Cost-effectiveness of sitagliptin-based treatment regimens in European patients with type 2 diabetes and haemoglobin A1c above target on metformin monotherapy

Pharmacoeconomics and aging

The aging of the general population in industrialized countries has brought to public attention the increasing incidence of age-related clinical conditions, because the long-term impact of diseases on functional status and on costs are greater in older people than in any other age group. With the aging of the population, it is becoming increasingly important to quantify the burden of illness in the elderly; this will be vital not only in planning for the necessary health services that will be required in coming years, but also in order to measure the benefit to be expected from interventions to prevent disability in older people. The management of multiple and chronic disorders has become a more important issue for healthcare authorities because of increasing requests for medical assistance and healthcare interventions. Among these, pharmacological treatments and drug utilization in older people are pressing issues for healthcare managers and politicians; indeed, a relatively small proportion of the population accounts for a substantial part of public drug costs. Two key sources of pressure are well known: the growing number of elderly persons, who are the highest per-capita users of medicines, and the introduction of new, often more expensive, medicines. On the other hand, the development of strategies for controlling costs, while providing the elderly with equitable access to needed pharmaceuticals, should be based on an evaluation of the economic impact of pharmacological care in older people, taking into account the burden of illness, drug utilization data, drug technology assessment evidence and results. Furthermore, there are major factors affecting pharmacological care in older people: for example inappropriate prescribing, lack of adherence and compliance, and the burden of adverse drug events. The assessment of these factors should be considered a priority in pharmacoeconomic evaluations in the aging population, and the most relevant evidence will be reviewed in this paper with examples referring to particular settings or conditions and diseases, such as the presence of cardiovascular risk factors, diabetes and chronic pain.

Understanding the inter-relationship between improved glycaemic control, hypoglycaemia and weight change within a long-term economic model

BACKGROUND

Current guidelines for the management of type 2 diabetes advocate the attainment of sustained near normal glycaemia levels. Metformin is widely accepted as the treatment of choice for the initiation of pharmacotherapy; however, secondary failure of oral monotherapy occurs in 60% of patients resulting in the need for multiple pharmacotherapies. Therapy-related consequences of treatment, such as weight gain and hypoglycaemia impact on the cost-effectiveness profile of various agents. We therefore sought to ascertain the respective contribution of hypoglycaemia, weight change and improved blood glucose control on second-line therapy options added to metformin.

METHODS

This study uses a simulation model designed to evaluate the cost utility of new therapies in a population of patients with type 2 diabetes mellitus. Standard model outputs include incidence of micro- and macrovascular complications and diabetes-specific and all-cause mortality.

RESULTS

The mean discounted quality-adjusted life year (QALY) predicted by the model was 12.31 years. Reducing Glycosylated haemoglobin (HbA1c) by 1% gave a predicted gain of 0.413 QALYs per patient. A 3-kg weight loss and 30% reduction in hypoglycaemia frequency produced a combined QALY gain of 0.355, whereas the reverse gave a QALY decrement of 0.356.

CONCLUSIONS

The results of this analysis quantify the QALY decrement that may result from adverse therapy effects. The beneficial effects of improved glycaemic control on QALYs may be offset by characteristic treatment-specific adverse effects, such as weight gain and hypoglycaemia frequency.

Costs and consequences associated with newer medications for glycemic control in type 2 diabetes

OBJECTIVE

Newer medications offer more options for glycemic control in type 2 diabetes. However, they come at considerable costs. We undertook a health economic analysis to better understand the value of adding two newer medications (exenatide and sitagliptin) as second-line therapy to glycemic control strategies for patients with new-onset diabetes.

RESEARCH DESIGN AND METHODS

We performed a cost-effectiveness analysis for the U.S. population aged 25-64. A lifetime analytic horizon and health care system perspective were used. Costs and quality-adjusted life years (QALYs) were discounted at 3% annually, and costs are presented in 2008 U.S. dollars. We compared three glycemic control strategies: 1) glyburide as a second-line agent, 2) exenatide as a second-line agent, and 3) sitagliptin as a second-line agent. Outcome measures included QALYs gained, incremental costs, and the incremental cost-effectiveness ratio associated with each strategy.

RESULTS

Exenatide and sitagliptin conferred 0.09 and 0.12 additional QALYs, respectively, relative to glyburide as second-line therapy. In base case analysis, exenatide was dominated (cost more and provided fewer QALYs than the next most expensive option), and sitagliptin was associated with an incremental cost-effectiveness ratio of 169,572 dollars per QALY saved. Results were sensitive to assumptions regarding medication costs, side effect duration, and side effect-associated disutilities.

