Comparative Analysis of Post-Transplant Cyclophosphamide (PTCy) and ATG Platforms for Haploidentical Transplantation in Resource-Constrained Settings: A Preliminary Experience.

Abstract

Background

Worldwide, two common platforms for haploidentical-stemcell-transplantation are being used based either on post-transplant-cyclophosphamide (PTCy), developed by the Baltimore group or on anti-thymocyte globulin (ATG) developed by the Beijing group. The ideal platform that suits for countries with limited resources is not known. In this study, we analysed the outcomes of the haploidentical transplants at our center, to derive a comparison between the two platforms.

Method

A retrospective chart review of all haploidentical-transplantation done between December 2020 to July 2024 was conducted. Patients had been nonrandomly assigned to either of the two platforms based on different treating teams beforehand.

Results

Out of total 60 patients, 27 received ATG and 33 received PTCy based haploidentical-transplant-conditioning. Majority were males (63.3%), with median age 20(2-48) years. Apart from the median age (25vs14 yrs), CD34/CD3 cell-doses, all baseline parameters were comparable between two groups (Table1).

While, time to neutrophil-engraftment was similar (14 vs 15 days), platelet engraftment was delayed (20 vs 16 days), requiring more frequent transfusions with ATG-platform. Overall cohort had high incidence of bacterial (63.3%), fungal (26.7%) and CMV (73.3%) infections, irrespective of the platform. Although, duration of hospitalization was higher in ATG group, rates of acute-graft-versus-host-disease (aGVHD), chronic-GVHD, transplant-associated-microangiopathy (TMA), sinusoidal-obstruction-syndrome (SOS), post-transplant hemophagocytic lymphohistiocytosis (HLH) and non-relapse mortality (NRM) were all comparable between the two groups. With a median follow-up of 249 (11-1512) days, projected 1yr-disease-free-survival (DFS), although seemingly higher with ATG-platform (80.8% vs 70.0%), is not statistically different from the PTCy-platform, possibly due to lesser sample size (Figure 1).

Conclusions

In this preliminary report, we found comparable short-term survival-outcomes between ATG and PTCy platforms. Larger comparative studies with longer follow-up are needed to find whether the two haploidentical-platforms are comparable in terms of outcomes, toxicity and need of resources and supportive-care.