GEOFF BENNETT: Ozempic and Wegovy Wegovy are some of the most popular drugs in the country, driven by their remarkable success treating diabetes and obesity.

But the drugs are extremely expensive, and the drugmaker's CEO appeared on Capitol Hill today to face questions about why those prices are so high.

William Brangham reports.

SEN. BERNIE SANDERS (I-VT): What we are dealing with today is not just an issue of economics.

WILLIAM BRANGHAM: At a Senate Health Committee hearing, Chairman Bernie Sanders, independent of Vermont, pressed the CEO of Novo Nordisk about why Americans pay so much more for the same drugs compared to other nations.

SEN. BERNIE SANDERS: The net price for Ozempic is still nearly $600, over nine times as much as it costs in Germany.

And the estimated net price of Wegovy is over $800, nearly 4.5 times as much as it costs in Denmark.

WILLIAM BRANGHAM: CEO Lars Jorgensen defended his Danish firm, pointing the finger for high costs principally at the U.S. health care system.

LARS JORGENSEN, CEO, Novo Nordisk: We don't decide the price for patients.

And that's set by the insurance companies.

WILLIAM BRANGHAM: He specifically blamed what are known as pharmacy benefit managers, or PBMs.

They act as third-party middlemen between drug companies on one side and insurers, pharmacies and hospitals on the other, often determining which drugs get covered and at what prices.

LARS JORGENSEN: Insurance companies and PBMs, the big conglomerate, have more than doubled, actually close to tripled their profits.

WILLIAM BRANGHAM: Jorgensen argued those prices are high because Novo Nordisk has to pay the PBMs' rebates to ensure his drugs are covered.

More expensive drugs lead to higher rebates.

But Sanders said he'd receive pledges from major PBMs that would change that equation.

SEN. BERNIE SANDERS: We have in writing, we will certainly share it with you, commitments from the three major PBMs that, if you substantially lower your list price, they would not limit coverage.

Will you work with this committee and the PBMs?

LARS JORGENSEN: If it works in a way where patients get access to a more affordable medicine.

WILLIAM BRANGHAM: Republican Roger Marshall of Kansas echoed the point that PBMs should be the focus.

SEN. ROGER MARSHALL (R-KS): Novo Nordisk is not the villain in this story.

They're a hero.

We should be here celebrating this miracle innovation.

WILLIAM BRANGHAM: Fellow Republican Bill Cassidy of Louisiana: SEN. BILL CASSIDY (R-LA): We still have to preserve the profit incentive for the creativity for drug companies to invest in order to develop the drugs that are going to affect, that are going to positively affect the burden of disease in our society.

That is the tension.

WILLIAM BRANGHAM: The hearing comes at the same time a new government study finds that, in the last 10 years, the U.S. obesity rate remained largely unchanged at about 40 percent and that severe obesity rose slightly in the last decade.

LARS JORGENSEN: And we talk about the cost of the medicine, but it's really the cost of the diseases that's breaking the system.

WILLIAM BRANGHAM: Jorgensen told senators that the price of Ozempic and Wegovy pales in comparison to the hundreds of billions that diabetes and obesity cost the U.S. every year.

LARS JORGENSEN: These are very, very expensive diseases.

And we talk about the cost of the medicine, but typically, in these diseases, the cost of the medicine is less than 10 percent of the total disease burden.

WILLIAM BRANGHAM: Experts predict that one or both drugs may be involved in the next round of Medicare price negotiations.

For the "PBS News Hour," I'm William Brangham.