Continuing trends in U.S. brand-name and generic drug competition

Journal of Medical Economics, 2021


To provide updated evidence in a series of analyses of U.S. trends over the past two decades in key financial metrics for branded drugs: market exclusivity periods (MEPs, the time between launch and first generic entry) for new molecular entities (NMEs); the probability, timing and number of patent challenges under Paragraph IV of the Hatch-Waxman Act; and the intensity of generic penetration.


As previously, we used IQVIA National Sales Perspectives U.S. data to calculate MEPs for the 356 NMEs experiencing initial generic entry from 1995 through 2019, the number of generic competitors for twelve months afterward (by prior sales level), and generic shares. We calculated the probability, timing and number of Paragraph IV challengers using Abbreviated New Drug Application (ANDA) approval letters, the FDA website, public information searches, and


For NMEs experiencing initial generic entry in 2017-19, the MEP was 13.0 years for drugs with sales greater than $250 million in 2008 dollars the year before generic entry (NMEs>$250 million), 14.1 years overall. One year later, brands' average unit share was 18% for NMEs>$250 million, 23% overall. Ninety-three percent of NMEs>$250 million experiencing initial generic entry faced at least one Paragraph IV challenge (2019, three-year rolling average), an average of 6.0 years after brand launch (81% and 6.3 years for all NMEs). NMEs faced an average of 6.8 and 8.9 Paragraph IV challengers per NME, for all and NMEs>$250 million, respectively (2017-19 figures).


All analyses were restricted to NMEs experiencing generic entry.


The average 2017-19 MEP of 13.0 years for NMEs>$250 million has changed relatively little over the past decade and remains lower than for all NMEs (14.1 years). Paragraph IV challenges are more frequent and occur earlier for NMEs>$250 million. Generic share erosion remains high for both NME types.

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Grabowski H, Long G, Mortimer R, Bilginsoy M