Borad, Mitesh J.

8523 Background: ISIS 481464 is a synthetic bicyclic nucleic acid-containing antisense oligonucleotide that is complementary to the mRNA for signal transducer and activator of transcription 3 (STAT3). Methods: Primary objective of the dose-escalation study (3+3 design) was to establish the maximum tolerated dose (MTD) and recommended phase II dose (RP2D). Secondary objectives included safety, tumor response, pharmacokinetics (PK), and pharmacodynamics (PD) using IL-6 and tumor markers. Patient (pt) eligibility included : >18 yrs old, solid tumors or lymphomas refractory to at least 1 prior systemic therapy. ISIS 481464 was administered IV as a loading dose on Days 1, 3, and 5 and then weekly. Results: 15 pts were dosed (4 at 2 mg/kg and 11 at 4 mg/kg). 6 pts had advanced lymphoma (3 DLBCL, 2 Hodgkin’s lymphoma, 1 mantle cell lymphoma) and 9 pts solid tumors. There was one dose limiting toxicity (DLT), a possibly related thrombotic microangiopathy at 4 mg/kg. Treatment emergent thrombocytopenia was observed with an average reduction of approximately 70% from baseline. Three pts, 1 at 2 mg/kg and 2 at 4 mg/kg, experienced nadirs in platelet count below 50x109/L (range 16 to 33x109/L). MTD was not reached; however, given the thrombocytopenia at 4mg/kg, the RP2D was 2mg/kg. Partial responses were observed in 2/3 DLBCL pts. The 1st DLBCL pt (2 mg/kg) with 10 prior treatments had a durable 55% reduction in tumor size and is ongoing treatment at 11 months. This pt had a 76% reduction in IL-6. The 2nd DLBCL pt (4 mg/kg) with 2 prior treatments had a 65% reduction for 4 months and was able to undergo autologous stem cell transplantation. There were no responses in the solid tumor pts. PKs revealed increased plasma trough levels (indicative of tissue concentrations) with increased dose. Conclusions: ISIS 481462 was well-tolerated and the RP2D was determined to be 2 mg/kg. Initial tumor activity was observed in DLBCL pts and a dose expansion in advanced lymphomas is ongoing. Clinical trial information: NCT01563302.

TPS2621 Background: TKM-080301 is a lipid nanoparticle formulation of a small interfering RNA (siRNA) directed against PLK1, a serine/threonine kinase that regulates multiple critical aspects of cell cycle progression and mitosis. Anti-tumor activity, RNA interference and pharmacodynamic effects of PLK1 inhibition have been conclusively demonstrated in preclinical models. Demonstration of pharmacodynamic effects of PLK1 inhibition in patient biopsy samples is an exploratory objective of this first-in-human study. Methods: TKME080301 is being evaluated in an open-label, non-randomized, dose-escalation study in patients with advanced solid tumors or lymphoma. Sequential cohorts of 3 to 6 patients receive TKME080301 as a 30-minute intravenous infusion on Days 1, 8 and 15 of a 28-day cycle. Treatment can continue until disease progression, based on overall clinical benefit. Tumor response is determined according to RECIST criteria. Primary study objectives include determination of safety, maximum tolerated dose and dose limiting toxicities. Secondary objectives include characterization of pharmacokinetics and the preliminary assessment of anti-tumor activity. Five cohorts have been enrolled and a tentative Phase 2 dose has been identified. An expansion cohort of 10 patients began enrolling in February, 2013. The focus of the expansion cohort will be to collect additional safety and pharmacokinetic data at the tentative Phase 2 dose, as well as pharmacodynamic data from mandatory biopsy samples. Pre- and post-dose biopsy samples will be evaluated for potential evidence of PLK1 inhibition using 5’ RACE (rapid amplification of cDNA ends) polymerase chain reaction (to identify the predicted PLK1 mRNA cleavage product), histology (to assess for the presence of aberrant mitotic figures) and immunohistochemistry. An update on enrollment and pharmacodynamic evaluations will be presented. Clinical trial information: NCT01262235.

