Cost-effectiveness model of cytomegalovirus management strategies in renal transplantation. Comparing valaciclovir prophylaxis with current practice

Cost-effectiveness of Preemptive Therapy Versus Prophylaxis in a Randomized Clinical Trial for the Prevention of Cytomegalovirus Disease in Seronegative Liver Transplant Recipients With Seropositive Donors

BACKGROUND

The relative costs of preemptive therapy (PET) or prophylaxis for the prevention of cytomegalovirus (CMV) disease in high-risk donor CMV-seropositive/recipient-seronegative (D+/R-) liver transplant recipients have not been assessed in the context of a randomized trial.

METHODS

A decision tree model was constructed based on the probability of outcomes in a randomized controlled trial that compared valganciclovir as PET or prophylaxis for 100 days in 205 D+/R- liver transplant recipients. Itemized costs for each site were obtained from a federal cost transparency database. Total costs included costs of implementation of the strategy and CMV disease treatment-related costs. Net cost per patient was estimated from the decision tree for each strategy.

RESULTS

PET was associated with a 10% lower absolute rate of CMV disease (9% vs 19%). The cost of treating a case of CMV disease in our patients was $88 190. Considering cost of implementation of strategy and treatment-related cost for CMV disease, the net cost-savings per patient associated with PET was $8707 compared to prophylaxis. PET remained cost-effective across a range of assumptions (varying costs of monitoring and treatment, and rates of disease).

CONCLUSIONS

PET is the dominant CMV prevention strategy in that it was associated with lower rates of CMV disease and lower overall costs compared to prophylaxis in D+/R- liver transplant recipients. Costs were driven primarily by more hospitalizations and higher CMV disease-associated costs due to delayed onset postprophylaxis disease in the prophylaxis group.

Overview of Human Cytomegalovirus Pathogenesis

Human cytomegalovirus (HCMV) is a betaherpesvirus with a global seroprevalence of 60-90%. HCMV is the leading cause of congenital infections and poses a great health risk to immunocompromised individuals. Although HCMV infection is typically asymptomatic in the immunocompetent population, infection can result in mononucleosis and has also been associated with the development of certain cancers, as well as chronic inflammatory diseases such as various cardiovascular diseases. In immunocompromised patients, including AIDS patients, transplant recipients, and developing fetuses, HCMV infection is associated with increased rates of morbidity and mortality. Currently there is no vaccine for HCMV and there is a need for new pharmacological treatments. Ongoing research seeks to further define the complex aspects of HCMV pathogenesis, which could potentially lead to the generation of new therapeutics to mitigate the disease states associated with HCMV infection. The following chapter reviews the advancements in our understanding of HCMV pathogenesis in the immunocompetent and immunocompromised hosts.

Cytomegalovirus infection in immunosuppressed patients after kidney transplantation

The first kidney transplantation was performed in 1951 and ever since then living donor transplantation became a more and more important solution for patients with end-stage renal disease (ESRD).

Renal transplantation is a life-saving procedure. Morbidity and mortality on waiting-lists are strongly correlated with the time of dialysis and end-stage renal disease is one of the most important causes of death; this is the reason why transplantation has to be performed as soon as possible in order to reduce the time of dialysis.

Once the transplantation is performed, a number of complications may occur in post-transplant evolution, the most important of which is rejection.

The rejection may appear through several mechanisms, but one of the most frequent causes of rejection is cytomegalovirus (CMV) infection. It is very important to have a precocious and fast diagnosis of CMV infection in order to maintain the functionality and survival of the graft. PP65 CMV antigenemia has proven its effectiveness in detecting and monitoring the CMV infection in transplanted patients.

In the laboratory of the Clinical Institute of Urology and Renal Transplantation (ICUTR) of Cluj Napoca the CMV infection is evidenced by two methods: PP65antigenemia and IgM antibody identification by chemiluminiscence.

