Valganciclovir for the Early Prophylaxis of Cytomegalovirus (CMV) Infection after Allogeneic Stem Cell Transplantation.

Despite improvements in methods for the early diagnosis of CMV infection, 5% of HSCT patients receiving preemptive therapy develop CMV disease. In addition, the use of highly immunosuppressive therapies prior to and after transplant and the use of matched unrelated (MUD) and mismatched related (MRD) donors have increased the incidence of CMV infection and disease. We designed a prospective trial examining the safety and efficacy of valganciclovir for the prophylaxis of early CMV infection.

Methods: CMV seropositive patients or CMV seronegative patients receiving CMV seropositive stem cell products with an estimated creatinine clearance of ≥ 50 mL/min, platelet count ≥ 50,000/μL, and WBC count ≥ 1,000/μL are eligible. Patients receive valganciclovir 900 mg daily Mondays through Fridays starting 21 to 35 days after transplant and continuing through Day 100, with dosage adjustments for myelosuppression and/or reduced creatinine clearance. Patients are monitored with weekly CMV PCR analysis at a central lab according to the Roche assay.

Results: Twenty four (24) out of 50 planned subjects have been enrolled to date (MUD 9, MRD 15). All were CMV seropositive at the time of transplant. Stem cell source included peripheral blood = 21, bone marrow = 3. A total of 7 patients required corticosteroids for treatment of graft versus host disease. Three patients developed myeloid toxicity related to valganciclovir (absolute neutrophil count < 1,000/μL = 1, platelets < 50,000/μL = 2). All three (3) patients recovered their counts and restarted valganciclovir with dose adjustments. A total of 11 patients required dose adjustments due to myelosuppression (3), creatinine clearance (4), weight (1), institutional decision (3). Twelve (12) patients have not completed therapy due to: progressive disease or death before day +100 = 4, CMV infection =2, too early for analysis = 6. CMV infection occurred in 2/24 and CMV disease occurred in 0/24. The two (2) patients with positive CMV-PCR developed infection one (Day 40) and two (Day 36) weeks after starting valganciclovir. These two (2) patients were successfully treated with IV ganciclovir. Ten (10) patients have been followed between day +100 and 6 months post transplant. Three (3) of these 10 patients continued valganciclovir off study and had no evidence of CMV infection. Two (2) of the 10 patients who were not receiving valganciclovir developed CMV infection but were successfully treated with valganciclovir. Survival is 80% (16/20) at day +100 and 82% (9/11) at 6 months post transplant.

Conclusions: We conclude that valganciclovir at the dose used in this study is well tolerated with minimal reversible myelosuppression. These preliminary findings suggest that prophylaxis with oral valganciclovir appears to be a promising strategy to prevent CMV infection and disease.