Cost effectiveness of darunavir/ritonavir combination antiretroviral therapy for treatment-naive adults with HIV-1 infection in Canada

OBJECTIVE

The AntiRetroviral Therapy with TMC114 ExaMined In naive Subjects (ARTEMIS) clinical trial examined the efficacy and safety of two ritonavir-boosted protease inhibitors (PI/r), darunavir/r 800/100 mg once daily (QD) and lopinavir/r 800/200 mg daily, both used in combination with tenofovir disoproxil fumarate/emtricitabine. This study aimed to assess the cost effectiveness of the darunavir/r regimen compared with the lopinavir/r regimen in treatment-naive adults with HIV-1 infection in Canada.

METHODS

A Markov model with a 3-month cycle time and six CD4 cell-count-based health states (>500, 351-500, 201-500, 101-200, 51-100, and 0-50 cells/mm(3)) followed a cohort of treatment-naive adults with HIV-1 infection through initial darunavir/r or lopinavir/r combination therapy and a common set of subsequent regimens over the course of their remaining lifetimes. Population characteristics and transition probabilities were estimated from the ARTEMIS clinical trial and other trials. Costs (in 2014 Canadian dollars), utilities, and mortality were estimated from Canadian sources and published literature. Costs and health outcomes were discounted at 5% per year. One-way and probabilistic sensitivity analyses were performed, including a simple indirect comparison of the darunavir/r initial regimen with an atazanavir/r-based regimen.

RESULTS

In the base-case lifetime analysis, individuals receiving initial therapy with the darunavir/r regimen experienced 0.25 more quality-adjusted life-years (QALYs) with lower antiretroviral drug costs (-$14,246) and total costs (-$18,402) than individuals receiving the lopinavir/r regimen, indicating that darunavir/r dominated lopinavir/r. In an indirect comparison with an atazanavir/r-based regimen, the darunavir/r regimen remained the dominant choice, but with lower cost savings (-$2,303) and QALY gains (0.02). Results were robust to a wide range of other changes in input parameter values, population characteristics, and modeling assumptions. The probabilistic sensitivity analysis demonstrated that the darunavir/r regimen was cost effective compared with the lopinavir/r regimen in over 86% of simulations for willingness-to-pay thresholds between $0 and $100,000 per QALY gained.

CONCLUSIONS

Darunavir/r 800/100 mg QD may be a cost-effective PI/r component of initial antiretroviral therapy for treatment-naive adults with HIV-1 infection in Canada.

[Comparative cost-effectiveness analysis between darunavir/ritonavir and other protease inhibitors in treatment-naive human immunodeficiency syndrome type 1-infected patients in Spain]

INTRODUCTION

GESIDA (AIDS Study Group) has proposed preferred regimens of antiretroviral treatment as initial therapy in HIV infected patients. The objective of this analysis is to compare the costs and effectiveness of darunavir/r QD and other ritonavir-boosted (/r) protease inhibitors (PIs) currently recommended in GESIDA guidelines for treatment-naïve patients.

METHODS

A cost-efficacy model compared the boosted PIs recommended as preferred or alternative treatment choices, each used with a nucleoside reverse transcriptase inhibitor backbone. Efficacy was measured by 48-week virological response (viral load < 50 copies/mL) adjusted by baseline viral load and CD4 cell count. To generate efficiency frontiers and cost-efficacy ratios, one-year antiretroviral therapy costs in Spain, and 48-week efficacy values were used.

RESULTS

The model estimated that starting treatment with darunavir/r QD was the most cost-effective choice compared with the other preferred PI/r based therapies. The average cost per patient with a virological response was lower for darunavir/r QD (13,420€) than for atazanavir/r QD (14,000€), or lopinavir/r BID (13,815€). Among the preferred PI/r-based therapies, darunavir/r QD also was estimated to be the most efficient option for treatment-naïve patients. Atazanavir/r QD and lopinavir/r BID were found to be «dominated» by darunavir/r) and, consequently, were outside the efficiency frontier of PI/r-based first-line treatment. Given a fixed budget of 10 million euros for PI/r-based first-line therapy, the model estimated that darunavir/r QD would yield more responders (745) than atazanavir/r QD (714), or lopinavir/r BID (724). At the same time, darunavir/r QD would reduce the number of individuals failing treatment (150) compared with atazanavir/r QD (172) and lopinavir/r BID (286).

CONCLUSIONS

In this model, darunavir/r QD was found to be the most cost-effective choice, among the preferred PI/r-based therapies recommended in the Spanish guidelines for treatment-naïve patients.

Reliability, validity and ability to detect change of the clinician-rated Personal and Social Performance scale in patients with acute symptoms of schizophrenia

OBJECTIVE

To describe the measurement properties of the Personal and Social Performance scale (PSP), a clinician-reported measure of severity of personal and social dysfunction, in subjects with acute symptoms of schizophrenia.

METHODS

Pooled data from three paliperidone extended-release clinical studies (n = 1665) and data from a separate noninterventional, cross-sectional, validation study (n = 299) were analyzed.

