Medicare Part D changes enacted in the Bipartisan Budget Act of 2018, which was passed earlier this year, will save American healthcare consumers about $4 billion more than previously thought, reported the Congressional Budget Office (CBO) this week.

The CBO’s initial estimate was that the law would provide approximately $7.7 billion in prescription cost relief to Medicare Part D beneficiaries in “donut hole” periods (when out-of-pocket drug expenses exceed coverage benefits).

The non-partisan budget oversight body has now revised its savings estimate to $11.8 billion, after discovering that the law mandated pharmaceutical companies provide 70% discounts to such consumers for brand-name medications, rather than the 50% discounts it initially believed were provided for in the bill.

The revised healthcare cost savings estimate has triggered backlash against the bill by pharmaceutical companies and by some lawmakers.

“Drug companies hope the savings discrepancy revelation will force Congress to change course,” reported Modern Healthcare‘s Virgil Dickson.

Now, “Republican think tanks, advocacy organizations and consulting firms have launched a grassroots effort to void the Part D changes now that they know their true financial impact,” he wrote.

Get the full story here, in Modern Healthcare.