Assessing the value of atomoxetine in treating children and adolescents with ADHD in the UK

Is adjunctive pharmacotherapy in attention-deficit/hyperactivity disorder cost-effective in Canada: a cost-effectiveness assessment of guanfacine extended-release as an adjunctive therapy to a long-acting stimulant for the treatment of ADHD

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a common psychiatric disorder in children, with worldwide prevalence of ADHD varying from 5.9 to 7.1 %, depending on the reporter. In case of inadequate response to stimulants, combination therapy of stimulants and an adjunctive medication may improve the control of ADHD symptoms, reduce the dose-limiting adverse events, and help control comorbidities. To date, the only medication to be used for adjunctive therapy to psychostimulants is guanfacine extended release (GXR). The aim of this study was to assess the economic impact of GXR as an adjunct therapy with long-acting stimulants (GXR + stimulant) compared to long-acting stimulant monotherapy (stimulant alone) in the treatment of children and adolescents with ADHD in Canada.

METHOD

A Markov model was developed using health states defined based on the clinician-reported Clinical Global Impression-Severity (CGI-S) score (normal, mild, moderate, severe). Transition probabilities were calculated based on patient-level data from a published study. Long-acting stimulants available in Canada were considered in the base-case model: amphetamine mixed salts, methylphenidate HCl formulations, and lisdexamfetamine dimesylate. Analyses were conducted from a Canadian Ministry of Health (MoH; Ontario) and a societal perspective over a 1-year time horizon with weekly cycles.

RESULTS

Over a 1-year time horizon, GXR + stimulant was associated with 0.655 quality-adjusted life year (QALY), compared to 0.627 QALY with stimulant alone, for a gain of 0.028 QALY. From a MoH perspective, GXR+ stimulant and stimulant alone were associated with total costs of $CA1,617 and $CA949, respectively (difference of $CA668), which resulted in an incremental cost-effectiveness ratio (ICER) of $CA23,720/QALY. From a societal perspective, GXR + stimulant and stimulant alone were associated with total costs of $CA3,915 and $CA3,582, respectively (difference of $CA334), which resulted in an ICER of $CA11,845/QALY. Probabilistic sensitivity analysis (PSA) of GXR + stimulant showed that it remains a cost-effective strategy in 100 % of the simulations from both perspectives in numerous PSA and one-way sensitivity analyses, relative to a willingness to pay threshold of $50,000/QALY.

CONCLUSIONS

This economic evaluation demonstrates that GXR +  stimulant is cost-effective compared to stimulant alone in the treatment of children and adolescents with ADHD in Canada.

Is the UK NICE "reference case" influencing the practice of pediatric quality-adjusted life-year measurement within economic evaluations?

OBJECTIVES

To report findings from a systematic review, this article sought to address two related questions. First, how has the practice of UK pediatric cost-utility analyses evolved over time, in particular how are health-related outcomes assessed and valued? Second, how do the methods compare to the limited guidance available, in particular, the National Institute for Health and Care Excellence (NICE) reference case(s)?

METHODS

Electronic searches of MEDLINE, Embase, and Cochrane databases were conducted for the period May 2004 to April 2012 and the Paediatric Economic Database Evaluation database for the period May 2004 to December 2010. Identified studies were screened by three independent reviewers.

RESULTS

Forty-three studies were identified, 11 of which elicit utility values through primary research. A discrepancy was identified between the methods used for outcome measurement and valuation and the methods advocated within the NICE reference case. Despite NICE recommending the use of preference-based instruments designed specifically for children, most studies that were identified had used adult measures. In fact, the measurement of quality-adjusted life-years is the aspect of economic evaluation with the greatest amount of variability and the area that most digressed from the NICE reference case.

CONCLUSIONS

Recommendations stemming from the review are that all studies should specify the age range of childhood and include separate statements of perspective for costs and effects as well as the reallocation of research funding away from systematic review studies toward good quality primary research measuring utilities in children.