CONCLUSIONS

Exenatide and sitagliptin may confer substantial costs to health care systems. Demonstrated gains in quality and/or quantity of life are necessary for these agents to provide economic value to patients and health care systems.

Use of DPP-4 inhibitors in type 2 diabetes: focus on sitagliptin

Inhibition of dipeptidyl peptidase-4 (DPP-4) prevents the inactivation of glucagonlike peptide-1 (GLP-1). This increases circulating levels of active GLP-1, stimulates insulin secretion and inhibits glucagon secretion, which results in lowering of glucose levels and improvement of the glycemic control in patients with type 2 diabetes. This review summarizes experiences with DPP-4 inhibition in the treatment of type 2 diabetes, with a focus on sitagliptin. Sitagliptin has in several clinical studies been shown to improve metabolic control in type 2 diabetes, both when used as monotherapy and when used in combination with metformin, sulfonylurea, thiazolidinediones or insulin. The reduction in HbA(1c) is ≈ 0.6% to 1.0% from baseline levels of 7.5% to 8.7% over 6 to 12 months therapy. Sitagliptin has a favorable safety profile, is highly tolerable, and there is a minimal risk of hypoglycemia. Furthermore, sitagliptin is body weight neutral or induces a slight body weight reduction. Sitagliptin may be used in the early stages of type 2 diabetes in combination with metformin or other treatments in subjects with inadequate glycemic control on these treatments alone. Sitagliptin may also be used in monotherapy and, finally, sitagliptin may be used in combination with insulin in more advanced stages of the disease.

Incretin-based therapies: new treatments for type 2 diabetes in the new millennium

The advent of 'incretin-based therapies' - GLP-1 agonists and dipeptidyl-peptidase-4 inhibitors - which result in improvements in glycemic control comparable to those with existing oral hypoglycemic agents, and potentially improve cardiovascular and pancreatic beta-cell function, represents a major therapeutic advance in the management of type 2 diabetes. Gastrointestinal adverse effects occur commonly with GLP-1 agonists, and rarely with DPP-4 inhibitors, but are dose-dependent and usually transient. The low risk of hypoglycemia, and beneficial or neutral effects on body weight, render GLP-1 agonists and DPP-4 inhibitors suitable alternatives to insulin secretagogues and insulin in overweight and elderly patients. Incretin-based therapies also improve quality of life in patients with type 2 diabetes, and may be cost-effective in the long term.

Colesevelam hydrochloride for the treatment of type 2 diabetes mellitus

BACKGROUND

Colesevelam hydrochloride is a bile acid sequestrant approved in January 2008 by the US Food and Drug Administration (FDA) for the treatment of adult patients with type 2 diabetes mellitus (DM) in combination with a sulfonylurea, metformin, and/or insulin therapy.

OBJECTIVE

The purpose of this article was to review the pharmacology, pharmacokinetics, efficacy, adverse effects and tolerability, drug-drug interactions, contraindications/precautions, dosage and administration, pharmacoeconomics, and the overall role of colesevelam in the management of adult patients with type 2 DM.

METHODS

A literature search using MEDLINE (1966-October 27, 2008), PubMed (1950-October 27, 2008), Science Direct (1994-October 27, 2008), Web of Science (1980-October 27, 2008), American Diabetes Association Scientific Abstracts (2004-2008), and International Pharmaceutical Abstracts (1970-October 27, 2008) was performed using the term colesevelam. English-language, original research and review articles were examined, and citations from these articles were assessed. Manufacturer prescribing information and the FDA review of the new drug application for colesevelam were also examined.

RESULTS

Colesevelam is a hydrophilic, water-insoluble polymer, with negligible absorption and systemic distribution, that is excreted primarily in the feces. Through a mechanism still under investigation, colesevelam effectively lowers glycosylated hemoglobin (HbA(1c)) when used in combination with a sulfonylurea, metformin, and/or insulin therapy. Three completed, published Phase III clinical trials investigating colesevelam for the treatment of type 2 DM were evaluated for information, data, and conclusions. At dosing of 1.875 g BID or 3.75 g once daily in combination with one of the aforementioned agents versus placebo, reductions in HbA(1c) in all 3 Phase III clinical trials of colesevelam ranged from 0.5% to 0.7% (P < 0.02). In clinical trials, colesevelam was well tolerated, with hypoglycemia occurring in approximately 3% of studied patients.

CONCLUSIONS

When used in combination with a sulfonylurea, metformin, and/or insulin therapy, colesevelam has been reported to significantly reduce HbA(1c) in adult patients with type 2 DM. Colesevelam's role in the management of type 2 DM remains undefined, however; further investigation into its mechanism of action and long-term efficacy and safety should be performed.