A platform trial of neoadjuvant and adjuvant antitumor vaccination alone or in combination with PD-1 antagonist and CD137 agonist antibodies in patients with resectable pancreatic adenocarcinoma

Abstract

A neoadjuvant immunotherapy platform clinical trial allows for rapid evaluation of treatment-related changes in tumors and identifying targets to optimize treatment responses. We enrolled patients with resectable pancreatic adenocarcinoma into such a platform trial (NCT02451982) to receive pancreatic cancer GVAX vaccine with low-dose cyclophosphamide alone (Arm A; n = 16), with anti-PD-1 antibody nivolumab (Arm B; n = 14), and with both nivolumab and anti-CD137 agonist antibody urelumab (Arm C; n = 10), respectively. The primary endpoint for Arms A/B - treatment-related change in IL17A expression in vaccine-induced lymphoid aggregates - was previously published. Here, we report the primary endpoint for Arms B/C: treatment-related change in intratumoral CD8+ CD137+ cells and the secondary outcomes including safety, disease-free and overall survivals for all Arms. Treatment with GVAX+nivolumab+urelumab meets the primary endpoint by significantly increasing intratumoral CD8+ CD137+ cells (p = 0.003) compared to GVAX+Nivolumab. All treatments are well-tolerated. Median disease-free and overall survivals, respectively, are 13.90/14.98/33.51 and 23.59/27.01/35.55 months for Arms A/B/C. GVAX+nivolumab+urelumab demonstrates numerically-improved disease-free survival (HR = 0.55, p = 0.242; HR = 0.51, p = 0.173) and overall survival (HR = 0.59, p = 0.377; HR = 0.53, p = 0.279) compared to GVAX and GVAX+nivolumab, respectively, although not statistically significant due to small sample size. Therefore, neoadjuvant and adjuvant GVAX with PD-1 blockade and CD137 agonist antibody therapy is safe, increases intratumoral activated, cytotoxic T cells, and demonstrates a potentially promising efficacy signal in resectable pancreatic adenocarcinoma that warrants further study.

Fig. 1. J1568 study treatment schema.

Eligible patients with clinically resectable PDA received the first priming study treatment Cy-GVAX-based therapy (alone [Arm A], + PD-1 [Arm B], + PD-1 and CD137 [Arm C]) 2 weeks before the surgical resection, and the 2nd priming treatment 6–10 weeks following definitive surgical resection. Patients began SOC adjuvant therapy ~4 weeks following the 2nd study treatment. SOC adjuvant chemotherapy was administered as per the standard of care at the time at the discretion of the primary treatment oncologist. The 3rd (and up to 6th) priming study treatment was administered every 28 days beginning four weeks after the completion of SOC adjuvant therapy. Study treatment was given as follows: Day 1–Cyclophosphamide (Cy) 200 mg/m² IV (Arms A, B, C), nivolumab (PD-1) initially, 3 mg/kg, and later 480 mg IV following approval of every 4 week flat dose (Arms B, C), urelumab (CD137) 8 mg IV (Arm C Only); Day 2–GVAX intradermal (Arms A, B, C) was injected equally into six intradermal areas in both lower limbs and the non-dominant upper limb. This study began randomized enrollment to Arms A and B in March 2016. In October 2018, the study protocol was amended to add Arm C (due to limited supply of urelumab, Arm C had to enroll consecutively) as well as an optional “extended-treatment” phase. In this “extended-treatment” phase, all patients with no evidence of recurrence following the initial six priming doses of study treatment were given the option to receive additional Cy-GVAX every 12 weeks (up to 2 additional treatments), and, for Arm B and Arm C participants only, nivolumab (without ureulmab) every 4 weeks (up to six additional treatments).

Fig. 2. CONSORT diagram of patient enrollment and on-study participation.

^aCause of death was unknown, occurred during standard of care adjuvant course, and was outside time range of reporting SAE; ^bGrade 3 immune-colitis; ^cprotocol amendment with extended-treatment phase approved in October 2018.

