Borazanci, Erkut

358 Background: Effective therapy for the treatment of PDAC remains one of the greatest unmet oncology clinical needs. The addition of C to G and AP has shown promising clinical data in a previously reported study [J Clin Oncol 35, 2017 (suppl 4S; abstract 341)]. In preclinical work, vitamin D (Vit D) analog therapy decreases myeloid derived suppressor cells and regulatory T cells, turning PDAC into a more immune-friendly microenvironment. This trial combines AP/C/G with Vit D analog P and the anti-PD-1 antibody N as a combination therapy for patients with previously untreated metastatic PDAC. This trial evaluates the efficacy and safety of NAPPCG in that patient population (NCT02754726). Methods: Eligibility criteria include Stage IV PDAC, no prior chemotherapy for systemic disease, KPS ≥ 70, and measurable disease. Doses are AP 125 mg/m2 undiluted, G 1000 mg/m2 in 250 ml of normal saline (NS), each infused over 30 minutes with C 25 mg/ m2 in 500 ml of NS infused over 60 minutes on days 1, 8, 22, and 29 of a 42-day cycle. N is given at a fixed dose of 240 mg as a 60 minute infusion on days 1, 15, and 29. P is given at a fixed dose of 25 µg IV twice weekly. Primary objective is to determine the efficacy of the combination for patients with previously untreated metastatic PDAC through determining CR, ORR, PFS, and OS. The secondary objective is to evaluate safety in patients with previously untreated metastatic PDAC. Results: Trial was initiated May 2016 and10 patients have been enrolled in the initial phase of the study and are evaluable (baseline and ≥1 follow up CT scan). Most common drug-related grade (Gr) 3-4 adverse events (AE’s), n = 10, are thrombocytopenia 100% (gr 3 = 50%, gr 4 = 50%) with no serious bleeding events, anemia 50% (gr 3 = 50%, gr 4 = 0%), and colitis 20% (gr 3 = 20%, gr 4 = 0%). By RECIST 1.1 criteria, the best response is 8 PR and 2 SD, yielding an 80% ORR. Median PFS is 8.2 months. Median OS has not been reached. Conclusions: Although a small study, the high response rate is encouraging. This regimen is being expanded to 25 patients with plans to include exploratory inflammatory biomarkers. Clinical trial information: NCT02754726.

276 Background: BL-8040 is a novel CXCR4 antagonist being developed for multiple oncology indications. Preclinical studies demonstrated that BL-8040 increases the number of immune cells in peripheral blood and promotes CD8+ T cell infiltration into orthotropic pancreatic mouse tumors, reducing tumor load. BL-8040 is being evaluated in a Phase 2a, multicenter, open label trial in patients with metastatic pancreatic cancer (the COMBAT study). Patients are undergoing a 5-day period of monotherapy in which they receive daily doses of BL-8040, followed by 21-day cycles in which patients receive one dose of pembrolizumab and 3 doses/week of BL-8040 until disease progression or discontinuation. To date, 32 patients have been enrolled. Methods: On Day 1 and Day 5, blood samples were taken at pre- and post-dosing, to evaluate peripheral immune cell subset frequency by flow cytometry. In addition, core biopsies were taken from liver metastases, where possible, to assess immune cell infiltration into tumors and the tumor microenvironment (TME). Results: Here we present interim PD biomarker data from the BL-8040 monotherapy portion of the trial. Flow cytometry shows that BL-8040 monotherapy caused an approximately two-fold reduction in frequency of peripheral T regulatory cells, but had no effect on the frequency of T cells, NKT cells or cell populations that contain B cells (CD3- CD56-). Additionally, BL-8040 remained bound to CXCR4 on peripheral immune cells throughout the period of monotherapy. Analysis of available biopsies (N = 7) shows an up to 15-fold increase in the CD3+ population, and up to two-fold increase of CD8+ cells, in the tumor periphery and TME of 43% (3/7) of the patients after five days of BL-8040 monotherapy compared to baseline. Conclusions: In summary, the PD biomarker results in humans support the proposed mechanism of action for BL-8040 that was based on preclinical mouse models. Analysis of tumor biopsies is ongoing, with an emphasis on investigating the effects of BL-8040 on tumor-resident immune cells and the TME. Clinical trial information: NCT02826486.

