Lee Todd C, Kaouache Mohammed, Grover Steven A
Affiliations: Division of General Internal Medicine (Lee, Grover), Department of Medicine, McGill University; Clinical Practice Assessment Unit (Lee), McGill University Health Centre, Montréal, Que.; Department of General Sciences (Kaouache), Prince Sultan University, Riyadh, Kingdom of Saudi Arabia; Centre for the Analysis of Cost-Effective Care (Grover), Montreal General Hospital, Montréal, Que.
CMAJ Open. 2018 Apr 3;6(2):E162-E167. doi: 10.9778/cmajo.20180011.
Evolocumab, a proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitor, has been shown to reduce low-density lipoprotein levels by up to 60%. Despite the absence of a reduction in overall or cardiovascular mortality in the Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Subjects With Elevated Risk (FOURIER) trial, some believe that, with longer treatment, such a benefit might eventually be realized. Our aim was to estimate the potential mortality benefit over a patient's lifetime and the cost per year of life saved (YOLS) for an average Canadian with established coronary artery disease. We also sought to estimate the price threshold at which evolocumab might be considered cost-effective for secondary prevention in Canada.
We calibrated the Cardio-metabolic Model, a well-validated tool for predicting cardiovascular events and life expectancy, to the reduction in nonfatal events seen in the FOURIER trial. Assuming that long-term treatment will eventually result in mortality benefits, we estimated YOLSs and cost per YOLS with evolocumab treatment plus a statin compared to a statin alone. We then estimated the annual drug costs that would provide a 50% chance of being cost-effective at willingness-to-pay values of $50 000 and $100 000.
In secondary prevention in patients similar to those in the FOURIER study, evolocumab treatment would save an average of 0.34 (95% confidence interval [CI] 0.27-0.41) life-years at a cost of $101 899 (95% CI $97 325-$106 473), yielding a cost per YOLS of $299 482. We estimate that to have a 50% probability of achieving a cost per YOLS below $50 000 and $100 000 would require annual drug costs below $1200 and $2300, respectively.
At current pricing, the use of evolocumab for secondary prevention is unlikely to be cost-effective in Canada.
依洛尤单抗是一种前蛋白转化酶枯草溶菌素9型(PCSK9)抑制剂,已显示可使低密度脂蛋白水平降低达60%。尽管在“高危受试者PCSK9抑制进一步心血管结局研究(FOURIER)”试验中未观察到总体死亡率或心血管死亡率降低,但一些人认为,随着治疗时间延长,可能最终会实现这种益处。我们的目的是估计对于患有已确诊冠状动脉疾病的普通加拿大人,其一生潜在的死亡率获益以及每挽救一年生命的成本(YOLS)。我们还试图估计在加拿大二级预防中依洛尤单抗被认为具有成本效益的价格阈值。
我们将“心血管代谢模型”(一种预测心血管事件和预期寿命的经过充分验证的工具)校准为与FOURIER试验中观察到的非致命事件减少情况相符。假设长期治疗最终会带来死亡率获益,我们估计了与单独使用他汀类药物相比,使用依洛尤单抗加他汀类药物治疗的YOLS和每YOLS成本。然后,我们估计了在支付意愿值为50000加元和100000加元时具有50%成本效益可能性的年度药物成本。
在与FOURIER研究中类似患者的二级预防中,依洛尤单抗治疗平均可挽救0.34(95%置信区间[CI]0.27 - 0.41)个生命年,成本为101899加元(95%CI 97325 - 106473加元),每YOLS成本为299482加元。我们估计,要使每YOLS成本低于50000加元和100000加元的概率达到50%,分别需要年度药物成本低于1200加元和2300加元。
按照当前定价,在加拿大使用依洛尤单抗进行二级预防不太可能具有成本效益。