In a message posted on Truth Social, Trump said the executive order would be signed on Monday morning. "They will increase all over the world to level the playing field and, for the first time in many years, bring FAIRNESS TO AMERICA!" he said.

He also said he wanted to introduce a "most-favored nation policy," stipulating that the US would pay the same price for drugs as the country where they are cheapest in the world.

The White House's attacks on drug prices have contributed to making the healthcare sector one of the big losers on the stock market in recent weeks, as shown in this month-long chart: the MSCI Healthcare (MSCI ACWI Healthcare) is the only sector to have lost ground since April 12.

The appointment of Vinay Prasad as head of the Center for Biologics (CBER) at the FDA, the US drug agency, has also contributed to the negative mood.