Affordable Prescriptions for Patients Act of 2019 This bill prohibits product hopping by drug manufacturers. Product hopping is presumed when a drug manufacturer engages is a hard switch or a soft switch . A hard switch occurs when, after a manufacturer receives notice of an application for a generic drugs, either, (1) the manufacturer obtains removal of a drug from the Food and Drug Administration’s approved drug list or the drug is moved to the discontinued products list, and the manufacturer markets or sells a follow-on product; or (2) a manufacturer announces the withdrawal or discontinuance of a listed drug, or the manufacturer destroys the inventory of a listed drug in a manner that impedes generic drug competitors, and the manufacturer markets or sells a follow-on product. A follow-on product is a changed, modified, or reformulated version of a manufacturer’s already-approved drug or biological product that still treats the same medical condition. A soft switch occurs when a manufacturer receives notice of an application for a generic drugs, takes other actions that impede generic drug competitors, and the manufacturer markets or sells a follow-on product. A drug manufacturer may rebut a presumption of product hopping by demonstrating that its conduct was not intended to limit competition. This bill also limits the number of patents that may be included in infringement claims brought by approved biological product license holders against applicants for a biosimilar product license.