Control of cytomegalovirus-associated morbidity in renal transplant patients using intensive monitoring and either preemptive or deferred therapy

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

BACKGROUND

Cytomegalovirus (CMV) disease may occur following renal transplantation and has been shown to have health and cost consequences in this setting.

OBJECTIVE

To compare the cost effectiveness of different CMV management strategies for renal transplant patients: prophylaxis with (i) oral valaciclovir or (ii) intravenous ganciclovir; viral testing for CMV followed by (iii) pre-emptive therapy with intravenous ganciclovir or (iv) adjustment of immunosuppression and intensive monitoring; or (v) waiting to treat when CMV disease develops.

METHODS

A decision-tree model was constructed that included the different management strategies for the donor seropositive/recipient seronegative (D+R-) population. Clinical outcomes for the D+R- population came from clinical trials. Treatment algorithms and costs for CMV syndrome and tissue invasive disease were developed from published literature and UK physician interviews. One- and 2-way sensitivity analyses were performed.

STUDY PERSPECTIVE

UK National Health Service.

RESULTS

Prophylaxis with either oral valaciclovir or intravenous ganciclovir dominated (lower costs and fewer cases of CMV disease) the pre-emptive treatment and wait-and-treat strategies. The cost per patient was from 157 Pounds to 438 Pounds higher with oral valaciclovir prophylaxis compared with intravenous ganciclovir prophylaxis and the incremental cost per case of CMV disease avoided with valaciclovir prophylaxis ranged from 2243 Pounds to 8111 Pounds (1996 values). These results are sensitive to the efficacy of intravenous ganciclovir prophylaxis and CMV management costs.

CONCLUSIONS

For D+R- renal transplant patients, prophylaxis is the dominant (more effective and less costly) management strategy compared with pre-emptive and wait-and-treat strategies. The cost per patient with oral valaciclovir prophylaxis compared with intravenous ganciclovir prophylaxis is slightly higher in our base case scenario, but may be lower under reasonable alternative assumptions.

Comparison of quantitative cytomegalovirus (CMV) PCR in plasma and CMV antigenemia assay: clinical utility of the prototype AMPLICOR CMV MONITOR test in transplant recipients

The correlation between the prototype AMPLICOR CMV MONITOR test (Roche Molecular Systems), a quantitative PCR assay, and the cytomegalovirus (CMV) pp65 antigenemia assay was evaluated in transplant recipients. Sequential blood specimens were collected on 29 patients (491 specimens), the leukocyte fraction was tested by CMV antigenemia, and quantitative PCR was performed on plasma specimens. None of the 15 patients (242 specimens) who were antigenemia negative were positive for CMV DNA by PCR, and none of these patients developed active CMV disease. There were 14 antigenemia-positive patients, 8 of whom developed active CMV disease. In all patients, there was a good association between the antigenemia and PCR assays. Ganciclovir-resistant virus was isolated from three patients with active CMV disease. These three patients had persistently elevated levels of antigenemia and CMV DNA by PCR when resistance to ganciclovir developed. This standardized, quantitative CMV PCR assay on plasma has clinical utility for the diagnosis of active disease and in monitoring the response to antiviral therapy in transplant recipients.

Infectious complications in renal transplant recipients

Infectious complications present major challenges to physicians caring for renal transplant recipients. The high rate of infection reflects the net state of immunosuppression associated with end-stage renal disease, transplantation, donor and environmental exposure. An understanding of the factors that affect the patients' overall state of immunosuppression is essential to prevent and treat infectious complications, which may lead to significant morbidity, graft dysfunction, or mortality. Familiarity with the various pathogens, clinical presentation, diagnostic options, treatment, and prophylaxis is important to care for renal transplant patients. The authors present their approach, based on review of current literature, to these issues.

New strategies for prevention and therapy of cytomegalovirus infection and disease in solid-organ transplant recipients

In the past three decades since the inception of human organ transplantation, cytomegalovirus (CMV) has gained increasing clinical import because it is a common pathogen in the immunocompromised transplant recipient. Patients may suffer from severe manifestations of this infection along with the threat of potential fatality. Additionally, the dynamic evolution of immunosuppressive and antiviral agents has brought forth changes in the natural history of CMV infection and disease. Transplant physicians now face the daunting task of recognizing and managing the changing spectrum of CMV infection and its consequences in the organ recipient. For the microbiology laboratory, the emphasis has been geared toward the development of more sophisticated detection assays, including methods to detect emerging antiviral resistance. The discovery of novel antiviral chemotherapy is an important theme of clinical research. Investigations have also focused on preventative measures for CMV disease in the solid-organ transplant population. In all, while much has been achieved in the overall management of CMV infection, the current understanding of CMV pathogenesis and therapy still leaves much to be learned before success can be claimed.

