Indianapolis-based Eli Lilly is challenging a new federal rule that would require drug companies to include prices in TV ads.

Reducing high drug prices is one of President Donald Trump’s priorities, and the move for more transparency through advertising was announced last year.

The lawsuit comes before the rule is set to take effect in July. In it, Eli Lilly, Merck and Amgen, along with the Association of National Advertisers, say the move violates the First Amendment. The suit also claims the rule could harm the health of patients who may choose not to take a medication based on “list” price.

In the lawsuit, the companies say the rule would create confusion because patients do not usually pay the full price after insurance and other discounts are factored in.

They also argue there are better ways for patients to estimate costs, including a pharmaceutical website where some companies voluntarily offer insight on out-of-pocket costs.

The lawsuit names the Department of Health and Human Services, its secretary and former Eli Lilly leader Alex Azar, as well as the offices of Medicaid and Medicare.