Leerink analyst Seamus Fernandez wrote that the news "comes as a significant surprise" and gives Merck "another leg up" in the race to develop cancer drugs.
The three are in competition with Merck for a lung cancer treatment that could be used in tandem with chemotherapy for the disease, so when Merck announced that FDA will approve the drug by May 10, investors were scared off.
Bristol-Myers has a lung cancer drug, Opdivo, in development (though it failed to show a benefit back in October). The company's drug was seen as a potential superstar in the space. On the news, it's shares fell 5.3%, or $3.18 per share, to a close of $56.80 apiece Wednesday.
Meanwhile, AstraZeneca's shares fell 2.54%, hitting $28.03 apiece midday Wednesday. The company closed down 1.78% from market's open. AstraZeneca has a pill that has shown promise for lung cancer treatment in development, called Tagrisso.
And Roche saw shares slip as well, falling 1.7%, hitting $29.50 apiece. Roche has a drug already approved by the FDA for the treatment of lung cancer called Tecentriq.
Merck's shares, meanwhile, got a boost on the news. The company saw shares climb 2.85% from market's open, hitting $61.63 apiece before markets closed.
The company presented at the JP Morgan Healthcare Conference on Jan. 9.
Editor's note: This story was originally published at 12 pm ET and has been updated to reflect closing prices.