Ariceum Therapeutics GmbH has received approval from the U.K.'s Medicines and Healthcare products Regulatory Agency (MHRA) to conduct a phase I trial (CITADEL-123) of 123I-ATT-001, its iodine-123 labeled PARP inhibitor, in patients with recurrent glioblastoma. The study is expected to begin in the U.K. in June of 2024.