Long-Term Cost-effectiveness of Saxagliptin for the Treatment of Type 2 Diabetes in South Africa

Transcription

1 Long-Term Cost-effectiveness of Saxagliptin for the Treatment of Type 2 Diabetes in South Africa Deon Olivier October

2 Introduction Saxagliptin is a DPP-4 inhibitor for the treatment of type 2 diabetes (T2DM) SU in combination with metformin (MET) is the most common oral anti-diabetic (OAD) treatment strategy in patients that fail on metformin monotherapy and hence a relevant comparator for saxagliptin (SAXA)+MET To estimate economic and health impact of SAXA+MET compared to SU+MET in T2DM patients in South Africa, an economic analysis was conducted. 2

3 The model Objective: Evaluate the cost-effectiveness of SAXA+MET compared to a SU+MET, glimepiride Based on a previously published model 1, the SAXA CE model has been designed to determine the cost effectiveness of new T2DM therapies based on the UKPDS 68 2 UKPDS 68 shows the results of the UK designed model to estimate the lifetime health outcomes of patients with T2DM Data from a 52 week clinical trial comparing SAXA+MET vs. SU+MET 3 was included in the analysis. This trial demonstrated: 1 Non-inferiority of SAXA+MET vs SU+MET in A1C reduction at Week 52 Weight reduction with SAXA+MET vs weight gain with SU+MET Lower risk of hypoglycemic events with SAXA+MET 1.Mount Hood 4 Modeling Group. Computer modeling of diabetes and its complications: a report on the Fourth Mount Hood Challenge Meeting. Diabetes Care 2007 Jun;30(6): McEwan P, Peters JR, Bergenheim K, Currie CJ. Evaluation of the costs and outcomes from changes in risk factors in type 2 diabetes using the Cardiff stochastic simulation cost-utility model (DiabForecaster). Curr Med Res Opin 2006 Jan;22(1): Clarke PM, Gray AM, Briggs A, Farmer AJ, Fenn P, Stevens RJ, et al. A model to estimate the lifetime health outcomes of patients with type 2 diabetes: the United Kingdom Prospective Diabetes Study (UKPDS) Outcomes Model (UKPDS no. 68). Diabetologia 2004 Oct;47(10): Göke B, Gallwitz B, Eriksson J, Hellqvist Å, Gause-Nilsson I. Saxagliptin in non-inferior to glipizide in patients with type 2 diabetes mellitus inadequately controlled on metformin alone: a 52-week randomised controlled trial. The International Journal of Clinical Practice

4 Model Setting base case Perspective SA third-party payer Treatment Comparators Patient Population SAXA+MET vs. SU+MET Patients diagnosed with T2DM Patients aged years Model Design Stochastic simulation model of disease progression in 1-year increments Model Outcomes Total Cost Quality Adjust Life Years Time Horizon Life time 5 years 10 years Costs Inflated to 2011 values Discounted at 5% (both effectiveness and costs) Rescue therapy Insulin 4

5 Model Diagram Mean values for baseline demographic and clinical characteristics 1.Demographics 2.Modifiable Risk Factors* 3.Co morbidities 4.Event and management costs** 5.Utility values Model Costs Event Costs* * Cost of Therapy Follow up care Side Effects Events Macrovascular Microvascular Hypoglycaemia HE Output Cost per QALY *Modifiable risk factors include variables such as smoking status and weight **Event costs include costs of: ischemic heart disease, myocardial infarction, congestive heart failure, stroke, amputation, blindness and end-stage renal disease. Fatal, nonfatal, and maintenance costs were considered in these cost values 5

6 Model Population The model simulates patients based on characteristics aligned with South Africa demographic data Table 1 Baseline Demographics Mean/Proportion Baseline data specific Baseline demographics for SA population 1 Current Age (Yrs) Proportion female Duration diabetes (Years) 9.85 Height (m) 1.67 Proportion A 0.08 Proportion smokers 0.22 Weight (kg) Shestakova M et al,2008; 6