e13052 Background: The combination of GEM and CDDP has shown activity in a variety of cancers, including biliary tract/gallbladder. Preclinical testing shows a potential benefit to the addition of EV. Methods: Using a standard 3+3 design, the MTDs of GEM + EV (Cohort I) and GEM + CDDP + EV (Cohort II) were determined as shown in the table. The MTD was defined as the dose level below the lowest dose that induces a DLT in at least one-third of pts. At the MTD of Cohort II, 10 patients were enrolled with biliary tract/gallbladder cancer (Cohort III). A weekly CBC was obtained. Assessments occurred every 3 weeks and imaging for response at every other cycle. Results: In Cohort I (N=12), no DLT occurred at dose level 0, and in dose level 1, grade 3 thrombocytopenia was found in 2 of 6 pts. The MTD for Cohort I was determined to be dose level 0. Responses were seen in 3 pts: 2 CRs (primary peritoneal, pancreatic) and 1 PR (breast). In Cohort II (N=15) DLTs at dose level 0 were neutropenia and thrombocytopenia in 2 of 3 pts and at dose level -1, thrombocytopenia in 2 of 6 pts. At dose level -2, 1 of 6 pts experienced a DLT (grade 3 thrombocytopenia), establishing this dose level as the MTD. Responses were seen in 2 pts, both PRs (ampullary, pheochromocytoma). All 10 pts have been enrolled in Cohort III with 2 DLTs (neutropenia and thrombocytopenia). Stable disease seen in 5 of 7 evaluable pts. Conclusions: Gem + EV was well tolerated at dose level 0, though dose escalation was limited by thrombocytopenia. GEM + CDDP + EV had DLTs of neutropenia and thrombocytopenia leading to the MTD of dose level of -2. Cohort III is fully accrued and the 2 DLTs are hematologic. [Table: see text]

2579 Background: HA, a glycosaminoglycan, accumulates in ~25% of solid tumors and is associated with poor prognosis. Tumors that accumulate HA develop high interstitial fluid pressure (IFP) and become resistant to chemotherapy. In animal models, PEGPH20 reduced tumor-associated HA and increased efficacy of chemotherapy. Methods: This ongoing phase 1 study was designed to assess safety, tolerability, PK, PD, and the maximum tolerated dose (MTD) of PEGPH20 as a single agent in patients with treatment-refractory solid tumors. IV PEGPH20 was administered in a twice weekly or a once weekly dosing schedule with oral dexamethasone (dex) pre-and post dose. Biomarkers included tumor histochemistry to detect HA depletion, plasma HA catabolites, and DCE-MRI or FDG-PET. Results: Fifteen patients have been enrolled into the study. Dose administration ranged from 0.5 µg/kg to 5 µg/kg. Musculoskeletal events (MSEs) were the most common and dose limiting toxicities. To date, up to 3 µg/kg twice weekly IV infusions of PEGPH20 were well tolerated with manageable Grade 1 MSEs in most patients. MTD has not been reached. Plasma concentrations of PEGPH20 showed dose proportional exposure with a terminal half life of ~2 days. Enzymatic activity of PEGPH20 was reflected by dose-dependent HA catabolites in plasma. Pre- and post-dose tumor biopsies from 2 colon patients demonstrated 23-60% reduction in tumor HA after 4 weeks of dosing. Serial DCE-MRI and FDG-PET demonstrated increased tumor perfusion (Ktrans) and decreased metabolic activity 8 and 24hrs post-PEGPH20 in one patient each. Doses of ≤3 µg/kg were tolerated with intermittent Grade 1-2 MSE. Enrollment at dose levels > 3 µg/kg is ongoing. Conclusions: Repeated IV PEGPH20 infusion resulted in dose-dependent systemic exposure and is tolerated with concomitant dex treatment. HA catabolites in plasma demonstrated the in vivo enzymatic activity of PEGPH20. Reduced HA in tumor biopsies and serial DCE-MRI and FDG-PET images confirmed PD activity. Increased tumor perfusion by PEGPH20 may enhance drug delivery to tumor. Combination studies of PEGPH20 with cytotoxic chemotherapy are planned.

