The University of Chicago, Chicago, IL; Harvard University School of Public Health, Boston, MA; and Memorial Sloan-Kettering Cancer Center, New York, NY.
J Oncol Pract. 2012 May;8(3 Suppl):e18s-23s. doi: 10.1200/JOP.2012.000541.
The use of anticancer drugs (chemotherapies) is an important determinant of national spending trends. Recent policies have aimed to accelerate generic entry among chemotherapies to generate cost savings.
We examined the effects of generic entry on the choice of chemotherapy for the treatment of metastatic colorectal cancer (MCRC) between 2006 and 2009 using autoregressive-moving average modeling with case control. A nationally representative sample of oncologists and patients with cancer (age ≥ 65 years) was employed to estimate the magnitude and significance of the impact of the generic entry of irinotecan in February 2008 on the number of administrations of irinotecan compared with oxaliplatin.
The generic entry of irinotecan resulted in a 17% to 19% decrease (P < .001) in use among elderly patients with MCRC compared with oxaliplatin. The results were robust to multiple sensitivity checks.
This study provides novel and robust estimates of the decline in use of a chemotherapy to treat a common cancer in the elderly after patent expiration. The results suggest estimates from a previous Office of the Inspector General report of the potential savings derived from the generic entry of irinotecan for public payers are an overestimate, likely confounded by oncologists' response to financial incentives, changes in scientific evidence, and promotional activities. As calls for improving the quality and cost efficiency of oncology increase, future empirical work is needed to examine the responsiveness of oncologists' treatment decision making to incentives among patients of all ages and insurance types.
抗癌药物（化疗药物）的使用是决定国家支出趋势的一个重要因素。最近的政策旨在加速化疗药物的仿制药进入市场，以节省成本。
我们使用自回归移动平均模型和病例对照法，研究了 2006 年至 2009 年仿制药进入市场对转移性结直肠癌（MCRC）化疗选择的影响。我们使用了一个全国代表性的肿瘤学家和癌症患者（年龄≥65 岁）样本，以估计 2008 年 2 月伊立替康仿制药进入市场对伊立替康与奥沙利铂相比的使用次数的影响的大小和显著性。
伊立替康仿制药的进入导致 MCRC 老年患者中与奥沙利铂相比，伊立替康的使用减少了 17%至 19%（P<.001）。结果在多次敏感性检查中仍然稳健。
本研究提供了一种新颖而稳健的方法，可用于估计专利过期后治疗老年常见癌症的化疗药物使用量下降。结果表明，之前的监察长办公室报告中关于仿制药进入市场为公共支付者带来的潜在节省的估计值过高，可能与肿瘤学家对财务激励的反应、科学证据的变化和促销活动有关。随着对提高肿瘤学质量和成本效益的呼声越来越高，未来需要进行实证研究，以考察所有年龄段和保险类型的患者的激励因素对肿瘤学家治疗决策的反应。
