Subtype-specific outcome after allogeneic hematopoietic cell transplantation in advanced systemic mastocytosis: a registry study of the European competence network on mastocytosis.

Fiche publication

Date publication

août 2026

Journal

Experimental hematology & oncology

Auteurs

Membres identifiés du Cancéropôle Est :
Dr MARCAIS Ambroise

Tous les auteurs :
Haug S, Sperr WR, Wehr C, Bonofiglio F, Klein SK, Kluin-Nelemans HC, Mulder AB, Hermine O, Rossignol J, Suarez F, Marcais A, Shomali W, Perkins C, Christen D, Rabitsch W, Hadzijusufovic E, Voglová J, Jentzsch M, Schwaab J, Lübke J, Mattsson M, Hagglund H, Dybedal I, Baffoe D, Bonnadonna P, Bonifacio M, Tanasi I, Sciumè M, Niedoszytko M, Gorska A, Mital A, Triggiani M, Parente R, Yavuz AS, Elena C, Malcovati L, Ferrari J, Wortmann F, Brockow K, Franz TM, Makris M, Papageorgiou SG, Breynaert C, Ieven T, Angelova-Fischer I, Stefan A, Várkonyi J, Sabato V, Schug TD, van Daele PLA, Fortina AB, Caroppo F, Gulen T, Heizmann M, Hartmann K, Rüfer A, Doubek M, Panse J, Gotlib J, Arock M, Oude Elberink HNG, Reiter A, Valent P, Shoumariyeh K

Lien Pubmed

https://www.ncbi.nlm.nih.gov/pubmed/42625226

Résumé

Advanced systemic mastocytosis (AdvSM), comprising aggressive systemic mastocytosis, mast cell leukemia, and systemic mastocytosis with an associated hematological neoplasm, is a heterogeneous myeloid neoplasm with poor prognosis. Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only potentially curative treatment, yet its benefit across AdvSM subtypes in the era of KIT-targeted tyrosine kinase inhibitors (TKIs) such as midostaurin and avapritinib remains unclear. To identify patient subgroups benefiting from allo-HCT and to define prognostic factors for post-transplant survival, we analyzed 631 AdvSM patients from the European Competence Network on Mastocytosis registry, including 69 who underwent allo-HCT. Treatment effects were assessed using time-dependent Cox regression in a transplant-eligible complete-case cohort (n = 419). In this cohort, allo-HCT showed no overall survival (OS) benefit (hazard ratio [HR] 1.21, 95% CI 0.80-1.84; p = 0.37), whereas TKI response emerged as a strong independent predictor of survival (HR 0.42; p<0.001). Subtype-stratified analysis revealed an allo-HCT benefit exclusively in patients with systemic mastocytosis associated with acute myeloid leukemia (n = 30; HR 0.20; p = 0.020). Among the 69 transplanted patients, median OS was 49.6 months with 2-year and 5-year survival of 63% and 46%, respectively. The International Prognostic Scoring System for Mastocytosis (IPSM) at transplantation independently predicted both OS (HR per category 1.68; p = 0.026) and progression-free survival (HR 1.99; p = 0.003), whereas the Mutation-Adjusted Risk Score and diagnostic subtype did not reach statistical significance. Competing risk analysis demonstrated that higher IPSM captured both relapse-related and transplant-related mortality. These findings suggest that the survival benefit of allo-HCT in AdvSM is driven primarily by control of the associated myeloid neoplasm. Accordingly, allo-HCT should be prioritized in patients with SM-AML, whereas TKI-directed strategies may be preferred in other subtypes, with IPSM at transplantation potentially guiding transplant selection and timing.