Chinese generics and biosimilars should be allowed to flow into the U.S. without punitive tariffs, the generics makers’ largest trade association has said.

In a letter to  U.S. Trade Representative Robert Lighthizer, the Association for Accessible Medicines says that the Trump administration should stay the course and continue to exempt Chinese drugs and active pharmaceutical ingredients from the tariffs list. The administration has imposed tariffs of up to 25 percent on an array of goods and materials, but it would cause “disproportionate economic harm” if imported generics were hit with the duties, the association says.

AAM submitted the letter “because we wanted to support the Trump Administration’s decision, as described in the Federal Register, to exempt pharmaceuticals and pharmaceutical inputs, while also emphasizing why such a decision was important for the U.S. health care system, “ says Jonathan Kimball, the group’s vice president of trade and international affairs.

The letter cites unnamed analysts who believe that drug tariffs would likely hit generic drugmakers harder than name brand manufacturers, as generic drug production incurs higher manufacturing costs relative to their price.