Democratic lawmakers and Sen. Bernie Sanders, I-Vt., unleashed frustration Wednesday that President Trump hasn't done more to tackle high drug prices.

Reps. Elijah Cummings, D-Md., Peter Welch, D-Vt., and Lloyd Doggett, D-Texas, joined Sanders Wednesday to introduce a bill to let Medicare negotiate for lower drug prices. Cummings and Welch met with President Trump on March 8 and gave him a copy of the bill, but both said Wednesday that Trump has ignored multiple attempts by Democrats to ask for input and his support, even though he said during the campaign that drug companies were "getting away with murder" due to rising prices.

"President Trump, you are right but you are doing nothing," Welch said at the press conference. "It's time to put up or shut up."

Cummings said Trump has "basically ignored" three follow-up letters from Democrats, the latest of which was released Wednesday.

"I know there have been a lot of distractions," Cummings said, but "people are suffering tremendously."

Sanders said it was inconceivable that one agency, the Department of Veterans Affairs, has the power to negotiate for lower drug prices while Medicare doesn't have that option.

Doggett said he is introducing a bill that stiffens penalties for pay-for-delay deals, under which a brand-name drugmaker pays a generic drugmaker to delay marketing a generic of the brand name drug. The deal lets the brand name manufacturer continue to market the drug before a generic is available for a much cheaper price.

Doggett is also introducing a bill to increase transparency on how drugmakers set their prices, a key reform that several states have been seeking.

Cummings said after the press conference that he doubts the Medicare negotiations bill could get through the GOP-controlled Congress without Trump's support.

"It has to have Trump's support, no doubt about it," he said. "If Trump came out and made it clear that he would do everything in his power and put his efforts behind it, I think it would have a fairly good chance."

The GOP-controlled Congress has made some moves to address high drug prices, but only through improving the generic drug approval process for the Food and Drug Administration. Republicans have been reticent to support Democratic-led reforms such as Medicare negotiating power and letting Americans buy cheaper drugs from Canada.

Frustration has been building among proponents of Democratic reforms to tackle high drug prices.

Cummings, Sanders, Welch, and Doggett introduced a bill in February to let Americans get cheaper drugs from Canada. They called on Trump to support it and referenced his remarks on the campaign trail bashing the pharmaceutical industry.

However, Trump has not supported the bill and has instead sought to work on an executive order that Democrats say would contain a "wish list" for the drug industry.

The White House did not return a request for comment.