The FDA granted accelerated approval to Stealth BioTherapeutics’ elamipretide for Barth syndrome after a prolonged regulatory journey marked by earlier setbacks. Meanwhile, Bristol Myers announced that its experimental multiple myeloma drug, iberdomide, met a key Phase 3 endpoint, showing improved minimal residual disease negativity, though a full approval depends on further data. Conversely, Scholar Rock faced regulatory delays after receiving a complete response letter due to manufacturing issues, halting its spinal muscular atrophy drug. These developments reflect the ongoing challenges and milestones in rare disease and cancer drug approvals.