Program on Regulation, Therapeutics, and Law (PORTAL), Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
JAMA Intern Med. 2016 Sep 1;176(9):1317-23. doi: 10.1001/jamainternmed.2016.3384.
In November 2011, the cholesterol level-lowering medication atorvastatin calcium became available in the United States as a generic drug. However, only a single generic form (from a manufacturer that qualified for market exclusivity by challenging several of Pfizer's patents) and an authorized generic form (a brand-name drug sold as a generic) were available for the first 180 days.
To describe trends in the prescribing of generic atorvastatin after expiration of market exclusivity for the brand-name medication and the effect on patients' out-of-pocket spending.
DESIGN, SETTING, AND PARTICIPANTS: A US population-based study used commercial claims data from the Optum Clinformatics research database (UnitedHealth Group) from December 1, 2010, to May 31, 2013. Participants were 1 968 709 adults with commercial insurance who had been prescribed 1 or more statins (13 285 223 statin prescriptions). An interrupted times series model was used to examine the effect of limited and full generic competition on brand-name and generic atorvastatin prescriptions. Data were analyzed from December 1, 2010, to May 31, 2013.
Prescription of brand-name atorvastatin, generic atorvastatin, and authorized generic atorvastatin were distinguished using National Drug Codes.
Total number of prescriptions dispensed per month and out-of-pocket expenditures for a typical 30-day supply of 20-mg atorvastatin during the periods of brand-name availability only, limited generic competition (lasting 180 days after market exclusivity ended), and full generic competition.
Of the 1 968 709 beneficiaries, 1 483 066 (58.8% male and 41.2% female; mean [SD] age, 55.6 [10.2] years) received a prescription for a single statin and were included in the analysis. The introduction of the first generic competitor was associated with a reduction in monthly brand-name atorvastatin fills by 20 896 prescriptions (level change, P = .001), an 18.1% change compared with the month preceding loss of exclusivity. Full generic competition reduced brand-name fills by 54 944 prescriptions (level change, P < .001), a 47.6% change relative to the month preceding loss of exclusivity. During the first 180 days of generic competition, no meaningful difference in monthly out-of-pocket spending was found between brand-name (median, $16.98; interquartile range [IQR], $8.76-$48.66) and generic (median, $19.98; IQR, $7.50-$54.90) atorvastatin. After full generic competition, estimated monthly out-of-pocket spending for generic atorvastatin (median $5.10; IQR, $3.36-$19.98) or authorized generic atorvastatin (median, $5.52; IQR, $3.48-$19.98) was substantially lower than that for brand-name atorvastatin (median, $30.00; IQR, $15.00-$91.38).
Among patients with commercial health insurance, delays in generic uptake and high levels of out-of-pocket spending during the first 180 days after atorvastatin lost market exclusivity slowed changes in drug prescribing and decreases in patients' out-of-pocket costs.
2011 年 11 月，降胆固醇药物阿托伐他汀钙片在美国作为一种仿制药上市。然而，在品牌药失去市场专有权的最初 180 天内，仅有一种通用形式（来自一家通过对辉瑞公司的多项专利提出质疑而有资格获得市场专有权的制造商）和一种授权通用形式（作为通用药物销售的品牌药物）可用。
描述阿托伐他汀仿制药在品牌药失去市场专有权后处方的趋势及其对患者自付费用的影响。
设计、设置和参与者：一项基于美国人群的研究使用了 Optum Clinformatics 研究数据库（联合健康集团）的商业索赔数据，时间为 2010 年 12 月 1 日至 2013 年 5 月 31 日。参与者为 1968709 名有商业保险的成年人，他们曾开有 1 种或多种他汀类药物（13285223 份他汀类药物处方）。使用中断时间序列模型来检验有限和完全通用竞争对品牌和通用阿托伐他汀处方的影响。数据分析时间为 2010 年 12 月 1 日至 2013 年 5 月 31 日。
通过国家药物代码区分品牌阿托伐他汀、通用阿托伐他汀和授权通用阿托伐他汀的处方。
在品牌阿托伐他汀可用、有限通用竞争（在市场专有权结束后持续 180 天）和完全通用竞争期间，每月开具的典型 30 天 20 毫克阿托伐他汀供应量的处方总数和自付费用。
在 1968709 名受益人中，有 1483066 人（58.8%为男性，41.2%为女性；平均[SD]年龄为 55.6[10.2]岁）收到了单一他汀类药物的处方，并纳入了分析。第一个通用竞争对手的推出与每月品牌阿托伐他汀配药减少 20896 剂有关（水平变化，P=0.001），与失去专有权前一个月相比，变化率为 18.1%。完全通用竞争使品牌药配药量减少了 54944 剂（水平变化，P<0.001），与失去专有权前一个月相比，变化率为 47.6%。在通用竞争的最初 180 天内，品牌（中位数 16.98 美元；四分位距 [IQR] 8.76-48.66 美元）和通用（中位数 19.98 美元；IQR 7.50-54.90 美元）阿托伐他汀的每月自付费用没有显著差异。完全通用竞争后，通用阿托伐他汀（中位数 5.10 美元；IQR 3.36-19.98 美元）或授权通用阿托伐他汀（中位数 5.52 美元；IQR 3.48-19.98 美元）的每月自付费用明显低于品牌阿托伐他汀（中位数 30.00 美元；IQR 15.00-91.38 美元）。
在有商业健康保险的患者中，阿托伐他汀失去市场专有权后最初 180 天内通用药物采用延迟和自付费用水平高，减缓了药物处方的变化和患者自付费用的降低。
