How would a “competitive bidding process” for drugs work? We may soon find out, if President Donald Trump gets his way with the Republican healthcare bill.

Conservative House Republicans said Monday night that they have enough votes to block the GOP’s legislation to dismantle the Affordable Care Act, as House leaders proposed changes to the bill in a late effort to draw support.

In the past few months, four bills have been introduced in Congress calling for transparency in prescription drug pricing. These bills—HR 1038, HR 1316, S.3308 and, earlier this week, one called C-THRU—largely concern pharmacy benefit managers (PBMs), a heretofore largely unrecognized component of the pharmaceutical industry.

Marathon Pharmaceuticals is in plenty of hot water after its brazen $89,000 pricing on the old-turned-new Duchenne muscular dystrophy drug Emflaza—a decades-old product available overseas for $1,000 per year. Now, it’s scored a quick payoff by selling the med to PTC Therapeutics in a deal potentially worth more than $190 million.

The House is racing to find enough votes for its health-care bill this week, but even if it passes, prospects in the Senate have only darkened.

U.S. Rep. Mark Amodei says, if he had to vote Monday, he would likely vote against a Republican plan to reform federal health care laws.