The Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) regarding the Biologics License Application (BLA) for remestemcel-L (RyoncilTM; Mesoblast) for the treatment of pediatric steroid-refractory acute graft versus host disease (SR-aGVHD).

Remestemcel-L is an investigational allogeneic cell therapy consisting of culture-expanded mesenchymal stem cells derived from the bone marrow of an unrelated donor. It is believed to work by downregulating the production of proinflammatory cytokines, increasing production of anti-inflammatory cytokines, and enabling recruitment of naturally occurring anti-inflammatory cells to involved tissues.

In August 2020, the FDA’s Oncologic Drugs Advisory Committee voted 9:1 in favor of the approval of remestemcel-L in pediatric patients with SR-aGVHD. The BLA submission was supported by data from 3 clinical trials that included 309 children with SR-aGVHD, along with an open-label phase 3 trial in 55 children with SR-aGVHD. Results across all trials showed consistent treatment responses and survival outcomes.

Continue Reading

However, in the CRL, the FDA recommended that the Company “conduct at least 1 additional randomized, clinical study in adults and/or children to provide further evidence of the efficacy of remestemcel-L for SR-aGVHD.” The letter also identified that further scientific rationale was needed to demonstrate the relationship of potency measurements to the product’s biologic activity.

Related Articles

Remestemcel-L is also being investigated in an ongoing, randomized, controlled phase 3 trial in up to 300 ventilator-dependent adults with moderate to severe acute respiratory distress syndrome due to coronavirus disease 2019 (COVID-19)

For more information visit


Mesoblast receives Complete Response Letter from the FDA for Biologics License Application for steroid-refractory acute graft versus host disease in children. Accessed October 5, 2020. 

This article originally appeared on MPR