Overview of human cytomegalovirus pathogenesis

Human cytomegalovirus (HCMV) is a human pathogen that infects greater than 50 % of the human population. HCMV infection is usually asymptomatic in most individuals. That is, primary infection or reactivation of latent virus is generally clinically silent. HCMV infection, however, is associated with significant morbidity and mortality in the immunocompromised and chronic inflammatory diseases in the immunocompetent. In immunocompromised individuals (acquired immune deficiency syndrome and transplant patients, developing children (in utero), and cancer patients undergoing chemotherapy), HCMV infection increases morbidity and mortality. In those individuals with a normal immune system, HCMV infection is also associated with a risk of serious disease, as viral infection is now considered to be a strong risk factor for the development of various vascular diseases and to be associated with some types of tumor development. Intense research is currently being undertaken to better understand the mechanisms of viral pathogenesis that are briefly discussed in this chapter.

Cost-effective immunosuppressive options for solid organ transplantation: a guide to lower cost for the renal transplant recipient in the USA

Of the numerous risks associated with immunotherapy for the prevention of rejection, cost is perhaps the most universal. In the USA and some other countries, the costs of immunosuppression make transplantation unavailable for some medically viable transplant candidates, and for others who receive a transplant, the long-term costs are economically crippling. Minimization and tapering of immunosuppression, use of generics, manipulation of metabolism, infection surveillance instead of prophylaxis, and advantageous routes of administration are some strategies that can be employed to reduce immunotherapy expense. Using these strategies, we describe an immunosuppression regimen for kidney transplantation that might be only a third of the cost of current 'standard' regimens in the USA. Such a regimen might allow some patients who might not otherwise qualify economically to safely receive a kidney transplant. The purpose of creating an alternative, lower-cost immunotherapy regimen is to give patients a choice. Responsible stewardship of scarce donor organs is the primary, and clearly appropriate, limiting factor.

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.

Cost-effectiveness of a new combined immunosuppressive and anti-infectious regimen in kidney transplantation

Objectives:The aims of this study were to assess the 1-year cost-effectiveness of a new combined immunosuppressive and anti-infectious regimen in kidney transplantation to prevent both rejection and infectious complications.

Methods:Patients (pts) transplanted from January 2000 to March 2003 (Group A) and treated with a conventional protocol were compared with pts submitted to a combined regimen including universal cytomegalovirus (CMV) prophylaxis between April 2003 and July 2005 (Group B). Costs were computed from the hospital accounting system for hospital stays, and official tariffs for outpatient visits. Patients with incomplete costs data were excluded from analysis.

Results:Fifty-three patients were analyzed in Group A, and 60 in Group B. Baseline characteristics including CMV serostatus were not significantly different between the two groups. Over 12 months after transplantation, acute rejections decreased from 41.5 percent in Group A to 6.7 percent in Group B (p< .001), and CMV infections from 47 percent to 15 percent (p< .001). Overall, readmissions decreased from 68 percent to 55 percent (p= .160), and average hospital days from 28 ± 19 to 20 ± 11 days (p< .007). The average number of outpatient visits decreased from 49 ± 10 to 39 ± 8 (p< .001). Average 1-year immunosuppressive and CMV prophylaxis costs (per patient) increased from CHF20,402 ± 7,273 to 27,375 ± 6,063 (p< .001), graft rejection costs decreased from CHF4,595 ± 10,182 to 650 ± 3,167 (p= .005), CMV treatment costs from CHF2,270 ± 6,161 to 101 ± 326 (p= .008), and outpatient visits costs from CHF8,466 ± 1’721 to 6,749 ± 1,159 (p< .001). Altogether, 1-year treatment costs decreased from CHF39’957 ± 16,573 to 36,204 ± 6,901 (p= .115).

Conclusions: The new combined regimen administered in Group B was significantly more effective, and its additional costs were more than offset by savings associated with complications avoidance.