88 Background: BL-8040 is a novel CXCR4 antagonist being developed for multiple oncology indications. Preclinical studies demonstrated that BL-8040 increases the number of immune cells in peripheral blood and promotes CD8+ T cell infiltration into orthotropic pancreatic mouse tumors, reducing tumor load. BL-8040 is being evaluated in a Phase 2a, multicenter, open label trial in patients with metastatic pancreatic cancer (the COMBAT study). Patients are undergoing a 5-day period of monotherapy in which they receive daily doses of BL-8040, followed by 21-day cycles in which patients receive one dose of pembrolizumab and 3 doses/week of BL-8040 until disease progression or discontinuation. To date, 32 patients have been enrolled. Methods: On Day 1 and Day 5, blood samples were taken at pre- and post-dosing, to evaluate peripheral immune cell subset frequency by flow cytometry. In addition, core biopsies were taken from liver metastases, where possible, to assess immune cell infiltration into tumors and the tumor microenvironment (TME). Results: Here we present interim PD biomarker data from the BL-8040 monotherapy portion of the trial. Flow cytometry shows that BL-8040 monotherapy caused an approximately two-fold reduction in frequency of peripheral T regulatory cells, but had no effect on the frequency of T cells, NKT cells or cell populations that contain B cells (CD3- CD56-). Additionally, BL-8040 remained bound to CXCR4 on peripheral immune cells throughout the period of monotherapy. Analysis of available biopsies (N = 7) shows an up to 15-fold increase in the CD3+ population, and up to two-fold increase of CD8+ cells, in the tumor periphery and TME of 43% (3/7) of the patients after five days of BL-8040 monotherapy compared to baseline. Conclusions: In summary, the PD biomarker results in humans support the proposed mechanism of action for BL-8040 that was based on preclinical mouse models. Analysis of tumor biopsies is ongoing, with an emphasis on investigating the effects of BL-8040 on tumor-resident immune cells and the TME. Clinical trial information: NCT02826486.

TPS511 Background: Despite decades of basic and clinical research, effective therapy for the treatment of patients with pancreatic ductal adenocarcinoma (PDAC) remains one of the greatest unmet clinical needs in oncology today. Albumin-bound paclitaxel (AP) and gemcitabine (G) reported on an improvement in overall survival in metastatic (m) PDAC [NEJM 2013; 369:1691-1703]. The addition of cisplatin (C) has shown promising clinical data in previously reported studies [Cancer Res 2015; 75(15 Suppl):Abstract nr LB-003]. Through further preclinical work, vitamin D analog therapy decreases myeloid derived suppressor cell (MDSC) and regulating T cells (Tregs) thus turning PDAC into a more immune friendly microenvironment. This trial combines AP/C/G with the vitamin D analog paricalcitol (P) and the antibody-PD-1 drug Nivolumab (N) as a combination therapy for individuals with previously untreated metastatic PDAC. This trial evaluates the efficacy and safety of NAPPCG in patients in that population (NCT02754726). Methods: Key eligibility criteria include Stage IV PDAC, no prior chemotherapy for systemic disease, KPS ≥ 70; life expectancy ≥ 12 weeks and measurable disease. Key exclusion criteria include prior PD-1 or PD-L1 therapy. Doses are AP 125 mg/m2 undiluted, G 1000 mg/m2 in 500 ml of normal saline (NS), each infused over 30 minutes with C 25mg/ m2 in 500 ml of NS infused over 60 minutes on days 1, 8, 22, and 29 of a 42 day cycle. N is given at a fixed dose of 240 mg as a 60 minute infusion on days 1, 15, and 29. P is given at a fixed dose of 25 µg IV on days 1,4,8,12,15,22,26,29,32,36,and 39. Primary objective is to determine the efficacy of the combination NAPPCG for patients with previously untreated metastatic PDAC through determining CR, ORR, PFS, and OS. The secondary objective is to evaluate the safety of NAPPCG in patients with previously untreated metastatic PDAC. The study initiated accrual in April of 2016. If 4 of the first 10 patients are determined to have a PR the trial will expand to a total of 25 patients. Clinical trial information: NCT02754726.

