Key centrist Kyrsten Sinema just announced her support for lower prescription drug pricing - after reportedly opposing it for months

• Sen. Kyrsten Sinema's office released a statement on her support for lower prescription pricing.
• She's publicly backing a proposal that would let Medicare negotiate down prescription drug prices after reportedly opposing it throughout the fall.

Lower costs on prescription drugs are back in Democrats' social spending framework - and key centrist Sen. Kyrsten Sinema has thrown her support behind it.

In a statement, the senator's office said that Speaker of the House Nancy Pelosi reached out to Sinema over the weekend to keep negotiations going. The Washington Post reported that negotiators had been working through the weekend to get Sinema and some House moderates onboard. Sinema said on Tuesday that those talks bore fruit.

"The Senator welcomes a new agreement on a historic, transformative Medicare drug negotiation plan that will reduce out-of-pocket costs for seniors - ensuring drug prices cannot rise faster than inflation - save taxpayer dollars, and protect innovation to ensure Arizonans and Americans continue to have access to life-saving medications, and new cures and therapeutics," Sinema's office said.

In September, Politico reported that Sinema told the White House she was opposed to prescription drug proposals, including the Medicare drug pricing negotiation provision, prompting Sen. Bernie Sanders to tear into her for selling out Biden's agenda to big pharmaceutical firms.

And last week, President Joe Biden's slimmed-down social spending framework did not include any reforms around prescription drug prices. Axios reported that Democrats were working to find a compromise with moderates to let Medicare negotiate down drug prices, which now seems to be what's moving forward.

It's the latest example of the power that key Democratic centrists Sinema and Sen. Joe Manchin hold in the crafting of the social spending framework. In Senate Majority Leader Chuck Schumer's announcement on Tuesday that the proposal would move forward, he specifically noted that Sinema was onboard.

This measure is now the first progressive priority to be axed in the framework and reappear as a part of the package. It's unclear how this will change the pace of negotiations and voting on the social spending plan, especially after Manchin held a press conference on Monday that slammed the breaks on the plan again. He said that he wanted "greater clarity" on the framework's potential impact on the national debt and inflation.

"I'm open to supporting a final bill that helps move our country forward," Manchin said. "But I'm equally open to voting against a bill that hurts our country."

Still, Sinema showing public support for a policy overwhelmingly popular with voters is likely a good sign for Democrats, and for Biden's agenda.