Cytomegalovirus in transplantation ? challenging the status quo

BACKGROUND

Cytomegalovirus (CMV) infection of solid organ transplant (SOT) recipients causes both ''direct'' and ''indirect'' effects including allograft rejection, decreased graft and patient survival, and predisposition to opportunistic infections and malignancies. Options for CMV prevention include pre-emptive therapy, whereby anti-CMV agents are administered based on sensitive viral assays, or universal prophylaxis of all at-risk patients. Each approach has advantages and disadvantages in terms of efficacy, costs, and side effects. Standards of care for prophylaxis have not been established.

METHODS

A committee of international experts was convened to review the available data regarding CMV prophylaxis and to compare preventative strategies for CMV after transplantation from seropositive donors or in seropositive recipients.

RESULTS

Pre-emptive therapy requires frequent monitoring with subsequent treatment of disease and associated costs, while universal prophylaxis results in greater exposure to potential toxicities and costs of drugs. The advantages of prophylaxis include suppressing asymptomatic viremia and prevention of both direct and indirect effects of CMV infection. Meta analyses reveal decreased in mortality for patients receiving CMV prophylaxis. Costs associated with prophylaxis are less than for routine monitoring and pre-emptive therapy. The optimal duration of antiviral prophylaxis remains undefined. Extended prophylaxis may improve clinical outcomes in the highest-risk patient populations including donor-seropositive/recipient-seronegative renal transplants and in CMV-infected lung and heart transplantation.

CONCLUSIONS

Prophylaxis is beneficial in preventing direct and indirect effects of CMV infection in transplant recipients, affecting both allograft and patient survival. More studies are necessary to define optimal prophylaxis regimens.

A comparative randomised study of valacyclovir vs. oral ganciclovir for cytomegalovirus prophylaxis in renal transplant recipients

An open, prospective, randomised study was conducted to compare the safety and efficacy of valacyclovir vs. oral ganciclovir for cytomegalovirus (CMV) prophylaxis in renal transplant recipients. Eighty-three renal transplant recipients were assigned randomly to receive valacyclovir (n=43) or oral ganciclovir (n=40) for the first 3 months after transplantation. Both groups were similar in terms of demographics, primary renal disease, graft source, HLA matching, immunosuppressive therapy and donor-recipient CMV antibody status. CMV infection was diagnosed by detection of virus DNA in plasma with the Amplicor CMV Test. CMV disease was observed in only one patient belonging to the ganciclovir group, who developed enterocolitis 6 months post-transplantation. No difference was observed between the two treatment groups with respect to detection of CMV DNA, virus infections other than CMV, acute rejection episodes, and serum creatinine levels at 3 and 6 months following transplantation. An increased number of bacterial infections was noted in the ganciclovir group (p 0.003). No adverse reactions with either treatment were reported. The estimated cost of valacyclovir treatment was 20% higher than that of ganciclovir treatment. Overall, both valacyclovir and oral ganciclovir were found to be effective and safe for CMV prophylaxis in renal transplant recipients. Decisions regarding prophylactic regimens should include additional criteria, such as cost or possible development of resistance.

The cost-effectiveness of prophylaxis with valaciclovir in the management of cytomegalovirus after renal transplantation

Prophylaxis-based antiviral treatment and intensive monitoring followed by pre-emptive antiviral treatment are both commonly used management strategies to reduce risk of cytomegalovirus (CMV) infection following renal transplantation. This study employed a decision-model approach using published efficacy data and information from a recent survey of French clinical practice to consider the relative costs and outcomes associated with CMV prevention strategies for high-risk patient groups. The cost per case of treating tissue invasive and symptomatic CMV disease was estimated at euro 15,431 and euro 10,852, respectively. In the highest infection-risk patient group (positive donor with no previous CMV history) prophylactic oral valaciclovir was shown to avoid the greatest number of CMV disease cases (35 cases per 100 transplanted patients) and reduced the overall CMV-related costs per transplanted patient by around 14% over a'wait-and-treat' baseline strategy. In contrast, intensive monitoring and preemptive treatment resulted in a much higher cost per transplanted patient. This analysis suggests that prophylactic treatment remains the most cost-effective approach to the management of CMV in renal-transplanted patients. Further comparative studies between prophylactic and pre-emptive treatment would be a valuable addition to the current evidence based on CMV prevention.

