Date of Award

January 2018

Document Type


Degree Name

Medical Doctor (MD)



First Advisor

Joseph S. Ross


Every year, novel therapeutic agents enter the United States healthcare marketplace following regulatory agency approval. Such approval has traditionally been viewed as the final step in the long research and development (R&D) process designed to safely provide patients with innovative products that treat disease and improve human health. Regulatory approval, however, ensures neither payer reimbursement nor patient access.

Regulatory agencies such as the U.S. Food and Drug Administration (FDA) are tasked with determining whether medical products are safe and effective for public use. Insurers and payers, however, determine which medical products and services should be covered. As a result, patient access to new therapies following FDA approval is effectively determined by a complex system of private and public payers, such as the Centers for Medicare and Medicaid Services (CMS).

Novel therapeutic agents are a diverse set of medical technologies that may have widely varying coverage rates depending on clinical need, evidence of clinical efficacy, negotiated cost, and regulatory status. In the United States, the largest payer is CMS, which provides Part D prescription drug benefits to over 43 million Americans. While Part D plans are subject to federal regulation and oversight, plans maintain wide latitude in structuring benefits to control risk and manage patient utilization.

This thesis explores the effects of FDA and CMS policies on patient access to novel therapeutic agents by examining the rate of Part D prescription drug plan coverage for therapies first approved by the FDA between 2006 and 2012. A cross-sectional study design was used to evaluate Medicare Part D prescription drug benefit plans from 2007 to 2015. The primary outcome was drug coverage, defined by inclusion of a drug on a plan formulary, at year one and three following FDA approval. For covered drugs, coverage was categorized as unrestrictive or restrictive, which was defined as requiring step therapy or prior authorization. In addition, coverage was analyzed by a number of FDA and CMS designations, including year of approval, biologics vs small molecules, priority review, accelerated approvals, orphan drug status, CMS protected status, and therapeutic area.

Among 144 newly FDA-approved therapies, 90% were covered by at least one plan one year following approval. Therapeutics were covered by a median of 61% (Interquartile Range [IQR], 39%-90%) of plans at one year, 79% (IQR, 57%-100%) at three years. Nonetheless, when therapeutics were covered, most plans restricted coverage through prior authorization or step therapy; only 4% of therapeutics were covered by all plans without restrictions at year three. Several drug characteristics, including FDA priority review or accelerated approval and CMS protected drug class, were associated with higher rates of coverage. While most Medicare Part D plans covered the majority of novel therapeutics in the year following FDA approval, access to many therapies was dependent on plan choice, and coverage was often restricted. Policy makers may have opportunities to improve patient access to novel therapy through innovative regulatory mechanisms.


This thesis is restricted to Yale network users only. It will be made publicly available on 06/25/2100