359 Background: GA, FOLFIRINOX and FOLFIRI are standard chemotherapy (CTX) regimens for mPC.The optimal introduction of these regimens following GA is not known. This phase II study evaluated 2 different approaches to this question. Methods: Eligibility criteria included 1) untreated mPC, 2) ECOG PS 0/1, 3) organ function adequate for Rx. Patients (pts) were treated according to one of 2 methods following GA given per standard dose/schedule: FOLFIRINOX (bolus 5-FU omitted) for up to 12 cycles at 24 weeks or at time of disease progression (S); or GA alternating with FOLFIRI q8 weeks up to 48 weeks total Rx (A). Results: 54 evaluable pts (28S, 26A) were enrolled . Pt characteristics included median age 65, M/F 48/52% , liver involvement 89%. 17/53 pts (31%) did not achieve disease control at 8 weeks (8 toxicity/complications , 6 disease progression, 3 declined further protocol therapy). Of the remaining 37 pts, 24/13 were treated with S/A regimens, respectively. Grade ≥ 3 treatment toxicities reported while on study with frequency ≥ 10% included anemia 21%, neutropenia 43%, thrombocytopenia 15%, and fatigue 22%. Grade ≥ 3 neuropathy occurred in 8% of pts. For all 54 pts using RECIST 1.0, CR/PR/SD/DC was 2 (4%)/20 (37%)/19 (35%)/41(76%). Ca19.9 response ≥ 90% was seen in 20/37 (54%). For all pts, median OS was 12.3 months ( 95% CI 8.6-14.5 mo); 12 and 24 mo OS was 51% and 11%, respectively. For the 37 pts with DC on GA at 8 weeks (calculated from start Rx) median OS was 13.5 mo (95% CI 10.7-15.4 mo); 12 and 24 mo OS was 55% and 16% , respectively. No statistically significant differences were seen between S and A with respect to toxicity, response or survival. Conclusions: 1) As opposed to introduction of 5FU-based CTX at the time of disease progression/prohibitive toxicity, introduction prior to that time may be at least comparable regarding both toxicity and OS. 2) This approach may further enhance OS in pts who achieve DC on GA at 8 weeks. 3) Neither S nor A method of 5FU-based CTX introduction following GA was clearly superior in this study. 4) How best to combine 5FU-based combination CTX following GA in mPC merits further study. Supported by the Seena Magowitz Foundation.

341 Background: Genomes of metastatic pancreatic cancers frequently contain intrachromosomal aberrations indicating DNA repair abnormalities associated with sensitivity to DNA damaging agents such as the platinums. Cisplatin was added to a nab-paclitaxel + gemcitabine regimen, which has been determined to improve survival over gemcitabine alone (NEJM 2013; 369:1691-1703). The objectives are to determine the efficacy and safety of nab-paclitaxel and gemcitabine plus cisplatin in patients with Stage IV pancreatic cancer. Methods: Eligibility criteria included Stage IV adenocarcinoma of the pancreas, no prior chemotherapy for systemic disease, KPS ≥ 70; life expectancy ≥ 12 weeks and measurable disease. Doses are nab-paclitaxel 125 mg/m2 undiluted, gemcitabine 1000 mg/m2 in 500 ml of normal saline (NS), each infused over 30 minutes on days 1 and 8 of a 21 day cycle, along with 3 different dose levels of cisplatin (25, 37.5 or 50 mg/m2) in 500 ml of NS infused over 60 minutes, after the nab-paclitaxel infusion. Pre and post cisplatin hydration was given. The maximum tolerated dose and phase II dose of cisplatin is 25 mg/m2. Results: 25 pts were treated; 24 were evaluable (baseline and ≥ 1 follow up CT scan). The most common drug related grade (gr) 3 - 4 adverse events (AEs), n = 25, were thrombocytopenia 76% (gr 3 = 36%, gr 4 = 40%) with no serious bleeding events, anemia 32% (gr 3 = 32%, gr 4 = 0%), neutropenia 24% (gr 3 = 20%, gr 4 = 4%), infection 20% (gr 3 = 16%, gr 4 = 4%), and diarrhea 16% (gr 3 = 16%, gr 4 = 0%). Peripheral neuropathy ≥ gr 3 was seen in only 1 pt (gr 3 = 4%). Grade 5 AEs were infection (1), cardiac arrest (1), and stroke (1). Median time on therapy was 5.5 months, range (1 – 9.5). By RECIST 1.1 criteria, 2 pts had complete response (8.3%), 15 partial response (62.5%), 4 stable disease (16.7%), and 3 progressive disease (12.5%). Median overall survival to date as of 11/10/16 is 16.5 months. Conclusions: Although a small study, the high response rate and landmark evolving median survival are very encouraging. This regimen is being expanded in patients with stage IV pancreatic cancer, neoadjuvant and adjuvant settings. Clinical trial information: NCT01893801.

