Dec. 20, 2024 – The FDA has approved remestemcel-L, a new treatment for children ages 2 months and older with steroid-refractory acute graft-versus-host disease (SR-aGVHD), a major complication of donor bone marrow transplantation. The approval marks the first stem cell therapy for the condition and will be marketed under the brand name Ryoncil.
SR-aGVHD, a life-threatening condition, affects about 25% of the 1,500 children in the U.S. who have bone marrow transplants each year. These transplants replace unhealthy bone marrow with healthy blood-forming stem cells from a donor, often to treat blood cancers, blood disorders, or immune diseases. But in about 50% of cases, the donated cells attack the recipient’s body shortly after the transplant, causing aGVHD, which can affect multiple body systems including the skin, liver, stomach, and intestines. For almost half of these patients, the condition doesn’t respond to standard steroid treatments and is linked to poor outcomes.
Remestemcel-L is derived from special stem cells taken from a donor’s bone marrow and is given to patients through a series of IV infusions. It helps control the immune system’s response in patients with SR-aGVHD by reducing harmful inflammation and boosting the body’s natural anti-inflammatory processes The drug is also the first-ever FDA-approved treatment for children ages 2 months and older, including adolescents and teenagers, according to a news release from Mesoblast, the company that makes Ryoncil.
The approval is based on a clinical trial that tested the safety and effectiveness of Ryoncil in 54 children with SR-aGVHD after a donor stem cell transplant. The children received Ryoncil infusions twice a week for four weeks. After 28 days, 70% of them responded to the treatment, with 30% showing a complete response (improvement in all affected organs) and 41% showing a partial response (improvement in one organ, with either no change or worsening in another organ) to the treatment. Children showing partial improvement received infusions once a week for another four weeks. On average, the improvements lasted for 54 days before the condition worsened, a new treatment was needed, or the patient died. The most common side effects observed were infections, fever, bleeding, swelling, stomach pain, and increased blood pressure. Other complications may include allergic or infusion-related reactions and unusual growth of tissues.
The FDA, in its statement, warned that Ryoncil should not be used in people allergic to dimethyl sulfoxide (DMSO) or animal proteins from pigs or cows.