Cost-effectiveness of enfuvirtide in HIV therapy for treatment-experienced patients in the United States

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.

Cost-Effectiveness of Antiretroviral Therapy for Multidrug-Resistant HIV: Past, Present, and Future

In the early years of the highly active antiretroviral therapy (HAART) era, HIV with resistance to two or more agents in different antiretroviral classes posed a significant clinical challenge. Multidrug-resistant (MDR) HIV was an important cause of treatment failure, morbidity, and mortality. Treatment options at the time were limited; multiple drug regimens with or without enfuvirtide were used with some success but proved to be difficult to sustain for reasons of tolerability, toxicity, and cost. Starting in 2006, data began to emerge supporting the use of new drugs from the original antiretroviral classes (tipranavir, darunavir, and etravirine) and drugs from new classes (raltegravir and maraviroc) for the treatment of MDR HIV. Their availability has enabled patients with MDR HIV to achieve full and durable viral suppression with more compact and cost-effective regimens including at least two and often three fully active agents. The emergence of drug-resistant HIV is expected to continue to become less frequent in the future, driven by improvements in the convenience, tolerability, efficacy, and durability of first-line HAART regimens. To continue this trend, the optimal rollout of HAART in both rich and resource-limited settings will require careful planning and strategic use of antiretroviral drugs and monitoring technologies.

A literature review of reporting standards of HIV progression models

OBJECTIVE

We conducted a systematic review of HIV progression models to identify the mathematical structures used, the main research questions and key model aspects in terms of quality and robustness.

METHODS

We searched for articles published before February 2009 that described models of HIV progression in humans. We included two strategies of search with and without MeSH terms. We classified the models by their mathematical structure and research question. We created a checklist of desirable features of the models, reviewed and classified the articles to inform our conclusions.

RESULTS

Among 3491 articles found, 93 met the inclusion criteria. Among the selected articles, 60 used transition models, 25 applied differential equations, and eight had other structures. We did not find a relation between the type of question explored and the modeling method used. None of the studies complied with the complete set of items in the checklist, but 6.5% cover at least 90% of them.

CONCLUSION

There is an enormous heterogeneity of HIV modeling exercises in terms of methods used and topics addressed, as well as in the presentation of key aspects of the articles in terms of quality and robustness.

T20QoL: an observational multicenter cohort study to evaluate the quality of life in HIV-patients treated with enfuvirtide (ENF, T-20) in combination with an optimized background therapy

AIM

To evaluate the impact of health-related quality of life (HRQoL) enfuvirtide-based (ENF-based) salvage regimens of treatment-experienced HIV patients, in an observational multicenter cohort study.

METHODS

HRQoL was measured in a cohort of 16 patients over a 6-month follow-up using 2 instruments: the ISSQoL (Istituto Superiore di Sanità Quality of Life), a recently validated HIV-specific questionnaire; the EQ-5D (EuroQol), a generic widely used instrument. ENF was given at standard dosage along with an optimized background regimen.

RESULTS

Most of HRQoL dimensions showed improvement in ENF-treated patients at the post-baseline time points. Social functioning was the only dimension showing a negative effect. Monthly care costs of antiretroviral drugs for HIV patients taking ENF plus an optimized background regimen were approximately euro2,348 per patient-month (range euro382-euro2,940).

CONCLUSION

Our results show that the addition of ENF to an optimized background salvage-HAART may positively affect HRQoL not only in clinical trials but also in a sample population of patients used in a routine clinical practice.

A microsimulation of the cost-effectiveness of maraviroc for antiretroviral treatment-experienced HIV-infected individuals

PURPOSE

Maraviroc (MVC) is the first approved CCR5 antagonist. The aim of this study was to explore the cost-effectiveness of MVC in treatment-experienced or treatment-resistant HIV-infected adults.

METHODS

The validated HIV microsimulation model ARAMIS was used to predict clinical and economic outcomes of treating patients with optimized background therapy (OBT) alone, as compared to a strategy of testing for the patient's viral tropism and treating with OBT with or without (+/-) MVC in a cohort corresponding to the MOTIVATE screening cohort.

