More than 160 biotech executives, investors and researchers have signed on to a letter opposing President Trump’s executive order restricting immigration from seven Middle Eastern and African countries.

Cosigners included representatives from Biogen, Egalet and Bluebird Bio, as well as MIT and Harvard University — although the country’s largest pharmaceutical companies did not sign the letter.

“At a stroke, the new administration has compromised years of investment in this national treasure,” they wrote, noting the U.S. biopharmaceutical industry is the largest in the world in terms of research support and production.