The FDA rejected ITM Isotope Technologies Munich’s radiopharmaceutical candidate for neuroendocrine tumors, citing manufacturing problems and delaying a potential challenger to Novartis’ Lutathera. The decision halts progress tied to ITM-11, which had previously shown tumor-growth control in earlier reporting. ITM said the agency’s refusal was related to deficiencies in manufacturing, according to the company’s statements summarized in the FDA action coverage. The setback shifts timing for any follow-on submissions that would address the issues raised by regulators. For the radiopharmaceutical space, the action underscores how tightly manufacturing compliance can gate clinical momentum, even when early efficacy signals exist. It also increases the competitive pressure on other developers targeting similar radioligand classes in GEP-NETs. The rejection is a reminder that the regulatory bar for complex isotope supply chains remains a central bottleneck for the sector’s buildout.