Ramanathan, Ramesh K.

BACKGROUNDThere are limited therapeutic options for treatment‐refractory pancreatic ductal adenocarcinoma (PDAC), with a paucity of data to support the best option after progression on gemcitabine‐based regimens. The authors performed a meta‐analysis to determine the effectiveness of adding oxaliplatin (OX) or various irinotecan formulations to a fluoropyrimidine (FP) after first‐line treatment progression in patients with PDAC.METHODSDifferent databases, including PubMed, EMBASE, and Cochrane, were searched to identify randomized controlled trials comparing FP monotherapy versus FP combination therapy that included either oxaliplatin (FPOX) or various irinotecan formulations (FPIRI) in patients with PDAC who progressed after first‐line treatment. Secondary analyses were planned to assess the effectiveness of FPOX and FPIRI compared with FP. Outcomes of interest included overall survival (OS) and progression‐free survival (PFS).RESULTSFive studies with 895 patients were identified. Patients randomized to receive FPIRI/FPOX had a significantly improved PFS and a trend toward improved OS compared with those who received FP monotherapy. When comparing FPIRI with FP, there was an improvement in both PFS (hazard ratio, 0.64; 95% confidence interval, 0.47‐0.87; P = .005) and OS (hazard ratio, 0.70; 95% confidence interval, 0.55‐0.89; P = .004) in patients who received the combination. Conversely, FPOX produced only a modest improvement in PFS with no improvement in OS.CONCLUSIONSCombination chemotherapy with OX or various IRI formulations appears to improve PFS compared with single‐agent FP. FPIRI, but not FPOX, appears to confer an OS advantage. The combination of FP with irinotecan formulations appears to be the appropriate next line of treatment upon progression after gemcitabine‐based chemotherapy regimens. Cancer 2017;123:4680‐4686. © 2017 American Cancer Society.

Abstract Taselisib is a potent and selective tumor growth inhibitor through PI3K pathway suppression. Thirty-four patients with locally advanced or metastatic solid tumors were treated (phase I study, modified 3+3 dose escalation; 5 cohorts; 3–16 mg taselisib once-daily capsule). Taselisib pharmacokinetics were dose-proportional; mean half-life was 40 hours. Frequent dose-dependent, treatment-related adverse events included diarrhea, hyperglycemia, decreased appetite, nausea, rash, stomatitis, and vomiting. At 12 and 16 mg dose levels, dose-limiting toxicities (DLT) were observed, with an accumulation of higher-grade adverse events after the cycle 1 DLT assessment window. Pharmacodynamic findings showed pathway inhibition at ≥3 mg in patient tumor samples, consistent with preclinical PIK3CA-mutant tumor xenograft models. Confirmed response rate was 36% for PIK3CA-mutant tumor patients with measurable disease [5/14: 4 breast cancer (3 patients at 12 mg); 1 non–small cell lung cancer], where responses started at 3 mg, and 0% in patients with tumors without known PIK3CA hotspot mutations (0/15). Significance: Preliminary data consistent with preclinical data indicate increased antitumor activity of taselisib in patients with PIK3CA-mutant tumors (in comparison with patients with tumors without known activating PIK3CA hotspot mutations) starting at the lowest dose tested of 3 mg, thereby supporting higher potency for taselisib against PIK3CA-mutant tumors. Cancer Discov; 7(7); 704–15. ©2017 AACR. See related commentary by Rodon and Tabernero, p. 666. This article is highlighted in the In This Issue feature, p. 653

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.

