The conversations involve a group of Senate Democrats, including Sen. Kyrsten Sinema of Arizona, House leadership and rank-and-file, as well as the White House. Prescription drug reform was left out of last week’s draft proposal due to ongoing disagreements between moderates like Sinema and House Democrats like Energy and Commerce Chair Frank Pallone (D-N.J.), who is hoping for a more expansive effort to lower drug prices.

Yet after that omission, Democrats have redoubled their efforts. Leaving out prescription drug reform from Biden’s climate and social spending bill would be a massive loss for Democrats, who have campaigned on lowering drug prices for several years.

“Much progress was made on a compromise agreement on prescription drugs that would involve some amount of negotiation” between Medicare and the drug companies, said a source familiar with the talks. There’s “optimism that something can be added before House votes” on Biden’s package early this week.