President Trump announced Thursday that he’s reached a drug pricing deal with Regeneron, the last holdout among the 17 large pharmaceutical companies to agree to most-favored-nation prices in the U.S.

The administration made similar deals with drug companies to lower U.S. pharmaceutical prices to the same level they sold at in other developed countries, which is known as most-favored-nation pricing.

“The numbers will come down at levels that nobody has ever seen,” Mr. Trump said of drug prices during an Oval Office ceremony that included Regeneron executives.

In July, Mr. Trump sent letters to executives at 17 major pharmaceutical companies asking them to offer MNF pricing in the U.S. Regeneron is the final one of those companies to do it. The 17 companies account for 80% of the drug market.

As part of the deal, Regeneron has also committed to spending nearly $27 billion to bring pharmaceutical production to the United States. In exchange, Mr. Trump will offer the company relief on his tariffs, which have become a trademark of the deals with drug companies.

Earlier this week, Regeneron gained Food and Drug Administration approval for its gene therapy, Otarmeni, which will be prescribed to treat a rare type of hearing loss that affects about 50 newborns in the U.S. each year.

Regeneron said in a news release that it will provide the gene therapy at no cost to eligible patients in the U.S., though some consumers might pay for costs under their insurance plan for charges billed by medical providers to administer Otarmeni.

The president has made MFN pricing pacts with pharmaceutical companies a cornerstone of its agenda to make health care more affordable. He signed an executive order in May outlining his initiative, and administration officials have been negotiating with drug companies to get them to voluntarily match their American prices to their overseas pricing.