RYONCIL®: First FDA-Approved MSC Therapy by Mesoblast

NEW YORK, NY, USA I December 18, 2024 I Mesoblast Limited, a prominent player in the field of allogeneic cellular medicines focusing on inflammatory diseases, has achieved a groundbreaking milestone with the recent approval from the U.S. Food and Drug Administration (FDA) of their innovative therapy, Ryoncil (remestemcel-L). This therapy is now the first mesenchymal stromal cell (MSC) therapy sanctioned in the United States, and notably, it remains the sole therapy approved for addressing steroid-refractory acute graft versus host disease (SR-aGvHD) in children as young as two months, extending to adolescents and teenagers.

Dr. Joanne Kurtzberg, a well-respected transplant physician affiliated with Duke University Medical Center, underscored the significance of this advancement. She highlighted the severe nature of SR-aGvHD, a condition traditionally burdened with a grim prognosis. With Ryoncil, medical professionals now have access to a treatment that holds the potential to significantly improve outcomes for young patients, thereby also positively impacting their families.

Each year, the United States witnesses approximately 10,000 cases of allogeneic bone marrow transplants, with around 1,500 involving pediatric patients. Of these, roughly half of the patients encounter acute graft versus host disease (aGvHD), and nearly 50% of these cases are unresponsive to steroids, the established first-line treatment.

In a pivotal Phase 3 clinical trial involving children with SR-aGvHD, an impressive 70% of participants achieved an overall response by the 28th day of treatment with Ryoncil. The study, which encompassed patients predominantly suffering from severe cases of Grade C or Grade D aGvHD, demonstrated that treatment with Ryoncil was well tolerated. No treatment discontinuations occurred due to laboratory abnormalities, and over 85% of patients completed the full course without interruption. The complete results of this trial have been published in the journal Biology of Blood and Marrow Transplantation.

Dr. Silviu Itescu, CEO of Mesoblast, expressed satisfaction with the FDA's endorsement of Ryoncil, emphasizing the company's dedication to providing essential treatments for the GVHD community. He noted that Ryoncil's approval signifies a significant achievement for Mesoblast, marking the introduction of the first MSC product to the market. The company plans to continue collaborating with the FDA to pursue approvals for other advanced-stage products, such as REVASCOR for cardiovascular diseases and rexlemestrocel-L for pain management in inflammatory conditions. Additionally, there are plans to broaden the indications for Ryoncil to include both pediatric and adult patients suffering from various inflammatory conditions.

Ryoncil will soon be accessible across the United States at transplant centers and numerous hospitals, paving the way for wider treatment availability.

Ryoncil represents a significant advancement in the treatment of pediatric SR-aGvHD. This allogeneic bone marrow-derived MSC therapy is specifically indicated for young patients starting from two months old. The recommended treatment regimen involves administering a dosage of 2 × 10^6 MSC per kilogram of body weight through intravenous infusion two times per week over a span of four weeks. The therapy's response is evaluated after approximately 28 days from the initial dose, with further treatments provided as needed.

Despite the promising outcomes, certain safety considerations are associated with Ryoncil. It is contraindicated for patients with known hypersensitivity to dimethyl sulfoxide (DMSO) or porcine and bovine proteins. Notable adverse reactions reported in clinical trials include pyrexia, respiratory failure, and infections, although no grade 4 or 5 adverse reactions were observed. A small number of patients discontinued treatment due to severe reactions or complications.

Mesoblast's commitment to developing innovative cell therapies for severe inflammatory conditions is underscored by Ryoncil's FDA approval. The company continues to explore potential applications for its proprietary technologies and has established partnerships across global markets, ensuring that these groundbreaking therapies are available to patients worldwide.