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Cost-effectiveness of tipranavir versus comparator protease inhibitor regimens in HIV infected patients previously exposed to antiretroviral therapy in the Netherlands |
Hubben G A, Bos J M, Veltman-Starkenburg C A, Stegmeijer S, Finnern H W, Kappelhoff B S, Simpson K N, Tramarin A, Postma M J |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. CRD summary This study investigated the cost-effectiveness of ritonavir-boosted tipranavir (TPVr) compared with a ritonavir-boosted protease inhibitor (CPIr) in regimens for HIV infected patients, who had previously received antiretroviral therapy. The cost-effectiveness of TPVr over CPIr was approximately EUR 40,000, which might be acceptable from the perspective of the Dutch health care payer. The study was well conducted and satisfactorily presented. In general, the authors’ conclusions appear to be valid and robust. Type of economic evaluation Cost-effectiveness analysis, cost-utility analysis Study objective This economic evaluation investigated the cost-effectiveness of a tipranavir regimen boosted with ritonavir (TPVr) compared with a protease inhibitor (PI) regimen boosted with ritonavir (CPIr), for human immunodeficiency virus (HIV)-infected patients who had previously received antiretroviral therapy. Interventions The TPVr regimen was compared with a standard CPIr regimen, which was selected by a physician and defined by genotype. Both regimens included at least two optimised non-PI antiretrovirals, such as nucleotide or nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, or enfuvirtide. Location/setting Netherlands/secondary care. Methods Analytical approach:The economic evaluation was based on a Markov model for three consecutive highly active antiretroviral therapy (HAART) regimens. The analysis had a lifetime horizon, which was until 90% of the patients had died. The authors stated that the analysis was carried out from the perspective of the health care system.
Effectiveness data:The clinical data came from a selection of known, relevant studies. The Randomized Evaluation of Strategic Intervention in multidrug resistant patients with Tipranavir (RESIST-2) trial supplied the patient characteristics and 48-week treatment effect for TPVr and CPIr. A large US cohort of 1,546 HAART-experienced patients was used to extrapolate this short-term clinical data to a lifetime horizon. The key clinical endpoint was the rate of progression with the two regimens.
Monetary benefit and utility valuations:The utility valuations were derived from a clinical trial of about 21,000 patients with HIV, using the European Quality of life (EQ-5D) questionnaire.
Measure of benefit:The summary benefit measures were life-years (LYs) and quality-adjusted life-years (QALYs). These were discounted at an annual rate of 1.5%.
Cost data:The economic analysis included the costs of drugs, routine visits to the clinic, a cluster of differentiation 4 positive (CD4+) cell count, viral load measurement, switching to a different antiretroviral regimen, and treatment of acquired immunodeficiency syndrome (AIDS) events, which included 22 opportunistic infections and other HIV events. The unit costs of the two regimens were presented and were derived from official Dutch prices. The resource use of these agents was based on data from the RESIST-2 trial. AIDS events and their costs were based on data from the University Medical Centre Groningen, using a bottom-up approach. When data were not available from this database, reimbursement prices were obtained from Dutch tariffs. Costs were in Euros (EUR) and were discounted at an annual rate of 4%. The price year was 2006.
Analysis of uncertainty:A deterministic one-way sensitivity analysis was undertaken on all model inputs, except the utility values. The authors arbitrarily defined the ranges of values, which were ± 25% for costs, 0% and 5% for the discount rate, etc. Results The lifetime costs per patient were EUR 167,200 with TPVr and EUR 145,400 with CPIr.
The expected LYs were 7.43 with TPVr and 6.91 with CPIr and the expected QALYs were 6.31 with TPVr and 5.80 with CPIr.
The incremental cost with TPVr in comparison with CPIr was EUR 41,600 per LY gained and EUR 42,500 per QALY gained.