TPS600 Background: Pts with adv CCA have poor survival outcomes, and chemotherapy offers limited survival benefit (5-year survival rates, 5–10%; median overall survival [OS], 8–12 months). FGFR2 gene rearrangements are known to be early drivers of oncogenesis in ~15% of pts with intrahepatic (i) CCA. Futibatinib, an oral, highly selective, irreversible FGFR1-4 inhibitor has shown antitumor activity against a broad spectrum of FGFR-deregulated tumors in preclinical studies. In a previous study, futibatinib demonstrated clinical activity and tolerability in heavily pretreated pts with adv CCA harboring FGFR2 gene rearrangements. This phase 3 trial (FOENIX-CCA3) is designed to evaluate futibatinib vs gem-cis as 1L therapy for pts with adv iCCA harboring FGFR2 rearrangements. Methods: FOENIX-CCA3 is a multicenter, open-label, randomized phase 3 study that will be conducted in pts with metastatic or unresectable iCCA harboring FGFR2 rearrangements (assessed at screening by a central laboratory). Pts must have an ECOG performance status of 0 or 1 and should not have received previous systemic anticancer therapy for adv disease (adjuvant/neoadjuvant therapy ≥6 mo prior to randomization is permissible). Pts with clinically-significant alterations in calcium-phosphorus homeostasis or ectopic mineralization/calcification will be excluded. Approximately 216 pts will be randomized (1:1 ratio) to receive 20 mg futibatinib once daily until disease progression or other discontinuation criteria are met or gem-cis (on days 1 and 8 of a 21-day cycle) for 8 cycles or until disease progression, whichever occurs first. Pts will be stratified by prior surgical excision (yes vs no), geographic region, and locally adv vs metastatic disease. The primary endpoint is progression-free survival (PFS) assessed by independent central review (ICR). Secondary endpoints include objective response rate and disease control rate based on ICR, OS, PFS per investigator assessment, and safety. The anticipated start date is in April, 2020.

TPS597 Background: Deregulation of the FGFR signaling pathway is implicated in various cancers. In iCCA, FGFR genetic aberrations include FGFR2 fusions and, less commonly, FGFR2 M/A. iCCA prognosis is poor, and chemotherapeutic and targeted treatment options are limited. While FGFR2 fusions are acknowledged oncogenic drivers, the oncogenic potential of FGFR2 M/A is less well defined. Derazantinib (DZB) is an investigational, oral small-molecule kinase inhibitor with activity against FGFR1, 2 and 3, which demonstrated antitumor activity in patients with unresectable iCCA with FGFR2 fusions. Based on preliminary efficacy data demonstrating durable responses of > 6 months and a clinically meaningful progression-free survival in a subset of iCCA patients harboring FGFR2 M/A (NCT01752920), the multicenter, multicohort open-label phase 2 study FIDES-01 is evaluating the effect of DZB in separate cohorts of iCCA patients with FGFR2 fusions or FGFR2 M/A. Methods: The new cohort evaluates 300 mg once daily dosing of DZB in patients with unresectable iCCA with FGFR2 M/A per liquid or tissue biopsy-based next generation sequencing and at least one previous systemic therapy. Treatment will continue until progressive disease, intolerance, withdrawal of informed consent, or death. Using a Simon’s two-stage design, the primary endpoint to assess the antitumor activity of DZB is the proportion of patients with PFS at 3 months (PFS3; per RECIST 1.1 central review). Secondary objectives are evaluation of median PFS, objective response rate, duration of response, safety profile, quality of life (incl., QLQ-C30, QLQ-BIL21, EQ-5D), and symptom response from baseline. Current status: The study was initiated in July 2019 with planned enrollment of 43 patients with confirmed FGFR2 M/A. Clinical trial information: NCT03230318.

