Mesoblast (ASX:MSB) reported encouraging real-world outcomes for its FDA-approved therapy Ryoncil (remestemcel-L-rknd) in children with steroid-refractory acute graft-versus-host disease.
Ryoncil, the first mesenchymal stromal cell product approved by the US Food and Drug Administration for any indication, has been commercially available since March 2025 for children aged two months and older.
Among the first 25 pediatric patients treated in real-world clinical settings, 21 children (84%) survived and completed the initial 28-day treatment regimen.
The four patients who did not complete the course had previously failed other therapies and succumbed to severe SR-aGvHD within 28 days.
Mesoblast noted that these early outcomes align with prior clinical trial data and emphasise the importance of initiating Ryoncil therapy promptly after steroid resistance to maximise survival chances.
To facilitate access, Mesoblast has launched a patient support program, MyMesoblast, allowing healthcare providers to order Ryoncil efficiently.
Currently, 45 US transplant centers are onboarded, with a target of 64 centers covering 94% of U.S. transplants. The therapy is covered by federal and state Medicaid programs as well as commercial insurers, reaching over 260 million lives.
Mesoblast plans to expand the FDA label for Ryoncil to adults with severe SR-aGvHD—a population roughly three times larger than pediatric cases.
"We are delighted to see excellent early survival rates in children with this devastating disease," said Mesoblast CEO Dr. Silviu Itescu.
At the time of reporting, Mesoblast's share price was $2.69.