The utility of genotypic tropism testing in clinical practice.

A review of a large number of HIV-1 tropism test requests (n = 1148) performed at a London tertiary referral centre was carried out. The aim was to establish whether these were being performed in line with recommendations from published guidelines and whether this represented the most cost-effective use of these tests in informing prescribing decisions of the CCR5 antagonist drug, maraviroc. The cost of these assays within the UK was covered by commercial funding until April 2013 which has subsequently been withdrawn. Furthermore, all healthcare settings are under increasing cost constraints and hence establishing the real utility and appropriate use of these tests is of vital importance.

From evidence assessments to coverage decisions?: the case example of glinides in Germany.

In Germany, coverage decisions in the statutory health insurance (SHI) system are based on the principles of evidence-based medicine. Recently, an evidence assessment by the Institute for Quality and Efficiency in Health Care (IQWiG) of the oral antidiabetics of the glinide class showed that their long-term benefit is not proven. Accordingly, the responsible Federal Joint Committee (G-BA) decided to exclude glinides from prescription in the SHI system. This was, however, objected to by the Ministry of Health, which is charged with legal supervision. We use this case to illustrate the path from evidence assessments to coverage decisions in Germany against the background of the latest health reform, which has changed the legal requirements for evidence assessments and the ensuing coverage decisions.

Cost-effectiveness of maraviroc for antiretroviral treatment-experienced HIV-infected individuals in Mexico.

OBJECTIVE: Maraviroc is the first approved drug in a new class of antiretrovirals, the CCR5 antagonists. The objective of this study was to predict the long-term clinical impact and cost-effectiveness of maraviroc in treatment-experienced adults with HIV/AIDS in Mexico. METHODS: The AntiRetroviral Analysis by Monte Carlo Individual Simulation (ARAMIS) model was adapted to the Mexican context to predict clinical and economic outcomes of treating with optimized background therapy (OBT) versus testing for viral tropism status and treating with OBT ± maraviroc accordingly in treatment-experienced adults in Mexico. Baseline characteristics and efficacy were from the MOTIVATE trials' screening cohort. Costs and population mortality data were specific to Mexico. Results were reported from the perspective of health care payers in 2008 Mexican pesos (converted to 2008 US$ in parentheses). RESULTS: Compared to treatment with OBT alone, treatment with OBT ± maraviroc contingent on tropism test result increased projected undiscounted life expectancy and discounted quality-adjusted life expectancy from 7.54 to 8.71 years and 4.42 to 4.92 quality-adjusted life years (QALYs), respectively, at an incremental cost of $228,215 (US$21,329). The resultant incremental cost-effectiveness ratio (ICER) was $453,978 (US$42,429) per QALY gained. The ICER was somewhat lower when maraviroc was modeled in individuals susceptible to ≤ 2 components of OBT ($407,329; US$38,069), while the ICER was higher in individuals susceptible to ≥3 OBT components ($718,718; US$67,171). CONCLUSION: In treatment-experienced individuals with HIV/AIDS in Mexico, maraviroc may be cost-effective, particularly in individuals with limited options for active antiretroviral therapy (ART).

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.

Maraviroc: a review of its use in the management of CCR5-tropic HIV-1 infection.

Maraviroc (Celsentri; Selzentry) is a CCR5 coreceptor antagonist used in the treatment of CCR5-tropic HIV-1 infection. Administered orally twice daily, maraviroc, in combination with optimized background therapy regimens, showed good virological and immunological efficacy over 48 weeks in antiretroviral treatment-experienced patients aged > or = 16 years with CCR5-tropic HIV-1 infection, in the randomized, double-blind, placebo-controlled, multicentre, MOTIVATE 1 and MOTIVATE 2 studies. Initial data indicate that the efficacy of maraviroc in this patient population is sustained for up to 96 weeks. In the MERIT study in antiretroviral therapy-naive patients aged > or = 16 years with CCR5-tropic HIV-1 infection, maraviroc was noninferior to efavirenz (each in combination with zidovudine/lamivudine) for one primary virological endpoint (HIV-1-RNA levels < 400 copies/mL), but not for the other primary endpoint (HIV-1 RNA levels < 50 copies/mL) in the primary analysis at 48 weeks. However, in a subsequent analysis, which used a more sensitive tropism testing assay than the one originally used and retrospectively excluded patients with non CCR5-tropic HIV-1 infection who were ineligible for inclusion in the study, maraviroc demonstrated noninferiority to efavirenz on both primary virological endpoints. Maraviroc showed sustained virological efficacy in this patient population and improved immunological markers for up to 96 weeks. Maraviroc was generally well tolerated by both treatment-experienced and treatment-naive patients with CCR5-tropic HIV-1 infection. Thus, maraviroc, as a component of antiretroviral combination therapy regimens, is an important option for use in treatment-experienced adults with CCR5-tropic HIV-1 infection. Available data indicate that maraviroc may also have a role in treatment-naive adults with CCR5-tropic HIV-1 infection, a population in whom CCR5-tropic HIV-1 is often the major quasispecies.

