Pharmaco-economic study of FK 506 (Prograf) and cyclosporine A Neoral in cadaveric renal transplantation

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.

Economic evaluations of calcineurin inhibitors in renal transplantation: a literature review

People receiving a renal transplant require long-term treatment with immunosuppressant drugs. Contemporary regimens usually include a calcineurin inhibitor (CI), either ciclosporin or tacrolimus, in conjunction with at least one other drug. The aim of this study was to review the economic literature relating to the choice of CIs in patients following renal transplantation, with the specific intention of highlighting the challenges in estimating their cost effectiveness.A systematic literature search and narrative analysis was carried out, and 12 studies of varying quality and complexity were reviewed. All of the studies compared ciclosporin, azathioprine and a corticosteroid (CAS) with tacrolimus, azathioprine and a corticosteroid (TAS) but only three also evaluated the costs and effects of other possible treatment regimens. A variety of different evaluative frameworks were employed, from single randomised controlled trial-based studies over relatively short-time periods (6 months) to more complex Bayesian modelling techniques.The studies were broadly consistent in concluding that TAS was more effective than CAS in terms of reducing the rate of acute rejection episodes. Of the studies that undertook decision modelling, all but one estimated that TAS was associated with better graft-related outcomes such as rejection-free life-years, patient-survival and QALYs. Six of the studies concluded that the healthcare costs associated with TAS were lower than those for CAS. A seventh study suggested that TAS was the least costly option if costs were considered over a relatively long time period (14 years). Only one study clearly concluded that CAS was more cost effective than TAS.Clinical evidence clearly shows that TAS is more effective than CAS in terms of reducing the incidence of acute rejection following renal transplantation. The majority of published economic evaluations suggest that TAS is also the more cost-effective option. However, the economic evaluations contained a number of methodological limitations, undermining the confidence that can be attached to their results. Future economic evaluations of the CIs, and immunosuppressants in general, should address these issues in order to produce more robust cost-effectiveness estimates. Most importantly, they should evaluate a wider range of potential treatment options.

Kidney transplantation in the elderly: a decision analysis

Transplantation offers superior life expectancy and quality of life compared with dialysis in young patients with end-stage renal failure. However, the initial risks of mortality and morbidity are high. This study used a decision analysis model to evaluate the costs and benefits of kidney transplantation versus continued dialysis for older patients with renal failure. A decision analytic model comparing cadaveric renal transplantation to continued hemodialysis treatment was developed. The base case considered a theoretical cohort of patients aged 65 yr without known comorbidity or contraindications to transplantation who would have to wait 2 yr for a cadaveric transplant. Separate models were constructed for patients with diabetes or cardiovascular disease and for patients receiving an organ after a variety of wait-list times. Probability, utility, and survival data were obtained from published reports and renal registries. For 65-yr-old patients, quality-adjusted life expectancy increased by 1.1 quality-adjusted life years (QALY) at an incremental cost of $67,778 per QALY. Assuming a 2-yr wait-listed time, transplantation remained economically attractive for 70-yr-old patients (incremental cost effectiveness [ICE], $79,359 per QALY) but was less economically attractive for those over 75 yr of age (ICE, $99,553) or for 70-yr-olds with either cardiovascular disease or diabetes (ICE, $126,751 and $161,090 per QALY, respectively). The analytic results were sensitive only to the time spent waiting for the graft. The cost-effectiveness reduced such that the costs associated with one QALY were in excess of $100,000/yr when the probability of a complication was > or = 50% per 3-mo cycle and when the utility of transplantation fell below 0.62. If available within a timely period, transplantation may offer substantial clinical benefits to older patients at a reasonable financial cost. Prolonged waiting times dramatically decrease the clinical benefits and economic attractiveness of transplantation, suggesting that living donor transplantation may be of particular benefit in this population.

The cost effectiveness of tacrolimus versus microemulsified cyclosporin: a 10-year model of renal transplantation outcomes

INTRODUCTION AND OBJECTIVE

In 1983, the launch of cyclosporin was a significant clinical advance for organ transplant recipients. Subsequent drug research led to further advances with the introduction of cyclosporin microemulsion (cyclosporin ME) and tacrolimus. This paper presents the results from a long-term model comparing the clinical and economic outcomes associated with cyclosporin ME and tacrolimus immunosuppression for the prevention of graft rejection following renal transplantation.

STUDY DESIGN

A model was developed to project the costs and outcomes over a 10-year period following transplantation. The model was based on the results of a prospective, randomised study of 179 renal transplantation recipients receiving either cyclosporin ME or tacrolimus, which was conducted by the Welsh Transplantation Research Group (median follow-up: 2.7 years).

