Advanced Systemic Mastocytosis with associated haematological neoplasm: Treatment with avapritinib can facilitate successful bridge to allogeneic haematopoietic cell transplant

Advanced systemic mastocytosis (AdvSM) is a rare, life-limiting mast cell (MC) neoplasm, with approxi-mately 70% patients having an associated haematological neoplasm (AHN). Avapritinib, a selective tyrosine kinase inhibitor targeting KIT D816V, has shown potent activity translating clinically into durable responses in the phase 1 EXPLORER (NCT02561988) and phase 2 PATHFINDER (NCT03580655) studies. We report three patients with AdvSM-AHN on avapritinib who achieved complete remission (CR) of SM and were successfully bridged to allogeneic haematopoietic cell transplant (allo-HCT). Two cases additionally highlight the risk of clonal evolution within the AHN component and requirement for close monitoring while on targeted therapy. (c) 2023 Elsevier Masson SAS. All rights reserved.

Automated summary

Advanced systemic mastocytosis (AdvSM) is a rare, life-limiting mast cell (MC) neoplasm, which is often associated with a hematological neoplasm (AHN) in approximately 70% of patients. Avapritinib, a selective tyrosine kinase inhibitor, has shown potent activity in treating AdvSM and has successfully bridged three patients to allogeneic hematopoietic cell transplant (allo-HCT). Two cases also highlight the risk of clonal evolution within the AHN component and the necessity of close monitoring during targeted therapy.