A Phase 3 trial wasn't technically a condition for approval of Amylyx Pharmaceuticals' Relyvrio, a drug for amyotrophic lateral sclerosis (ALS) that was greenlit in the US and Canada in 2022. The Food and Drug Administration and Health Canada both approved the drug based on a successful Phase 2 study. But there was pressure for a confirmatory trial, both from patient advocacy groups and from regulators. Billy Dunn, then the director of the FDA's neuroscience office, went so far as to ask the company's cofounders during a public meeting in 2022 if they'd be willing to pull their drug from the market, should it fail in a 664-person Phase 3 study that was already underway. The cofounders—Justin Klee and Joshua Cohen, who are also Amylyx's co-CEOs—agreed. "If the drug's not helping patients, then why would we want to be giving it to them?" Klee said at the time. But that's