Mesoblast Limited announced it has resubmitted its BLA for approval of Ryoncil (remestemcel-L) in the treatment of children with SR-aGVHD. The filing comes after Mesoblast was informed by FDA at the end of March that, following additional consideration, the available clinical data from the Phase 3 study MSB-GVHD001 appears sufficient to support submission of the proposed BLA for remestemcel-L for treatment of pediatric patients with SR- aGVHD. As a result, the filing addresses remaining CMC (Chemistry, Manufacturing, and Control) items. FDA granted remestemcel-L Fast Track designation, a process to facilitate the development and expedited review of therapies for serious conditions that fill unmet medical needs, and Priority Review designation, which is given to drugs that treat a serious condition and provide a significant improvement in safety or effectiveness over existing treatments.

The BLA resubmission upon acceptance is expected to have a review period of between two and six months from receipt. In addition, results of a 4-year survival study performed by the Center for International Blood and Marrow Transplant Research (CIBMTR) on 51 evaluable patients with SR-aGVHD who were enrolled in the Phase 3 trial, demonstrated durability of the survival benefits, with 67% survival at 6 months, 63% Exhibit 99.1. Over 30,000 patients worldwide undergo an allogeneic BMT annually, primarily during treatment for blood cancers, including about 20% in pediatric patients.5,6 SR-aGVHD is associated with mortality as high as 90% and significant extended hospital stay costs.7,8 There are currently no FDA-approved treatments in the US for children under 12 with SR-aGVHD". These cell therapies, with defined pharmaceutical release criteria, are planned to be readily available to patients worldwide.

Mesoblast is developing product candidates for distinct indications based on its remestemcel-L and rexlemestrocel-L allogeneic stromal cell technology platforms. Remestemcel-L is being developed for inflammatory diseases in children and adults including steroid refractory acute graft versus host disease, and biologic-resistant inflammatory bowel disease.