The FDA issued a complete response letter for ITM Isotope Technologies Munich SE’s radiotherapeutic ITM-11 (177Lu-edotreotide) targeting gastroenteropancreatic neuroendocrine tumors, citing manufacturing issues at a third-party facility. The agency did not flag concerns about the clinical data package or safety profile. ITM-11 had been positioned as a potential challenger to Novartis’ approved Lutathera, with earlier reporting suggesting patients experienced longer time to tumor progression compared with historical controls. Despite that, the regulatory setback delays the path to approval in the U.S. The development is a reminder that radiopharmaceutical timelines remain highly sensitive to supply chain and process controls, where even well-performing therapies can stall when manufacturing requirements are not met.