If at first you don’t succeed, try, try again. That certainly seems to be Mesoblast’s motto—and it may pay off yet.
The Australian cell therapy biotech’s original request for FDA approval of remestemcel-L for children with steroid-refractory acute graft-versus-host disease was knocked back in October 2020. Undeterred, the company said last month that it had asked the agency to reconsider the application. Now, Mesoblast has announced that the FDA has accepted the resubmission and set a decision date of August 2.
The resubmission includes the new information set out by the company in February, including four-year survival data assessing 51 patients from a phase 3 trial, the majority of whom had grade C or D disease. The analysis showed that almost two-thirds were alive after one year and more than half survived past two years.
Mesoblast also submitted more efficacy and biomarker data, some of which were compared to a database of patients with acute graft-versus-host disease that the Mount Sinai medical system maintains.
New efficacy data shared with the FDA covered 25 treated children in Mesoblast's phase 3 trial who were compared to 27 children not treated with remestemcel-L who were identified in the Mount Sinai database. The analysis showed that 67% of remestemcel-treated patients responded positively within 28 days and were alive after six months, while only 10% from the database had the same outcomes. A total of 54 patients were treated in the phase 3 trial.
Making up the rest of the package was new data showing that the potency assay adequately demonstrated manufacturing consistency and reproducibility, as well as new specifications for how the therapy would be commercially released “to provide assurance that future batches of remestemcel-L will have attributes supportive of expected survival outcomes.”
“Over the last two years we have worked tirelessly to address the issues previously raised by FDA,” Mesoblast CEO Silviu Itescu said in the post-market release Tuesday.
It appears investors are also optimistic about the cell therapy’s chances, sending the biotech’s shares up 20% in the first hour of trading this morning to $3.63 from a Tuesday closing price of $3.03.
The FDA’s original knock-back for remestemcel-L in 2020 was over a request for Mesoblast to conduct an additional study of the cell therapy. At the time, the agency took the unusual step of going against its independent expert reviewers, who voted nine to one that the existing data supported the efficacy of remestemcel-L in children with steroid-resistant graft-versus-host disease.