An FDA advisory panel vote of 9-1 to recommend the approval of Mesoblast Limited’s graft versus host disease (GVHD) cell therapy was a cruel tease for the Australian company.
More than four years later—and after two rejections from the agency—Mesoblast has finally gained an endorsement from the U.S. regulator for its first approved drug.
Wednesday afternoon the FDA signed off on Ryoncil (remestemcel-L), an off-the-shelf cell therapy to treat patients 2 months and older who have acute GVHD and don’t respond to steroids.
Ryoncil becomes the first FDA-approved treatment to use mesenchymal stromal cells (MSC) in any indication. MSCs are taken from the bone marrow of unrelated donors and can differentiate into a variety of cell types.
For as long as Mesoblast waited, the nod came three weeks ahead of the FDA's target date for an approval decision.
“It gives everybody a lovely Christmas present—and a happy new year,” Mesoblast CEO Silviu Itescu, who founded the company 20 years ago, said on a conference call.
Times were tough for the company after the second FDA thumbs down, as Mesoblast's cost cuts included a 30% reduction in pay for Itescu. But with the nod, Mesoblast’s share price zoomed by 36% by mid-morning on Thursday.
The approval helps ease the sting from FDA rejections in October 2020 and August 2023. On both occasions, the agency requested more efficacy data. In the first complete response letter, the FDA asked for another trial. Mesoblast eventually won the regulator over by supplying long-term data and additional information on high-risk patients, as well as agreeing to conduct a trial for adults.
Mesoblast also adjusted its potency assays—which had been a long-standing issue with the FDA—to show the standardization of the identity, strength, quality, purity and dosage form of the product tested in the pediatric trial.
In the phase 3 study, patients who had Grade C or Grade D severity of GVHD—which accounted for 89% of the patients in the trial—70% achieved overall responses (OR) by day 28, including 30% who experienced complete responses. OR predicts survival in acute GVHD, Mesoblast said.
Of the roughly 10,000 patients who undergo an allogeneic bone marrow transplant each year in the U.S., 1,500 are children, with approximately half of them developing acute GVHD. Roughly half of that subset are resistant to standard-of-care steroids.
In a statement, transplant physician Joanne Kurtzberg, M.D., who is the director of the Marcus Center for Cellular Cures at Duke University Medical Center, called acute GVHD “a devastating condition with an extremely poor prognosis.”
“(Ryoncil) will be life-saving for so many children and will have a great impact on their families,” Kurtzberg said in the company’s release.
Mesoblast will launch Ryoncil in the “coming weeks.” Itescu did not reveal its price but said it will be comparable to other “cell and gene therapies that have been approved in the past couple of years.”
Itescu said that the company is looking to expand the approval of Ryoncil in children and adults with inflammatory conditions. The company also is hoping to eventually get a nod for revascor, a heart failure medicine that it gained in an acquisition of Angioblast 14 years ago.