Competition is the key to low prices in the pharmaceutical industry. For decades, Americans have benefited from affordable generic versions of brand-name drugs. But now, we stand poised on the wave of a revolution. Biologics, which include lifesaving cancer-treating drugs, can cost hundreds of thousands of dollars per year and are forecast to be the “fastest growing segment of drug spending” in coming years.

The hope, then, is that just like generic drugs, competition from follow-on products known as biosimilars will lower prices. But the fear is that they will not. Why? One main reason is disparagement.

Biosimilars are nearly the same as biologics. In fact, they are required to be “highly similar” to and have “no clinically meaningful differences” from biologics. Despite this, biologic companies have raised ominous warnings that biosimilars are not the same, with differences posing grave safety consequences. Doctors are getting the message loud and clear, refusing to prescribe appropriate — and more affordable — biosimilars. It thus comes as no surprise that the government agencies have serious concerns about the behavior.

This Essay addresses biologics’ disparagement of biosimilars. It sketches the background of the industry and introduces the unique regulatory setting. It then sets forth the caselaw and explains how disparagement can violate antitrust law.