“The law allows developers to use nonanimal models, such as cell-based assays, organ chips, organoids, and computer modeling, to prove safety and efficacy during the approval of new drugs. It further removes a requirement for animal studies as part of the process for licensing a biological product that is biosimilar or interchangeable with another biological product. Theoretically, it's a big switch. Until now, the FDA has required the testing of products in at least two animal species before it can advance to human trials. It is also the culmination of years of effort to significantly reduce the use of animals in research and development.

Surprisingly, however, it only took a single congressional session to pass the law, which had significant bipartisan support, said Wayne Pacelle, president of Animal Wellness Action, a Washington-based nonprofit that lobbies for animal welfare. "The fact that we essentially got this passed almost unanimously is a watershed," Pacelle told Medscape Medical News. He said members of Congress had been influenced by the increasing move away from animal testing in the cosmetics and chemicals industries, where the Environmental Protection Agency (EPA) ordered an end to animal use by 2035.”