Estimating the potential annual welfare impact of innovative drugs in use in Switzerland

Expenditures of health care systems are increasing from year to year. Therefore, this study aimed to estimate the difference in costs and benefits of innovative pharmaceuticals launched 2000 onward compared to standard treatment on the national economy of Switzerland in 2010. The approach and formula described in the pilot study by Tsiachristas et al. (1), which analyzed the situation of welfare effects in the Netherlands, served as a model for our own calculations. A literature search was performed to identify cost-utility or cost-effectiveness studies of drugs launched 2000 onward compared to standard treatment. All parameters required for the calculation of welfare effects were derived from these analyses. The base-case threshold value of a quality-adjusted life year was set to CHF 100,000. Overall, 31 drugs were included in the welfare calculations. The introduction of innovative pharmaceuticals since 2000 onward to the Swiss market led to a potential welfare gain of about CHF 781 million in the year 2010. Univariate sensitivity analysis showed that results were robust. Probably because of the higher benefits of new drugs on health and quality of life compared to standard treatment, these drugs are worth the higher costs. The literature search revealed that there is a lack of information about the effects of innovative pharmaceuticals on the overall economy of Switzerland. Our study showed that potential welfare gains in 2010 by introducing innovative pharmaceuticals to the Swiss market were substantial. Considering costs and benefits of new drugs is important.

The estimation of utility weights in cost-utility analysis for mental disorders: a systematic review

OBJECTIVE

To systematically review approaches and instruments used to derive utility weights in cost-utility analyses (CUAs) within the field of mental disorders and to identify factors that may have influenced the choice of the approach.

METHODS

We searched the databases DARE (Database of Abstracts of Reviews of Effects), NHS EED (National Health Service Economic Evaluation Database), HTA (Health Technology Assessment), and PubMed for CUAs. Studies were included if they were full economic evaluations and reported quality-adjusted life-years as the health outcome. Study characteristics and instruments used to estimate utility weights were described and a logistic regression analysis was conducted to identify factors associated with the choice of either the direct (e.g. standard gamble) or the preference-based measure (PBM) approach (e.g. EQ-5D).

RESULTS

We identified 227 CUAs with a maximum in 2009, 2010, and 2012. Most CUAs were conducted in depression, dementia, or psychosis, and came from the US or the UK, with the EQ-5D being the most frequently used instrument. The application of the direct approach was significantly associated with depression, psychosis, and model-based studies. The PBM approach was more likely to be used in recent studies, dementia, Europe, and empirical studies. Utility weights used in model-based studies were derived from only a small number of studies.

LIMITATIONS

We only searched four databases and did not evaluate the quality of the included studies.

CONCLUSIONS

Direct instruments and PBMs are used to elicit utility weights in CUAs with different frequencies regarding study type, mental disorder, and country.

Cost effectiveness of guanfacine extended-release versus atomoxetine for the treatment of attention-deficit/hyperactivity disorder: application of a matching-adjusted indirect comparison

BACKGROUND

About 7% of children and adolescents are diagnosed with attention-deficit/hyperactivity disorder (ADHD) in the US. Patients with ADHD who are intolerant of or do not have an optimal response to stimulants often use non-stimulants as alternative therapies. Guanfacine extended-release (GXR) and atomoxetine (ATX) are the only non-stimulants approved by the US Food and Drug Administration for once-daily use in the treatment of children and adolescents with ADHD in the US. ATX has been on the market since 2002 while GXR was recently approved in 2009. To date, there is no comparative effectiveness or cost-effectiveness study comparing the two drugs.

OBJECTIVES

The aim of this study was to assess the cost effectiveness of GXR versus ATX for the treatment of ADHD in children and adolescents, using the comparative efficacy results from a matching-adjusted indirect comparison (MAIC).

