The Supreme Court rattled the pharmaceutical industry Monday when it ruled that antitrust regulators should be able to challenge the arrangements that allow rival drugmakers to delay the sale of a generic drug.

Under such arrangements, known as "reverse payments" or "pay for delay," brand-name drugmakers facing a patent challenge from generic competitors pay the companies to temporarily stay out of the market.

For more than a decade, the Federal Trade Commission has tried to restrict these kinds of deals, arguing that they're anti-competitive. But the agency and private plaintiffs pursuing similar cases suffered a string of defeats.

In its 5-3 decision, written by Justice Stephen Breyer, the Supreme Court ruled that the FTC should have been given the opportunity to prove its claims in a case involving a testosterone gel called AndroGel. These types of arrangements can "sometimes" violate antitrust laws and should be subject to more scrutiny, the justices concluded.