METHODS

The short-term costs and outcomes were the averages from the actual head-to-head trial data. From this, the long-term costs and outcomes were extrapolated based on the rate of change in patient and graft survival at 3, 5 and 10 years post transplant, as reported in the 1995 United Kingdom Transplant Support Service Authority Renal Transplant Audit. PERSPECTIVE AND YEAR OF COST DATA: The analysis was conducted from the perspective of a UK transplant unit. Costs were at 1999 prices (pounds sterling 1 = dollars US 1.42 = Euro 1.5) and costs and outcomes were discounted at 6% and 1.5%, respectively.

RESULTS

The model estimated that 10 years after transplantation, the proportion of patients surviving was 56% of the cyclosporin ME cohort and 64% of the tacrolimus cohort. The cumulative cost of maintenance therapy at 10 years was pounds sterling 23204 per patient maintained on cyclosporin ME versus pounds sterling 23803 per patient on tacrolimus. The cost per survivor at 10 years was pounds sterling 37000 (tacrolimus) versus pounds sterling 41000 (cyclosporin ME) and the cost per patient with a functioning graft was pounds sterling 39000 versus pounds sterling 45000. A Monte Carlo simulation of the model (10000 simulations) gave an average cost at 10 years of pounds sterling 23279 (SD pounds sterling 3457) for cyclosporin ME and pounds sterling 22841 (SD pounds sterling 3590) for tacrolimus. A (second order) probabilistic sensitivity analysis was also performed. The average cost at 10 years from a simulated cohort of 1000 was pounds sterling 23473 (SD pounds sterling 2154) for cyclosporin ME and pounds sterling 24087 (SD pounds sterling 2025) for tacrolimus.

CONCLUSION

Renal transplant recipients maintained on tacrolimus have better short- and long-term outcomes than patients maintained on cyclosporin ME. The long-term use of tacrolimus is a more cost-effective solution in terms of the number of survivors, patients with a functioning graft and rejection-free patients.

Cyclosporin: an updated review of the pharmacokinetic properties, clinical efficacy and tolerability of a microemulsion-based formulation (neoral)1 in organ transplantation

Cyclosporin is a lipophilic cyclic polypeptide immunosuppressant that interferes with the activity of T cells chiefly via calcineurin inhibition. The original oil-based oral formulation of this drug (Sandimmun)l was characterised by high intra- and interpatient pharmacokinetic variability, with poor bioavailability in many patients; a novel microemulsion formulation (Neoral)1 was therefore developed to circumvent these problems. Studies show increases, attributable chiefly to improved absorption in patients who absorb the drug only poorly from the original formulation, in mean systemic exposure to cyclosporin with the microemulsion, with no clinically significant differences in tolerability or drug interaction profiles. Cyclosporin microemulsion is at least as effective as the oil-based formulation in renal, liver and heart transplant recipients, with trends towards decreased incidence of acute rejection with the microemulsion formulation in some (statistically significant in a few) trials. Cyclosporin microemulsion and tacrolimus appear to have similar efficacy in preventing acute rejection episodes in most renal, pancreas-kidney, liver and heart transplant recipients. However, there are indications of superior efficacy for tacrolimus in some trials, particularly in the prevention of severe acute rejection and in Black transplant recipients. Current 12-month data also indicate equivalent efficacy of sirolimus in renal transplantation. Conversion from the oil-based to microemulsion formulation in stable renal, liver and heart transplant recipients is achievable with no change in acute rejection rates. The addition of an anti-interleukin-2 receptor monoclonal antibody and/or mycophenolate mofetil to cyclosporin microemulsion plus corticosteroids decreases rates of acute rejection; corticosteroid withdrawal without increased acute rejection rates was also achieved on the addition of these agents in some trials. Pharmacoeconomic analyses have shown savings in direct healthcare costs in kidney or liver transplantation when cyclosporin microemulsion is used in preference to the oil-based formulation, although studies incorporating indirect costs or expressing costs in terms of therapeutic outcomes are currently unavailable.

CONCLUSIONS

The introduction of cyclosporin microemulsion has consolidated the place of the drug as a mainstay of therapy in all types of solid organ transplantation; research into optimisation of outcomes through more effective therapeutic monitoring in patients receiving this formulation is ongoing. Several novel immunosuppressants have been introduced in recent years: further clinical and pharmacoeconomic research will be needed to clarify the relative positioning of these agents, particularly with respect to specific patient groups. Other new drugs (basiliximab/daclizumab and mycophenolate mofetil) offer particular advantages when used in combination with cyclosporin.

A model for analyzing the cost of the main clinical events after lung transplantation

BACKGROUND

The aim of this project was to model clinically important events experienced by lung transplant patients (from the day after transplant to 5 years or death) and costs associated with these events, and to assess the economic impact of different immunosuppression therapies.

