DDEL-09. FRACTIONATED INTRACAVITARY RADIOIMMUNOTHERAPY WITH LU-177 LABELED 6A10 FAB FRAGMENTS IN PATIENTS WITH GLIOBLASTOMA

Abstract Background Radio-immunotherapy (RIT) with Lu- 177 labeled 6A10-Fab fragments, targeting tumor-associated carbonic anhydrase XII (CA12) and applied directly into the resection cavity, offers a promising strategy to address hibernating tumor burden after completion of adjuvant treatment for glioblastoma. We report on first in human applications. METHODS Three patients underwent microsurgical After radio- chemotherapy, RIT was offered compassionate use setting. implantation an injection reservoir three consecutive doses Lu-177 6A10 Fab fragments were administered over months, corresponding 25% - 50% total activity. The injected dose adapted size cavity. Dosimetry performed planar whole-body scintigraphy SPECT/CT 12h, 24h, 48h, 76h 5-7 days injection. RESULTS Patient 1 (IDH1-Mutation) received (total 592 MBq) stable disease 12 months therapy 26 initial diagnosis. 2(IDH-Wildtype) had histologically proven progression second cycle 526 MBq). 3 (IDH-Wildtype) has so far one (327 MBq planned 1300 No toxicity according CTCAE version 6.0 or other adverse events related observed. did not reveal absorbed above upper limits organs at risk. Conclusions Intracavitary radioimmunotherapy appears be safe maintenance glioblastoma patients, albeit only assessed situations far. A multicenter confirmatory phase-I-trial will initiated May 2022 (EudraCT-No: 2015-004417-25) determine maximum tolerated safety fragments.