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. 2025 Sep 22.
doi: 10.1111/bjh.70154. Online ahead of print.

Allogeneic haematopoietic cell transplantation in advanced systemic mastocytosis in new era: A CIBMTR study

Celalettin Ustun  1 , Mei-Jie Zhang  2 , Andrew Peterson  2 , Alexander Baek  2 , Mounzer Agha  3 , Hassan Alkhateeb  4 , Saurabh Chhabra  5 , Alex Coltoff  6 , Marcos de Lima  7 , Arpita Gandhi  8 , Vincent Ho  9 , Adetola Kassim  10 , Adam Lin  11 , Lohith Gowda  12 , Gautam Borthakur  13 , Daniel J DeAngelo  14 , Joseph McGuirk  15 , Felix Mensah  16 , Kalyan V Nadiminti  17 , Taiga Nishihori  18 , Jeremy Pantin  19 , Andrew Trunk  20 , Joseph Uberti  21 , Guido Marcucci  22 , Jason Gotlib  23 , Cem Akin  24 , Mehdi Hamadani  2 , Vinod Pullarkat  22 , Peter Valent  25 , Michael Grunwald  26 , Mark Juckett  27 , Betul Oran  28 , Wael Saber  2 , Linda J Burns  2
Affiliations

Allogeneic haematopoietic cell transplantation in advanced systemic mastocytosis in new era: A CIBMTR study

Celalettin Ustun et al. Br J Haematol. .

Abstract

We investigated the outcomes of patients with advanced systemic mastocytosis (AdvSM) undergoing allogeneic haematopoietic cell therapy (alloHCT) in the US. Twenty-seven adult (median age, 58 years) patients with AdvSM received alloHCT from 2014 to 2021. Most patients were white (93%), male (63%) and had systemic mastocytosis (SM) with associated haematological neoplasm (SM-AHN, 70%), received peripheral blood grafts (89%) and non-myeloablative regimens. KIT mutation was detected in 14 of the reported 16 patients (87.5%). Post-transplantation cyclophosphamide (PTCy) was used in approximately 50% of the cohort. Approximately 1 year after alloHCT, median bone marrow mast cell burden decreased from 15% pre-alloHCT to 1.5% (range 0-8) at 1 year post-alloHCT. The median serum tryptase decreased from 55 ng/mL (range 3-400 ng/mL) pre-alloHCT to 18 ng/mL (range 0-481 ng/mL) at 1 year post-alloHCT. At 1 year, progression-free survival (PFS) and overall survival (OS) were 59% (95% confidence interval [CI], 41%-77%) and 74% (95% CI, 56%-89%) respectively. In the subset of patients with SM-AHN, 1-year PFS and OS were 74% (52%-91%) and 79% (95% CI, 58%-94%) respectively. The cumulative incidence of relapse/progression for the entire population of patients with SM (n = 27) was 4% (95% CI, 0-14) at 100 days and 15% (95% CI, 4-31) at 1 year. For the subset of patients with AHN, the cumulative incidence was 11% (95% CI, 1-28) at 100 days and 21% (95% CI, 6-42) at 1 year. Relapse/progression was the cause of death in six of 12 patients (5 died of AHN and 1 died of SM progression). Eighteen and nine patients received a KIT inhibitor before alloHCT and after alloHCT respectively. In addition, six patients received a KIT inhibitor for the treatment of relapse/progression of SM after alloHCT. Although it is difficult to delineate the exact effect of alloHCT and KIT inhibitors because of the size of the study in this era, the use of alloHCT and KIT inhibitors pre- and post- alloHCT is increasing. In the near future, larger studies are required to provide further insights into this subject.

Keywords: allogeneic; bone marrow transplantation; mast cells; systemic mastocytosis; tryptase.

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References

REFERENCES

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