Mesoblast Limited (Nasdaq: MESO) announced that the United States Food and Drug Administration (US FDA) has confirmed receipt of Mesoblast's filing of clinical efficacy and safety data for remestemcel-L in its rolling Biologics License Application (BLA) for the treatment of children with steroid-refractory acute graft versus host disease (SR-aGVHD). The final module will be filed during January, and Mesoblast will request an expedited FDA review of the BLA under the product candidate's existing Fast Track designation. If approved, remestemcel-L is planned to be launched in the US in 2020.
The clinical submission included analyses of 309 children with SR-aGVHD who have received remestemcel-L across three separate studies. In addition, Mesoblast provided new data in control pediatric subjects from the contemporaneous database of the Mount Sinai Acute GVHD International Consortium (MAGIC) to provide an unbiased and independent estimate of response rates and outcomes in matched pediatric control patients treated with institutional standard of care.
The results of the comparative analysis between Mesoblast's open-label Phase 3 study and contemporaneous controls receiving institutional standard of care demonstrate the effectiveness of remestemcel-L in this patient population, with particular efficacy and survival benefit in patients with the most severe forms of aGVHD. These conclusions are supported by prior results from an Expanded Access Program in 241 children where remestemcel-L was used as salvage therapy after failure of steroids and other agents.
Acute GVHD is a potentially life-threatening condition which occurs in about 50% of patients who receive an allogeneic bone marrow transplant. Over 30,000 patients worldwide receive an allogeneic bone marrow transplant, primarily during treatment for blood cancers, and 20-25% are children1. Mortality at 12 months is as high as 90% in those with aGVHD and Grade C/D or III/IV disease severity2,3, and there are no approved treatments in the US for children under 12.
In Mesoblast's open-label Phase 3 trial of remestemcel-L in 55 children with SR-aGVHD, 89% of whom had Grade C/D disease, the primary endpoint of Day 28 Overall Response in those exposed to remestemcel-L was achieved in 70% and Day 100 survival was 75%. These outcomes were superior to those from a cohort of 30 pediatric patients with SR-aGVHD from the MAGIC consortium matched for inclusion criteria and disease severity (80% Grade C/D). In the MAGIC controls, Day 28 Overall Response was 43% and Day 100 survival was 57%.
Mesoblast Chief Medical Officer Dr Fred Grossman said: "We are pleased to have submitted to the FDA clinical efficacy and safety data for remestemcel-L, as well as comparative clinical outcome data from contemporaneous controls. We are working closely with the FDA to make our cellular medicine available and improve outcomes in children with this devastating condition."