BACKGROUND Despite multiple clinical trials in young patients with newly diagnosed high grade gliomas (HGG), survival remains poor. PNOC008 is a single-arm, multi-center pilot trial, investigating the feasibility, toxicity, and efficacy of a molecularly guided individualized treatment approach following radiotherapy. METHODS Patients aged ≤21 years with newly diagnosed, localized, hemispheric HGG (Stratum A) or non DIPG, diffuse midline glioma (DMG) (Stratum B) were eligible. Comprehensive molecular profiling (targeted gene panel, whole exome, and whole transcriptome sequencing) was performed on primary tumor tissue. The molecular data was reviewed by a dedicated tumor board that recommended an individualized treatment plan combining up to four FDA approved drugs. Patients were followed for toxicity and efficacy. Circulating tumor DNA (ctDNA), imaging, and quality of life (QOL) measures were collected at multiple timepoints. RESULTS Fifty-five HGG patients enrolled between 2018 and 2023 (median age 11 years [range 2-20], n=31 female, n=29 Stratum A), including H3K27-altered (n=17), H3/IDH-wildtype diffuse pediatric-type (n=16), and H3G34-mutant diffuse hemispheric glioma (n=12). In 44 patients that followed the recommended treatment, median overall survival (OS) from time of study enrollment was 26.5 months in Stratum A (lower 95% CI: 18.5) and 23.6 months in Stratum B (lower 95% CI: 16.8), and 30 months in H3G34-mutant patients (n=10, lower 95% CI:24.6) with median follow-up of 34.5 months for all patients (lower 95% CI: 32.2). The treatment recommendations most commonly included alkylator with targeted therapy combinations. The often novel drug combinations were generally well tolerated with grade 3 or 4 treatment-related adverse events being mostly hematologic. Central imaging, ctDNA, and QOL analyses are underway. CONCLUSIONS A personalized treatment approach using comprehensive transcriptomic and genomic analysis is feasible and well tolerated with encouraging survival data in children and young adults with HGG. Further analyses of molecular subgroups and correlatives are ongoing.