Abstract CT038: Results of a Phase Ib trial of an autologous cell vaccine for newly diagnosed glioblastoma

Background: We evaluated an autologous cell vaccine, a combination of GBM tumor cells and an antisense molecule against insulin-like growth factor type 1 receptor DNA/mRNA (IGF-1R AS ODN), in adults with newly diagnosed GBM (NCT02507583). Methods: Tumor cells collected during resection were treated ex vivo with IGF-1R AS ODN, encapsulated in biodiffusion chambers with IGF-1R AS ODN, irradiated, then implanted in an abdominal acceptor site on the first post-operative day. Four vaccine exposures were evaluated: lowest (10 chambers implanted for 24 hours); lower (10 / 48 hours); higher (20 / 24 hours); and highest (20 / 48 hours). Standard of care (SOC; ie, radiotherapy and temozolomide) was initiated after 4-6 weeks. Randomization was halted after patient 23 and subsequent patients received the highest exposure. Evaluation of safety and tumor responses were the primary and secondary objectives, respectively. Exploratory objectives included assessment of progression-free survival (PFS) and overall survival (OS). The SOC comparator group was an antecedent cohort of 35 newly diagnosed, GBM patients treated at the same center. Results: Thirty-three patients were enrolled between September 1, 2015 and March 1, 2018. Six, 5, 5, and 17 patients received the lowest, lower, higher, and highest exposures. Median (range) follow-up was 13 (4-39) months. As of the January 1, 2019 cutoff, no vaccine-related adverse events were observed. Seventeen of 33 (51.5%) remained progression-free, 12 of whom are alive and functioning well. The autologous cell vaccine significantly prolonged PFS and OS vs. SOC (Table). Survival advantages were conferred by the highest exposure to the autologous cell vaccine and good T cell function prior to surgery. Conclusions: This vaccine was well-tolerated and prolonged PFS and OS when compared with SOC alone. Citation Format: David W. Andrews, Samantha Garcia, Kevin D. Judy, Larry A. Harshyne, Sanjana Govindarajan, Lawrence Kenyon, Kiran Talekar, Adam Flanders, Kofi-Buaku Atsina, Lyndon Kim, Nina L. Martinez, Wenyin Shi, Maria Werner-Wasik, Mikhail Prosniak, Mark T. Curtis, Rhonda Kean, Emily Bongiorno, Sami Sauma, Kara Pigott, Charles B. Scott, D Craig Hooper. Results of a Phase Ib trial of an autologous cell vaccine for newly diagnosed glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT038.