RESULTS

The PSP showed good interrater (intraclass correlation coefficient [ICC] = 0.87) and test-retest (ICCs > 0.90) reliability. Pearson correlation coefficient for association between baseline PSP and Positive and Negative Syndrome Scale (PANSS) total scores was -0.32 for subjects assessed by the same rater and -0.29 for subjects assessed by different raters, suggesting low overlap in measurement constructs between the PANSS and PSP. Spearman Rank correlation coefficient for association between baseline PSP and Clinical Global Impression-Severity (CGI-S) scores was -0.51 with the same rater and -0.15 with different raters. Hypothesized relationships between the PSP and the PANSS or CGI-S based on levels of disease severity were prospectively defined. These hypotheses were confirmed by analyses showing statistically significant differences between baseline mean PSP scores in subjects grouped by severity rating on the CGI-S (mild or less vs. at least moderate) (p < 0.001) and the PANSS ('low symptom severity' vs. 'high symptom severity') (p = 0.005). The PSP was sensitive to change based on statistically significant correlations between change in the PSP and change in the CGI-S (p < 0.001) and the PANSS (p < 0.001). Limitations of analyses include pooling data across studies, interrater reliability assessment in the validation study only, post hoc assessment of test-retest reliability in the paliperidone ER studies, different raters for the PSP and PANSS not specified in the paliperidone ER studies, PSP validity assessment based on the PANSS and the CGI-S as comparators rather than another social function instrument.

CONCLUSION

These initial reliability and validity assessments suggest the PSP has promise as a measure of social functioning in patients with acute symptoms of schizophrenia.

A Markov model of treatment of newly diagnosed epilepsy in the UK. An initial assessment of cost-effectiveness of topiramate

Long-term comparative trials among newer antiepileptic drugs are lacking; therefore decision models are needed to guide treatment decisions. The goal of this study was to develop an economic model of newly diagnosed epilepsy in the UK and to provide the first assessment of topiramate. A Markov model was developed combining data from clinical trials, cost-of illness, mortality, and utility studies. Expected costs and utilities associated with treatment strategies (first- and second-line treatments) were compared to find the cost-effectiveness frontier. First- and second-line monotherapy with topiramate or carbamazepine in partial seizures was less costly and more effective than other scenarios. In generalised seizures first-line topiramate was cost-effective with valproate or lamotrigine as second-line treatments depending on the set of utilities used. Models provide a relevant framework within which costs and health gains of antiepileptic drugs treatment options can be studied. Our findings are further evidence of the promising role of topiramate for patients with newly diagnosed epilepsy.

A pooled analysis of adjunctive topiramate in refractory partial epilepsy

OBJECTIVES

To evaluate the impact of different dosages of topiramate (TPM) add-on to stable antiepileptic therapy for refractory partial epilepsy in adults.

MATERIAL AND METHODS

Pooled intention-to-treat analysis of six similarly designed double-blind, placebo-controlled trials, including 481 patients treated with doses of TPM 200, 400, 600 and 800 mg/day, and 265 patients receiving placebo.

RESULTS

Seizures were reduced by >/=50% from baseline in 41% of TPM-treated patients and 15% of placebo-treated patients (P < 0.001); 5 and 0.8%, respectively, were seizure-free (P < 0.003). TPM was significantly better than placebo regardless of gender, age, baseline seizure rate as well as number and type of concomitant antiepileptic drugs. Efficacy was statistically significant in favour of TPM at all dose levels: at least 50% seizure reduction was achieved in 40% of patients with 200 mg, 41% with 400 mg, 44% with 600 mg and 41% with 800 mg TPM when compared with 15% with placebo (P </= 0.001 for each dosage arm vs placebo). The median reduction in monthly seizure frequency was 38%, 42%, 45% and 38% vs 8%, respectively (P </= 0.001). Moreover, response to TPM was significantly superior to placebo at each of the dose levels tested for most of the baseline variables. The total percentage of withdrawals increased with the dosage, and the withdrawals caused by adverse events increased from 3% with placebo to 7% with 200 mg TPM (not significant vs placebo), 15% with 400 mg TPM (P = 0.08), 16% with 600 mg TPM (P = 0.002) and 15% with 800 mg TPM (P = 0.003).

CONCLUSION

The efficacy of TPM add-on in partial epilepsy is consistent across efficacy endpoints and independent of study population characteristics. The response at 200 mg TPM is similar to the response at higher doses, but as drop-outs caused by adverse events are more frequent above the 200 mg dose, this pooled analysis supports that 200 mg daily is a good target dose for add-on therapy in most patients with partial epilepsy, showing an excellent balance between efficacy and tolerability.

