According to Express Scripts 2013 Drug Spending Trends report, spending on hepatitis C drugs will soar 102% this year and more than 200% next year, as doctors increasingly prescribe next-generation treatments from Gilead (GILD -0.17%) and Johnson & Johnson (JNJ -1.13%).

Those two treatments, both of which won FDA approval late last year, posted significant sales during the first quarter. However, another new wave of promising hepatitis C treatments are awaiting FDA approval, suggesting there may be significant shifts in market share by the end of the year.

In the following slideshow, you'll learn how much Gilead and Johnson generated in revenue from their new drugs during the first quarter, and why AbbVie (ABBV -0.74%) and Bristol-Myers (BMY -0.56%) may win away market share later this year.