RESULTS

Compared to treatment with OBT alone, a treatment strategy of OBT +/- MVC (twice daily) according to tropism test result was predicted to increase CD4+ cell count after 5 years (from mean 249 to 360 cells/microL), undiscounted life expectancy (7.6 to 8.9 years), and quality-adjusted life years (QALYs; from 4.99 to 5.71) for an additional $40,500, giving an incremental cost-effectiveness ratio of $56,400 per QALY gained. The result was relatively insensitive to alternative clinical and cost assumptions within reasonable ranges, but for individuals with HIV susceptible to only two or fewer components of OBT, the ICER decreased to $52,000 per QALY gained.

CONCLUSION

MVC is cost-effective, especially among individuals with few remaining options for active antiretroviral therapy.

A review of economic evaluations of darunavir boosted by low-dose ritonavir in treatment-experienced persons living with HIV infection

Darunavir boosted by low-dose ritonavir (DRV/r), at a daily dose of 600/100 mg twice a day (bid), has been shown to be superior to alternative highly active antiretroviral therapy (HAART) regimens for the management of treatment-experienced, HIV-infected adults in the phase IIb POWER trials and the phase III TITAN trial. Economic analyses of different types that have been performed for several countries to investigate the cost effectiveness and budgetary impact of DRV/r 600/100 mg bid for treatment-experienced people living with HIV (PLHIV) based on the clinical data gathered in the POWER and TITAN trials are reviewed for consistency and their value to different decision-makers is assessed. Cost-utility analyses for the USA and several European countries indicate that DRV/r-based HAART is cost effective compared with other standard of care protease inhibitor (PI)-based regimens in PLHIV with evidence of PI resistance. For all of these countries, the estimated cost-utility ratio is well below typical benchmark values and these ratios are robust, as demonstrated by one-way sensitivity and variability analyses and multi-way probabilistic sensitivity analyses. Studies using other metrics including the average 1-year drug cost per patient with a plasma HIV-RNA level less than 50 copies/mL at 48 weeks, the incremental drug cost per additional patient with a plasma HIV-RNA level less than 50 copies/mL at 48 weeks, the total (antiretroviral and non-antiretroviral) costs during the first year of treatment, and the total healthcare budget impact during the first 5 years of treatment provided further evidence of the positive economic outcomes with the use of DRV/r in treatment-experienced PLHIV. Different measures of economic outcomes are useful for different types of decision-makers and different types of decisions. In general, the results of these different types of analyses will be consistent with each other. For darunavir, the economic analyses reviewed in this paper demonstrate that the use of DRV/r 600/100 mg bid in the management of HIV-infected, treatment-experienced adults who have failed at least one of the other currently available PIs is cost effective and may be cost saving.

The impact of disease stage on direct medical costs of HIV management: a review of the international literature

The global prevalence of HIV infection continues to grow, as a result of increasing incidence in some countries and improved survival where highly active antiretroviral therapy (HAART) is available. Growing healthcare expenditure and shifts in the types of medical resources used have created a greater need for accurate information on the costs of treatment. The objectives of this review were to compare published estimates of direct medical costs for treating HIV and to determine the impact of disease stage on such costs, based on CD4 cell count and plasma viral load. A literature review was conducted to identify studies meeting prespecified criteria for information content, including an original estimate of the direct medical costs of treating an HIV-infected individual, stratified based on markers of disease progression. Three unpublished cost-of-care studies were also included, which were applied in the economic analyses published in this supplement. A two-step procedure was used to convert costs into a common price year (2004) using country-specific health expenditure inflators and, to account for differences in currency, using health-specific purchasing power parities to express all cost estimates in US dollars. In all nine studies meeting the eligibility criteria, infected individuals were followed longitudinally and a 'bottom-up' approach was used to estimate costs. The same patterns were observed in all studies: the lowest CD4 categories had the highest cost; there was a sharp decrease in costs as CD4 cell counts rose towards 100 cells/mm³; and there was a more gradual decline in costs as CD4 cell counts rose above 100 cells/mm³. In the single study reporting cost according to viral load, it was shown that higher plasma viral load level (> 100,000 HIV-RNA copies/mL) was associated with higher costs of care. The results demonstrate that the cost of treating HIV disease increases with disease progression, particularly at CD4 cell counts below 100 cells/mm³. The suggestion that costs increase as the plasma viral load rises needs independent verification. This review of the literature further suggests that publicly available information on the cost of HAART by disease stage is inadequate. To address the information gap, multiple stakeholders (governments, pharmaceutical industry, private insurers and non-governmental organizations) have begun to establish and support an independent, high quality and standardized multicountry data collection for evaluating the cost of HIV management. An accurate, representative and relevant cost-estimate data resource would provide a valuable asset to healthcare planners that may lead to improved policy and decision-making in managing the HIV epidemic.

