Economic evaluation of dabigatran etexilate for the prevention of venous thromboembolism after total knee and hip replacement surgery.

OBJECTIVE: This was an evaluation of the cost-effectiveness of oral dabigatran etexilate compared with subcutaneous low-molecular-weight heparin (enoxaparin) for the prevention of venous thromboembolism (VTE) after total knee replacement (TKR) and total hip replacement (THR) surgery from the perspective of the UK National Health Service. METHODS: Dabigatran etexilate (220 mg once daily) was compared with enoxaparin (40 mg once daily) in patients undergoing TKR (duration of prophylaxis, 6-10 days) and THR (duration of prophylaxis, 28-35 days). The 10-week acute postsurgical phase was modeled using a decision tree. A Markov process (1-year cycle length) was used to model long-term events (recurrent VTE, postthrombotic syndrome, and consequences of intracranial hemorrhage) for patients' remaining lifetimes. Relative risks for VTE and bleeding events were derived from 2 Phase III studies that compared dabigatran etexilate with enoxaparin 40 mg once daily. The probabilities of long-term events were estimated using data from published longitudinal studies. RESULTS: Rates of VTE and bleeding events did not differ significantly between dabigatran etexilate and enoxaparin. Dabigatran etexilate was less costly than enoxaparin in TKR and substantially less costly in THR, primarily due to differences in administration costs. The cost of prophylaxis for THR patients, including drugs and administration costs, was estimated at pound 137 for dabigatran etexilate and pound 237 for enoxaparin ( pound 7 for nursing time during the hospital stay, pound 91 for nurse home visits for administration after hospital discharge, and an additional pound 2 in drug costs). At a willingness-to-pay threshold of pound 20,000 per quality-adjusted life-year, the probability of cost-effectiveness for dabigatran etexilate was 75% in TKR and 97% in THR. These results were robust across a range of sensitivity analyses. CONCLUSION: From the perspective of the UK National Health Service, thromboprophylaxis with dabigatran etexilate was cost-saving compared with enoxaparin 40 mg once daily, with comparable efficacy and safety profiles.

Cost effectiveness of pegaptanib for the treatment of age-related macular degeneration in the UK.

BACKGROUND: Age-related macular degeneration (AMD) is the primary cause of vision loss in the elderly and results in significant economic and humanistic burden. The selective vascular endothelial growth factor inhibitor, pegaptanib (Macugen) is indicated for patients with neovascular AMD. Guidance is needed regarding the cost effectiveness of treatment, any variation between sub-populations of differing clinical characteristics and the optimum duration of treatment. OBJECTIVE: To estimate the cost effectiveness of pegaptanib versus best supportive care (BSC) for AMD from the perspective of the UK government, and to evaluate the impact of patient characteristics and differing treatment discontinuation scenarios. METHODS: A cohort of 1000 patients aged >45 years with a best-corrected visual acuity (VA) in their better-seeing eye of < or =6/12 was modelled. Patients were either treated with pegaptanib (0.3mg every 6 weeks for a maximum of 2 years in their better-seeing eye only) or received BSC (no active treatment). Supportive services were provided for patients with a VA < or =6/60. A 10-year Markov model composed of 12 VA states (defined by individual Snellen lines) and a dead state was constructed. The model reported herein was used to support submissions to the National Institute for Health and Clinical Excellence (NICE) and the Scottish Medicines Consortium (SMC). NICE guidance is expected to be available in October 2007 and the SMC advice was issued on 7 July 2006. SMC accepted pegaptanib for use in patients with visual acuity between 6/12 and 6/60 (inclusive) and should be stopped if visual acuity falls below 6/60 during treatment or where severe visual loss is experienced. Time-dependent transition probabilities for the loss and gain of Snellen lines were derived from parametric survival curves fitted to patient-level data from the VISION trials. Survival curves were fitted with treatment and baseline Snellen scores as covariates; additional curves were fitted with the addition of age, gender, lesion type or lesion size as covariates. Mortality rates were adjusted for the age, gender and VA of the population. Cost effectiveness was expressed as the incremental cost (IC) per vision-year saved and IC/QALY. Uncertainty was explored by probabilistic and univariate sensitivity analysis. Costs (year 2005 values) and outcomes were discounted at 3.5% per anum. RESULTS: In the base-case analysis, treatment was targeted to patients with a VA of 6/12 to 6/95 and discontinued after 2 years, or earlier if VA fell below 6/95 or by > or =6 lines. The IC/QALY was estimated as 8023 pounds(upper 95% CI 20,641 pounds). Cost effectiveness varied by age (age <75 years = 2033 pounds/QALY; age > or =75 years = 11,657 pounds/QALY) and by pre-treatment VA (6/12-6/95 = 8023 pounds/QALY; 6/12-6/60 = 6664 pounds/QALY; 6/12-6/24 = 1920 pounds/QALY). Gender and lesion type or size had little effect. Cost effectiveness was not sensitive to precise rules for treatment discontinuation, but was maximised if treatment was discontinued in patients no longer likely to benefit. CONCLUSIONS: The results suggest that pegaptanib treatment is likely to be cost effective across all groups studied, and marginally more cost effective in younger patients and those with better pre-treatment VA. Cost effectiveness appears to be optimised if treatment is discontinued after 1 year if individual patients' VA has dropped by > or =6 lines from pre-treatment levels, or at any time if it drops below 6/95. However, strict application of discontinuation rules does not appear to be necessary for pegaptanib to be cost effective. Clinical judgement and patient preference should be an important determinant in decisions about stopping treatment.

