# Clonal Evolution of Myeloid Malignancies Treated With Microtransplantation: A Single‐Centre Experience

## TL;DR

Microtransplantation shows promise as a safe and effective maintenance therapy for high-risk myeloid malignancies in patients who cannot undergo regular transplants.

## Contribution

This study provides insights into the clonal evolution and mutational dynamics following microtransplantation in myeloid malignancies.

## Key findings

- Founder mutations persisted, while nonfounder mutations decreased in variant allele frequency over time.
- Relapses were linked to the emergence or increase of TP53 mutated clones.
- Microtransplantation was safe, with no graft versus host disease and manageable cytokine release syndromes.

## Abstract

Microtransplantation is a cellular therapy used in acute myeloid leukaemia and myelodysplastic syndromes as a maintenance therapy in patients ineligible for a regular allogeneic stem cell transplantation. We performed a monocentric retrospective study of acute myeloid leukaemia, myelodysplastic syndromes, and chronic myelomonocytic leukaemia patients who underwent microtransplantations at Nice University Hospital. We analysed the evolution of the disease mutational status after microtransplantation. We report 18 patients who underwent microtransplantation courses, with a total of 47 microtransplantations performed between February 2020 and June 2022. We observed long‐term remissions even in high‐risk patients. Founder mutations persisted throughout the follow‐up, whereas it was more variable for other nonfounder mutations, with most of the nonfounder mutations variant allele frequency decreasing over time. Safety data were reassuring; no graft versus host disease was recorded, and cytokine release syndromes were manageable. Relapses or progressions were associated with the emergence or increase of a TP53 mutated clone. Microtransplantation is a promising therapy for patients ineligible for regular allogeneic stem transplantation. Further larger and randomised studies are required to establish its place as a maintenance therapy in myeloid malignancies.