Haploidentical Stem Cell Transplantation for Hematological Disorders: Real-World Experience from India

Area of Science:

• Hematology
• Oncology
• Transplant Immunology

Background:

• Haploidentical stem cell transplant (haploSCT) is an alternative for patients lacking matched donors.
• Posttransplant cyclophosphamide (PTCy) has emerged as a key strategy to mitigate graft-versus-host disease (GVHD) in haploSCT.
• Outcomes of haploSCT with PTCy in India, particularly in a dedicated cancer center, require detailed evaluation.

Purpose of the Study:

• To evaluate the outcomes of haploidentical stem cell transplants (haploSCT) performed with posttransplant cyclophosphamide (PTCy) at a cancer hospital in India.
• To analyze the incidence of graft rejection, relapse, GVHD, and infections following haploSCT.
• To determine survival rates and identify major causes of mortality in patients undergoing haploSCT.

Main Methods:

• Retrospective analysis of 101 haploSCTs performed between March 2015 and August 2022.
• Patients received myeloablative (MA), nonmyeloablative (NMA), or reduced intensity conditioning (RIC).
• Outcomes assessed included engraftment, graft rejection, relapse, GVHD, infections, non-relapse mortality, and overall survival (OS).

Main Results:

• Ninety-nine patients (95 malignant, 4 nonmalignant) underwent 101 haploSCTs.
• Median time to neutrophil and platelet engraftment was 15 and 15.5 days, respectively.
• Acute GVHD occurred in 32.6%, primary graft rejection in 8.9%, and relapse in 17.8%.
• Common infections included BK virus (47.3%) and cytomegalovirus (CMV; 65.3%).
• The 1- and 2-year OS rates were 56.7% and 49.3%, respectively.
• Sepsis (56.2%), relapse (22.2%), and GVHD (8.8%) were the main causes of death, with non-relapse mortality at 37.3%.

Conclusions:

• Haploidentical stem cell transplant (haploSCT) with PTCy offers a viable treatment option with reasonable survival for patients in India.
• Infections, particularly viral infections like BK and CMV, and acute GVHD remain significant challenges post-transplant.
• Further strategies are needed to optimize infection control and GVHD prophylaxis to improve outcomes in haploSCT.