IMPORTANCE New therapeutic options for patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) are needed. This study evaluated dual checkpoint combination therapy in patients with mPDAC. OBJECTIVE To evaluate the safety and efficacy of the anti-PD-L1 (programmed death-ligand 1) antibody using either durvalumab monotherapy or in combination with the anticytotoxic T-lymphocyte antigen 4 antibody using durvalumab plus tremelimumab therapy in patients with mPDAC. DESIGN, SETTING, AND PARTICIPANTS Part A of this multicenter, 2-part, phase 2 randomized clinical trial was a lead-in safety, open-label study with planned expansion to part B pending an efficacy signal from part A. Between November 26, 2015, and March 23, 2017, 65 patients with mPDAC who had previously received only 1 first-line fluorouracil-based or gemcitabine-based treatment were enrolled at 21 sites in 6 countries. Efficacy analysis included the intent-to-treat population; safety analysis included patients who received at least 1 dose of study treatment and for whom any postdose data were available. INTERVENTIONS Patients received durvalumab (1500 mg every 4 weeks) plus tremelimumab (75 mg every 4 weeks) combination therapy for 4 cycles followed by durvalumab therapy (1500 mg every 4 weeks) or durvalumab monotherapy (1500 mg every 4 weeks) for up to 12 months or until the onset of progressive disease or unacceptable toxic effects. MAIN OUTCOMES AND MEASURES Safety and efficacy were measured by objective response rate, which was used to determine study expansion to part B. The threshold for expansion was an objective response rate of 10% for either treatment arm. RESULTS Among 65 randomized patients, 34 (52%) were men and median age was 61 (95% CI, 37-81) years. Grade 3 or higher treatment-related adverse events occurred in 7 of 32 patients (22%) receiving combination therapy and in 2 of 32 patients (6%) receiving monotherapy; 1 patient randomized to the monotherapy arm did not receive treatment owing to worsened disease. Fatigue, diarrhea, and pruritus were the most common adverse events in both arms. Overall, 4 of 64 patients (6%) discontinued treatment owing to treatment-related adverse events. Objective response rate was 3.1% (95% CI, 0.08-16.22) for patients receiving combination therapy and 0% (95% CI, 0.00-10.58) for patients receiving monotherapy. Low patient numbers limited observation of the associations between treatment response and PD-L1 expression or microsatellite instability status. CONCLUSION AND RELEVANCE Treatment was well tolerated, and the efficacy of durvalumab plus tremelimumab therapy and durvalumab monotherapy reflected a population of patients with mPDAC who had poor prognoses and rapidly progressing disease. Patients were not enrolled in part B because the threshold for efficacy was not met in part A.

4000 Background: In metastatic pancreatic cancer (PC), nab-P/G demonstrated significantly longer overall survival (OS) vs G. APACT assessed efficacy & safety of nab-P/G vs G in surgically resected PC. Methods: Treatment (tx)-naive patients (pts) with histologically confirmed PC, macroscopic complete resection, ECOG PS 0/1, & CA19-9 < 100 U/mL were eligible. Stratification factors: resection status (R0/R1), lymph node status (LN+/−), & geographic region. Tx was initiated ≤ 12 wks postsurgery. Pts received nab-P 125 mg/m2 + G 1000 mg/m2 or G 1000 mg/m2 on days 1, 8, 15 of six 28-day cycles. Primary endpoint was disease-free survival (DFS) by independent reviewer (IR); IRs received baseline clinical data & scans. Secondary endpoints were OS & safety. ≈438 DFS events were needed for 90% power to detect an HR for disease recurrence or death of 0.73 with nab-P/G vs G at a 2-sided significance level of 0.05. Results: 866 pts were randomized. Median age was 64 y (range, 34 - 86); most pts had ECOG PS 0 (60%), LN+ (72%), & R0 (76%). 69% of pts completed 6 tx cycles ( nab-P/G, 66%; G, 71%). Median follow up for OS was 38.5 mo. Median IR-assessed DFS (439 events) was 19.4 mo ( nab-P/G) vs 18.8 mo (G) (HR, 0.88; 95% CI, 0.729 - 1.063; stratified log-rank P = 0.1824). Investigator-assessed DFS (571 events) was 16.6 mo ( nab-P/G) vs 13.7 mo (G) (HR, 0.82; 95% CI, 0.694 - 0.965; nominal P = 0.0168). Interim OS (427 events) was 40.5 mo ( nab-P/G) vs 36.2 mo (G) (HR, 0.82; 95% CI, 0.680 - 0.996; nominal P = 0.045). Grade ≥ 3 TEAEs were reported in 86% vs 68% of pts with nab-P/G vs G. The most common grade ≥ 3 hematologic & nonhematologic TEAEs with nab-P/G vs G were neutropenia (49% vs 43%) & fatigue (10% vs 3%). TEAEs led to death in 2 pts in each arm. Conclusions: IR DFS with nab-P/G was not significantly longer vs G; median DFS with G was longer than historical data. DFS by investigator (sensitivity analysis) and interim OS were improved with nab-P/G vs G (HR 0.82 for both). Adjuvant nab-P/G may be an option for pts who are ineligible for FOLFIRINOX. Additional OS follow-up may better support nab-P/G as an option in the adjuvant setting. Clinical trial information: NCT01964430.

