Incidence and impact of invasive fungal infection comparing post-transplant cyclophosphamide with cyclosporine plus methotrexate GVHD prophylaxis in allogeneic HSCT

Background: In recent years, haploidentical hematopoietic stem cell transplantation (haploHSCT) with post-transplant cyclophosphamide (PTCy) has become increasingly prevalent. However, the precise impact of invasive fungal disease (IFD) in relation to graft-versus-host disease (GVHD) prophylaxis and donor type remains to be elucidated.

Methods: In this study, we analyzed data from 580 HSCT patients, comprising 80 patients who received haploidentical grafts and 500 patients who received grafts from other donor types. PTCy was exclusively administered to haploidentical HSCT recipients, while cyclosporine A (CsA) in combination with short-course methotrexate (scMTX) was used for patients receiving grafts from other donors.

Results: The IFD rate by PTCy and CsA plus scMTX was 15 % and 15.6 %, respectively. At 6 months and 1 year post-transplant, the cumulative incidence of IFD was 9.4 % and 14.8 % for the PTCy group, and 7.9 % and 12.3 % for the CsA plus scMTX group, respectively. Both groups exhibited poor survival outcomes associated with IFD. Identified risk factors for IFD included age ≥ 45 years, disease relapse, and grade III-IV acute GVHD. Aspergillus spp. and Candida spp. were the most commonly isolated pathogens. High rate of cytomegalovirus reactivation was also noticed in PTCy or CsA plus scMTX group, but not a risk factor for IFD.

Conclusion: The similar IFD rate between haploHSCT with PTCy and others with CsA plus scMTX was documented, with Aspergillus spp. and Candida spp. as the most common pathogens. Further research is needed to investigate IFD following haploHSCT with PTCy and to explore differences with other types of allogeneic HSCT.