Prescription drugs in the United States must be approved by the Food and Drug Administration (FDA) before they can be sold. A drug maker whose product is approved through the FDA’s “abbreviated new drug application” (ANDA) process cannot later change the label without FDA approval. Pfizer, Inc., makes and sells Depo-T, a testosterone replacement drug classified as an ANDA-approved drug. Rodney Guilbeau filed a claim in a federal district court against Pfizer, alleging that he had suffered a “cardiovascular event” after taking Depo-T. He sought recovery based on a state-law product liability theory, arguing that Pfizer had failed to warn patients adequately about the risks. He claimed that after the drug’s approval, its maker had become aware of a higher incidence of heart attacks, strokes, and other cardiovascular events among those who took it but had not added a warning to its label. What is Pfizer’s best defense to this claim? Explain. [Guilbeau v. Pfizer, Inc., 880 F.3d 304 (7th Cir. 2018)] (See Defenses to Product Liability.)