The makers of popular diabetes and weight-loss drugs responded to a Tuesday column by President Joe Biden and Sen. Bernie Sanders (D-Vt.) that called for lower drug prices. Their response: The issue is far more complex due to the US drug pricing system.

The column in USA Today focuses on Novo Nordisk (NVO), maker of Ozempic and Wegovy, which has been a target for Sanders. Novo CEO Lars Jørgensen has agreed to testify before Sanders' committee in late September.

But the column also mentioned competitor Eli Lilly (LLY) — maker of Mounjaro and Zepbound — and "other pharmaceutical companies" for exhorbitant prices.

"If Novo Nordisk and other pharmaceutical companies refuse to substantially lower prescription drug prices in our country and end their greed, we will do everything within our power to end it for them. Novo Nordisk must substantially reduce the price of Ozempic and Wegovy," Biden and Sanders wrote.

The column is weighing on both companies' stocks, with Lilly down 1% and Novo down nearly 2% in trading Tuesday.

In a statement to Yahoo Finance, Novo Nordisk said the difficult and complex problem of US drug pricing "is being oversimplified and mischaracterized for political purposes. Each country has its own healthcare system and making isolated and limited comparisons ignores this fundamental concern."

Eli Lilly also said the criticism from Biden and Sanders was unfair.

"Comparing list prices in the United States to other countries ignores patient affordability programs and hundreds of billions of dollars in discounts and fees paid to PBMs by pharmaceutical companies that should lower the costs of medicines for Americans, but unfortunately this system can drive prices higher," Lilly said.

Both companies also said that most Americans have access to the drugs for $25 through savings cards or insurance. The monthly list prices for the injectables have been at or over $1,000; Sanders has repeatedly linked to a study at Yale University that found the drugs can be manufactured for less than $5 per month.

Analysts expect Ozempic and Wegovy combined to bring in sales of $26 billion for Novo for the full year 2024; Mounjaro and Zepbound could bring in $13.5 billion or so for Lilly, per Bloomberg.

Novo also said that the cost of both of its GLP-1s has decreased 40% since launch.

"Unfortunately, even when we lower our prices, patients in the United States often don’t receive the savings — this is a problem," Novo said.

Anjalee Khemlani is the senior health reporter at Yahoo Finance, covering all things pharma, insurance, care services, digital health, PBMs, and health policy and politics. Follow Anjalee on all social media platforms @AnjKhem.

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