Immu-11. Clinical Experience With the Concept of Multiphase Combined Treatment for Adults With GBM

Abstract BACKGROUND We published survival data of 50 adults with GBM treated with individualized multimodal immunotherapy (IMI) as part of a multiphase combined treatment (Van Gool et al, https://doi:org/10.1016/bs.mcb.2023.06.001). Analysis was repeated with new observation data. METHODS Patient definition for retrospective analysis: start IMI between 27/05/2015 and 31/10/2023, 18y, newly diagnosed, IDH1 wild-type, MGMT promoter-methylation status documented, survival known, no second malignancy. RESULTS Forty (14 female, 26 male) GBM patients were MGMT-promoter-unmethylated (unmeth), while 31 (15 female, 16 male) were MGMT-promoter-methylated (meth). Comparing the molecular subgroups, both respective median age; 48 years (range 18-65) and 54 years (range 26-72), and respective Karnofsky performance index; 70 (range 50-100) and 80 (range 60-100), were equal. Patient distribution ( complete resection, complete resection, not documented) was equal: 17/15/8 (unmeth) versus 17/11/3 (meth). Both groups were treated similarly: in median 37 (range 0-147) sessions of modulated electrohyperthermia, in median 37 (range 5-147) bolus injections of Newcastle Disease Virus, in median 2 (range 0-6) IO-Vac® vaccines with a median total number of 30.7x10e6 DCs (range 0-158x10e6). The median overall survival (mOS) for the total group was 27 months. The 2-year overall survival (OS) was 57.9 % and the 3-year OS 37.1 %. The mOS for unmeth patients was 22.1 month, with a 2-year OS of 42.7%. The mOS for meth patients was 37.7 months, with a 2-year OS of 75.5%. Sampling five control arms of contemporary RCTs as external control arm (Liau et al, JAMA Oncol 2023) showed for unmeth and meth patients a mOS of 14.6 resp. 21.3 months with a 2-year OS of 21% resp. 42%, which reflects the current prognosis for these patients. CONCLUSIONS Our analysis confirms that the integration of IMI during and after standard of care improves the OS. Similar multiphase combined treatment strategy, including IMI, should be considered to treat childhood GBM.