Lack of Emergence of Cytomegalovirus UL97 Mutations Conferring Ganciclovir (GCV) Resistance following Preemptive GCV Therapy in Allogeneic Stem Cell Transplant Recipients

Abstract

Fifty allogeneic stem cell transplant recipients were enrolled in a prospective cytomegalovirus pp65 antigenemia-guided preemptive therapy trial. Among these, 10 of 34 patients who received ganciclovir exhibited sustained and/or recurrent antigenemia despite treatment. Thirteen leukocyte preparations from these 10 subjects were screened for the presence of the most frequent cytomegalovirus UL97 mutations conferring ganciclovir resistance. None of these mutations were detected after mean and median ganciclovir exposures of 31.6 and 28.0 days, respectively.Cytomegalovirus (CMV) infections represent a serious threat in patients undergoing allogeneic bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT) (15). In order to reduce the morbidity and mortality associated with CMV disease, most centers have now adopted one of the two following preventive strategies. The first approach, referred to as universal prophylaxis, is based on the administration of a potent anti-CMV drug, usually ganciclovir (GCV), to all patients for the first 3 months after transplantation. Prophylaxis with GCV has been reported to be highly effective in reducing the occurrence of early CMV disease (prior to day ϩ100) but is also associated with an increased incidence of bacterial and fungal infections and with significant bone marrow toxicity (4, 13). Long-term use of GCV has raised concerns about the development of delayed CMV disease and the possibility of selecting GCV-resistant strains (11,25). The second strategy, called preemptive or early treatment, is based on early identification of patients with active CMV blood infections using sensitive detection assays followed by antiviral treatment for various lengths of time.A successful CMV pp65 antigenemia-guided preemptive strategy for allogeneic hematopoietic stem cell recipients was recently reported (5). In that study, 50 patients with hematologic malignancies received a transplant (not T cell depleted) from matched sibling donors. The subjects were monitored weekly for the presence of CMV antigens and DNA (COBAS AMPLICOR CMV MONITOR test; Roche Diagnostics, Laval, Canada) in polymorphonuclear leukocytes (PMNL) from initiation of the conditioning regimen until day ϩ98 after transplantation. Among these 50 patients, 34 (68%) were treated with GCV (14 days of intravenous [i.v.] administration [5 mg/kg of body weight twice a day] followed by 14 days of oral administration [1,000 mg three times a day]) upon a positive pp65 antigenemia assay. Eight (23.5%) of these 34 patients received a second course of therapy based on the reemergence of CMV pp65 antigens in the blood. Only one patient (2%) enrolled in the study developed CMV disease despite a negative antigenemia test. To further support the use of such a preventive approach, we now report the results of genotypic markers of CMV resistance to GCV among the same cohort of patients.Among samples from the 50 patients enrolled in our study, 13 from 10 patients were selected for genotypic analysis on the basis of...

Paradoxical Rising Cytomegalovirus Antigenemia during Preemptive Ganciclovir Therapy in Hematopoietic Stem Cell Transplant Recipients: Incidence, Risk Factors, and Clinical Outcomes

“…Third, we did not perform quantitative realtime CMV PCR prior to and during preemptive GCV therapy, so we could not evaluate the emergence of GCV-resistant infection during preemptive GCV therapy. However, we assume that it may be rare that 1 week of GCV use results in the emergence of resistance, because prolonged GCV exposure with ongoing high viral replication and impaired host defenses is usually associated with the emergence of GCV-resistant strains (10,12,14). Indeed, the previous studies showed that no GCV-resistant strain was detected in patients with rising CMV PCR levels during 1 week of GCV therapy (4,9,10).…”

Rapid development of ganciclovir-resistant cytomegalovirus infection in children after allogeneic stem cell transplantation in the early phase of immune cell recovery

“…3,4 As reported, 6 the GCV resistance mutations can emerge rapidly. In one patient it happened within 9 days (Figure 3).…”

“…After BMT in adults there exists to date only one report about a patient with phenotypic, as well as genotypic GCV resistance, 3 whereas a recent study using RFLP analysis limited to the detection of some frequent occurring UL97 mutations (codons: 460, 520, 594, 595) did not reveal any evidence for the emergence of GCV resistance in 10 out of 34 adults treated after PBSCT. 4 However, according to our experience the rapid emergence of GCV resistance in codons 591/603 should not be ignored. 5,6 Initially, Wolf et al 7 reported on the early emergence of GCV resistance in children with primary combined immunodeficiency (CID) after T cell-depleted BMT in four out of six cases.…”

Prevention of Cytomegalovirus Disease in Recipients of Allogeneic Stem Cell Transplants

“…In a study of 50 allogeneic SCT recipients, 10 patients exhibited sustained or recurrent Ag despite GCV treatment. Samples from these 10 patients were screened for the presence of the most frequent CMV UL97 mutations by restriction enzyme analysis, and none of these mutations were detected (30). Overall, antiviral drug resistance in adult SCT recipients has been reported only sporadically (24,30,84,91).…”