A group of 15 vulnerable House Democrats is calling on leadership to include a measure to lower prescription drug prices in President Biden’s social spending bill, as negotiations on the issue intensify. 

The letter, led by Rep. Angie Craig (D-Minn.), cites Democrats’ repeated campaign promises to lower the cost of drugs. 

“As majority-makers in competitive districts, we promised our constituents that we would come to Washington to fight on their behalf for lower drug prices,” the lawmakers write. “We cannot turn back now on our promise to the American people. We urge you in the strongest terms possible to include legislative language in the Build Back Better Act that will be voted on by the full House to accomplish this.”

Provisions to lower drug prices were left out of the framework of the Build Back Better package that the White House unveiled last week. But there is now a scramble to get a deal on the issue before the House votes on the package as early as this week, and sources say negotiators have made progress.

Democratic leadership is involved in negotiations on the issue with a handful of moderates who have raised concerns with previous versions of the drug pricing measure, including Sen. Kyrsten Sinema (D-Ariz.) and Rep. Scott Peters (D-Calif.). 

A flurry of talks continued over the weekend. “I spent all of yesterday on the telephone,” Sen. Bernie Sanders (I-Vt.) said Sunday on CNN’s “State of the Union,” saying he is pushing to add a drug pricing measure. 

The lawmakers signing the letter pointed to the power of the pharmaceutical industry in fighting the proposal. Drug companies have warned that sweeping measures would harm innovation that leads to the development of new treatments. 

“If we fail, those on the other side of this issue will need to explain to Americans why they let Big Pharma win, why entrenched special interests take precedence over the American people,” the lawmakers wrote. 

Recent discussions have centered on a proposal that is significantly scaled back from earlier Democratic bills. For example, the compromise will likely apply only to older drugs that are no longer in their period of “exclusivity,” when they are protected from competition. The proposal under discussion would also limit drug price increases to the rate of inflation and cap out of pocket costs for seniors.