FDA rejects Mesoblast cell therapy, again

Aug. 4, 2023

The U.S. FDA has issued a complete response letter to Mesoblast’s BLA resubmission for remestemcel-L for the treatment of pediatric steroid-refractory acute graft versus host disease (SR-aGVHD), asking for more data to support marketing approval.

The drugmaker's first BLA submission for remestemcel-L was rejected by the agency in 2020, with the FDA recommending that Mesoblast conduct at least one additional randomized, controlled study in adults and/or children to provide further evidence of effectiveness.

Mesoblast resubmitted its BLA in January 2023, including long-term follow-up data from a phase 3 trial by the Center for International Blood and Marrow Transplant Research showing 50% survival through more than 4 years of follow-up for remestemcel-L treated patients.

But the agency still wants more data, and Mesoblast isn't giving up. Now, the company plans to launch a targeted study in high-risk adults who comprise 80% of the SR-aGVHD market. According to the company, pilot data from an emergency IND program in adults have already shown that remestemcel-L provides a survival benefit in this particular group.

GVHD can occur after an allogeneic stem cell transplant when the donated cells initiate an immune response and attack the transplant recipient’s organs. The condition, which can be acute or chronic, can affect multiple organ systems including the skin, gastrointestinal tract, and liver. While there are currently no approved treatments for the life-threatening condition in children under 12, the FDA approved Incyte's Jakafi back in 2021 to treat the disease in in adult and pediatric patients 12 years and older.