A randomized, double-blinded comparison of Thymoglobulin versus Atgam for induction immunosuppressive therapy in adult renal transplant recipients

BACKGROUND

The aim of this study was to compare the efficacy and safety of Thymoglobulin (a rabbit-derived polyclonal antibody) to Atgam (a horse-derived polyclonal antibody) for induction in adult renal transplant recipients.

METHODS

Transplant recipients (n=72) were randomized 2:1 in a double-blinded fashion to receive Thymoglobulin (n=48) at 1.5 mg/kg intravenously or Atgam (n=24) at 15 mg/kg intravenously, intraoperatively, then daily for at least 6 days. Recipients were observed for at least 1 year of follow-up.

RESULTS

By 1 year after transplantation, 4% of Thymoglobulin-treated patients experienced acute rejection compared with 25% of Atgam-treated patients (P=0.014). The rate of acute rejection was lower with Thymoglobulin than Atgam (relative risk=0.09; P=0.009). Rejection was less severe with Thymoglobulin than Atgam (P=0.02). No recurrent rejection occurred with Thymoglobulin compared with 33% with Atgam (P=NS). Patient survival was not different, but the composite end point of freedom from death, graft loss, or rejection, the "event-free survival," was superior with Thymoglobulin (94%) compared with Atgam (63%; P=0.0005). Fewer adverse events occurred with Thymoglobulin (P=0.013). Leukopenia was more common with Thymoglobulin than Atgam (56% vs. 4%; P<0.0001) during induction. The mean absolute lymphocyte count remained below baseline with Thymoglobulin throughout the study (P<0.007), but with Atgam, significant lymphocyte reductions occurred only at day 7. The incidence of cytomegalovirus disease was less with Thymoglobulin than Atgam at 6 months (10% vs. 33%; P=0.025).

CONCLUSIONS

Brief (7-day) induction with Thymoglobulin resulted in less frequent and less severe rejection, a better event-free survival, less cytomegalovirus disease, fewer serious adverse events, but more frequent early leukopenia than induction with Atgam. These results may in fact be explained by a more profound and durable beneficial lymphopenia.

Prophylactic oral ganciclovir compared with deferred therapy for control of cytomegalovirus in renal transplant recipients

BACKGROUND

Treatment with prophylactic oral acyclovir, intravenous ganciclovir, or immunoglobulins to prevent cytomegalovirus (CMV) infection and disease in renal transplantation is associated with variable efficacy and significant expense. We studied control of CMV in renal transplant recipients using either prophylactic oral ganciclovir or deferred therapy with intensive monitoring with polymerase chain reaction (PCR) analysis.

METHODS

Forty-two recipients were followed for 6 months after transplantation. Ganciclovir (1000 mg p.o. t.i.d.; n=19) or acyclovir (200 mg p.o. b.i.d.; n=23) was begun at transplantation and continued for 12 weeks. PCR for CMV was performed on buffy-coat specimens every week for 15 weeks and at months 5 and 6.

RESULTS

No patients in the ganciclovir group, compared with 14 of 23 patients (61%) in the deferred-therapy group (P<0.0001), developed CMV disease during the first 12 weeks. In the ganciclovir group, 4 of 19 patients (21%) subsequently experienced 5 episodes, whereas 14 patients in the deferred-therapy group experienced 18 episodes (P=0.013 for subjects and P=0.026 for episodes). The time to disease was also delayed in the ganciclovir group compared with the deferred-therapy group (133+/-17 days vs. 51+/-7 days; P<0.0001). Oral ganciclovir also prevented CMV viremia during prophylaxis (2/19 patients [11%] vs. 23/23 patients [100%]). Time to CMV viremia was delayed in the ganciclovir group; however, 13/19 patients (68%) ultimately showed PCR evidence for CMV viremia (P=0.005).

CONCLUSIONS

An initial 12-week course of oral ganciclovir prevents CMV disease and infection in renal transplant recipients during prophylaxis, and the benefits persist after discontinuation.

Effects of storage temperature and time on qualitative and quantitative detection of cytomegalovirus in blood specimens by shell vial culture and PCR

Cytomegalovirus (CMV) infectious titers and DNA levels were determined by quantitative shell vial culture and quantitative-competitive PCR with blood samples from 10 renal transplant recipients with active CMV infection. Blood samples were stored at either room temperature or 4 degrees C and were processed at intervals of 0, 6, 24, 48, and 72 h. All samples were culture and PCR positive at baseline. Whereas the sensitivity of shell vial culture progressively declined, with only 55% positive at 24 h and 10% positive at 48 h, all samples remained PCR positive at all time points. Furthermore, the infectious titer diminished by 83 to 91% by 24 h compared to that at baseline (P < 0.0001), but quantitative DNA levels did not decline over time. Storage temperature had no significant effect on either infectious titer or DNA levels.