TPS594 Background: Effective treatment options are very limited for patients with advanced refractory biliary tract cancer (BTC). Fluoropyrimidine-based chemotherapy regimen such as 5-fluorouracil and irinotecan are frequently utilized for these patients after first-line therapy despite lack of FDA approval. Trifluridine/tipiracil (FTD/TPI) is a novel oral nucleoside with antitumor activity in both fluoropyrimidine sensitive and resistant tumors due to its unique mechanisms of action. Given early toxicity and efficacy data from our previous study on single-agent trifluridine/tipiracil (FTD/TPI) in advanced BTC, the clinical evaluation of its combination with irinotecan represents a rational approach for the treatment of advanced refractory BTC. Methods: This is a single-arm phase II trial with a two-stage design to assess the efficacy of trifluridine/tipiracil (FTD/TPI) and irinotecan in advanced refractory BTC. Key eligibility criteria include histologically confirmed advanced, unresectable BTC who have progressed on at least one line of systemic therapy and have measurable disease per RECIST v1.1. Target accrual is 25. Treatment includes trifluridine/tipiracil (FTD/TPI) 25 mg/m2 on days 1-5 and irinotecan 180 mg/m2 on day 1 in 14-day cycles. Patients will be evaluated for response every 4 cycles and in the absence of disease progression, therapy may be given up to 2 years. The primary end point is the progression-free survival rate at 16 weeks. Secondary endpoints include overall response rate, disease control rate, progression-free survival, overall survival, and incidence of adverse events. Correlative biomarker studies include evaluations of circulating tumor DNA and circulating tumor cells at baseline, after 4 cycles and at progression; and development of patient-derived tumor organoids from pre-treatment biopsies for parallel treatments. This study was approved and funded in part by the National Comprehensive Cancer Network (NCCN) Oncology Research Program from general research support provided by Taiho Oncology, Inc. Clinical trial information: NCT 04072445.

TPS592 Background: For advanced CCA, standard of care 1L systemic treatment is GEM + CIS. Genetic alterations in intrahepatic CCA provide potential therapeutic targets. Fibroblast growth factor receptor (FGFR) 2 gene rearrangements driving CCA tumorigenesis were identified almost exclusively in intrahepatic CCA patients (pts) (incidence, 10–16%). In phase 2, PEM (INCB054828), a selective, potent, oral FGFR1–3 inhibitor elicited an objective response rate (ORR) of 35.5% and median progression-free survival (PFS) of 6.9 months (mo) in previously treated, locally advanced or metastatic CCA with FGFR2 rearrangements (NCT02924376). FIGHT-302, a randomized, open-label, phase 3 study will evaluate efficacy and safety of 1L PEM vs GEM + CIS in unresectable/metastatic CCA with FGFR2 fusions or rearrangements (NCT03656536). Methods: Eligible pts are adults with confirmed unresectable/metastatic CCA; no prior systemic therapy for advanced disease < 6 mo before enrollment; radiographically measurable/evaluable disease (per RECIST v1.1); ECOG PS ≤1; documented FGFR2 fusions or rearrangements. Exclusions include clinically significant corneal or retinal disorder; history of calcium and phosphate homeostasis disorder or systemic mineral imbalance with ectopic soft tissue calcification; untreated CNS metastases or history of uncontrolled seizures. Pts will be randomized (1:1; stratified by region and tumor burden) to PEM 13.5 mg QD on a 21-day (d) cycle or GEM (1000 mg/m2) + CIS (25 mg/m2) on D1 and D8 of 21-d cycles (max 8). Crossover to PEM allowed after confirmed progression. PEM titration to 18 mg from cycle 2 allowed for pts without hyperphosphatemia (serum phosphate > 5.5 mg/dL) and Grade ≥2 treatment-related adverse events during cycle 1. Hyperphosphatemia will be managed with diet modifications, phosphate binders, diuretics, or dose adjustments. Treatment will continue until progression or unacceptable toxicity. Primary endpoint is PFS (by independent review). Secondary endpoints are ORR, overall survival, duration of response, disease control rate, safety, and quality of life. Four pts (target N = 432) are enrolled as of Sep 25, 2019. Clinical trial information: NCT03656536.

