It is known that large pharmaceutical companies are increasingly investing in high-price later-in-class-entrants for new lucrative markets, such as immune checkpoint inhibitors, SGLT2 inhibitors, hepatitis C treatments, and HIV antivirals.15,16 Consistent with this strategy, we found that in markets with many later-in-class-entrants, manufacturers were sensitive to competitors’ coupon availability. This evidence concerns the gene SLC5A2 and hepatitis C virus infection.