Lykos Therapeutics announced the resignation of CEO Amy Emerson following a regulatory setback when the FDA rejected its MDMA-assisted therapy for post-traumatic stress disorder. Emerson, who has been with the company since its founding in 2014, will transition to a senior advisor role while COO Michael Mullette takes over as interim CEO. The company also revealed plans to cut 75% of its workforce and has parted ways with founder Rick Doblin as part of a major reorganization. The FDA's rejection cited insufficient data and required an additional late-stage trial for the investigational treatment. Alongside these changes, David Hough has been promoted to chief medical officer to lead the company's clinical development efforts. Emerson expressed gratitude for her tenure and optimism about the company's future direction under Mullette's leadership.