Valganciclovir for CMV Prophylaxis After PTCy-Based Allogeneic Hematopoietic Cell Transplantation

Area of Science:

• Hematopoietic Stem Cell Transplantation
• Infectious Disease Management
• Immunocompromised Patient Care

Background:

• Cytomegalovirus (CMV) reactivation poses a significant risk post-allogeneic hematopoietic cell transplantation (alloHCT), especially with post-transplant cyclophosphamide (PTCy) based prophylaxis.
• Letermovir is effective but costly, necessitating affordable alternatives for CMV infection (csCMVi) prevention.
• Limited data exists on valganciclovir's utility for CMV prophylaxis in PTCy-based alloHCT.

Purpose of the Study:

• To assess the feasibility and effectiveness of using valganciclovir for CMV prophylaxis in adults undergoing alloHCT with PTCy-based GVHD prophylaxis.
• To compare valganciclovir prophylaxis outcomes against a pre-emptive CMV strategy.

Main Methods:

• Retrospective analysis of 244 adults undergoing alloHCT, focusing on CMV-seropositive recipients receiving PTCy-based GVHD prophylaxis and intended valganciclovir prophylaxis.
• Valganciclovir (900 mg daily) initiated post-engraftment until day +100; weekly CMV PCR monitoring was performed.
• Outcomes compared with a contemporaneous cohort using pre-emptive CMV therapy.

Main Results:

• 124 patients met inclusion criteria; 86 (69%) initiated valganciclovir prophylaxis, with delayed count recovery being the primary reason for non-initiation (31%).
• Initiation was less frequent in haploidentical versus matched donor alloHCT (56% vs 80%).
• Valganciclovir prophylaxis significantly reduced csCMVi incidence (13% vs 63% in non-prophylaxis group; aHR 0.09). Haploidentical transplants increased csCMVi risk (aHR 4.5).

Conclusions:

• Valganciclovir is a cost-effective option for preventing csCMVi in CMV-seropositive PTCy-based alloHCT recipients.
• Delayed hematopoietic recovery is a key challenge for prophylaxis initiation, particularly in haploidentical transplantation.
• Valganciclovir prophylaxis demonstrates significant efficacy compared to pre-emptive strategies.