7 Model assumptions Clinical input variables, 52 week follow up. Variable a SAXA+MET SU+MET Reference Rescue therapy Reference HbA1c reduction, year 1 (%, SD) 0.57 (0.041) b 0.66 (0.043) b ( Göke B, 2010) 1.00% Assumed Number symptomatic hypoglycemias (SD) 0.04 (0.02) c 1.73 (0.08) c ( Göke B, 2010) 1.73 Assumed Probability severe hypoglycemia ( Göke B, 2010) ( UKPDS 33) and (UKPDS 16) Weight change (kg, SD) -1.1 (0.017) b +1.1 (0.018) b ( Göke B, 2010) +2.5 ( UKPDS 33) HbA1c = glycosylated haemoglobin SD = Standard deviation, which are reported for those values sampled from a normal distribution in the PSA. a All efficacy variables are taken from the intention to treat analysis. Where these were not available in Göke et al. (2010) they have been obtained from the clinical trial report. b Reported as standard error in the clinical trial report. c Calculated as rate/ number of subjects. 7

8 Model assumptions HrQoL decrements HRQoL decrements (Clarke et al, 2002, UKPDS 62) HRQoL decrement Event First Year Subsequent year Ischaemic Heart Disease Myocardial Infarction Congestive Heart Failure Stroke Pre-Blind Blind ESRD Transplant Amputation Hypoglycemia (ref) - Severe - Symptomatic - Nocturnal Weight gain (per unit gain of BMI) (ref)

9 Model Costs treatment medication Treatment Costs Saxagliptin 5mg Annual Cost (2011 ZAR) 3,901 Glimepiride 3 mg 2,822 Metformin 1500mg 647 Insulin Glargine(dose based on dispensed claimed data) 3,889 Source:Single Exit Price plus current dispensing tariff. 9

10 Costs diabetes related events Fatal, non-fatal, and maintenance costs were considered Direct costs for diabetes-related events. Annual Cost Data (2011 ZAR) Event Fatal Non-fatal Maintenance Ischaemic Heart Disease 53,786 13,367 Myocardial Infarction 34, , ,312 Congestive Heart Failure 47,379 47,379 13,455 Stroke 82,518 57,738 22,503 Amputation 108, ,356 3,843 Blindness*1 5,181 1,666 ESRD*2 297, ,000 Severe hypoglycemia*3 4,254 ESRD = End Stage Renal Disease Sources: Quark Healthcare Consulting [*1]blindness (UK costs applying PPP method).[*2]national Renal Care, personal communication.only severe hypoglycemia is associated with a cost in the model. 10

11 Results base case Compared with SU+MET, the cost per QALY gained with SAXA+MET is ZAR 20,848 Patients treated with SAXA + MET gain on average 0.11 QALYs at an incremental cost of around ZAR 2,213 ICER =ZAR 20,848 per QALY Per Patient SU+MET SAXA+MET Difference Discounted Cost (ZAR) 249, ,660 2,213 Discounted QALYs Cost /QALY (ZAR) 20,848 The main differences between the treatments is the occurrance of side effects. The number of hypoglicemic events is lower with the SAXA strategy. This strategy is also associated with a weight decrease, whereas SU+MET increase body weight. 11

12 Sensitivity analysis CEA Results: 10 years horizon Per Patient SU+MET SAXA+MET Difference Discounted Cost (ZAR) 60,906 62,849 1,943 Discounted QALYs Cost/QALY (ZAR) 27,809 CEA, Results: 5 years horizon Per Patient SU+MET SAXA+MET Difference Discounted Cost (ZAR) 24,760 26,777 2,017 Discounted QALYs Cost/QALY (ZAR) ZAR 38,850 12

13 Sensitivity Analysis: Cost effectiveness results where SAXA weight reduction is not lost at rescue therapy Cost-effectiveness SAXA+MET (treatment) SU+Met (control) Difference Per patient Discounted costs (ZAR) 250, ,447 1,550 Discounted QALYs Discounted LYG Cost/QALY (ZAR) 8,705 13

14 Conclusions Variable side effect profiles of diabetes treatments may have an impact on patients QoL and the cost to the healthcare system Proper glycemic control decreases the risk and prevents the potential high costs of future hypoglycemic events SAXA +MET is expected to be cost effective while demonstrating fewer hypoglycemic events and weight loss compared to SU+MET for the treatment of T2DM Cost effectiveness of SAXA+MET vs SU+MET is driven by: fewer hypoglycemic events weight loss 14

15 Thank you 15