At least four drugmakers are expected to launch new copycat versions of AbbVie's top-selling rheumatoid arthritis drug, Humira, over the next week, but experts expect little change in prices for the treatment even with the new competition. Drugmakers Boehringer Ingelheim, Sandoz and Organon are expected to launch their biosimilars on Saturday, adding to U.S. competition for the drug that started when Amgen released its copy in January. Usually prices fall, often dramatically, when multiple generic versions of a widely used medication enter market.