The cost-effectiveness of rituximab in non-Hodgkin's lymphoma.

Rituximab was the first available genetically engineered monoclonal antibody that targets CD20 proteins on the surface of B-cells. Rituximab is indicated: as the first-line treatment of diffuse-large B-cell non-Hodgkin's lymphoma (NHL) in combination with cyclophosphamide, vincristine, doxorubicin and prednisone (CHOP); as the first-line treatment of stage III-IV follicular NHL in combination with cyclophosphamide, vincristine and prednisolone (CVP); for the treatment of patients with stage III-IV follicular lymphoma who are chemoresistant or in their second or subsequent relapse after chemotherapy; and as maintenance therapy for patients with relapsed/refractory follicular lymphoma responding to induction therapy with chemotherapy with or without rituximab. This article reviews the published economic evaluations of rituximab in the treatment of NHL. The conclusion of these analyses is that rituximab, used both as monotherapy and in combination with chemotherapy, is a cost-effective intervention in the most common forms of NHL, diffuse large B-cell lymphoma and follicular NHL. However, there exists a paucity of published studies on both the clinical and economic analysis of rituximab in the less common NHLs. Currently, rituximab is being evaluated in clinical trials within other NHLs. If it has the same clinical success in these trials as it has had in diffuse large B-cell lymphoma and follicular lymphoma, then it is possible that within a few years rituximab could play a key role in treating patients in all forms of NHL.

A decision model to compare health care costs of olanzapine and risperidone treatment for schizophrenia in Germany.

Second-generation atypical antipsychotics such as clozapine, olanzapine, risperidone, quetiapine, ziprasidone, amisulpride and ariprazole offer the potential to reduce the significant health care resource demands in the treatment of schizophrenia through improved levels of initial clinical response and reduced levels of long-term acute relapse. However, the optimal sequencing of these drugs remains unclear. To consider this issue from a health economic viewpoint a decision model approach was used comparing healthcare costs and clinical outcomes when treating patients with alternative sequences of atypical antipsychotic treatment. Treated patients were assumed to be in a current acute episode with at least a 10-year history of disease and to be naive to previous atypical treatments. Treatment strategies were based on either first-line olanzapine or risperidone with switching to the alternative drug as second-line treatment following an inadequate clinical response to first-line drug therapy. Clinical response data were derived from a pivotal published comparative study of both olanzapine and risperidone. Published data on the long-term use of antipsychotic drugs where used wherever possible to populate the model for relapse rates during the maintenance phase. Health care resource data were defined for Germany based on expert clinical opinion. A treatment strategy of first-line olanzapine was shown to be cost saving over a 1-year period, with additional clinical benefits in the form of avoided relapses. The model suggests that over the first year of treatment a strategy of first-line olanzapine is associated with lower risk of additional relapse (0.33 fewer acute relapses per 100 patients per year) and with cost savings (euro 35,306 per 100 patients per year). There is a need for longer term direct in-trial comparisons of atypical antipsychotics to confirm these indicative results.

Integrated transcriptional profiling and linkage analysis for identification of genes underlying disease.