4504 Background: Clinical outcomes after curative treatment of resectable PDA remain suboptimal. To assess the potential of early control of systemic disease with multiagent peri-op CTx, we conducted a prospective trial in the National Clinical Trials Network. Methods: S1505 was a randomized phase II trial of peri-op CTx (12 weeks pre-, 12 weeks post-op) with either mFOLFIRINOX (Arm 1) or Gem/nabP (Arm 2). Eligibility required confirmed tissue diagnosis of PDA, ECOG PS 0 or 1, and resectable disease per Intergroup criteria. Primary outcome was 2-year overall survival (OS), using a “pick the winner” design; for 100 eligible patients (pts), accrual up to 150 pts was planned to account for cases deemed ineligible at central radiology review. We previously presented data on eligibility (ASCO 2019 abstr 4137). Here we present the final efficacy and toxicity results for the eligible pts. Results: From 2015 to 2018, 147 pts were enrolled; there were 102 eligible pts; 55 in Arm 1; 47 in Arm 2. For Arms 1 and 2 respectively: median age, 66 (44-76) and 64 (46-76) years; males, 36 (65%) and 24 (51%); and ECOG PS 0, 34 (62%) and 31 (66%) pts. Treatment details are shown in Table. For Arm 1 and Arm 2, respectively: Two-year OS was 41.6% and 48.8%; median OS was 22.4 months and 23.6 months. Neither arm’s 2-year OS estimate was statistically significantly higher than the a priori threshold of 40% (p=0.42 in Arm 1 and p=0.12 in Arm 2). Median disease-free survival (DFS) after resection was 10.9 months in Arm 1 and 14.2 months in Arm 2 (p=0.87). Conclusions: We have demonstrated: 1) two-year OS of 41.6% (median 22.4 months) with mFOLFIRINOX and 48.8% (median 23.6 months) with Gem/nabP for all eligible pts starting treatment for resectable PDA; 2) post-resection DFS of 10.9 months and 14.2 months, respectively; 3) adequate safety and high resectability rates with peri-op CTx; 4) little evidence that either regimen improves OS compared with the historical standard. Clinical trial information: NCT02562716 . [Table: see text]

