Nilotinib efficacy and safety as salvage treatment following imatinib intolerance and/or inefficacy in steroid refractory chronic graft-versus-host-disease (SR-cGVHD): a prospective, multicenter, phase II study on behalf of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC).

Imatinib is used for patients with SR-cGVHD. However, in 50% of cases imatinib is discontinued due to intolerance or inefficacy. In order to investigate nilotinib's role as salvage therapy in those patients, we conducted a prospective, multicenter, phase II study. (NCT02891395). Patients with SR-cGVHD were included to receive imatinib. Patients who stopped imatinib due to intolerance or inefficacy switched to Nilotinib. The primary endpoint was defined as the week-12 response rate to Nilotinib. The response was considered successful if superior to the 30% endpoint. Sixty-two patients started the IM-phase. Fourteen patients (22%) discontinued imatinib before week 12 due to: cGVHD progression (10%) or TKI-class-specific intolerance (12%). At week 12, we observed complete remission in 13 patients (21%) and partial response in 8 patients (13%). Twenty-nine patients switched to Nilotinib. Nilotinib response at week-12 was observed in 6 patients (21%) while 23 patients (79%) discontinued Nilotinib due to intolerance/cGVHD progression. The primary endpoint was not reached. This prospective study confirmed the efficacy of imatinib in patients with steroid refractory cGVHD. It failed to demonstrate the efficacy of nilotinib as a salvage therapy in patients who were intolerant/unresponsive to imatinib.