The top 20 drugs by 2018 U.S. sales

Take a look at most global drugmakers income statements, and its obvious the U.S. is all important for pharma. Sales in the country typically outshine those in other regions. And its no wonder: The U.S. is a $485 billion market, according to IQVIA's latest report on the global drug industry. That size opportunity is one reason the U.S. is the first place most drugs launch. But the U.S. is also where drugmakers have the most pricing power, and where regulators, for all the criticism they face for any delays, tend to speed worthy new treatments to market. And these days, when many of the world's biggest drugs are also biologics, the U.S. is also where top brands face less copycat competition. While biosimilars overseas are seriously eating into sales for several big brands—including AbbVie's behemoth Humira—in the U.S., patent protections have kept many biosims at bay. That's certainly the case for Humira, which now won't face U.S. biosims until 2023, thanks to AbbVie's series of patent settlements with its potential rivals. Check out the list below, and you'll notice several major blockbusters benefiting from biosimilar delays. You'll also see some small-molecule meds that are about to fall hard to generic competition. Overall, the assortment of drugs spans specialty fields such as cancer and immunology, and mass-market indications such as diabetes. In general, the top of the list is a lineup of successful legacy drugs, including Humira, Celgene's Revlimid (No. 2), Amgen's Enbrel (No. 3) and Roche's Rituxan (No. 4). But driven by successful launches for some precocious challengers—and a mix of generic competition, tighter discounts and slow growth for older blockbusters—a few newbies are quickly moving up the rankings.