Pfizer Inc.’s $11.6 billion deal for migraine specialist Biohaven Pharmaceutical has kindled expectations on Wall Street that the transaction may usher in more buyouts as cash-flush drugmakers look to snap up beaten-down smaller biotechs.

Pfizer Inc. on April 29 said a large trial found that the company’s COVID-19 oral antiviral treatment Paxlovid was not effective at preventing coronavirus infection in people living with someone infected with the virus.

Gilead Sciences Inc. announced that first-quarter 2022 revenue rose 3 percent, helped by sales of the HIV drug Biktarvy and the COVID antiviral Veklury, but reported a net loss as the biotech company wrote down the value of its 2020 acquisition of Immunomedics following recent trial results for the cancer medicine Trodelvy.

Johnson & Johnson rescinded the company’s forecast for sales of its COVID-19 vaccine, as hesitancy in low income countries has led to a glut of supply of a shot once hoped to be the inoculation of choice for the developing world.

Sanofi’s shares slid 5 percent on March 14 after a product candidate to fight a common type of breast cancer failed to slow progression of the disease in a clinical trial, knocking confidence in the French drugmaker’s drug development prowess.

Johnson & Johnson said the company’s single-shot Covid-19 vaccine showed promise against the highly contagious Delta variant in a laboratory study.

Amgen

U.S. biotech Amgen Inc. provided a 2021 earnings forecast below Wall Street estimates and said the company paused or halted enrollment for clinical trials of three cancer drugs.

Biogen Inc.’s shares slumped as the drugmaker’s chances of getting a regulatory approval for the experimental Alzheimer’s treatment aducanumab suffered a blow after a panel of experts to the U.S. Food and Drug Administration voted against the medicine.

Biogen Inc. showed “exceptionally persuasive” evidence that the company’s experimental Alzheimer’s disease drug aducanumab is effective, U.S. Food and Drug Administration staff said, elevating chances of a swift approval and sending company shares soaring.

Biogen announced the widely awaited submission of a U.S. marketing application for the experimental Alzheimer’s therapy aducanumab, sending the company’s shares up more than 8 percent before the bell.