Drug Prices Post Steepest Drop Since 1963

"It's difficult to know in one number what's going on beneath the hood," said Cubanski, a vice president and director of the Program on Medicare Policy at the healthcare research nonprofit KFF. "I don't think we can attribute this price reduction to any one specific policy change or initiative."

"When big blockbuster products face generic competition, their prices fall," said Rome, a health policy researcher at Harvard Medical School. He pointed to biosimilars that treat the same autoimmune conditions as the brand-name drug Humira. Dusetzina, a professor of health policy at Vanderbilt University School of Medicine, said competition has also cut the price of Stelara, a biologic that treats chronic inflammatory conditions.

On the White House's signature policy, Dusetzina was blunt. "These policies are under development and have not affected payers in the index," she told the AP in an email. "Ultimately, I believe that the change is likely to be more directly related to the IRA's policies and the Medicare drug price negotiation program than it is to current policies."

The White House said TrumpRx has generated $700 million in savings for patients but did not explain how it reached that number. Warren challenged it, writing that Health Secretary Robert F. Kennedy Jr. has acknowledged TrumpRx does not store patient, health or prescription information: "Without this information, the accuracy of any claim of savings made by the Trump administration is unreliable."