332 Tumor collection and establishment of tumor-initiating cell cultures as antigen source for AV-GBM-1 dendritic cell vaccines for a phase II trial in patients with newly diagnosed glioblastoma

Background Despite standard aggressive therapy (maximum safe surgical resection, concurrent radiation and temozolomide chemotherapy (RT/TMZ), then maintenance TMZ), 2-year survival is only about 25% for patients with newly diagnosed primary glioblastoma (GBM). Adding AV-GBM-1, a vaccine consisting of autologous dendritic cells (DC) pulsed tumor antigens (ATA) may improve survival. One objective multi-center phase II clinical trial was to determine the feasibility collecting fresh GBM establishing short-term cell cultures tumor-initiating (TIC) serve as ATA source. Methods Key eligibility criteria collection were (1) suspicion new GBM, (2) age 18 70 years (3) tentative agreement undergo leukapheresis procedure after recovery from surgery, (4) plans RT/TMZ. Fresh placed in media shipped transport kit by overnight courier AIVITA where suspension culture incubated serum-free medium factors that favor proliferation TICS (stem early progenitor cells). The intent produce patient-specific DC-ATA incubating lysate irradiated TICs DC subsequent subcutaneous injection. Results Patients enrolled five sites California, one Kentucky New Jersey. Tumors collected between August 2018 January 2020. 106 consented collection, but 15 not 4 had insufficient tissue send, 2 withdrew consent, ineligible because age, 1 autoimmune disease. Of 80 tumors into culture, 7 discontinued patient withdrawal. 71/73 (97%) resulted successful culture; two unsuccessful contamination. 60/71 subsequently intent-to-treat ; 46/60 (77%) 28 days or less, 11 30 35 days, remaining 3 cultured 46, 54, 55 days. average number per at time irradiation 14.0 million (range 0.78 63.3 million). 58/60 yielded more than lysate; 36/60 (60%) 10 irradiated. 57 treated AV-GBM-1 Conclusions Self-renewing TIC can be reliably rapidly established use antigen source personal vaccines. Trial Registration Clinicaltrials gov NCT03400917 Ethics Approval This study approved Western IRB, approval 20182582; all participants gave written informed consent before taking part