The results of the sensitivity analysis were presented in a tornado diagram, which identified the cost of the two regimens as the most influential model inputs. Changes in the other model inputs did not alter the conclusions of the base-case analysis. Authors' conclusions The authors concluded that the cost-effectiveness of TPVr over CPIr was approximately EUR 40,000, which could be acceptable from the perspective of the Dutch health care payer. CRD commentary Interventions:The selection of the comparators was appropriate and reflected the current treatment pattern in the authors’ setting. A clear description of each regimen was given.
Effectiveness/benefits:The clinical data were derived from two studies, which were known to the authors. Although their identification was not based on a systematic search of the best available evidence, each had some important features, which make them relevant and valid. A randomised controlled trial is a strong design and its methodological rigour should have minimised potential biases. The methodological characteristics of the trial were reported in an appendix. The US study enrolled, and followed over the long-term, a large number of patients. The impact of the clinical assumptions on the study results was assessed by sensitivity analysis, which showed that the use of different plausible estimates would not have changed the conclusions. The source used to derive utility valuations was reported. A validated instrument was used to elicit the patient preferences. Both QALYs and LYs are appropriate benefit measures, which allow cross-disease comparisons and capture the impact of the interventions on patients’ health.
Costs:The analysis of costs was consistent with the perspective in terms of cost categories and sources of data, both of which reflected the viewpoint of the health care system. The extra cost of changes in the HAART regimen due to toxicities and the treatment of toxicities were not included. A justification for the exclusion of this cost category was provided and was based on the fact that the inclusion of these costs in analyses of HAART in other countries had a minimal impact on the results. The unit costs were presented for most items, but resource quantities were not reported. Each AIDS-related event was reported as a macro-category, without a breakdown of the cost items. Other aspects of the economic analysis were clearly presented.
Analysis and results:The analysis appropriately used an incremental ratio to combine the costs and benefits. A deterministic approach was used to investigate whether the findings were robust to variation in the individual model inputs. A more comprehensive and simultaneous methodology would have been useful, but the results were robust and were clearly presented. The authors showed that their results were in line with those found in other countries.
Concluding remarks:The study was well conducted and satisfactorily presented. In general, the authors’ conclusions might be considered to be valid and robust. Funding Funding from Boehringer Ingelheim bv, Alkmaar, The Netherlands. Bibliographic details Hubben G A, Bos J M, Veltman-Starkenburg C A, Stegmeijer S, Finnern H W, Kappelhoff B S, Simpson K N, Tramarin A, Postma M J. Cost-effectiveness of tipranavir versus comparator protease inhibitor regimens in HIV infected patients previously exposed to antiretroviral therapy in the Netherlands. Cost Effectiveness and Resource Allocation 2007; 5: 15 Other publications of related interest Cahn P, Villacian J, Lazzarin A, et al. Ritonavir-boosted tipranavir demonstrates superior efficacy to ritonavir-boosted protease inhibitors in treatment-experienced HIV-infected patients: 24-week results of the RESIST-2 trial. Clin Infect Dis 2006;43:1347-56.
Gathe J, Cooper DA, Farthing C, et al. Efficacy of the protease inhibitors tipranavir plus ritonavir in treatment experienced patients: 24-week analysis from the RESIST-1 trial. Clin Infect Dis 2006;43:1337-46.
Miners AH, Sabin CA, Trueman P, et al. Assessing the cost-effectiveness of HAART for adults with HIV in England. HIV Med 2001;2:52-58.
Anis AH, Guh D, Hogg RS, et al. The cost effectiveness of antiretroviral regimens for the treatment of HIV/AIDS. Pharmacoeconomics 2000;18:393-404. Indexing Status Subject indexing assigned by CRD MeSH Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Cost-Benefit Analysis; HIV Infections; Humans; Markov Chains; Netherlands; Protease Inhibitors; Quality-Adjusted Life Years AccessionNumber 22008000500 Date bibliographic record published 03/02/2009 Date abstract record published 09/09/2009 |
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