Cost-effectiveness of optimized background therapy plus maraviroc for previously treated patients with R5 HIV-1 infection from the perspective of the Spanish health care system.

OBJECTIVE: The aim of this work was to evaluate the cost-effectiveness, from the perspective of the Spanish health care system, of optimized background therapy (OBT) plus maraviroc 300 mg BID versus OBT plus placebo in previously treated patients with R5 HIV-1 infection. METHODS: A lifetime cohort model was developed, based on 24- and 48-week pooled results from the Maraviroc Versus Optimized Therapy in Viremic Antiretroviral Treatment-Experienced Patients (MOTIVATE) studies 1 and 2, to reflect the Spanish health care system's perspective. Treatment duration was based on clinical trial follow-up from MOTIVATE 1 and 2. Clinical data, cohort characteristics, success probability, CD4 increase rate, CD4 cell status link to disease states, and adverse-event probability were taken from the MOTIVATE trials and other published literature. Other input parameters were taken from published sources. Antiretroviral (ARV) costs were derived from local sources. Non-ARV drug costs were obtained from published literature and a cost database. All costs were calculated as year-2009 euros. The annual discount rate was set at 3.0%. The main outcomes were cost per life-year gained (LYG) and cost per quality-adjusted life-year (QALY) gained. Uncertainty was assessed with one-way and probabilistic sensitivity analyses. RESULTS: In the model analysis, adding maraviroc to OBT was associated with an increase of 0.952 LYG and 0.909 QALY. Total costs were €275,970 for maraviroc plus OBT and €254,655 for placebo plus OBT (difference: €21,315). The incremental cost per LYG was €22,398 and the incremental cost per QALY gained was €23,457. The model appeared to be robust for variations in key parameters. Results from the probabilistic sensitivity analyses indicated that the probability of the cost per QALY being below €30,000 was 99%. CONCLUSION: Despite the limitations of the model, our analysis suggested that OBT plus maraviroc 300 mg BID is a clinically valuable option, and cost-effective from the perspective of the Spanish health care system, for previously treated patients with R5 HIV-1 infection.

Maraviroc: a CCR5-receptor antagonist for the treatment of HIV-1 infection.

