Mesoblast gives allogeneic cell therapy a 2nd try with FDA—but without a new trial

Mesoblast is giving its off-the-shelf cell therapy a second go with regulators. More than two years after the therapy was rejected, it is now submitting a new approval application.

The company announced Wednesday that it has formally asked the FDA to once again consider its therapy, remestemcel-L, for children with steroid-refractory acute graft-versus-host disease. The new application is based on what Mesoblast called “substantial new information” that was teased in October 2022. The submitted data include 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.

Efficacy data from 25 treated children in Mesoblast's phase 3 trial 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.

A separate four-year survival study assessing 51 patients from the phase 3 trial, the majority of whom had grade C or D disease, found that almost a third were alive after one year and more than half survived the past two years.

The new data and new application will compete against the FDA’s original request when the cell therapy was first rejected in October 2020, asking for at least one additional trial. The company elected not to, spurring the obvious question of whether the new data package will prove a clear benefit. 

The resubmission will receive a speed boost from the FDA after the therapy previously earned fast-track designation and a priority review green light, cutting the review period by four months if the application is accepted. 

“We are grateful for the agency’s active dialogue and constructive feedback that will ensure a high bar is met in terms of product consistency and predictability of clinical outcomes,” said CEO Silviu Itescu in a release. 

Wall Street congratulated the company with a jump in its share price, rising 13% from $3.30 to $3.73. That’s still considerably lower than the nearly $20 per share peak attained in the middle of 2020.