The amendment would have been attached to a Food and Drug Administration bill the Senate is set to vote on later Thursday.

The Senate defeated the vote 28-67.

Prior to the vote, Sen. Jeff Bingaman (D-N.M.), one of the sponsors of the amendment, said that it would not raise healthcare costs, contrary to what critics said.

"If you're interested in promoting competition in the healthcare field so that we can keep prices down, then you need to support this amendment. That's exactly what this amendment does," Bingaman said.

The amendment would have changed a provision in the Hatch-Waxman Act that encourages brand-name drug companies to develop new medications. Bingaman's amendment was meant to speed up the introduction of cheaper drugs to the market by stopping generic-drug companies that filed a patent on a specific drug from being the only company allowed to sell the drug for the first 180 days.

"If you're worried about the cost of healthcare to the federal government, the federal government's paying too much to prescription drugs because of this flaw in the Hatch-Waxman Act that we're trying to correct."

Sen. Mike EnziMichael (Mike) Bradley EnziA failure to protect students and taxpayers Corker: Why can the Pentagon 'turn entire countries into craters' but not audit itself? Sales tax battle moves to the Supreme Court MORE (R-Wyo.) said he was "sympathetic" to the amendment's intent but opposed it because the language was too broad.

"The problem with this amendment is that its scope is much broader and could lead to unintended consequences that could harm consumers and increase costs," Enzi said. "And that's why I have to oppose it. Not all patent settlements are abusive; they do not all lead to higher costs."

The amendment's defeat was followed by the Senate shooting down two other amendments. One amendment, by Sen. Rand PaulRandal (Rand) Howard PaulSenate approves .3 trillion spending bill, sending to Trump GOP senator threatened to hold up bill over provision to honor late political rival: report Conservatives balk over funding bill ahead of shutdown  MORE (R-Ky.), was tabled in a vote of 78 to 15. Paul's amendment would have kept the federal government from doing anything to limit claims about food supplements having specific limited effects on diseases

Shortly after the amendment's defeat, another amenmdent to the FDA bill, this one sponsored by Sen. Lisa MurkowskiLisa Ann MurkowskiProposed budget for Indian Health Services won't treat Native American patients equally Keep anti-environment riders for Alaska out of spending bill Industry should comply with the Methane Waste Prevention Rule MORE (R-Alaska), was defeated. Murkowski's amendment would have limited the federal government's ability to approve genetically modified fish or wildlife.

—Updated at 2:22 p.m.