265 Background: Treatment options for cholangiocarcinoma (CCA) after progression on first-line gemcitabine-based therapy are limited. Fibroblast growth factor receptor 2 ( FGFR2) gene fusions occur in 13–17% of intrahepatic CCA. A single-arm, phase II study (NCT02150967) evaluated infigratinib, an ATP-competitive FGFR1–3-selective oral tyrosine kinase inhibitor, in previously-treated advanced CCA with FGFR fusions/rearrangements. Methods: Adult patients with advanced/metastatic CCA with progression on ≥1 line of systemic therapy received infigratinib 125 mg orally for 21 days of each 28-day cycle until unacceptable toxicity or disease progression. All patients received prophylaxis with the oral phosphate binder sevelamer. Primary endpoint: objective response rate (ORR) by independent central review per RECIST v1.1, with duration of response (DOR). Secondary endpoints: progression-free survival (PFS), disease control rate, overall survival, safety, pharmacokinetics. Approximately 160 patients are planned (120/20/20 patients in Cohorts 1/2/3). This analysis focuses on Cohort 1 (patients with FGFR2 gene fusions or rearrangements without receiving a prior FGFR inhibitor). Results: As of 31 March 2020, 108 patients, including 83 (77%) with FGFR2 fusions, received infigratinib: median age 53 years (range 23–81 years); 54% had received ≥2 prior treatment lines. Median follow-up was 10.6 months (range 1.1–55.9 months). 96 patients (88.9%) discontinued treatment (12 ongoing). Centrally reviewed ORR was 23.1% (95% CI 15.6–32.2) including 1 CR and 24 PRs; median DOR was 5.0 months (range 0.9–19.1 months). Among responders, 8 (32.0%) patients had a DOR of ≥6 months. Median PFS was 7.3 months (95% CI 5.6–7.6 months). Prespecified subgroup analysis: ORR was 34% (17/50) in the second-line setting and 13.8% (8/58) in the third-/later-line setting (3–8 prior treatments). Most common treatment-emergent adverse events (TEAEs, any grade) were hyperphosphatemia (76.9%), eye disorders (67.6%, excluding central serous retinopathy/retinal pigment epithelium detachment [CSR/RPED]), stomatitis (54.6%), and fatigue (39.8%). CSR/RPED occurred in 16.7% of patients (including 1 G3 event; 0 G4). Other common grade 3/4 TEAEs were stomatitis (14.8%; all G3), hyponatremia (13.0%; all G3), and hypophosphatemia (13.0%; 13 G3, 1 G4). Conclusions: Infigratinib is associated with promising anticancer activity and a manageable AE profile in patients with advanced, refractory CCA with an FGFR2 gene fusion or rearrangement. A phase III study of infigratinib versus gemcitabine/cisplatin is ongoing in the front-line setting (NCT03773302). Clinical trial information: NCT02150967.

No abstract

335 Background: CCA is a hepatobiliary malignancy with poor prognosis and few treatment options following cytotoxic therapy in the first-line metastatic setting. The fibroblast growth factor receptor (FGFR) axis may promote CCA tumorigenesis. FGFR2 fusions (in up to 17% of intrahepatic CCAs) may predict FGFR inhibitor sensitivity. A prior phase 1 trial of the selective pan-FGFR inhibitor BGJ398 showed antitumor activity in a pt with CCA harboring an FGFR2 fusion. Methods: This ongoing phase 2, open-label study is evaluating oral BGJ398 125 mg once daily on a 3-week-on/1-week-off schedule (28-day cycle) in pts with advanced or metastatic CCA with FGFR2 fusions (n ≈ 40) or other FGFR genetic alterations (n ≤ 15) who progressed after cisplatin/gemcitabine or are cisplatin intolerant (NCT02150967). The primary endpoint is investigator-assessed overall response rate (ORR) per RECIST v1.1. Secondary endpoints include progression-free survival, best overall response (BOR), disease control rate (DCR), overall survival, safety, and pharmacokinetics. Results: As of 10 July 2015, 26 pts with CCA harboring FGFR2 fusions (n = 22) or other FGFR alterations (n = 4), pretreated with 1 to ≥ 4 prior regimens, were enrolled. Common adverse events (AEs; ≥ 20% of pts), were hyperphosphatemia (50%), fatigue (42%), constipation (38%), cough (23%), and nausea (23%). Grade 3/4 AEs occurring in ≥ 2 pts were hyper/hypophosphatemia, lipase increase, and hyponatremia. AEs were manageable, reversible, and rarely led to treatment discontinuation. Among 22 pts evaluable for BOR, 3 achieved partial response and 15 had stable disease, including 10 with tumor reductions (-41%, n = 1; -2% to -29%, n = 9). Overall DCR was 82%. As of the cutoff date, 18 pts remained on therapy, of which 13 were on for > 120 days. Kaplan-Meier estimated lower limit (95% CI) of median time on study was 143 days. Conclusions: BGJ398 shows impressive anti-tumor activity and a manageable safety profile in pts with advanced FGFR-altered CCA, an indication of high unmet medical need. Updated data including additional responses post data cutoff will be presented. Clinical trial information: NCT02150967.

