Cytomegalovirus Infections Following Reduced-Intensity Allogeneic Stem Cell Transplantation.

Reduced intensity allogeneic stem cell transplantation is increasingly used for patients who are at high risk for mortality following conventional full-intensity regimens. Defining the risk of CMV-related events in this growing modality has a significant implication in future immunologic interventions to improve their transplant outcomes. Therefore, we analyzed 160 patients at risk for CMV (R+ and/or D+) who received a reduced intensity transplant (RIT) between May 2000 and February 2004 from either a matched-related (n=91) or unrelaed donor (n=69) under the City of Hope IRB protocol #02047. The median age of the cohort was 51 (range: 15–71) and recipient/donor CMV serostatus was; R+D+=87, R+D-=44, R-D+=29. Conditioning regimens were reduced but myeloablative (fludarabine + melphalan or busulfan) in 124 or truly non-myeloablative (TBI 200cGy +/− fludarabine) in 36 patients. Fourteen received a bone marrow graft and the remaining 146 received PBSC graft. GVHD prophylaxis consisted of cyclosporine and mycophenolate +/− short course of methotrexate. CMV reactivation was monitored by shell vial blood culture (BC) twice a week from d21 until d100 or longer if clinically indicated. Additional monitoring with quantitative PCR was available in 57 patients. Preemptive therapy with ganciclovir was started at the first positive BC at 5mg/kg twice a day for a week, followed by maintenance therapy for 5 weeks. Of 160 patients, at the time of analysis 94 patients are alive with a median follow up of 12.2 months. The actuarial probabilities of overall survival, disease-free survival, and relapse for the entire cohort at 1 year were 55.9 %, (95%CI: 51.1–60.5), 40.4% (95% CI: 37.1–43.7), and 40.1% (95%CI: 34.8–46.2), respectively. Grade 2–4 acute GVHD occurred in 91 (56%) patients. Eighty-one patients developed CMV reactivation (actuarial probability of 52+/−4%) at the median of 44 days post-transplant (range: d20-d216, 8 after d100). Of these, 42 (52%) had either persistent or recurrent reactivation. Nineteen patients (12%) developed CMV disease (8 with pneumonitis, 11 with GI tract) at the median onset of 56 days (range d28-d591: 5 after d100). Seven of these 19 patients had both BC and PCR data, which were consistent each other in all but one. CMV viremia itself did not predict poorer survival (p=NS), but CMV disease was associated with lower overall survival (37% vs. 65%, p=0.02). The univariate analysis revealed two major findings: 1) CMV seropositive patients were at seven times the ‘hazard’ (HR: 7.2, 95%CI: 2.3–22.9) for CMV reactivation compared to those who were CMV seronegative (p<0.001); and 2) patients who received a true non-myeloablative regimen were at decreased ‘risk’ for CMV reactivation compared to those who received fludarabine + melphalan or busulfan (HR: 0.42, 95%CI: 0.2–0.8) (p<0.01). In multivariate analysis these factors remained significant.

In summary, our data demonstrate the significant incidence of CMV reactivation and disease in RIT, but true non-myeloablative transplants may have lower risk. Future immunologic or pharmacologic interventions should include RIT patients.