A senior US politician is planning legislation to prevent big drugmakers from striking deals to restrict the introduction of cheaper generic drugs.
Generic drugs can be much cheaper than their big name alternative
Senator Patrick Leahy said he wants to target the growing trend of large drug firms paying rivals to restrict the sale of generic alternatives.
Mr Leahy, a Democrat, said the practice was "harmful to consumers and a crime".
Federal authorities have filed several lawsuits in recent years challenging such settlements as anti-competitive.
"Congress never intended brand-name drug companies to be able to pay off generic companies not to produce generic medicines," said Mr Leahy, who is chair of the Senate Judiciary Committee.
During the committee's latest hearing, a government anti-monopoly official warned that such legal settlements between major drugmakers and their generic rivals was a fast-growing problem.
The official said it was stunting competition in the market for prescription drugs.
Under federal law, generic drugmakers are allowed to seek approval to produce their own version of brand name drugs before the a pill's patent expires.
Yet they must certify that the patent is invalid or will not be infringed by the new generic version.