CTNI-57. RADIONUCLIDE THERAPY WITH 177LU-DOTATATE (LUTATHERA) IN ADULTS WITH ADVANCED INTRACRANIAL MENINGIOMA - INTERIM ANALYSIS RESULTS OF A SINGLE-ARM, OPEN-LABEL, MULTICENTER PHASE II STUDY

Abstract BACKGROUND While most meningiomas are considered benign tumors, a subset of these tumors characterized by more aggressive clinical course and require multimodal treatment. Beyond surgical radiotherapeutic options, there no effective medical treatments available. Somatostatin receptor 2 (SSTR2) is expressed the majority meningiomas. 177Lu-DOTATATE SSTR2-targeting radionuclide that has been successful in neuroendocrine tumors. Here we report results interim analysis an ongoing trial (NCT03971461) evaluating effect treating progressive intracranial METHODS In this Simon two-stage design phase II study, adults with advanced received 7.4 GBq (200 mCi) every eight weeks for four doses. 68Ga-DOTATATE PET-MRI was performed before at end The primary endpoint progression-free survival 6 months (PFS-6). Correlative studies evaluated association PFS-6, objective response rate, survival, overall radiographic tumor measurements, uptake on PET-MRI, SSTR2 expression tumor, meningioma methylation subclass. RESULTS Fourteen patients (F = 11, M 3) (WHO I 3, 10, III 1) have enrolled. Median age 63.1 (range 49-78) years. All previously underwent resection least one radiation. Treatment well tolerated, treatment-limiting toxicities were observed. Six 14 (42%) achieved PFS-6. Radiographically, all six had Stable Disease. A functional alteration tumoral PET-MR imaging observed three patients. CONCLUSIONS tolerated. analysis, This exceeds predefined threshold to continue stage two study. now open patient enrollment study sites US.