The Supreme Court is considering a dispute between rival drug companies that could affect how quickly life-saving generic medicines are available to the public.
The case before the justices on Wednesday involves biologics — drugs made from living cells instead of chemicals. The drugs have led to major advances in treating diseases, but come at steep prices.
A 2010 law allows cheaper generic versions known as biosimilars to be produced after a 12-year exclusive run for the original.
At issue is whether companies that make biosimilars must tack on an additional six months after gaining federal approval before selling the drugs.
Several of the justices seemed to agree that biosimilars maker Sandoz had to wait for approval before giving notice to rival Amgen of its near-copy of cancer drug Neupogen.