Estimating survival gain for economic evaluations with survival time as principal endpoint: a cost-effectiveness analysis of adding early hormonal therapy to radiotherapy in patients with locally advanced prostate cancer

The problem of estimating expected outcomes for the economic evaluation of treatments for which the outcome of principal interest is (quality adjusted) survival time has so far not received sufficient attention in the literature. The best estimate of expected survival is mean survival time, but with censored survival data, the true survival time for all the subjects is not known, so the mean is not defined.A possible solution to this estimation problem is illustrated by a retrospective cost-effectiveness analysis of the addition of hormonal therapy to standard radiotherapy for patients with locally advanced prostate cancer. A recently proposed method is used to approach the problem caused by censored cost data, and the impact of uncertainty is assessed by bootstrap resampling techniques. Mean survival time is estimated by a restricted means analysis with the time point of restriction determined by statistical criteria. When average total costs and mean survival time is evaluated at this time point of restriction, the result is that the combined therapy (radiotherapy plus hormonal therapy) increases mean survival time by about 1 year, while reducing the costs per patient for the French health insurance system by 12 700 FF. The time point of restriction may also be determined by other criteria and mean survival time may be estimated by extrapolating the survival curves by means of various parametric survival distributions. We show that the exact results of the economic evaluation are decisively determined by the restriction time point chosen and the approach taken to estimate mean survival time.

Cost effectiveness of paclitaxel/cisplatin compared with cyclophosphamide/cisplatin in the treatment of advanced ovarian cancer in Belgium

OBJECTIVE

To assess the economic impact of two polychemotherapy regimens for patients with advanced ovarian cancer from the perspective of the Belgian health insurance and financing system.

DESIGN

An economic evaluation was integrated in an intergroup randomised controlled trial (EORTC 55931) in which patients were randomised to receive the new treatment of paclitaxel and cisplatin or the standard therapy of cyclophosphamide and cisplatin. Data on the use of medical resources were collected prospectively for the 231 European Organization for Research and Treatment of Cancer (EORTC) patients in the trial and costs were valued by using unit prices. The outcome for the economic evaluation was mean survival time as determined by the so-called restricted means method, with the time point of restriction fixed by statistical criteria. A correction of censoring of the cost data collected in the trial was also performed.

MAIN OUTCOME MEASURES AND RESULTS

The paclitaxel and cisplatin group experienced a statistically significant improvement in mean survival time of 4 months, which was associated with an increase in the average total cost per patient of 6795 euros (EUR; 1998 values), when costs were assessed over the same period as the gain in mean survival time. This corresponds to a point estimate of the incremental cost-effectiveness ratio of EUR20 385 per life-year gained. The impact of uncertainty was assessed by using a bias-corrected and accelerated bootstrap method with 5000 resamples, and the final results of the analysis are expressed in terms of a cost-effectiveness acceptability curve.

CONCLUSIONS

The present economic evaluation has shown that the substitution of paclitaxel for cyclophosphamide in the chemotherapy regimen for women with advanced ovarian cancer leads to a significant improvement in patient survival, which is associated with an increase in costs for the Belgian health insurance system.

Cost-effectiveness of the addition of early hormonal therapy in locally advanced prostate cancer: results decisively determined by the cut-off time-point chosen for the analysis

We present a retrospective cost-effectiveness analysis using data from a randomised controlled trial (EORTC 22863) of the addition of early hormonal therapy with a luteinising hormone-releasing hormone (LHRH) analogue to radiotherapy in the treatment of patients with locally advanced prostate cancer. Data on the use of medical resources were extracted from the hospital charts of 90 patients recruited into the trial by one French hospital. Costs are assessed from the viewpoint of the French healthcare financing system and adjusted for censoring. Expected costs per patient of each treatment is related to the expected outcome, mean survival time, estimated by a restricted means analysis. The time point of restriction is determined by statistical criteria. In the base case analysis with a cut-off time point at 8.58 years, the combined therapy group (COMB) had a gain in mean survival time of 1.06 years (7.05 versus 5.99 years) and a reduction of average total costs of 12700 French francs (FF) (58300 FF versus 71000 FF). The analysis of uncertainty uses bootstrap techniques with 5000 replicates to examine the joint distribution of cost and survival outcomes. In 76% of the cases, COMB results in longer mean survival time and lower costs than the radiotherapy group (RT). In cases where COMB therapy raises costs (13% of the cases), it is rarely by more than 20000 FF per patient, no matter the size of the associated survival gain. It is thus highly likely that COMB should be considered a cost-effective option compared with RT for these patients. The exact result of the economic evaluation is decisively determined by the restriction time point selected for the determination of mean survival time, partly also because the average total costs of the two treatments develop entirely differently as a function of the survival time.

The costs of managing patients with advanced colorectal cancer in 10 different European centres

With the aim of estimating and comparing the direct hospital costs of managing patients with advanced colorectal cancer in various countries, data on resource utilisation and unit prices were collected. Data on the consumption of medical resources were collected by a retrospective examination of the hospital charts for 20 patients in each of 10 centres in five European countries. To make cost comparisons meaningful, a complete and consistent set of unit prices for all the medical resources used in each of the countries would be required, but this could not be achieved. As an alternative method of comparison, the most complete set of unit prices (from Belgium) was used here to estimate the imputed average total cost of patient management in each centre. By using this approach, a summary index was created, which reflected only differences in resource utilisation. This index showed that there were considerable differences in the amounts of resources used for treating these patients, between, as well as within, countries. Differences of the same order of magnitude were found, when the treatment of subgroups of patients, according to site and stage of disease, were examined.