BACKGROUND: The emergence of viral resistance is one of the greatest challenges in the treatment of HIV infection. Maraviroc is the first member of a new class of antiretroviral medications, the CCR5-receptor antagonists. It is approved by the US Food and Drug Administration (FDA) for use in combination with other antiretroviral agents in treatment-experienced patients infected with multidrug-resistant, CCR5-tropic HIV-1. OBJECTIVE: This article provides an overview of the pharmacology, efficacy, and tolerability of maraviroc in the treatment of HIV-1 infection. METHODS: Relevant information was identified through a search of MEDLINE (January 2000-May 2008) using the terms maraviroc, UK-427,857, and CCR5-receptor antagonist. Also consulted were abstracts from the International AIDS Society Conference, the Conference on Retroviruses and Opportunistic Infections, and other relevant scientific meetings. Additional publications were found by searching the reference lists of the identified articles and the FDA Web site. RESULTS: Maraviroc is a selective, reversible, small-molecule CCR5-receptor antagonist. In vitro, it has potent anti-HIV-1 activity, with a mean 90% inhibitory concentration of 2.0 nmol/L. It is widely distributed, with a V(d) of approximately 194 L. Maraviroc is moderately metabolized in the liver (65.3%), primarily via the cytochrome P450 3A4 isozyme. It has an elimination t(1/2) of 15.9 to 22.9 hours. Until more data are available, maraviroc should be avoided in patients with severe hepatic insufficiency; dose adjustment does not appear to be necessary on the basis of age, sex, or renal function. In 2 Phase IIb/III studies, maraviroc 300 mg PO QD or BID was found to be more efficacious than placebo in reducing the viral load at 48 weeks in treatment-experienced, CCR5-tropic HIV-1-infected patients receiving an optimized background regimen (difference vs placebo-QD arm: -0.89 log(10) copies/mL [97.5% CI, -1.17 to -0.62]; BID arm: -1.05 log(10) copies/mL [97.5% CI, -1.33 to -0.78]). The proportion of patients with a viral load < 50 copies/mL was 43.2% in the QD arm and 45.5% in the BID arm, compared with 16.7% in the placebo arm (P < 0.001, both treatment arms vs placebo). In treatment-naive patients infected with CCR5-tropic virus only, maraviroc 300 mg PO BID was not noninferior to oral efavirenz 600 mg QD (difference = -4.2%; lower bound of the 1-sided 97.5% CI, -10.9 [predefined statistical cutoff for noninferiority, -10]). Maraviroc was generally well tolerated in clinical trials. The most frequently reported (> or = 5%) adverse events were upper respiratory tract infection (20.0%), cough (12.7%), pyrexia (12.0%), rash (9.6%), musculoskeletal complaints (8.7%), gastrointestinal and abdominal pain (8.2%), dizziness (8.2%), appetite disorders (7.3%), insomnia (7.0%), herpes infection (6.8%), sinusitis (6.3%), joint complaints (6.1%), bronchitis (5.9%), and constipation (5.4%). The recommended dose of maraviroc differs based on concomitant medications, ranging from 150 to 600 mg BID. CONCLUSION: When used in combination with other antiretroviral agents, maraviroc appears to be a promising agent for treatment-experienced patients infected with multidrug-resistant, CCR5-tropic HIV-1.

Maraviroc (Celsentri) for multidrug-resistant human immunodeficiency virus (HIV)-1.

(1) Maraviroc belongs to a new class of antiretroviral drugs designed to block entry of HIV-1 into CD4+ T-cells via the CCR5 coreceptor. It is indicated for combination therapy in treatment-experienced adults infected with CCR5-tropic HIV-1 that is resistant to multiple antiretroviral agents. (2) Results from two randomized controlled trials (RCTs) indicate that in treatment experienced patients, maraviroc, combined with optimized background therapy (OBT), significantly decreases the level of HIV-1 RNA in the blood (viral load) when compared with OBT alone. The number of patients achieving undetectable viral loads and CD4+ cell count increases were also significantly higher in those receiving maraviroc. (3) Most patients experiencing treatment failure with maraviroc exhibit tropism changes from CCR5-tropic to CXCR4-using virus, but there is no evidence of disease progression. (4) Adverse effects reported with maraviroc include cough, fever, upper respiratory tract infections, rash, muscle and joint pain, abdominal pain, and postural hypotension (dizziness). No significant increases in cardiovascular events, hepatotoxicity, infections or malignancies have been reported with short-term maraviroc therapy. Several post-marketing studies will assess maraviroc's long-term safety for immune function, liver function, malignancy, cardiac events, and risks associated with changes in tropism. (5) Results from an ongoing trial in treatment naive patients suggest that maraviroc may not be superior in terms of viral suppression to standard therapy, but may significantly increase the number of CD4+ T-cells.

Comparing the long-term cost-effectiveness of repaglinide plus metformin versus nateglinide plus metformin in type 2 diabetes patients with inadequate glycaemic control: an application of the CORE Diabetes Model in type 2 diabetes.

