Feasibility study of a personalized tumor membrane vesicle vaccine immunotherapy for head and neck squamous cell carcinoma (HNSCC).
Authors: Ramireddy Bommireddy, Christopher D. Pack, Sampath Ramachandiran, Kristen Jacobsen, Shaker JC Reddy, Nicole C. Schmitt, Mihir R. Patel, Qiuying Shi, Conor Ernst Steuer, Nabil F. Saba, Periasamy Selvaraj, Dong Moon Shin
Journal: Journal of Clinical Oncology (2024)

e14673 Background: Head and neck cancer exhibits a high degree of heterogeneity, with lack of common therapeutic targets. Our phase 1 clinical trial will evaluate a novel personalized immunotherapy approach using tumor membrane vesicles (TMV) prepared from the patients’ own surgically excised tumor tissue and modifying them by attaching GPI-B7-1 and GPI-IL-12 as immune boosting molecules. This personalized vaccine will then be administered to boost the tumor-specific immunity. We report here the feasibility of developing an effective personalized therapeutic cancer vaccine from surgically collected tumor tissue from patients with HNSCC. Methods: After obtaining informed consent, a total of 10 tumor specimens from 10 patients with HNSCC of various sites were collected (0.29-1.23 grams) and graded for cellularity by a pathologist. Tumor samples were then homogenized using sterile, disposable probes. The homogenate was ultracentrifuged over a sucrose gradient to enrich tumor membrane vesicles (TMV). Yield was evaluated by protein concentration and particle size was assessed by dynamic light scattering. TMV preparations were incorporated with GPI-B7-1 and GPI-IL-12 to generate the TMV vaccine using protein transfer, a spontaneous process. For the in vivo murine studies, TMV vaccine is prepared from murine oral cancer (MOC1) tumors and incorporated with murine GPI-B7-1 and GPI-IL-12. To investigate the protective anti-tumor immune response of TMV vaccine in combination with anti-PD1 antibody therapy, we used established murine oral cancer models. We administered two doses of TMV vaccine to naïve C57BL/6 mice and four doses of anti-PD-1 mAb. Mice were monitored for 21 months and then challenged with MOC1 tumor cells 1 week prior to euthanasia. Spleens were flash frozen in liquid nitrogen and stored in -80 o C until RNA is isolated for RNA-seq analysis. Results: The yields of TMV were 2.5 – 5 mg per gram of tumor tissue from four human tumor samples. Further refinement of the TMV production process yielded up to 6 mg of TMV/gram of tumor tissue. All samples passed for incorporation of GPI-B7-1 and GPI-IL-12. GPI-B7-1 is able to bind to a natural ligand, CTLA-4 suggesting it is biologically active. All samples also demonstrated biologic activity for GPI-IL-12 as tested using a reporter cell line for IL-12 and displayed acceptable endotoxin levels in a range of 1-34 EU/mg TMV vaccine. The remaining 6 tumor samples are being processed. RNA-seq data from mouse model suggests that the TMV vaccine showed synergistic activity when combined with anti-PD1 antibody, with enhanced T cell responses. Conclusions: TMV vaccine production is feasible for a phase 1 clinical trial for patients whose resected tumor is at least 0.5 g in weight and 40% cellularity. Data in mice show that TMV vaccine synergizes with anti-PD1 in inducing tumor responses.