Abstract Background: The genomes of metastatic pancreatic cancers contain a myriad of intrachromosomal aberrations indicating a likely high prevalence of DNA repair deficiencies indicating sensitivity to DNA damaging agents such as the platinum’s. Because of this, the drug cisplatin was added to an albumin-bound paclitaxel + gemcitabine regimen, which has already been determined to improve survival over gemcitabine alone in a randomized phase III trial (NEJM 2013; 369:1691-1703). Objectives: To determine the efficacy and safety of albumin-bound paclitaxel and gemcitabine plus cisplatin for patients with advanced pancreatic cancer Methods: Eligibility criteria included Stage IV pancreatic cancer, no prior chemotherapy for systemic disease, KPS ≥ 70; life expectancy ≥ 12 weeks and measurable disease. The doses were albumin-bound paclitaxel 125 mg/m2 undiluted, gemcitabine 1000 mg/m2 in 500 ml of normal saline (NS), each infused over 30 minutes on days 1 and 8 of a 21 day cycle, along with 3 different dose levels of cisplatin (25, 37.5 or 50 mg/m2) in 500 ml of NS infused over 60 minutes, after the nab-paclitaxel infusion. Pre and post cisplatin hydration was given. Results: To date, 10 patients have been entered on study with all patients being evaluable, (baseline and at least one follow up CT scans completed). There have been 2 complete responses (20%), 6 partial responses (PR), (60%), 1 stable disease (10%), and 1 patient with progressive disease (10%), by RECIST 1.1 criteria. An exponential decrease in CA19-9 correlating with the t1/2 of the marker was noted. Response was seen rapidly with PR observed at the first staging evaluation at 9 weeks in 7 of 10 patients. The 8th patient achieved a PR at 18 weeks. Serious adverse events occurred in 4 patients: non-neutropenic sepsis/pneumonia (n = 1), and non-neutropenic bacteremia (n = 1) in the cisplatin 25 mg/m2 cohort; clostridium difficile colitis (n = 1) with cisplatin 37.5 mg/m2; and neutropenic fever/pneumonia (n = 1) with cisplatin 50mg/m2. Discussion: The study has completed phase Ib and will be expanded at the phase II dose of cisplatin 25 mg/m2 for a total of 25 patients. If this favorable response rate is confirmed, this 3 drug regimen could be further developed both for patients with advanced disease as well as in neoadjuvant and adjuvant settings. Supported by grants from the Seena Magowitz Foundation and the SU2C Dream Team Citation Format: Gayle S. Jameson, Erkut Borazanci, Elizabeth Poplin, Michael T. Barrett, John Crowley, Adam Rosenthal, Amy Stoll-D'Astice, Karen L. Ansaldo, Steven Boone, Leticia Lebron, Ramesh K. Ramanathan, Ronald L. Korn, Daniel D. Von Hoff. High complete and partial response rate in a phase Ib pilot trial with cisplatin plus albumin-bound paclitaxel and gemcitabine in patients with advanced pancreatic cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-003. doi:10.1158/1538-7445.AM2015-LB-003