Costs to achieve undetectable HIV RNA with darunavir-containing highly active antiretroviral therapy in highly pretreated patients: the POWER experience

BACKGROUND

Very few studies have evaluated the cost of highly active antiretroviral therapy (HAART) per successful treatment in HIV-infected patients.

OBJECTIVES

To evaluate the cost of achieving undetectable plasma HIV-RNA levels in highly treatment-experienced, HIV-1-infected adults receiving darunavir/ritonavir (DRV/r 600 mg/100 mg twice a day) or control protease inhibitor (PI)-based HAART.

METHODS

The mean annual per-patient cost of DRV/r and control PI-based HAART was determined from the proportional use of antiretroviral agents in the DRV/r and control PI arms of the pooled POWER 1 and 2 trials, applying drug acquisition costs for 13 healthcare settings. The mean annual cost per patient of achieving undetectable plasma HIV-RNA levels (<50 copies/mL) was calculated by dividing the cost of each treatment by the proportion of patients with undetectable plasma HIV-RNA levels after 48 weeks in the DRV/r (45%) and control PI (10%) arms of the POWER trials.

RESULTS

Whereas absolute costs of treatment were 1-19% higher with DRV/r versus control PI-based HAART depending on the healthcare setting, the mean annual per-patient cost of achieving undetectable plasma HIV-RNA levels was 73-78% lower. These cost savings were maintained in the sensitivity analyses, adjusting for control PI and enfuvirtide use, and the number of active drugs in the background regimen. The incremental annual cost per additional patient achieving undetectable plasma HIV-RNA levels with DRV/r versus control PI-based HAART in POWER 1 and 2 (£4148) compared favourably with that determined for enfuvirtide (£137, 740; TORO trials) and tipranavir/ritonavir (£32,176; RESIST) versus control therapy.

CONCLUSIONS

DRV/r-based HAART provided consistent reductions in the cost of achieving undetectable plasma HIV-RNA levels compared with control PI-based therapy in highly treatment-experienced patients across various healthcare settings. The incremental cost per additional patient achieving undetectable plasma HIV-RNA levels with DRV/r versus control PI-based HAART was also lower than that calculated for other treatment options in this population. These results suggest that DRV/r is an economically viable option for highly treatment-experienced patients.

Cost effectiveness of darunavir/ritonavir in highly treatment-experienced, HIV-1-infected adults in the USA

INTRODUCTION

Darunavir is a new protease inhibitor (PI) that is co-administered with low-dose ritonavir and has demonstrated substantial efficacy in clinical trials of highly treatment-experienced patients when combined with an optimized background regimen (with or without enfuvirtide). This study estimates the cost effectiveness of darunavir with ritonavir (DRV/r) in this population over 5-year and lifetime time horizons in the USA.

METHODS

A Markov model was used to follow a treatment-experienced HIV-1 cohort through six health states, based on CD4 cell count: greater than 500, 351-500, 201-350, 101-200, 51-100 and 0-50 cells/mm³, and death. The magnitude of the CD4 cell count increase and duration of increasing and stable periods were derived from week 48 DRV/r clinical trial results (POWER 1 and 2). The treatment pathway assumed one regimen switch following treatment failure on the initial regimen. The use of antiretroviral drugs was based on usage in DRV/r clinical trials. US daily wholesale acquisition costs were calculated using the recommended daily doses. For each CD4 cell count range, utility values, HIV-1-related mortality rates and costs for medical resources (other than antiretroviral drug costs) were obtained from published literature. Non-HIV-1-related mortality rates were calculated by applying a relative risk value to the US general population age and gender-specific mortality rates. Costs and outcomes were discounted at 3% per year. One-way and probabilistic sensitivity analyses and variability analysis were performed.

