Kenvue, a two-year-old spinoff from Johnson & Johnson, is confronting a public-relations nightmare as President Trump and others suggest unproven links between the pain reliever and autism.
The F.D.A. approved Merck’s injected version of its blockbuster infusion Keytruda. The company says it will be quicker and easier, but it stands to slow the adoption of cheaper competitors and increase costs by billions of dollars.