414 Background: Clinical outcomes after curative therapy of resectable pancreatic ductal adenocarcinoma (PDA) remain suboptimal. For early control of systemic disease with aggressive perioperative chemotherapy (CTx), we conducted a prospective trial in the National Clinical Trials Network (NCTN) setting. Methods: S1505 was a randomized phase II trial of periop (12 weeks pre-, 12 weeks post-op) CTx with either mFOLFIRINOX (5-fluorouracil, irinotecan, oxaliplatin – without bolus 5-FU and leucovorin; Arm 1), or gemcitabine/nab-paclitaxel (Arm 2). Eligibility required adult patients with ECOG PS 0 or 1, confirmed tissue diagnosis of PDA, and resectable disease: no involvement of the celiac, common hepatic, or superior mesenteric arteries (and, if present, variants); < 180° interface between tumor and vessel wall, of the portal or superior mesenteric veins; patent portal vein/splenic vein confluence; no metastases. Primary outcome is 2-year overall survival (OS), using a “pick the winner” design; for 100 eligible patients, accrual up to 150 patients was planned, to account for cases deemed ineligible at central radiology review. Results: From 2015 to 2018, 147 patients were enrolled; 74 to Arm 1; 73 to Arm 2. At central radiology review, 42/147 (29%) were ineligible; of these, 15 (36%) had venous involvement ≥ 180°, 22 (52%) had arterial involvement, 28 (67%) had distant disease. One patient had distal cholangiocarcinoma (ineligible); one withdrew consent after randomization. Eligible patients (n = 103) had median age 64 years; males 58%; whites 89%; PS 0 64%. Of 103, 99 (96%) started and 86 (83%) completed preop CTx. There was one death due to sepsis and 61 additional patients experienced grade 3/4 toxicities. To date, 76 of 99 (77%) patients went to surgery and 72 (73%) underwent resection. Conclusions: This is the first-ever NCTN study of periop CTx for resectable PDA. Accrual was brisk, establishing feasibility. Ineligible cases after central radiology review highlight quality control and physician education imperatives for neoadjuvant PDA trials. Preop CTx safety and resection rates are encouraging. Follow up for OS is ongoing. Clinical trial information: NCT02562716.

4014 Background: PC is characterized by DNA Damage Repair (DDR) deficiencies, including in BRCA1/2, ATM, and FANC genes. Given preclinical synergism between veliparib with irinotecan, safety and preliminary efficacy, we designed a randomized phase II study of mFOLFIRI (no 5-FU bolus) + veliparib vs FOLFIRI alone for 2nd line mPC patients (pts). Methods: Eligible pts had mPC, adequate organ function, ECOG PS 0-1, and 1 prior non-irinotecan systemic therapy.143 pts were to be randomized (1:1) to veliparib vs control. Primary endpoint was overall survival (OS). All pts had blood and tumor biopsies at baseline to assess germline and somatic BRCA1/2 mutations (integrated), and homologous recombination (HR) or DDR biomarkers (exploratory). Results: 123 pts were accrued between 09/2016 to 12/2017, and 108 were included in this analysis. 117 pts were biomarker evaluable: 109 blood/106 tumors. 11 cancers (9%) had HR deficiency (HRD), including 4 germline ( BRCA1, BRCA2, ATM) and 7 somatic mutations ( BRCA2, PALB2, ATM, CDK12). Additional 24 cancers (20%) had germline (n = 11, e.g., FANC, BLM, SLX4, CHEK2) or somatic mutations (n = 13, e.g., FANC, BLM, POLD1, RIF1, MSH2, MSH6) in other DNA repair genes, not classified as HRD. A planned interim futility analysis at 35% of expected PFS events determined the veliparib arm was unlikely to be superior to control. Most common grade 3/4 treatment related toxicities were neutropenia (33% vs 20%), fatigue (19% vs 4%), and nausea (11% vs 4%), for veliparib vs control. Treatment exposure was similar for veliparib vs control: median 4 cycles (range 1-31 vs 1-32). Median OS was 5.1 vs 5.9 mos (HR 1.3, 95%CI 0.9-2.0, p = 0.21), and median PFS was 2.1 vs 2.9 mos (HR 1.5, 95%CI 1.0-2.2, p = 0.05) for veliparib vs control arms, respectively. Correlations of gene mutations and signatures with efficacy outcomes will be presented. Conclusions: Nearly 30% of mPC pts had DNA repair gene abnormalities, including 9% with HRD. Veliparib increased toxicity and did not improve OS when added to mFOLFIRI in biomarker unselected pts. BRCA1/2 and DDR biomarkers will be correlated with efficacy to inform patient selection for future PARP inhibitor clinical trials. Clinical trial information: NCT02890355.