RESULTS

In a 5-year analysis, patients receiving DRV/r experienced 3.80 quality-adjusted life-years (QALYs) and incurred total medical costs of US$217,288, while those receiving control PIs experienced 3.60 QALYs and incurred costs of US$218,962. DRV/r was both more effective and less costly than control PIs. For the lifetime analysis, the QALYs and lifetime medical costs with DRV/r were 10.03 and US$565,358, compared with 8.76 and US$527,287 with control PIs. The incremental cost-effectiveness ratio for DRV/r compared with control PIs was US$30,046. One-way sensitivity analyses for both time horizons indicated that the results were most sensitive to changes in the rate of CD4 cell count change during stable and declining periods (lifetime only), duration of stable period (5-year only) and HIV-1-related mortality rates. The results of the variability analysis were most sensitive to the model time horizon. Nevertheless, for all ranges and scenarios tested in these analyses, the incremental cost per QALY gained remained below US$50,000. The probabilistic sensitivity analysis showed that there was a 0.921 and 0.950 probability of a cost-effectiveness ratio below US$50,000 per QALY for the 5-year and lifetime time horizon, respectively.

CONCLUSIONS

DRV/r is predicted to be cost effective compared with control PI in highly treatment-experienced patients and is predicted to yield an average of 0.20 additional QALYs per treatment-experienced patient over 5 years and 1.27 additional QALYs over a lifetime in this population.

A predictive model of health state utilities for HIV patients in the modern era of highly active antiretroviral therapy

OBJECTIVE

Existing estimates of human immunodeficiency virus (HIV)-related health state utilities are inadequate for comparing alternative treatments on the basis of regimen-specific attributes such as dosing requirements or tolerability. The objective of this study was to examine the marginal impact of dosing, adverse events (AEs), and other factors on patients' health state utilities.

METHODS

Treatment naive and experienced HIV patients participating in five open-label trials of highly active antiretroviral therapy (HAART) completed the 36-Item Short Form Health Survey (SF-36) instrument at various time points. SF-36 responses were converted to utilities using a previously reported algorithm. Expected utilities were estimated as a function of patient demographics, regimen attributes, disease status, and AEs using a mixed-effects maximum likelihood model. Mean utilities for five HIV health states were derived from predicted patient utilities.

RESULTS

Negative predictors of utility included greater age (-0.001), prior acquired immune deficiency syndrome-defining events (-0.036), female gender (-0.038), and injection drug use (-0.056; P < 0.01 for all). Utility also depended on CD4+ cell count (P < 0.01), but not the presence of undetectable viral load. Regimen attributes were marginally associated with changes in utility. Depression was associated with the largest decrease in utility (-0.054, P < 0.001) among the AEs examined. Using the model to generate predicted utilities from the sample provided mean estimates ranging from 0.742 (SD 0.058) to 0.798 (0.052) for CD4+ counts between 0 and 99 and > or =500 cells/mm(3), respectively.

CONCLUSIONS

HIV patients' health-related quality of life may be substantially affected by clinically relevant patient-, disease-, and treatment-related factors, such as injection drug use, disease status, food/drink restrictions, and AEs.

Raltegravir with optimized background therapy for resistant HIV-1 infection

BACKGROUND

Raltegravir (MK-0518) is an inhibitor of human immunodeficiency virus type 1 (HIV-1) integrase active against HIV-1 susceptible or resistant to older antiretroviral drugs.

METHODS

We conducted two identical trials in different geographic regions to evaluate the safety and efficacy of raltegravir, as compared with placebo, in combination with optimized background therapy, in patients infected with HIV-1 that has triple-class drug resistance in whom antiretroviral therapy had failed. Patients were randomly assigned to raltegravir or placebo in a 2:1 ratio.

RESULTS

In the combined studies, 699 of 703 randomized patients (462 and 237 in the raltegravir and placebo groups, respectively) received the study drug. Seventeen of the 699 patients (2.4%) discontinued the study before week 16. Discontinuation was related to the study treatment in 13 of these 17 patients: 7 of the 462 raltegravir recipients (1.5%) and 6 of the 237 placebo recipients (2.5%). The results of the two studies were consistent. At week 16, counting noncompletion as treatment failure, 355 of 458 raltegravir recipients (77.5%) had HIV-1 RNA levels below 400 copies per milliliter, as compared with 99 of 236 placebo recipients (41.9%, P<0.001). Suppression of HIV-1 RNA to a level below 50 copies per milliliter was achieved at week 16 in 61.8% of the raltegravir recipients, as compared with 34.7% of placebo recipients, and at week 48 in 62.1% as compared with 32.9% (P<0.001 for both comparisons). Without adjustment for the length of follow-up, cancers were detected in 3.5% of raltegravir recipients and in 1.7% of placebo recipients. The overall frequencies of drug-related adverse events were similar in the raltegravir and placebo groups.

