Efficacy of Valganciclovir in the Treatment of Cytomegalovirus Disease in Kidney and Pancreas Transplant Recipients

Strategies to control human cytomegalovirus infection in adult hematopoietic stem cell transplant recipients

Human cytomegalovirus (HCMV) represents the major viral complication after hematopoietic stem cell transplantation. HCMV infection may be controlled by the reconstituting immune system and remain subclinical or can lead to severe systemic and/or organ disease (mainly pneumonia and gastroenteritis) when immune reconstitution is delayed or impaired. In order to prevent the occurrence of HCMV disease, a prompt diagnosis of HCMV infection is mandatory. The adoption of pre-emptive therapy strategies guided by virological monitoring dramatically reduced the occurrence of HCMV disease. However, late-onset end-organ disease may occur in some patients with apparent immune reconstitution. In the near future, introduction of immunological monitoring and immunotherapies could markedly improve management of HCMV infection.

Cytomegalovirus Treatment

In treating cytomegalovirus (CMV) infection, it is crucial to decide whether one is treating pre-emptively or if one is treating established disease. Disease may be further divided into viral syndrome and tissue-invasive disease. Generally, mild disease in immunosuppressed patients may be treated with oral valganciclovir. Treatment may also be started with valganciclovir for CMV retinitis in AIDS patients. In other tissue-invasive syndromes, starting with intravenous ganciclovir or foscarnet at full doses (adjusted for renal function) is preferred. Treatment at full doses should be continued until symptom resolution and until blood antigenemia (or DNAemia) is cleared. Patients receiving treatment must be closely monitored for side effects to the drugs, as well as for response. Drug-resistant CMV is a therapeutic challenge; combination therapy with both ganciclovir and foscarnet may be tried. In extreme cases, resorting to unconventional agents like leflunomide or maribavir may be necessary. Immune reconstitution, through reduction in immunosuppression, or the introduction of anti-retroviral therapy, should be attempted. CMX001 is a novel agent active against double-stranded viruses; thus far, resistance to CMX001 does not confer resistance to ganciclovir or foscarnet. Hence, prophylaxis or pre-emptive treatment with CMX001 may allow the use of ganciclovir or foscarnet for treatment.

Six-month prophylaxis is cost effective in transplant patients at high risk for cytomegalovirus infection

The risk of late-onset cytomegalovirus (CMV) infection remains a concern in seronegative kidney and/or pancreas transplant recipients of seropositive organs despite the use of antiviral prophylaxis. The optimal duration of prophylaxis is unknown. We studied the cost effectiveness of 6- versus 3-mo prophylaxis with valganciclovir. A total of 222 seronegative recipients of seropositive kidney and/or pancreas transplants received valganciclovir prophylaxis for either 3 or 6 mo during two consecutive time periods. We assessed the incidence of CMV infection and disease 12 mo after completion of prophylaxis and performed cost-effectiveness analyses. The overall incidence of CMV infection and disease was 26.7% and 24.4% in the 3-mo group and 20.9% and 12.1% in the 6-mo group, respectively. Six-month prophylaxis was associated with a statistically significant reduction in risk for CMV disease (HR, 0.35; 95% CI, 0.17 to 0.72), but not infection (HR, 0.65; 95% CI, 0.37 to 1.14). Cost-effectiveness analyses showed that 6-mo prophylaxis combined with a one-time viremia determination at the end of the prophylaxis period incurred an incremental cost of $34,362 and $16,215 per case of infection and disease avoided, respectively, and $8,304 per one quality adjusted life-year gained. Sensitivity analyses supported the cost effectiveness of 6-mo prophylaxis over a wide range of valganciclovir and hospital costs, as well as variation in the incidence of CMV disease. In summary, 6-mo prophylaxis with valganciclovir combined with a one-time determination of viremia is cost effective in reducing CMV infection and disease in seronegative recipients of seropositive kidney and/or pancreas transplants.

Immunocompromised hosts: perspectives in the treatment and prophylaxis of cytomegalovirus disease in solid-organ transplant recipients

Cytomegalovirus (CMV) infection is an important complication of solid-organ transplantation. The availability of potent antiviral therapies has decreased the incidence of CMV disease among solid-organ transplant recipients but has also led to challenges, including ganciclovir resistance, late-onset CMV disease, and uncertainty about the optimal duration of prophylaxis or therapy for CMV disease. Specific therapies and management of CMV resistance will be addressed here. The best approach for CMV disease in solid-organ transplant recipients is prevention, but which strategy--prophylaxis or preemptive therapy--is optimal remains debatable. Ganciclovir and valganciclovir remain the best options for prevention and treatment of CMV disease in solid-organ transplant recipients, but they are costly and associated with toxicity. Foscarnet and cidofovir, indicated for the treatment of patients who fail to respond to ganciclovir, are less attractive alternatives because of renal toxicity. Therefore, new therapeutic agents for CMV and an immunogenic, safe CMV vaccine are critically needed.

Management of human cytomegalovirus infection in transplant recipients by the pre-emptive therapy approach

Human cytomegalovirus (HCMV) infections are still a major infectious complication in the post-transplant period of both solid organ transplant recipients (SOTRs) and hematopoietic stem cell transplant recipients (HSCTRs). For many years, the major diagnostic assay has been antigenemia, allowing semi-quantification of HCMV load in blood from transplanted patients with disseminated HCMV infection. More recently, the real-time PCR assay has replaced antigenemia for HCMV DNAemia quantification. Prevention of HCMV disease is based on either prophylaxis or pre-emptive therapy with antiviral drugs. The latter approach has been in use in our department for the last 15 years. A cut-off of 300,000 DNA copies/ml whole blood in SOTRs with either primary or reactivated infection, and a cut-off of 10,000 DNA copies/ml blood in HSCTRs proved to be safe and effective in prospective randomized, controlled trials. With this approach, HCMV disease is consistently prevented, except for a limited number of cases of organ localization in the absence of virus in blood. In these cases, HCMV infection/disease must be diagnosed by local biopsy samples.

Variations in the assessment practice for renal transplantation across the United Kingdom

BACKGROUND

To investigate whether there are any variations in the evaluation of adult candidates for cadaveric renal transplantation among transplant centers in the United Kingdom.

METHODS

An online survey of transplant units in the United Kingdom, including nephrologists, surgeons, and transplant coordinators, measured differences in the assessment process and evaluation of patient's age, body mass index (BMI), cardiovascular comorbidity, and viral serology.

RESULTS

A response was received from 20 out of the 23 centers (87%). These centers perform 90% of all renal transplants in the United Kingdom. In 30% of the units, there is no formal transplant assessment clinic. There is no cutoff age limit for assessment across the United Kingdom, but 12 centers (60%) exclude patients with a high BMI, with a median cutoff BMI of 35. Eight out of the 20 centers do not give cytomegalovirus (CMV)-negative patients the option to receive kidneys from a CMV-positive donor. Hepatitis C antibody-positive donors are not used in 50% of the units. There is considerable variation in the investigation of cardiovascular disease and exclusion criteria based on cardiovascular status of the patients. Five units have no consistent policy of re-evaluating patients once they are listed.

CONCLUSIONS

There is evidence, from this study, of significant variations in the assessment of patients for renal transplantation across the United Kingdom. Further research and better-defined guidelines are required for a uniform assessment process and to ensure equity of access to the renal transplant waiting list.