METHODS

The MAIC method was used to compare the efficacy between GXR (target dose and lower doses) and ATX (target dose) in the absence of head-to-head clinical trials. Individual patients in the GXR trials were weighted such that the summary baseline characteristics and the efficacy of the placebo arm of the GXR trials matched exactly with those from published ATX trials. After weighting, the efficacy (i.e. change in the ADHD rating scale, fourth edition [ADHD-RS-IV] total score from baseline) was compared between each GXR dosing group and the ATX group. The results from the MAIC analyses were used to populate a 1-year Markov model that is used to compare the cost effectiveness of GXR versus ATX from a US third-party payer perspective. Effectiveness outcomes for each treatment group were estimated as the proportion of responders, defined as patients with ≥25% reduction in ADHD-RS-IV total score from baseline, and average quality-adjusted life years (QALYs). Utilities associated with response/non-response and disutilities due to adverse events were applied in the model. Costs included drug and medical service costs and were inflated to 2011 US dollars ($US). Incremental cost/QALY and incremental cost/responder were estimated. Univariate sensitivity analyses were conducted by varying all model parameters, including costs, utilities, and response rate.

RESULTS

The target dose of GXR was 0.12 mg/kg/day. In match-adjusted populations with balanced baseline characteristics, patients receiving GXR at the dose of 0.09-0.12(p = 0.0016) [DOSAGE ERROR CORRECTED] and 0.075-0.09 mg/kg/day (p = 0.0248) had better efficacy, while those receiving GXR at the dose of 0.046-0.075 mg/kg/day had comparable efficacy (p = 0.0699), compared with patients receiving ATX at the target dose of 1.2 mg/kg/day. In the base case of the cost-effectiveness analysis (CEA), GXR had incremental cost-effectiveness ratios of $US10 637/QALY and $US853/responder, compared with ATX (incremental costs: $US74; incremental effectiveness: 0.007 QALYs and 86 responders per 1000 patients treated). Results of all univariate sensitivity analyses showed that the model results were robust to changes in model inputs.

CONCLUSIONS

To our knowledge, this is the first application of the novel comparative efficacy method of MAIC to a CEA model. The MAIC results indicate that GXR (0.075-0.12 mg/kg/day) was more effective than ATX (1.2 mg/kg/day) in the trial population. The CEA results indicate that GXR is cost effective compared with ATX for the treatment of ADHD in children and adolescents.

The ADHD-susceptibility gene lphn3.1 modulates dopaminergic neuron formation and locomotor activity during zebrafish development

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity, increased impulsivity and emotion dysregulation. Linkage analysis followed by fine-mapping identified variation in the gene coding for Latrophilin 3 (LPHN3), a putative adhesion-G protein-coupled receptor, as a risk factor for ADHD. In order to validate the link between LPHN3 and ADHD, and to understand the function of LPHN3 in the etiology of the disease, we examined its ortholog lphn3.1 during zebrafish development. Loss of lphn3.1 function causes a reduction and misplacement of dopamine-positive neurons in the ventral diencephalon and a hyperactive/impulsive motor phenotype. The behavioral phenotype can be rescued by the ADHD treatment drugs methylphenidate and atomoxetine. Together, our results implicate decreased Lphn3 activity in eliciting ADHD-like behavior, and demonstrate its correlated contribution to the development of the brain dopaminergic circuitry.

Cost effectiveness of guanfacine extended release as an adjunctive therapy to a stimulant compared with stimulant monotherapy for the treatment of attention-deficit hyperactivity disorder in children and adolescents

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) is a common psychiatric disorder in childhood, affecting 3-7% of school-age children in the US and imposing substantial economic burden. Stimulants are considered first-line pharmacological treatment and are the most prescribed treatment for ADHD. However, approximately 30% of children with ADHD do not have an optimal response to a single stimulant and may require adjunctive therapy.

OBJECTIVE

Our objective was to conduct a cost-effectiveness analysis (CEA) of adding a non-stimulant, guanfacine extended release (GXR), to stimulants versus maintaining existing stimulant monotherapy in the treatment of ADHD in children and adolescents with suboptimal response to stimulant monotherapy.

