Paradis Pierre Emmanuel, Latrémouille-Viau Dominick, Moore Yuliya, Mishagina Natalia, Lafeuille Marie-Hélène, Lefebvre Patrick, Gaudig Maren, Duh Mei Sheng
Groupe d'analyse, Ltée, Montréal, Québec, Canada.
Curr Med Res Opin. 2009 Jul;25(7):1793-805. doi: 10.1185/03007990903044374.
To explore the effects of generic substitution of the antiepileptic drug (AED) topiramate (Topamax) in Canada; to convert observed Canadian costs into the settings of France, Germany, Italy, and the United Kingdom (UK); and to forecast the economic impact of generic topiramate entry in these four European countries.
Health claims from Régie de l'assurance maladie du Québec (RAMQ) plan (1/2006-9/2008) and IMS Health data (1998-2008) were used. Patients with epilepsy and > or = 2 topiramate dispensings were selected. An open-cohort design was used to classify observation into mutually-exclusive periods of branded versus generic use of topiramate. Canadian healthcare utilization and costs (2007 CAN$/person-year) were compared between periods using multivariate models. Annualized per-patient costs (2007 euro or 2007 pound sterling/person-year) were converted using Canadian utilization rates, European prices and service-use ratios. Non-parametric bootstrap served to assess statistical significance of cost differences. Topiramate market was forecasted following generic entry (09/2009-09/2010) using autoregressive models based on the European experience. The economic impact of generic topiramate entry was estimated for each country.
A total of 1164 patients (mean age: 39.8 years, 61.7% female) were observed for 2.6 years on average. After covariates adjustment, generic-use periods were associated with increased pharmacy dispensings (other AEDs: +0.95/person-year, non-AEDs: +12.28/person-year, p < 0.001), hospitalizations ( + 0.08/person-year, p = 0.015), and lengths of hospital stays (+0.51 days/person-year, p < 0.001). Adjusted costs, excluding topiramate, were CAN$1060/person-year higher during generic use (p = 0.005). Converted per-patient costs excluding topiramate were significantly higher for generic relative to brand periods in all European countries (adjusted cost differences per person-year: 706-815 euro, p < 0.001 for all comparisons). System-wide costs would increase from 3.5 to 24.4% one year after generic entry.
Study limitations include the absence of indirect costs, possible claim inaccuracies, and IMS data limitations.
Higher health costs were projected for G4 European countries from the Canadian experience following the generic entry of topiramate.
探讨加拿大抗癫痫药物（AED）托吡酯（妥泰）的仿制药替代效果；将加拿大观察到的成本换算到法国、德国、意大利和英国的情况；并预测仿制药托吡酯进入这四个欧洲国家后的经济影响。
使用了魁北克医疗保险局（RAMQ）计划（2006年1月 - 2008年9月）的健康索赔数据和艾美仕市场研究公司（IMS Health）的数据（1998 - 2008年）。选取患有癫痫且有≥2次托吡酯配药记录的患者。采用开放队列设计将观察期分为托吡酯品牌药使用期和仿制药使用期这两个相互排斥的阶段。使用多变量模型比较各阶段加拿大的医疗保健利用率和成本（2007加元/人年）。利用加拿大的利用率、欧洲的价格和服务使用率将年化人均成本（2007欧元或2007英镑/人年）进行换算。非参数自助法用于评估成本差异的统计学显著性。基于欧洲经验，使用自回归模型预测仿制药进入市场后（2009年9月 - 2010年9月）托吡酯的市场情况。估算了仿制药托吡酯进入市场对每个国家的经济影响。
共观察了1164名患者（平均年龄：39.8岁，61.7%为女性），平均观察时间为2.6年。在对协变量进行调整后，仿制药使用期与药房配药量增加相关（其他抗癫痫药物：+0.95/人年，非抗癫痫药物：+12.28/人年，p < 0.001）、住院次数增加（+0.08/人年，p = 0.015）以及住院时长增加（+0.51天/人年，p < 0.001）。不包括托吡酯的调整后成本在仿制药使用期比品牌药使用期高1060加元/人年（p = 0.005）。在所有欧洲国家，不包括托吡酯的仿制药人均成本相对于品牌药时期均显著更高（人均年调整成本差异：706 - 815欧元，所有比较p < 0.001）。仿制药进入市场一年后，全系统成本将增加3.5%至24.4%。
研究局限性包括未考虑间接成本、可能存在的索赔不准确以及IMS数据的局限性。
根据加拿大的经验，预计托吡酯仿制药进入市场后，欧洲四国的医疗成本将会增加。
