AbbVie Inc. (NYSE: ABBV) peeled off about $20 billion in market value after a critical new medicine for arthritis faced a major setback. Rinvoq, which already carries the U.S. Food and Drug Administration’s most stern warning, a so-called black box on the immune therapy’s label, will now add new warnings that the drug carries an increased risk of blood clots and death. AbbVie shares plunged as much as 12%, the biggest drop since March 2020 but finally closed 7,05% lower at $112,27.