OBJECTIVES: As an example application of the CORE Diabetes Model in type 2 diabetes, we simulated the cost-effectiveness of repaglinide/metformin combination therapy versus nateglinide/metformin for treatment of individuals with type 2 diabetes with an inadequate response to sulphonylurea, metformin, or fixed dose glyburide/metformin. METHODS: The CORE Diabetes Model was used to simulate long-term outcomes for a cohort of individuals with type 2 diabetes treated with either repaglinide/metformin or nateglinide/metformin. HbA1c changes for each regimen were taken from a comparative study. At the end of the study, changes in HbA1c from baseline were -1.28% points and -0.67% points for repaglinide/metformin and nateglinide/metformin, respectively. Median final doses were 5.0 mg/day for repaglinide, 360 mg/day for nateglinide and 2000 mg/day metformin in each treatment arm. Costs were calculated as the annual costs for drugs plus costs of complications (US Medicare perspective) over a 30-year period. Life expectancy (LE) and quality-adjusted life expectancy (QALE) were calculated. Outcomes and costs were discounted at 3% annually. RESULTS: With repaglinide/metformin, improved glycaemic control led to projected decreases in complication rates, improvement of LE and QALE by 0.15 and 0.14 years respectively, and total cost savings of 3,662 dollars/person over the 30-year period. Repaglinide/metformin had a 96% probability that the incremental costs per quality-adjusted life year gained would be 20,000 dollars or less, and a 66% probability that repaglinide/metformin would be cost-saving compared to nateglinide/metformin. Sensitivity analyses supported the validity and reliability of the results. CONCLUSIONS: In the health economic context, repaglinide/metformin combination was dominant to nateglinide/metformin. The CORE Diabetes Model is a tool to help third-party reimbursement payers identify treatments for type 2 diabetes that are good value for money.

Modeling the efficiency of reaching a target intermediate end point: a case study in type 2 diabetes in the United States.

OBJECTIVE: The objective of this study was to describe an approach to modeling the efficiency of an intervention by focusing on an established intermediate end point directly. A case study addresses the economic efficiency of obtaining dual glycemic control over time, according to initial choice of treatment. METHODS: From the perspective of a payer in the United States, instead of the usual approach of basing the model on projecting long-term diabetic complications from glycemic control, this model focuses directly on glycemic control. Treatment changes and associated health-care utilization needed to address postprandial glucose. After assigning each of 10000 drug-naïve patients, HbA1c, age, race, and sex based on distributions from a randomized clinical trial, the model applies the efficacy of nateglinide compared to metformin. Sensitivity analyses were carried out for all parameters. Costs are reported in year 2000 US dollars and discounted at 3%. RESULTS: In the base case, starting on nateglinide and increasing the time in dual glycemic control over 3 years by 2.4 months led to savings of US dollars 295 compared to starting on metformin. Savings increased with stricter treatment criteria but decreased if glycemic control was better initially. CONCLUSIONS: This study illustrates the use of an efficiency model that focuses directly on the relevant short-term end point: glycemic control. Starting patients with nateglinide is shown to be an efficient way of obtaining dual glycemic control during the first 3 years of treatment.

Health and economic effects of adding nateglinide to metformin to achieve dual control of glycosylated hemoglobin and postprandial glucose levels in a model of type 2 diabetes mellitus.

BACKGROUND: Type 2 diabetes mellitus is a common disease whose complications have great costs, both in quality of life and expense of treatment. Improving glycemic control, as measured by monitoring glycosylated hemoglobin (HbA1c) levels, can reduce the rate of such complications. OBJECTIVES: The aims of this study were to estimate the lifetime costs associated with diabetes-related complications in a theoretical population receiving metformin monotherapy and to predict the health and economic effect of improving glycemic control in this theoretical population by combining metformin with nateglinide. METHODS: A pharmacoeconomic model was developed to simulate the long-term (30 years) complication rates (microvascular and macrovascular) of a cohort of patients with type 2 diabetes mellitus. The model simulated each year of life for each patient in a theoretical cohort of 10,000 patients until diabetes-related complications were present or death occurred. The mean accumulated costs (direct medical costs for acute care and subsequent care for diabetes-related complications), mean survival time, and the frequency of each type of complication were estimated. Both effectiveness and cost data were discounted at 3%. Sensitivity analyses were conducted on key model input parameters. RESULTS: Average costs of treating complications in theoretical patients undergoing metformin monotherapy were estimated at $29,565 per patient. Savings of $2,742 were estimated per patient for all complications--particularly, nephropathy ($1,166) and macrovascular disease ($632)--when nateglinide was added. The cost-effectiveness ratio of adding nateglinide to metformin was estimated at $27,131 per undiscounted life-year gained (95% CI, $23,710-$28,577) or $43,024 (95% CI, $37,285-$45,193) per additional discounted life-year gained. In the sensitivity analyses, decreasing HbA1c level at baseline, HbA1c upward drift, and duration of disease improved survival. CONCLUSIONS: Combination therapy with nateglinide and metformin, compared with metformin alone, was predicted to reduce the frequency of complications and, thus, treatment costs in this theoretical model. The major factor in cost savings was fewer complications due to nephropathy. The increased drug treatment costs were expected to be offset by the long-term savings from reducing complication rates.