Fig. 3. Combination GVAX, Nivolumab, and Urelumab increase infiltrating CD3+ CD8+ CD137+ and CD3+ CD8+ CD137+ GZMB+ T Cells.

a Shown was one representative ROI that contains TLA and epithelial neoplastic cells in the vicinity; quantification was done within TLA and the tumor vicinity area outside TLA, respectively; mIHC marker pseudocolors: green = CD137, yellow = CD8, pink = CD3, blue = nuclei; b Comparison of the density of CD3+ CD8+ CD137+ T cells within the TLA among treatment arms as indicated. GVAX (Arm A) vs GVAX+PD-1+CD137 (Arm C): p = 0.007; GVAX+PD-1 (Arm B) vs GVAX+PD-1+CD137 (Arm C): p = 0.003. Arm A: n = 7; Arm B: n = 8; Arm C: n = 8. c Comparison of the density of CD3+ CD8+ GZMB+ T cells within TLA among treatment arms as indicated. Arm A: n = 10; Arm B: n = 10; Arm C: n = 8. d Comparison of the density of CD3+ CD8+ CD137+ GZMB+ T cells within TLA among treatment arms as indicated, GVAX (Arm A) vs GVAX+PD-1+CD137 (Arm C): p = 0.004, GVAX+PD-1 (Arm B) vs GVAX+PD-1+CD137 (Arm C): p = 0.002. Arm A: n = 7; Arm B: n = 8; Arm C: n = 8. e Representative co-registered images of multiplex IHC showing CD3+ CD8+ CD137+ T cells within a tumor ROI; mIHC marker pseudocolors: green = CD137, pink = CD3, red = CD45, yellow = CD8, blue = nuclei. f Representative co-registered images of multiplex IHC showing CD3+ CD8+ GZMB+ T cells within a tumor ROI; mIHC marker pseudocolors: green = Granzyme B, pink = CD3, red = CD45, yellow = CD8, blue = nuclei. Two-sided Mann–Whitney were performed. Significance codes are displayed as follows: *<0.05; **<0.01; ***<0.001, ns = non-significance. All data shown as the mean ± SEM (standard error of the mean). Multiplex IHC analysis was repeated twice with consistent results.

Fig. 4. Disease-free (DFS) and overall survival (OS) by treatment arm.

a DFS Kaplan–Meier curve stratified by treatment arm (efficacy cohort [n = 40]); b OS Kaplan–Meier curve stratified by Treatment Arm (Efficacy Cohort [n = 40]). Both DFS and OS were measured starting at time of first study therapy treatment. For DFS, individuals were censored at the date of last restaging scan with documented disease status if they had no evidence of disease. For patients who died within 3 months of the last scan showing no recurrence, death was counted as an event. Otherwise, patients were censored at the time of last scan showing no recurrence.

Fig. 5. Potential effects of CD137 agonist treatment on t cell exhaustion, activation, and trafficking.

a Samples in Arm C were subgrouped, according to the density of CD137+ CD8+ T cells in TLAs by using the mean of the density as cutoff, into two cohorts: low (n = 4) vs. high (n = 4) CD137+ T cells. The density of CD45+ CD3+ CD8+ TIGIT+ T cells was compared between the two cohorts. b The percentage of CD45+ CD3+ CD8+ CD137+ T cells among CD45+ CD3+ CD8+ T cells was compared between treatment arms. GVAX (Arm A) vs GVAX+PD-1+CD137 (Arm C): p = 0.0012, GVAX+PD-1 (Arm B) vs. GVAX+PD-1+CD137 (Arm C): p = 0.0002. Arm A: n = 7; Arm B: n = 8; Arm C: n = 8. c The percentage of CD45+ CD3+ CD8+ GZMB+ T cells among CD45+ CD3+ CD8+ T cells was compared between treatment arms. Arm A: n = 10; Arm B: n = 10; Arm C: n = 8. d The density of CD45+ CD3+ CD8+ CD137+ T cells in the tumor vicinity area outside TLAs, calculated as the percentage among all cells, was compared between treatment arms, GVAX (Arm A) vs GVAX+PD-1+CD137 (Arm C): p = 0.0003, GVAX+PD-1 (Arm B) vs. GVAX+PD-1+CD137 (Arm C): p = 0.0002. Arm A: n = 7; Arm B: n = 8; Arm C: n = 8. All data shown as the mean ± SD. Treatment arms as indicated. Two-sided Mann–Whitney tests were performed; p values were shown: *<0.05; **<0.01; ***<0.001; if not shown, non-significance. Multiplex IHC analysis was repeated twice with consistent results.