In a statement on Tuesday, Pfizer said the majority of its primary care drugs would be available on TrumpRx, but did not disclose specific medicines.
The company also said it would invest an additional $70bn (£52bn) in US manufacturing, research and development.
Pfizer’s agreement is the latest example of concessions from pharmaceutical companies to avoid Trump’s tariffs on branded drugs for three years.
Albert Bourla, Pfizer’s chief executive, said: “We now have the certainty and stability we need on two critical fronts, tariffs and pricing.”
Pfizer shares rose nearly 7% on Tuesday following the announcement.
Trump conceded that drug prices may rise abroad because of his actions aimed at lowering prices in the US.
Eli Lilly, for example, has said it will raise drug prices in Europe “in order to make them lower” in the US.
It is unclear whether Trump’s push including the direct-to-consumer website, which is expected to launch early 2026, will actually bring down prices for American consumers, since insurance companies and other middlemen also influence costs.