中文摘要
本文研究了保险覆盖政策如何影响药物创新。在美国，大多数患者通过由药品福利管理者（PBMs）管理的保险计划获取处方药。从2012年起，当存在更廉价的替代品时，PBMs开始拒绝为许多新获批的药物提供覆盖。我们记录了该政策生效后药物研发战略的转变：面临更大被排除风险的治疗类别经历了投资的相对减少。这种转变减少了那些看似更具增量性的候选药物的开发：即那些在有更多既有疗法和科学新颖性较低的研究的药物类别中的候选药物。（JEL G22, I13, L65, O31）
Abstract
This paper studies how insurance coverage policies impact pharmaceutical innovation. In the United States, most patients obtain prescription drugs through insurance plans administered by Pharmacy Benefit Managers (PBMs). Beginning in 2012, PBMs began refusing to provide coverage for many newly approved drugs when cheaper alternatives were available. We document a shift in pharmaceutical R&D strategies after this policy took effect: therapeutic classes at greater risk of exclusion experienced a relative reduction in investments. This shift reduced development of drug candidates that appear more incremental: that is, those in drug classes with more preexisting therapies and less scientifically novel research. (JEL G22, I13, L65, O31)