The regulatory rejection arrived in a complete response letter, which explicitly pinned the decision on facility compliance rather than the drug itself. According to the Bedford, Massachusetts-based company, the FDA raised no objections regarding the safety profile, clinical efficacy, or the underlying data submitted for the treatment.

Lantheus is currently coordinating with its manufacturing partner to remediate the identified problems. While the company intends to resubmit the application, the timeline for resolution remains dependent on the facility meeting federal standards. LNTH-2501 remains a core component of the firm's oncology pipeline, and management stated they are working closely with federal regulators to facilitate a path toward eventual approval.