TPS482 Background: Two combination chemotherapy regimens have emerged as standard of care options for first-line treatment of mPAC: 5-fluorouracil (5-FU)/leucovorin (LV) + irinotecan + oxaliplatin (FOLFIRINOX), and nab-paclitaxel + gemcitabine. Nal-IRI (MM-398) is a nanoliposomal formulation of irinotecan. In a randomized phase 3 study (NAPOLI-1), of patients with mPAC who had been previously treated with gemcitabine-based therapy, nal-IRI + 5-FU/LV demonstrated its safety and significant clinical activity, increasing overall survival (OS) and progression-free survival (PFS) relative to 5-FU/LV. The goal of this current study is to determine the preliminary safety and efficacy of nal-IRI+ + 5-FU/LV with or without oxaliplatin as compared to nab-paclitaxel + gemcitabine in previously untreated patients with mPAC. Methods: This open-label, phase 2 comparative study will be conducted in two parts. Part 1 is a safety run-in of a nal-IRI+5-FU/LV + oxaliplatin regimen. The safety run-in will enroll small cohorts of patients following a traditional 3 + 3 dose escalation design to confirm the target dose of oxaliplatin (n = ~6-18). The primary objective of Part 1 is the safety and tolerability of nal-IRI + 5FU/LV + oxaliplatin. Part 2 is a randomized, efficacy study of a nal-IRI + 5-FU/LV + oxaliplatin regimen (Arm 1), the nal-IRI + 5-FU/LV combination that previously demonstrated efficacy in the NAPOLI-1 trial (Arm 2), versus a nab-paclitaxel + gemcitabine control arm (Arm 3) (n = ~156-168). The primary objective of Part 2 is to assess the efficacy of nal-IRI-containing regimens in first-line mPAC patients compared to nab-paclitaxel + gemcitabine using the progression-free survival (PFS) rate at 24 weeks as the primary endpoint. Secondary of part 1 is a PK study and Part 2 secondary endpoints will include OS, PFS, objective response rate (per RECIST, v1.1), decrease in CA19-9 levels and quality of life assessments. Clinical trial information: NCT02551991.

TPS474 Background: In pts with APC, the distal common bile duct is frequently obstructed, which can lead to elevated bilirubin levels. Normalization of bilirubin by stenting can take weeks, so treatment options that could be initiated in pts with elevated bilirubin are desirable. In a phase III trial of pts with metastatic PC, nab-P + Gem demonstrated superior efficacy vs Gem alone for all endpoints, including overall survival (OS; median, 8.7 vs 6.6 months; hazard ratio, 0.72; P < 0.001). This study will be the first to analyze safety and PK profiles of nab-P + Gem in pts with APC and CH secondary to bile duct obstruction. Methods: Treatment-naive pts (≈ 12 to 40) with APC, Karnofsky performance status ≥ 70, and CH due to bile duct obstruction are eligible. Pts with a biliary stent must have 2 stable (within 20% of each other) bilirubin readings within 48 to 72 hours of each other taken between 5 and 21 days after stenting. Exclusion criteria consist of brain metastases, any other active malignancy, infection requiring systemic therapy, a history of myocardial infarction, or current use of medications known to be strong inducers of CYP3A4 and CYP2C8. Pts will enter 1 of 2 cohorts based on bilirubin level: cohort 1, > 1.5 to 3 × upper limit of normal (ULN), or cohort 2, > 3 to 5 × ULN. Cohort 2 will proceed only after review of safety and PK data from cohort 1 by a safety monitoring committee (SMC) and a decision has been made to proceed. The starting doses are nab-P 100 mg/m2 and Gem 800 mg/m2 for cohort 1 and nab-P 75 mg/m2 and Gem 600 mg/m2 for cohort 2. Treatment will be administered on days 1, 8, and 15 of each 28-day cycle. Doses in each cohort will be modified according to tolerability as determined by the SMC. The primary endpoints are determination of maximum tolerated dose for each cohort and PK profile. Secondary endpoints include investigator-assessed objective response rate, progression-free survival, OS, PK profile of Gem, and safety. The exploratory endpoint is change in serum CA19-9 level from baseline. Enrollment is ongoing. ClinicalTrials.gov: NCT02267707. Clinical trial information: NCT02267707.

