The balm of Gilead no longer comes cheap.

With a price tag of up to $1,000 a pill in the United States, Gilead Sciences Inc. rung up $10 billion in the first year of marketing its hepatitis wonder drug, Sovaldi. The scale of the market is astonishing, because hepatitis C infects about 150 million people worldwide, and the medicine could theoretically save roughly 90 percent of the 700,000 of them who die each year from liver disease or liver cancer. But few hepatitis patients can pay full freight. Fortunately, Gilead has made generic versions available in the world’s poorest countries. Unfortunately, hepatitis is also endemic in middle-income countries such as Brazil and Argentina. By assaulting Sovaldi’s patents in those nations, law-savvy health advocates have become the bane of Gilead.