. The Company has established commercial partnerships in Japan, Europe and China.

About Mesoblast intellectual property: Mesoblast has a strong and extensive global intellectual property portfolio, with over 1,000 granted patents or patent applications covering mesenchymal stromal cell compositions of matter, methods of manufacturing and indications. These granted patents and patent applications provide commercial protection extending through to at least 2044 in all major markets.

About Mesoblast manufacturing: The Company’s proprietary manufacturing processes yield industrial-scale, cryopreserved, off-the-shelf, cellular medicines. These cell therapies, with defined pharmaceutical release criteria, are planned to be readily available to patients worldwide.

Mesoblast has locations in Australia, the United States and Singapore and is listed on the Australian Securities Exchange (MSB) and on the Nasdaq (MESO).

References / Footnotes

2. Please see the full Prescribing Information at
   
   

Release authorized by the Chief Executive.