METHODS

A 1-year Markov model was developed to estimate costs and effectiveness from a US third-party payer perspective. Effectiveness was measured by the QALY. The model assumed that patients transitioned among four health states (normal, mild, moderate and severe), defined by the Clinical Global Impression-Severity (CGI-S) scale. Transition probabilities were estimated in an ordered logit model using patient-level data from a multicentre, 9-week, double-blind, placebo-controlled, dose-optimization study, where subjects (n = 461) continued their stable morning stimulant and were randomized to GXR administered in the morning, GXR administered in the evening, or placebo. The model assumed that patients in moderate/severe health states after week 8 would discontinue ADHD treatment and remain in that state for the rest of the study period. Direct costs included drug wholesale acquisition costs and health state costs, all in $US, year 2010 values. Utility associated with each health state was obtained from the literature and disutilities associated with adverse events were applied for the first 4 weeks. One-way sensitivity analyses and probabilistic sensitivity analysis (PSA) were conducted by varying costs, utilities, adverse-event duration, and transition probabilities.

RESULTS

Compared with maintaining existing stimulant monotherapy, adding GXR to existing stimulant monotherapy was associated with an incremental drug cost of $US1016 but a lower medical cost of $US124, resulting in a total incremental cost of $US892 at 1 year. The addition of GXR to stimulants led to an incremental QALY of 0.03 and an incremental cost-effectiveness ratio (ICER) of $US31,660/QALY. In one-way sensitivity analysis, ICER values ranged from $US19,723, when 100% of patients were assumed to be severe in their initial health state, to $US46,631, when the last observed states from the clinical trial were carried forward to the end of the 1-year analysis period. PSA demonstrated a 94.6% likelihood that the ICER falls below $US50,000/QALY.

CONCLUSIONS

The impairment associated with residual ADHD symptoms after stimulant therapy is becoming increasingly recognized. This is the first analysis of the cost effectiveness of stimulants combined with an adjunctive medication. This study suggests that the adjunctive therapy of GXR with stimulants is a cost-effective treatment based on a willingness-to-pay threshold of $US50,000/QALY. This may address an unmet need among patients with suboptimal response to stimulant monotherapy.

Application of classic utilities to published pediatric cost-utility studies

OBJECTIVE

Economic analyses, such as cost-utility analyses (CUAs), are dependent on the quality of the data used. Our objective was to test how health utility values (measurements of patient preference) assessed by recommended methods (classic utilities) would impact the conclusions in published pediatric CUAs.

METHODS

Classic utilities for pediatric health states were obtained by recommended utility assessment methods, time trade-off, and standard gamble in 4016 parent interviews. To test the impact of these utilities on published studies, we obtained a sample of published pediatric CUAs by searching Medline, EMBASE, EconLit, Health Technology Assessment Database, Cochrane Database on Systematic Reviews, Database of Abstracts of Reviews of Effects, and the Cost Effective Analysis (CEA) Registry at Tufts Medical Center, using search terms for cost-utility analysis. Articles were included when results were presented as cost per quality adjusted life-years (QALYs), the interventions were for children <18 years of age and included at least one of the following health states: attention deficit hyperactivity disorder, asthma, gastroenteritis, hearing loss, mental retardation, otitis media, seizure disorder, or vision loss. Studies that did not include these or equivalent health states were excluded. For each CUA, we determined utilities (values for patient preference), the utility assessment method used, and presence of one-way sensitivity analyses (SAs) on utilities. When one-way SAs were conducted, we determined if using our classic utilities would change the result of the CUA. When an SA was not presented, we determined if using our classic utilities would tend to support or not support the published conclusions.

RESULTS

We evaluated 39 articles. Eighteen articles presented results of one-way SAs on utilities. Seven articles presented SAs over a range that included our classic utilities. In 4 of the 7, using classic utilities would change the conclusion of the study. For the 32 articles where no one-way SA were presented (n = 21), or where the classic utilities fell outside the range tested (n =11), a change to classic utility would tend against the study conclusion in 12 articles (31%).

CONCLUSIONS

More than a third of published CUA studies could change if pediatric utilities obtained by recommended, classic methods were used. One-way SAs on utilities are often not presented, making comparison between studies challenging.