METHODS

The population comprised 356 lung transplant patients (223 heart-lung, 102 single lung and 31 double lung) transplanted between April 1984 and December 1997. All patients received a cyclosporine-based triple-immunosuppression protocol. We designed a Markov model that included 3 time periods (0 to 6, 7 to 12, and 13 to 60 months), 5 clinical states (well, acute rejection, cytomegalovirus infection, non-cytomegalovirus infection and bronchiolitis obliterans syndrome), and death. For the well state, cost elements were immunosuppression, prophylaxis, and routine clinic visits. For all other states, cost elements were diagnosis, treatment, and bed days/visits. We excluded costs of the procedure.

RESULTS

The monthly costs associated with the well state decreased over time, from pound sterlings 1,778 ($2,658) in the first 6 months to pound sterlings 503 ($752) in months 7 to 12 and pound sterlings 350 ($523) after the first 12 months. The cost per event of the acute states remained reasonably constant over the 3 periods: pound sterlings 1,850 ($2,766) for rejection, pound sterlings 3,380 ($5,053) for cytomegalovirus, and pound sterlings 2,790 ($4,171) for other infections. The average cost per patient, discounted at 6%, over 5 years was pound sterlings 35,429 ($52,966) (95% range, pound1,435 [$2,145] to pound67,079 [$100,283]). This estimate is most sensitive to changes in immunosuppression. Substituting tacrolimus for cyclosporine increased 5-year costs by 5%; substituting mycophenolate mofetil for azathioprine increased 5-year costs by 26%.

CONCLUSIONS

This model is valuable in estimating the effect of new immunosuppression agents on the costs of follow-up care.

Tacrolimus: a further update of its pharmacology and therapeutic use in the management of organ transplantation

Tacrolimus (FK-506) is an immunosuppressant agent that acts by a variety of different mechanisms which include inhibition of calcineurin. It is used as a therapeutic alternative to cyclosporin, and therefore represents a cornerstone of immunosuppressive therapy in organ transplant recipients. Tacrolimus is now well established for primary immunosuppression in liver and kidney transplantation, and experience with its use in other types of solid organ transplantation, including heart, lung, pancreas and intestinal, as well as its use for the prevention of graft-versus-host disease in allogeneic bone marrow transplantation (BMT), is rapidly accumulating. Large randomised nonblind multicentre studies conducted in the US and Europe in both liver and kidney transplantation showed similar patient and graft survival rates between treatment groups (although rates were numerically higher with tacrolimus- versus cyclosporin-based immunosuppression in adults with liver transplants), and a consistent statistically significant advantage for tacrolimus with respect to acute rejection rate. Chronic rejection rates were also significantly lower with tacrolimus in a large randomised liver transplantation trial, and a trend towards a lower rate of chronic rejection was noted with tacrolimus in a large multicentre renal transplantation study. In general, a similar trend in overall efficacy has been demonstrated in a number of additional clinical trials comparing tacrolimus- with cyclosporin-based immunosuppression in various types of transplantation. One notable exception is in BMT, where a large randomised trial showed significantly better 2-year patient survival with cyclosporin over tacrolimus, which was primarily attributed to patients with advanced haematological malignancies at the time of (matched sibling donor) BMT. These survival results in BMT require further elucidation. Tacrolimus has also demonstrated efficacy in various types of transplantation as rescue therapy in patients who experience persistent acute rejection (or significant adverse effect's) with cyclosporin-based therapy, whereas cyclosporin has not demonstrated a similar capacity to reverse refractory acute rejection. A corticosteroid-sparing effect has been demonstrated in several studies with tacrolimus, which may be a particularly useful consideration in children receiving transplants. The differences in the tolerability profiles of tacrolimus and cyclosporin may well be an influential factor in selecting the optimal treatment for patients undergoing organ transplantation. Although both drugs have a similar degree of nephrotoxicity, cyclosporin has a higher incidence of significant hypertension, hypercholesterolaemia, hirsutism and gingival hyperplasia, while tacrolimus has a higher incidence of diabetes mellitus, some types of neurotoxicity (e.g. tremor, paraesthesia), diarrhoea and alopecia.

CONCLUSION

Tacrolimus is an important therapeutic option for the optimal individualisation of immunosuppressive therapy in transplant recipients.

Renal transplantation

There has been an increase in the transplantation of kidneys from living, genetically unrelated donors and from extended criteria cadaver donors. The past policies about paid renal donors are being reconsidered. Techniques have been developed to reduce morbidity for the living renal donor. The variety of immunosuppressants allows individuation of therapy. Guidelines for conception and pregnancy have been established.