CONCLUSIONS

In HIV-infected patients with limited treatment options, raltegravir plus optimized background therapy provided better viral suppression than optimized background therapy alone for at least 48 weeks. (ClinicalTrials.gov numbers, NCT00293267 and NCT00293254.)

Immunologic Benefits of Enfuvirtide in Patients Enrolled in a Drug Assistance Program

Background:

Randomized clinical trials have demonstrated that enfuvirtide plus an optimized background regimen can cause a significant increase in CD4+ cell counts and a reduction in HIV RNA levels.

Objective:

To describe and anaiyze CD4+ cell count and HIV RNA changes in HIV-infected patients receiving enfuvirtide and a prescribed background regimen (PBR) in a primarily clinical setting.

Methods:

A retrospective review from September 1998 through August 2005 of CD4+ cell counts and HIV RNA changes from baseline was conducted in patients receiving enfuvirtide. Data were stratified and analyzed according to baseline CD4+ cell count and HIV RNA.

Results:

A mean CD4+ cell count increase of approximately 102 cells/mm3 was observed, regardless of baseline CD4+ cell count, in 187 patients receiving enfuvirtide during a mean of 19.4 months of follow-up. During 3 years of follow-up, patients initiating enfuvirtide at CD4+ cell counts less than 100 cells/mm3 never achieved absolute CD4+ cell counts comparable to the counts in patients starting enfuvirtide at CD4+ cell counts of 100 cells/mm3 or more. In 38.3% of patients achieving an undetectable HIV RNA level, a mean CD4+ cell count increase of 185 cells/mm3 was observed. An unexpected finding was that a mean CD4+ cell count increase of 76 cells/mm3 occurred in 61.7% of patients not achieving complete viral suppression.

Conclusions:

Immunologic benefits were observed in subjects continuing enfuvirtide plus a PBR irrespective of baseline CD4+ cell count, complete viral suppression, or antiretroviral susceptibility data. Dala suggest that initiation of enfuvirtide at CD4+ cell counts greater than 100 celis/mm3 may be immunologically advantageous and independent of complete virologic response.

TORO: ninety-six-week virologic and immunologic response and safety evaluation of enfuvirtide with an optimized background of antiretrovirals

The additional 48-week optional treatment extension of the T-20 versus Optimized Regimen Only (TORO) studies evaluated long-term safety and efficacy of enfuvirtide (ENF) through week 96 in patients receiving ENF plus optimized background (OB) and patients switching to ENF plus OB from OB alone. Patient randomization was 2:1 to ENF plus OB (n = 663) and OB (n = 334), of which 89.7% and 89.8% were male, 89.3% and 88.6% were Caucasian, and median age was 41 and 42 years, respectively. HIV risk factors were comparable between the ENF plus OB and OB groups with the major factors being 65.2% versus 66.2% homosexual contact, 17.8% versus 19.8% heterosexual contact, 4.1% versus 4.8% bisexual contact, respectively, and 6.9% injection drug use in both groups. OB patients were allowed to switch to ENF plus OB at virologic failure before week 48 and required to switch at week 48 to continue in the study (n = 230). Efficacy and safety assessments were conducted for each group. At week 96, 55% of ENF plus OB subjects completed the study and 26.5% achieved a viral load of less than 400 copies per milliliter (17.5% achieved less than 50 copies per milliliter). Viral load and CD4 mean change from baseline was -2.1 and -1.1 log(10) HIV-1-RNA copies per milliliter and +166 and +116 CD4 cells/mm(3) for ENF plus OB and switch patients, respectively. No new ENF-related safety issues emerged in weeks 48-96. Injection site reactions led to discontinuation in 7% and 10% of ENF plus OB and switch patients, respectively. In conclusion, these data demonstrate durable efficacy and safety of ENF over 96 weeks and that early use of ENF in combination with other agents for the treatment of antiretroviral-experienced HIV-infected subjects is beneficial.