Partnering with Parent Project Muscular Dystrophy to ensure timely access to the trial for eligible patients

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

Mesoblast Limited (Nasdaq:MESO; ASX:MSB), global leader in allogeneic cellular medicines for inflammatory diseases, 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)². 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 10⁶ 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 support the successful execution of this study, Mesoblast is collaborating with Parent Project Muscular Dystrophy (PPMD) to foster patient identification and trial awareness through proactive community engagement.

“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