248 Background: Improved understanding of TME in CCA may allow for development of novel therapeutics targeting stromal components. Hyaluronic acid (HA) is a polysaccharide that has been found in the TME of a number of solid tumors characterized by desmoplastic stroma, such as pancreatic cancer. Elevated HA levels were prognostic in these malignancies. HA prevalence and association with clinic-pathological features in CCA is unknown. Methods: A retrospective study was conducted using clinically annotated formalin-fixed paraffin embedded tissue from resected intrahepatic CCA samples. Specimens were analyzed for HA, scored using a positive pixel count algorithm (Aperio Imagescope) and positivity was calculated as % of total pixel count. Clinical variables were examined by chi-square or ANOVA F-test. Overall survival (OS) and progression-free survival (PFS) were estimated using Kaplan-Meier method and compared via log-rank test. Multivariate analysis was conducted using Cox proportional hazards regression models. Results: 142 patient samples were stained for HA. HA was identified in all samples (100%), with a range of HA positivity of 32.8 – 91.8%. Median HA value was 67.1% and 95% of patients had HA positivity ≥ 45%. Factors associated with higher than median HA ( > 67%) included perineural invasion (PNI) (40% vs. 21%, p = 0.011), necrosis (67% vs. 41%, p = 0.003), lymph node positivity (32% vs. 14%, p = 0.027), and small tumor size ( < 6.8 cm vs. > 8.4cm, p = 0.014). Stratification of HA staining by median positivity value was not an independent predictor of survival based on multivariate analysis. OS for patients with HA > 67% was 40.1 months (mo) vs 48.5 mo with HA ≤ 67%, p = 0.537. PFS for patients with HA > 67% was 14.4 mo vs. 25.7 mo with HA ≤ 67%, p = 0.177. Conclusions: Prevalence of HA staining in resected CCA is higher than seen in many solid tumors and is ubiquitous in our study. Absence of statistically significant association with OS and PFS might be attributable to ubiquitous prevalence, narrow signal range, and association with known negative prognostic factors. Further pre-clinical and clinical evaluation would be warranted.

249 Background: HA, a glycosaminoglycan in the tumor matrix, accumulates in 20-30% of solid tumors and ≥28%, ≥42% and ≥87% of colon, gastric and pancreatic ductal adenocarcinoma (PDA) tumors, respectively. Tumors that accumulate HA can develop high interstitial fluid pressure (IFP) and are resistant to chemotherapy. HA in human PDA is associated with disease progression and poor prognosis. In animal models, PEGPH20 reduced tumor-associated HA, tumor IFP and tumor growth, and increased efficacy of chemotherapy. Pharmacodynamic (PD) activity of PEGPH20 is being evaluated in Phase 1 (Ph1) trials. Methods: Two Ph1 studies in pts with advanced solid tumors refractory to prior therapy examined the safety, tolerability, PK, PD and MTD of single-agent IV PEGPH20. Dosing in Study 1 was 2x/wk and then reduced to q21d and in Study 2 is 1-2x/wk x 4wks and 1x/wk thereafter with dexamethasone pre-medication regimen. Biomarkers evaluated: Histochemistry to detect depletion of tumor HA, serum HA catabolites, Dynamic Contrast Enhanced (DCE)-MRI and FDG-PET. Results: In Study 1, the first 3 pts demonstrated musculoskeletal events (MSE; 2 pts dosed with 50 µg/kg 2x/wk, severe; 1 pt dosed with 0.5µg/kg 2x/wk, moderate) not predicted from GLP safety studies. The frequency of drug administration was reduced to q21d and the next 10 pts tolerated ≤1.5 µg/kg. In Study 2, dexamethasone pre-medication regimen was evaluated while dosing at 1-2x/wk. Nine pts were dosed ≤5.0 µg/kg. Doses ≤3.0 µg/kg administered 2x/wk were tolerated with intermittent Grade 1-2 MSE. Activity of PEGPH20 was reflected by increased HA serum catabolites. Pre- and post-dose biopsies from 2 colon pts demonstrated a 23-60% reduction in tumor HA after 4 wks of PEGPH20 dosing. DCE-MRI of PDA and FDG-PET of lung metastases increased tumor perfusion (Ktrans) and decreased metabolic activity 8 and 24hrs post-PEGPH20 dose and was still apparent after 4 wks of treatment with PEGPH20. Conclusions: Ongoing Ph1 studies have shown in vivo activity of PEGPH20 through HA plasma catabolites, tumor HA depletion, DCE-MRI and FDG-PET.