scholarly journals Cost-Utility Analysis of Apixaban Compared to Usual Care for the Primary Thromboprophylaxis of Ambulatory Cancer Patients Initiating Chemotherapy

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 329-329
Author(s):  
Miriam Kimpton ◽  
Srishti Kumar ◽  
Philip S. Wells ◽  
Marc Carrier ◽  
Kednapa Thavorn

Introduction: Apixaban 2.5mg twice daily has been shown to significantly reduce the risk of venous thromboembolism (VTE) compared to placebo for the primary thromboprophylaxis of VTE in ambulatory cancer patients initiating chemotherapy, who are at intermediate-high risk of VTE, with a Khorana score of ≥2 (hazard ratio, 0.41; 95% confidence interval, 0.26 to 0.65; P<0.001). In this study, we estimated whether the health benefit gained from apixaban justified its costs. Method: We conducted a cost-utility analysis of apixaban (2.5mg twice daily) compared to usual care, whereby no apixaban is prescribed, from the perspective of Canada's healthcare system. Our target population was ambulatory cancer patients starting chemotherapy with an intermediate-high risk of VTE. We developed a Markov model with a cycle length of 1-week to simulate costs and quality-adjusted life years (QALYs) for patients receiving either apixaban or usual care over 6 months (Figure 1). To estimate the baseline time varying risk of VTE among ambulatory cancer patients undergoing chemotherapy, we created pseudo patient-level data from survival curves reported for patients in the placebo arm of the AVERT trial using 'WebPlotDigitizer'. We fitted parametric survival models to the patient-level data points to extrapolate VTE risk beyond the trial follow-up period (median follow-up 183 days). The best model was selected based on a visual inspection and the Akaike Information Criterion. The relative risk of VTE, clinically relevant non-major bleeding, and major bleeding (using the International Society of Thrombosis and Haemostasis criteria) as a result of apixaban was obtained from the AVERT trial using the on-treatment analysis. We conducted a targeted literature search to obtain the risk of complications among cancer patients receiving low-molecular-weight heparin for the initial treatment and secondary prevention of VTE using a meta-analysis technique. Hazard ratio for increased risk of death due to cancer was estimated as a weighted average of the age-standardized mortality rate by tumor type, based on the proportion of patients with each tumor type in the AVERT trial. Costs were obtained from published Canadian sources. Baseline health utility values for patients on chemotherapy and in remission were calculated as a weighted average of utility values by tumour type, also based on the proportion of patients with each tumour type in the AVERT trial. Utility values for chemotherapy and remission for each tumour type, as well as event specific disutility values, were obtained from the published literature. Both costs and QALYs were discounted using an annual rate of 1.5%, as recommended by the Canadian Agency for Drugs and Technologies in Health. We conducted deterministic and probabilistic sensitivity analyses to assess robustness of study findings. Results: Over a 6-month period, apixaban was associated with a lower health system cost (C$25,987 vs C$26,268) and a slight increase in QALYs (0.3339 vs 0.3337) compared to usual care (Table 1). The probability that apixaban was cost-saving compared to usual care was 90%; however, this probability decreased with the greater willingness to pay (WTP) values partly due to the high uncertainty in the difference in QALYs. At a WTP threshold of C$50,000/QALY, the probability of apixaban being cost effective was 57% (Figure 2). Over 1 year, apixaban reduced health care system costs by C$1,113 and improved QALYs by 0.0005 units compared to usual care. At a WTP threshold of C$50,000/QALY, the probability of apixaban being cost effective increased to 70%. Our results were robust to the change in time horizon; however, they were more sensitive to the relative risk of VTE, the relative risk of major bleeding, the costs amassed in the post-VTE period, and the treatment cost of acute VTE. Probabilistic sensitivity analysis indicated a high-level uncertainty around cost effectiveness estimates, which may be driven by the wide confidence intervals around estimates for relative risk of complications in patients receiving thromboprophylaxis with apixaban. Conclusion: From a publicly funded health system's perspective apixaban is a cost saving option for thromboprophylaxis among ambulatory cancer patients initiating chemotherapy. Disclosures Wells: BMS/Pfizer: Honoraria, Research Funding; Bayer: Honoraria; Sanofi: Honoraria; Daiichi Sankyo: Honoraria. Carrier:Servier: Honoraria; Bayer: Honoraria; Pfizer: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Leo Pharma: Honoraria, Research Funding. OffLabel Disclosure: Apixaban can be used as postoperative prophylaxis of DVT/PE and for treatment of DVT/PE. We performed a cost-utility analysis of apixaban 2.5mg BID for the primary thromboprophylaxis of ambulatory cancer patients initiating chemotherapy, at intermediate-high risk of venous thromboembolism.

2010 ◽  
Vol 8 (6) ◽  
pp. 242-251 ◽  
Author(s):  
Elenir B.C. Avritscher ◽  
Ya-Chen T. Shih ◽  
Charlotte C. Sun ◽  
Richard J. Gralla ◽  
Steven M. Grunberg ◽  
...  

2008 ◽  
Vol 31 (1) ◽  
pp. 194-194 ◽  
Author(s):  
J. Karnon ◽  
R. Jones ◽  
C. Czoski-Murray ◽  
K. Smith

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 6606-6606
Author(s):  
G. de Pouvourville ◽  
I. Borget ◽  
M. Allyn ◽  
M. Schlumberger

6606 Background: In thyroid cancer patients, follow-up is designed to detect recurrent disease and consists of neck- ultrasonography (US), thyroglobulin measurement (Tg) and radioiodine whole body scan (WBS). Recent guidelines have restricted the use of WBS to suspicious cases. To insure diagnostic accuracy, follow-up control requires TSH stimulation, either with thyroid hormone withdrawal (THW) or rhTSH, which have demonstrated similar diagnostic accuracy. THW induces significant morbidity associated with hypothyroidism, leading to a decrease in patient quality of life and ability to work, whereas rhTSH is an innovative costly drug that avoids such patient burden. A societal cost-utility analysis was conducted to compare 4 follow-up strategies, combining a method of stimulation (rhTSH or THW) and a testing protocol (US+Tg+WBS or US+Tg alone). Methods: A Markov model was built to describe the follow-up of thyroid cancer patients first treated by thyroidectomy and radioiodine ablation, over 5 years. Estimates for diagnostic accuracy values and recurrence rate were extracted from a French multicenter randomized trial. Costs were computed from the perspective of the society, including medical resources consumed (hospitalisation, rhTSH, tests, treatment of recurrence). The model also incorporated the benefits of rhTSH in terms of quality of life (utility scores derived from SF36) and the reduction in duration and overall cost of sick leave. Results: Among the 753 patients included, 13 patients presented recurrence. rhTSH stimulation resulted in a higher utility score (0.802 vs. 0.637) over the period of stimulation and a reduction of 1083 € of absenteeism costs in active patients. As compared to the THW+Tg+US+WBS strategy, the incremental cost-utility ratios (ICER) showed economic dominance for the rhTSH strategies with ratios of −16,876 and −19,297 €/QALY with and without WBS respectively. The ICER for the strategy THW+US+Tg reached 29,333 €/QALY, as compared to THW+Tg+US+WBS strategy. Conclusions: the recommended strategy combining Tg determination and US after rhTSH stimulation appears the most cost-effective in the follow-up of thyroid cancer patients, as it is the strategy the less costly and associated with improved patient quality of life. No significant financial relationships to disclose.


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