What does this research mean for the field?

The FABT-based conditioning regimen achieves 100% neutrophil engraftment and a 91.7% 2-year overall survival rate in patients with severe aplastic anemia undergoing haploidentical transplantation. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.CHALLENGES_CONSENSUS.

What question did this study set out to answer?

To assess the efficacy of a novel FABT-based conditioning regimen in haploidentical transplantation for patients with severe aplastic anemia.

February 24, 2026Open Access

Novel FABT-Based Conditioning Regimen with Haploidentical Transplantation for Severe Aplastic Anemia: A prospective, single-center, phase II clinical trial

Key Points

To assess the efficacy of a novel FABT-based conditioning regimen in haploidentical transplantation for patients with severe aplastic anemia.
Conducted a prospective phase II trial involving 36 patients with severe aplastic anemia.
Introduced thiotepa, combined with low-dose ATG and PTCy to prevent GVHD.
Measured engraftment rates, overall survival, and incidence of GVHD and CMV reactivation over a median follow-up of 21 months.
Achieved 100% neutrophil engraftment and 91.7% platelet engraftment.
Reported a 91.7% overall survival rate at two years, with 100% survival in patients under 40.
The incidence of grade II-IV aGVHD was 8.3%, while the cumulative incidence of CMV reactivation was only 11.1%.

Abstract

• The FABT-based regimen achieved 100% NE engraftment, a 91.7% 2-year OS rate, and no primary graft failure. • The incidence of grade II–IV aGVHD was 8.3%; cGVHD was limited to the skin in 11.1% of patients. CMV reactivation occurred in 11.1% with no CMV disease observed. • Patients under 40 years of age achieved 100% 2-year OS, with rapid hematopoietic recovery and manageable toxicity. Haploidentical hematopoietic stem cell transplantation (Haplo-HSCT) serves as an alternative treatment for severe aplastic anemia (SAA) patients lacking a suitable HLA-identical sibling donor. However, its development has been hindered by graft failure and severe graft-versus-host disease (GVHD). We conducted a prospective study to evaluate the efficacy of FABT regimen for AA in Haplo-HSCT. This regimen introduced thiotepa into the protocol for the first time, combined with low-dose ATG (2 mg/kg/day) and the PTCy regimen to prevent GVHD. From April 2022 to June 2024, 36 eligible AA patients were recruited for the study, with a median follow-up duration of 21 (2∼30) months. None of the 36 patients experienced primary graft failure, and the engraftment rates for NE and PLT were 100% and 91.7%, respectively. The median time to PLT and NE engraftment was 13 (8∼27) and 14 (8∼21) days, respectively. The 2-year cumulative incidence of CMV reactivation was only 11.1% and no CMV disease was observed. The incidence of aGVHD and grade II-IV aGVHD was 27.8% and 8.3%, respectively. Additionally, the incidence of cGVHD was 11.1%, all of which were mild cutaneous rejection. The 2-year OS and 2-year GRFS were both 91.7%. Surprisingly, patients under 40 years old have a 2-year OS of 100%. Compared to the traditional Baltimore regimen, this approach reduced the incidence of aGVHD, cGVHD, and CMV reactivation, while improving OS and GRFS, which may offer a new option for Haplo-HSCT in AA patients.

Novel FABT-Based Conditioning Regimen with Haploidentical Transplantation for Severe Aplastic Anemia: A prospective, single-center, phase II clinical trial

Key Points

Abstract

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