583 Background: Hepatocellular cancer (HCC) continues to grow in incidence despite approval of many new therapies including immune checkpoint inhibitors (ICIs) and TKIs. Genomic landscape of HCC is becoming increasing apparent through WGS and WES. One major driver of HCC is the Wnt/b-catenin pathway. Mutations in CTNNB1, which encodes for b-catenin, are evident in 26-37% of all human HCCs. However, expression of mutant-b-catenin in liver in mice is insufficient for HCC development. Indeed, analysis of HCC cases has revealed CTNNB1 mutations to significantly co-exist with other aberrations including activation/overexpression of Met and Myc and mutations in TERT promoter or mutations in NFE2L2/KEAP1, APOB and ARID2. Methods: Using sleeping beauty transposon/transposase and hydrodynamic tail vein injection, we co-expressed mutant-CTNNB1 (S45Y, S33Y or T41A) and one other clinically relevant co-occurrence to study significance and biology of HCC. Any novel findings in the preclinical model were validated in HCC patient cohorts. Results: Co-expression of mutant-CTNNB1 and one relevant co-occurrence led to development of HCC in mice in 6-10 weeks. All HCC in these models showed a dramatic increase in glutamine synthetase (GS), encoded by Glul, a known target of the Wnt/b-catenin signaling pathway in the liver. This led to an increase in glutamine levels in the tumor-bearing livers. Increased glutamine in the tumors in turn led to increased levels of phospho-mTOR-S2448, a marker of mTORC1 activation. In fact, examination of ~400 patient HCCs showed a significant correlation between positive GS and p-mTOR-S2448 staining. Treatment of Met-b-catenin model with Rapamycin led to notable and significant decrease in HCC burden. Conclusions: Our studydemonstrates b-catenin-mutated HCC to be positive for both GS and in turn mTORC1 active. This provides a novel opportunity for personalized medicine in HCC and CTNNB1-mutated HCCs may be vulnerable to therapeutic targeting by mTOR and more specially, mTORC1 inhibitors.

580 Background: Though studies indicate that the genomic profiles of ICC and ECC are distinct, the clinical features that differentiate them still remain to be well characterized. The purpose of this study was to further analyze these differences and patient treatment patterns in a multi-center cohort. Methods: A retrospective chart review was performed at 8 institutions on patients (pts) with ICC or ECC diagnosed after June 2009. Data on demographics, risk factors, treatments, pathology and overall survival (OS) were collected. Tumor genotyping results from CLIA-certified tissue assays were analyzed. Fisher’s exact, Wilcoxon rank sum and log-rank tests were used to compare sub-groups. Results: In a database of 737 pts with cholangiocarcinoma, 538(73%) had ICC and 199(27%) had ECC. Pts with ICC more often presented in later stages, had tumors > 5cm at resection (p < 0.0001) and had metastases to the liver, lymph nodes, lung and/or bone (p < 0.01). Pts with ICC more often received liver directed therapy, targeted therapy and multiple lines of systemic therapy and they more often enrolled in a clinical trial (all p < 0.01). Pts with ECC were more likely to be male, undergo surgery, receive adjuvant chemotherapy and/or chemoradiation (all p < 0.05). Mutation profiling performed in 381 (52%) pts (ICC/ECC = 301/80) showed that pts with ICC were more likely to have IDH1 mutations and FGFR2 fusions, whereas pts with ECC were more likely to have KRAS, APC, SMAD4, WNT, TGFb and TP53 mutations (all < 0.05). Factors that did not differ significantly between pts with ICC and ECC include race, rates of primary sclerosing cholangitis, median diagnosis CA19-9 levels and R1 resection rate. Median OS from diagnosis was 18.9 months in ICC and 17.3 months in ECC (p = 0.8471). Conclusions: While pts with ICC and ECC have some similarities in their clinical features, differences in metastases patterns and molecular profiling significantly impact their management such that pts with ICC receive more liver-directed therapy, targeted therapy and more lines of systemic therapy. Further prospective studies are needed as referral patterns to tertiary care centers may have impacted these results.