Post-transplantation cyclophosphamide is associated with increased bacterial infections

Area of Science:

• Hematopoietic Cell Transplantation (HCT)
• Immunosuppression
• Infectious Diseases

Background:

• Post-transplant cyclophosphamide (PTCy) is a common strategy to prevent graft-versus-host disease (GVHD) in hematopoietic cell transplantation (HCT).
• Concerns exist regarding an increased risk of infections associated with PTCy use.

Purpose of the Study:

• To evaluate the incidence of bacterial infections following HCT with PTCy-based versus calcineurin inhibitor (CNI)-based GVHD prophylaxis.
• To assess the impact of bacterial infections on transplant-related mortality (TRM) in different GVHD prophylaxis strategies.

Main Methods:

• Retrospective analysis of patients (≥2 years) undergoing haploidentical or matched sibling donor HCT for acute leukemias or myelodysplastic syndrome.
• Patients received either PTCy-based or CNI-based GVHD prophylaxis.
• Incidence of bacterial infections and TRM were compared across groups.

Main Results:

• Patients receiving PTCy (haploidentical HCT with PTCy [HaploCy] and sibling with PTCy [SibCy]) showed a significantly higher incidence of bacterial infections by day 180 compared to sibling with CNI-based [SibCNI] prophylaxis (46% and 48% vs. 35%, p < 0.001).
• Bacterial infections were associated with a significant increase in TRM across all groups, including HaploCy, SibCy, and SibCNI cohorts.
• PTCy was associated with increased bacterial infections irrespective of the donor type.

Conclusions:

• Post-transplant cyclophosphamide is associated with a higher incidence of bacterial infections following HCT.
• Bacterial infections significantly increase mortality risk, regardless of the GVHD prophylaxis used.
• Close monitoring for bacterial infections is recommended for patients receiving PTCy after HCT.