A decision-analytic economic evaluation of valaciclovir prophylaxis for the prevention of cytomegalovirus infection and disease in renal transplantation

OBJECTIVE

This analysis evaluates the cost-effectiveness of valaciclovir prophylaxis using clinically and economically important health outcomes including graft failure, life-years, and quality-adjusted life-years (QALYs).

METHODS

A Markov model was developed using a randomized, placebo-controlled trial of valaciclovir prophylaxis, together with a published epidemiological study and national renal transplant registry data. The model's population was stratified into two risk groups by donor/recipient cytomegalovirus (CMV) serostatus at transplantation: donor-positive/recipient-negative (D+R-) and recipient-positive (R+) patients. The model estimated costs and health outcomes over a 30-yr period from the perspective of Australian health care providers.

RESULTS

The total health care cost was $3619 lower for D+R- patients receiving valaciclovir prophylaxis compared with those not receiving prophylaxis. D+R- patients receiving valaciclovir gained an extra 0.33 yr of life and 0.27 QALYs. R+ patients receiving valaciclovir prophylaxis gained an extra 0.07 yr of life and 0.05 QALYs, with an incremental cost of $914. This equates to $17 127 per QALY gained, which is highly cost-effective compared with other drugs and health interventions.

CONCLUSIONS

Valaciclovir for the prophylaxis of CMV disease in renal transplant recipients is a cost-effective intervention, significantly reducing the burden of CMV disease to patients and health care providers.

Design and analysis of unit cost estimation studies: How many hospital diagnoses? How many countries?

We evaluated three questions that commonly arise when unit costing exercises for multinational trials are conducted: (1). In countries where investigators plan to collect hospital unit cost estimates for a selected set of diagnoses, how should one estimate unit costs for the remaining diagnoses observed in the trial for which cost data were not collected? (2). For how many hospital diagnoses should estimates be obtained? (3). For how many countries should they be obtained? We addressed these questions using unit cost data collected in four western European countries and three relative value measures from the US Medicare diagnosis-related group (DRG) payment system. We found that the arithmetic mean length of stay from the US DRG payment system was a good predictor of unit costs in four countries in Europe. We also found that the imputation error decreased as the number of hospital diagnoses and countries sampled increased, but that the rate of reduction in error shrank. Finally, we found that - given the existence of a reliable method for cost imputation - from a pure information standpoint, it is better to obtain estimates for fewer hospital diagnoses from more countries than the reverse.

Cytomegalovirus infection in solid organ transplantation: economic implications

Cytomegalovirus (CMV) is a pathogen, commonly encountered in the recipients of solid organ transplantation and is an important cause of morbidity and mortality in these patients. CMV infection and disease have been shown to increase the cost of care in transplant recipients and several different strategies of prevention have been shown to be effective in clinical trials. A systematic review of published information on the economic impact of CMV in solid organ transplantation was performed; both clinical- and decision-analysis-based studies were reviewed. Clinical studies have shown that CMV infection and disease is associated with increased length of hospital stay and overall costs. Decision-analysis-based studies suggest that in general, antiviral chemoprophylaxis against CMV in transplant recipients is a cost-effective intervention compared with other established healthcare interventions such as strategies for colorectal cancer screening. Prophylaxis with oral or parenteral ganciclovir is probably the most cost-effective strategy; however, restricting prophylaxis to high-risk groups (such as donor seropositive/recipient seronegative status and the use of an antilymphocyte antibody) or chemoprophylaxis for an extended period does not improve cost effectiveness. Pre-emptive therapy is an evolving strategy for prevention of CMV disease in transplant recipients and is rapidly gaining in popularity. Well-designed trials incorporating prospective cost data and comparing pre-emptive therapy versus conventional antiviral prophylaxis are needed to establish the superiority of one strategy over the other.

