To the Editor—Evidence of effectiveness and cost-effectiveness is inherently dynamic in nature. Cost-effectiveness models based on the best data available at the time are an important contribution to evidence-based decision-making if they reveal the likely outcomes of various scenarios and quantify the degree of uncertainty around the apparently optimal approach. Cost-effectiveness models also illustrate the trade-offs inherent in each potential alternative available to the decision-maker and should be updated as new evidence becomes available.

In 2000, The Academy of Managed Care Pharmacy issued its first Format for Formulary Submissions, which provided US payers with a new tool to proactively request clinical and economic data from health technology manufacturers. The Format, which has been revised substantially in recent years, is now used by health-care organizations covering some 150 million lives in the United States [1]. This guidance recommends that dossiers for new drug products be requested by health plans approximately 6 months before launch, and explicitly calls for the use of economic models “to inform decisions about the value or cost-effectiveness of pharmaceuticals, biologics, and vaccines.” Such models are to be based on International Society for Pharmacoeconomics and Outcomes Research (ISPOR)’s Good Research Practices—Modeling Studies [2], which stipulate that data sources be “clearly defined and from the most recent studies.”