Assessment of Low Dose Vigil ® Engineered Autologous Tumor Cell ( EATC ) Immunotherapy in Patients with Advanced Solid Tumors

Previously we demonstrated not only safety but also provided evidence of clinical benefit to Vigil® vaccine (1 x 107cells/injection 1x/month for 1-8 injections). In addition, we identified a relationship between survival and Vigil® induced circulating activated T-cells against autologous, preprocessed tumor cells (γIFN-ELISPOT) [1,2]. Here we review 15 patients with advanced, heavily pretreated progressive metastatic disease who underwent autologous tumor harvest and subsequent Vigil® construction but in whom manufacturing was only able to construct low-dose Vigil® (1 x 106 – 8.3 x 106 cells/injection 1x/month for 1-8 injections). Of the 12 patients for whom sequential γIFNELISPOT assessment was available, all were γIFN-ELISPOT response negative (<10 spots) at baseline and subsequently developed a positive response. Specifically, 11 converted after 1 cycle of Vigil® immunotherapy and one after 2 cycles. The median (range) γIFN-ELISPOT response was 143.5 (6-474) spots post Vigil® compared to 1 (0-2) pre Vigil®. Median overall survival for these 12 patients was 28.7 months. The three patients without γIFN-ELISPOT assessment had a median survival of 25.3 months. No ≥ grade 1 Vigil® related toxicity was observed. These data which suggest comparable immunological and clinical effectiveness of low-dose Vigil® imply that a smaller harvest tumor volume may be adequate for Vigil® construction, possibly allowing for an image guided core needle biopsy procedure rather than excisional resection for tumor acquisition. Luisa Manning1, Minal Barve2,3,4, Gladice Wallraven1, Padmasini Kumar1, Nicolas Taquet1, Ernest Bognar1, Eric Mendeloff4, Jonathan Oh3, Donald D. Rao5, Beena O. Pappen1, Neil Senzer1,2,5, John Nemunaitis1,2,3,4,5* 1Gradalis, Inc., Dallas, TX, USA 2Mary Crowley Cancer Research Centers, Dallas, TX, USA 3Texas Oncology, P.A., Dallas, TX, USA 4Medical City Dallas Hospital, Dallas, TX, USA 5Strike Bio, Dallas, TX, USA John Nemunaitis, et al., Clinics in Oncology Surgical Oncology Remedy Publications LLC., | http://clinicsinoncology.com/ 2017 | Volume 2 | Article 1254 2 We now report on 15 patients with less than optimal accessible disease volume for harvest or without sufficient tumor harvest for higher dose, in whom only lower dose Vigil® was able to be constructed and administered under protocol. Methods Study design These lower dose patients were participants in an expanded cohort of an ongoing open-label, non-randomized, single-arm Phase 1 study [1,2]. It was established in order to assess lower dose Vigil® above 1 x 106 cells/injection x 4 injections. The standard dose for other Vigil® dosing has been ≥ 1 x 107 cells/injection x 4 injections. Patients with solid tumors following prior standard of care cancer treatment were grouped into 1 of 3 lower dose (1 x 106, 4 x 106, 8 x 106 cells/intradermal injection) cohorts of plasmid transfected autologous tumor cells once a month for up to 12 doses as long as sufficient material was available (minimum of 4 injections). Selection of patients for each dose cohort was dependent on the amount of tumor cell yield following harvest and processing of patients entered into the Phase 1 study. Patients were followed for safety, sequential γIFN-ELISPOT response assessment and survival. Written documentation of full IRB approval of the protocol and consent document was required before a patient could be registered at the site. All patients were treated at a single site, The Mary Crowley Cancer Research Center (Dallas, TX). Inclusion criteria Histologically confirmed advanced or metastatic deemed noncurable with standard of care therapy (if limited to a single lesion may not be a candidate for curative surgery or radiation therapy) was required. Successful vaccine manufacture from one or more tissue sites or fluid obtained from the following major organ systems: digestive, endocrine, reproductive, respiratory and urinary was allowed. Clinically indicated surgical procedure to collect viable tumor for Vigil® EATC manufacturing was required for enrollment. All patients were required to have signed IRB approved informed consent. Vigil® manufacture The construction and GMP manufacturing of Vigil® immunotherapy have previously been described [1,2]. Vigil® cellular immunotherapy was constructed for every patient after surgical collection of autologous tumor tissue, dissociation into single-cell suspension, plasmid transfection, incubation and irradiation. γIFN-ELISPOT assay The γIFN-ELISPOT (enzyme-linked immunospot) assay as previously described [4] was performed using the enzyme-linked immunospot assay for IFN-γ, (BD Biosciences, San Jose, CA, USA). Target (Tumor) cells and Effector (mononuclear) cells were applied in a 3:1 ratio (7.5 x 103 : 2.5 x 103) on an antibody coated microplate reacting with IFN-γ. Quantitative results in form of reactive spots to IFN-γ, secreted by cytotoxic CD8+ T-cells, were measured and used for immune response function analysis. The reading of the γIFN-ELISPOT plates was performed independently by ZellNet Consulting, Inc. (Fort Lee, NJ, USA). A value of ≥ 10 spots and 2x baseline was considered as positive γIFN-ELISPOT response status. Serial γIFN-ELISPOT analyses were performed at baseline, month 2, month 4 and subsequent time points. Vigil® induced γIFN-ELISPOT conversion was defined as ≥ 10 spots and 2x baseline. All patients were γIFN-ELISPOT negative at baseline. Statistical evaluation Survival was analyzed from time of surgical procurement. Patients were censored for survival on the last known date alive. Analyses of time-to-event variables were performed with the use of log-rank statistics and Kaplan–Meier survival curves. Results Patient population Fifteen patients with advanced solid tumors received at least 1 dose of Vigil® (1.0 – 8.3 x 106 cells via ID injection). Demographics are shown in Table 1. All patients underwent tumor procurement as part of the standard medical management for palliative control of disease and qualified for Vigil® immunotherapy. Time of Vigil® treatment was a median of 166 days (range 45-369 days) after tissue procurement. Safety A total of 71 Vigil® autologous tumor cell administrations were given to the 15 patients. All treatment-related AE’s were limited to Vigil® (n=15)