Economic impact of cytomegalovirus in solid organ transplantation

Cytomegalovirus (CMV) infection has a direct effect on morbidity in solid organ transplantation patients, and indirect effects related to the development of opportunistic infections, allograft rejection, and patient mortality. Although intuitively it follows that costs attributable to CMV infections would be increased, direct proof has remained elusive. Accumulating evidence suggests, however, that CMV infection has a significant impact on the costs to transplantation programs, particularly in seronegative recipients of seropositive allografts (D+/R-), and additional costs may be incurred through the effects on CMV potentiating the risks of various opportunistic infections leading to graft rejection.

The economic value of valacyclovir prophylaxis in transplantation

Cytomegalovirus (CMV) infection and disease, with its extensive direct and indirect consequences, adds considerably to the cost of patient management in both solid organ and bone marrow transplantation. Antiviral prophylaxis for CMV infection can offer cost advantages over preemptive therapy and "wait-and-treat" approaches. Valacyclovir has demonstrated efficacy for CMV prophylaxis in renal, heart, and bone marrow transplantation and is cost-effective when compared with placebo in renal transplant recipients at high risk of CMV infection. In reducing CMV infection and disease, valacyclovir prophylaxis appears to be associated with reductions in indirect effects of CMV (acute graft rejection, other opportunistic infections) and, if these effects are considered, the potential exists for even greater savings to be made with valacyclovir therapy. Benefits of valacyclovir in transplantation extend beyond CMV to other herpesviruses and may be increased in some clinical situations by prolonging prophylaxis beyond 3 months.

Modeling costs and cost-effectiveness of different CMV management strategies in liver transplant recipients as a support for current and future decision making

OBJECTIVES

To develop a generic decision-analytic model to predict health and economic outcomes of different management options for cytomegalovirus (CMV) infection and disease in liver transplant patients.

METHODS AND DATA

The model considers different CMV management strategies, thereby emphasizing the important difference between infection and disease. The first strategy starts with prophylaxis prior to transplantation, followed by preemptive treatment if infection, based on positive CMV diagnostic tests, is confirmed. The second strategy is a preemptive strategy consisting of only testing followed by preemptive treatment. Finally, in the wait-and-treat strategy, antiviral treatment is only started when clinical signs of CMV disease appear. Management and resource-use data were obtained from clinical experts in large transplant centers in France, Germany, and the United Kingdom. Cost data were collected from the health care payer's perspective. A Bayesian revision technique was applied to distinguish effectiveness of current management options for CMV infection vs. CMV disease, an aspect that is currently underreported in literature.

RESULTS

CMV prophylaxis in liver transplant recipients is generally more cost-effective than preemptive and wait-and-treat strategies. In order of importance, changes in drug costs, drug efficacy, specificity of CMV testing, cost of hospitalization, probability of CMV relapse and baseline CMV risk are the most important factors influencing the cost-effectiveness.

CONCLUSION

This model describes different strategies applied for management of CMV in liver transplant patients and is useful both for current decision making, optimal disease management, and assessment of future research targets.

Early modelling for assessing health and economic outcomes of drug therapy

Models for assessing health and economic outcomes of new drugs have an increasing role in the early phases of drug development. Their input into go/no go and priority setting decisions can reveal that further development of a drug is unattractive from an economic viewpoint, or that developing a certain indication is more attractive than another. They may also influence the later choice of indication, positioning, comparators, length of follow-up, and other elements in the further development of drugs. Their specific nature, characterized by limited budget, timelines and data availability should not necessarily lead to compromises in design and conduct. It is argued that high quality early models form the breeding ground for later solid evidence on value for money, and are consequently both worthwhile to the pharmaceutical industry and to health care decision-makers and payers.