S. 355: FDA Modernization Act 3.0

In late 2022, Congress passed the FDA Modernization Act 2.0, which removed the long-standing federal requirement that drugs be tested on animals before human trials. Sponsors could instead submit nonclinical evidence: cell-based tests, microphysiological systems like organ chips, and computer modeling.

The law changed. The regulations that tell companies what to put in their applications mostly did not. The bill names 21 specific FDA rules, covering investigational drug applications, new drug approvals, generics, diagnostic imaging drugs, over-the-counter drug reviews, and biologics, that still refer to animal tests, data, studies, models, or research.

S. 355 orders the FDA to swap that animal-only wording for "nonclinical" wording within 1 year, so the agency's own rules stop presenting animal studies as the only route into human trials. It also writes the legal definition of "nonclinical test" into the FDA's core definition lists, and lets the agency fix any other rule needed for consistency.

The FDA would issue the change as an interim final rule that takes effect the day it is published. Normally an agency has to justify skipping advance public comment before a rule takes effect; this bill waives that requirement.

None of this bans animal testing. Companies that want to keep running animal studies can. What changes is the default: a reviewer reading the updated rules would see non-animal evidence named as an accepted way to show a drug is safe enough to test in people. Whether reviewers accept that evidence in practice is a separate question the bill does not settle.

The bill also carries a housekeeping fix: the 2022 omnibus accidentally created two subsections with the same letter in the drug-approval statute, and S. 355 relabels one of them.