Estimating the Timing of Future Generic Drug Entry- Study Reports Accuracy of New Prediction Method

Published Dec 18, 2018
Lawrenceville, NJ, USA—December 18, 2018—Value in Health, the official journal of ISPOR—the professional society for health economics and outcomes research, announced today the publication of new research describing a method to predict generic entry of top-selling drugs and a formal assessment of its accuracy. The method was reliable for drugs protected by active ingredient patents, but substantially overestimated the exclusivity period for drugs with only so-called “secondary” patents (such as patents for methods of treatment). The report, “A Method for Approximating Future Entry of Generic Drugs,” was published in the December 2018 issue of Value in Health. Researchers developed a method of estimating, shortly after a new drug is approved, the quarter and year of expected generic entry, and then tested the estimates against a set of 170 top-selling drugs that lost market exclusivity between 2000 and 2012. The method took account of the types of patents protecting the drug, whether the drug had been granted patent term restoration, and whether the drug qualified for any other exclusivities. The method performed reasonably well among the 131 drugs with active ingredient patents; the median predicted market exclusivity for these drugs was 12.25 years, compared with a median actual period of 13.0 years. However, among the 38 drugs protected only by secondary patents, the median predicted market exclusivity was 16.0 years, but the median actual market exclusivity was only 8.25 years, likely because secondary patents are weaker and more easily overturned in court. “Despite some limitations, our method’s estimation of the quarter-year of generic entry was found to be accurate in over half the cases in a recent cohort of top-selling drugs that went generic,” said lead author Reed Beall, PhD, University of Calgary, AB, Canada, and Harvard Medical School, Boston, MA, USA. “We therefore believe that the FDA should routinely make this date widely known so that physicians and patients can be aware of the forthcoming availability of less-expensive generic versions, and so that payers, legislators, and regulators can guard against strategies that brand-name manufacturers sometimes use to minimize the impact of generic drug entry.” Coauthor Jonathan Darrow, SJD, JD, MBA, Harvard Medical School and in the Program On Regulation, Therapeutics, And Law (PORTAL) at Brigham and Women’s Hospital, Boston, MA, USA explained that “knowledge of whether actual generic entry dates turn out to be long before or long after expected entry dates can help policymakers adjust rules if manufacturers’ business strategies lead to substantial delays or if unexpectedly short exclusivity periods appear to be deterring future investment.”


ABOUT ISPOR ISPOR, the professional society for health economics and outcomes research (HEOR), is an international, multistakeholder, nonprofit dedicated to advancing HEOR excellence to improve decision making for health globally. The Society is the leading source for scientific conferences, peer-reviewed and MEDLINE®-indexed publications, good practices guidance, education, collaboration, and tools/resources in the field. Web: | LinkedIn: | Twitter: (@ISPORorg) | YouTube: | Facebook: | Instagram:   ABOUT VALUE IN HEALTH Value in Health (ISSN 1098-3015) is an international, indexed journal that publishes original research and health policy articles that advance the field of health economics and outcomes research to help healthcare leaders make evidence-based decisions. The journal’s 2017 impact factor score is 5.494. Value in Health is ranked 3rd among 94 journals in healthcare sciences and services, 3rd among 79 journals in health policy and services, and 6th among 353 journals in economics. Value in Health is a monthly publication that circulates to more than 10,000 readers around the world. Web:| Twitter: (@ISPORjournals)

Related Stories

ISPOR’s Flagship Journal Value in Health Demonstrates High Impact

Jul 13, 2021

New data released by Clarivate’s Journal Citation Reports show that Value in Health's impact factor score is 5.725, which represents a 20.6% increase over the previous year.

New Recommendations on the Critical Appraisal of Systematic Reviews With Cost and Cost-Effectiveness Outcomes

Apr 13, 2021

ISPOR announced today the publication of new guidance on how to evaluate the quality and risk of bias in systematic reviews with cost and cost-effectiveness outcomes in a Good Practices Report in the April 2021 issue of Value in Health.

ISPOR’s Real-World Evidence Transparency Initiative: Creating a Road Map That Builds Trust

Oct 5, 2020

ISPOR announced the publication of a plan from the Real-World Evidence Transparency Initiative to encourage routine registration of noninterventional real-world evidence studies used to evaluate treatment effects.
Your browser is out-of-date

ISPOR recommends that you update your browser for more security, speed and the best experience on Update my browser now