Integration of genome-wide expression profiling with linkage analysis is a new approach to identifying genes underlying complex traits. We applied this approach to the regulation of gene expression in the BXH/HXB panel of rat recombinant inbred strains, one of the largest available rodent recombinant inbred panels and a leading resource for genetic analysis of the highly prevalent metabolic syndrome. In two tissues important to the pathogenesis of the metabolic syndrome, we mapped cis- and trans-regulatory control elements for expression of thousands of genes across the genome. Many of the most highly linked expression quantitative trait loci are regulated in cis, are inherited essentially as monogenic traits and are good candidate genes for previously mapped physiological quantitative trait loci in the rat. By comparative mapping we generated a data set of 73 candidate genes for hypertension that merit testing in human populations. Mining of this publicly available data set is expected to lead to new insights into the genes and regulatory pathways underlying the extensive range of metabolic and cardiovascular disease phenotypes that segregate in these recombinant inbred strains.

Physical and functional interactions between polo kinase and the spindle pole component Cut12 regulate mitotic commitment in S. pombe.

Commitment to mitosis is regulated by a protein kinase complex called MPF. MPF is inhibited by Wee1-related kinases and activated by Cdc25 phosphatase. MPF activation further boosts Cdc25 and represses Wee1. This feedback control probably involves polo kinase. A dominant cut12.s11 mutation in the Schizosaccharomyces pombe spindle pole body (SPB) component Cut12 both suppresses the conditional lethal mitotic commitment defect of cdc25.22 and promotes premature association of the S. pombe polo kinase, Plo1, with the SPB. We now show that Cut12 associated with Plo1 in two hybrid and immunoprecipitation assays. Plo1 function was required for recognition of the mitotic SPB by the phospho-specific antibody MPM-2. In vivo MPM-2 staining and in vitro kinase assays established that the loss-of-function mutation, cut12.1, reduced mitotic activation of Plo1, whereas the gain-of-function mutation, cut12.s11, promoted higher levels of Plo1 activity than were normally seen in interphase. cut12.s11 could not promote mitotic commitment of cdc25.22 cells when Plo1 function was compromised. Expression of a constitutively active plo1 allele suppressed the mitotic commitment defect of cdc25.22. These data suggest that cut12.s11 suppresses cdc25.22 by promoting Plo1 activity. Furthermore, the delayed mitotic commitment of plo1.ts2 cells suggests that Plo1 is an integral part of the core controls that modulate MPF activation in S. pombe.

A 'marker switch' approach for targeted mutagenesis of genes in Schizosaccharomyces pombe.

The completion of the Schizosaccharomyces pombe genome sequencing project has led to a dramatic acceleration of gene characterization in this system. Once a gene has been identified, the challenge then comes in using reverse genetics to generate a range of mutants in this gene of interest so that the powerful genetics and wealth of genetic backgrounds available in Sz. pombe can be exploited to study the function of the newly identified molecule. Beyond simple PCR-tagging approaches, the high frequency with which illegitimate recombination occurs in Sz. pombe has made the manipulation of some loci complex, time consuming and a process of trial and error. Here we describe a simple 'marker switch' approach that enables the rapid selection of integration events at the locus of interest from an excessive background of integration at heterologous sites. We use the generation of temperature-sensitive mutations in the plo1(+) gene to validate this approach.

Plo1(+) regulates gene transcription at the M-G(1) interval during the fission yeast mitotic cell cycle.

The regulation of gene expression plays an important part in cell cycle controls. We describe the molecular machinery that co-ordinates gene transcription at the M-G(1) interval during the fission yeast mitotic cell cycle. A sequence is identified in the cdc15(+) promoter that we call a PCB (pombe cell cycle box), which confers M-G(1)-specific transcription. Sequences similar to the PCB are present in the promoters of seven other genes, spo12(+), cdc19(+), fin1(+), sid2(+), ppb1(+), mid1(+)/dmf1(+) and plo1(+), which we find to be transcribed at M-G(1). A transcription factor complex is identified that binds to the PCB sequence, which we name PBF, for PCB-binding factor. Finally, we show that PBF binding activity and consequent gene transcription are regulated by the Plo1p protein kinase, thus invoking a potential auto-feedback loop mechanism that regulates mitotic gene transcription and passage through septation and cytokinesis.