CTIM-17. EO2401 THERAPEUTIC VACCINE FOR PATIENTS WITH RECURRENT GLIOBLASTOMA: PHASE 1/2 ROSALIE STUDY (NCT04116658)

Abstract EO2401 includes microbial-derived, synthetically produced HLA-A2 restricted peptides with molecular mimicry to antigens (IL13Rα2, BIRC5 and FOXM1) upregulated in glioblastoma, the CD4 helper peptide UCP2. Patients glioblastoma at first progression received (300µg/peptide, q2weeks x4 then q4weeks), EO2401+nivolumab (3mg/kg q2weeks), or E02401+nivolumab+bevacizumab (10mg/kg q2weeks). Cohort-1 included EO2401x2 EO2401+nivolumab. was evaluated Cohort-2a, as adjuvant treatment Cohort-2b, neoadjuvant/adjuvant Cohort-2c. Cohort-3 assessed EO2401+nivolumab+bevacizumab. Part 1 40 patients (Cohort-1/3, Cohort-2a/23, Cohort-2b/3, Cohort-3/11). 2 allowed low-dose-bevacizumab (5mg/kg q2weeks) for symptomatic edema enrolled 38 (Cohort-1/18, Cohort-2a/15, Cohort-2b/3; recruiting Cohort-2c/2 target 6, Cohort-3/0 15).Safety assessment of part showed EO2401+nivolumab+/-bevacizumab be well tolerated associated toxicity limited local administration site reactions (48%; all grade 1-2). The nivolumab-/bevacizumab-toxicity consistent historical single-agent data. Strong CD8 T cell ELISPOT responses against 3 vaccine cross-reactivity targeted demonstrated majority evaluable patients. Immune response confirmed tetramer staining specific either ex vivo after vitro stimulation. For 1, median progression-free survival (mPFS), (mOS) (Cohorts-1/2/2b, n=29 follow-up [mFU] 14.0 months) were 1.8 10.6 months. on EO2401+nivolumab+bevacizumab (n = 11 mFU 9.6 m) had mPFS 5.5 months 9 alive 7-12.4 Objective Response Rate/Disease Control Rate 10%/34% 55%/82%.Median duration Cohort-2a 6.1 weeks (1/23 treatment), while it 10.0 (8/15 treatment) 2. Overall, 2, 36% low-dose-bevacizumab.EO2401 generated strong immune tolerated. Addition standard bevacizumab improved PFS tumor response. Symptom driven supported longer durations. Outcome study will presented.