The Food and Drug Administration is requiring that its most serious warning be placed on high-profile drugs for treating hepatitis C, saying they can cause a reactivation of hepatitis B and subsequently have led to death in some patients.

The direct-acting antiviral drugs – which include medicines under the brand names Sovaldi and Harvoni, as well as seven others – have high list prices that state governments, the Department of Veterans Affairs and prison systems have struggled to afford, with Sovaldi and Harvoni specifically costing tens of thousands of dollars for a full treatment.

More than 3 million people in the U.S. have hepatitis C, which is spread through blood and can necessitate a liver transplant.

Read More