Morizane, Chigusa

538 Background: In biliary tract cancer (BTC), TP53 is the most commonly altered gene and may co-occur with KRAS alteration. The presence of a co-alterations in of TP53 and KRAS is associated with poor prognosis in many cancers. In patients (pts) with advanced BTC, the prognostic implications of such co-alterations have not been fully investigated. Methods: This is a pooled analysis of SCRUM-Japan GOZILA and MONSTAR-SCREEN-1 and -2 studies. Genomic profiling was conducted with Guardant360 for plasma in GOZILA, FoundationOne CDx for tissue and FoundationOne Liquid CDx for plasma in MONSTAR-SCREEN-1, and CARIS MI Profile for tissue in MONSTAR-SCREEN-2. Pts with advanced BTC receiving systemic therapy were included in this study. Results: Among 636 pts with advanced BTC, 85 had TP53/KRAS co-alteration, 293 had TP53, 44 had KRAS, and 214 had neither KRAS nor TP53 alteration (WT/WT). Tumors with TP53 alteration had significantly higher level of tumor mutation burden (TMB) compared to the other groups (3.8 mut/Mb for TP53/KRAS, 5.0 mut/Mb for TP53, 2.8 mut/Mb for KRAS, and 2.5 mut/Mb for WT/WT, respectively, P<0.001). In addition, the frequency of microsatellite instability-high (MSI-High) in the TP53/KRAS group (11.0%) was significantly higher compared to the TP53 group (3.1%, P<0.05), and the WT/WT group (0.6%, P<0.001), respectively. The objective response rate of first-line therapy in the TP53/KRAS group (8.2%) was significantly lower than in the other groups (20.8% for TP53, 23.3% for KRAS, and 19.7% for WT/WT groups, P=0.035). There was no pts treated with durvalumab plus gemcitabine and cisplatin. Two pts with TP53/KRAS alteration and MSI-High received pembrolizumab monotherapy, and partial response was achieved with a progression-free survival of 9.4 and 22.0 months. The median overall survival (OS) for pts treated with first-line therapy of the TP53/KRAS, KRAS, TP53, and WT/WT groups were 13.6 (95% confidence interval [CI], 11.5-15.5), 14.3 (95%CI, 9.7-25.9), 18.8 (95%CI, 16.9-20.6), and 22.7 months (95%CI, 20.4-25.9), respectively. Multivariate analysis identified TP53/KRAS alteration (hazard ratio [HR] 2.14, 95%CI 1.43-3.22, P<0.001), number of detected variants (≥2) (HR 1.50, 95%CI 1.04-2.16, P=0.029), locally advanced (HR 1.72, 95%CI 1.05-2.83, P=0.033), and metastatic status (HR 1.78, 95%CI 1.39-2.28, P<0.001) as independent prognostic factors for shorter OS. Conclusions: Patients with advanced BTC with co-occurring TP53/KRAS alterations have worse prognosis. Interestingly, the presence of these co-alterations was associated with a higher likelihood of MSI-High phenotype.

544 Background: Biliary tract cancer (BTC) is an aggressive malignancy with poor prognosis and limited treatment options. The prevalence of HER2 amplification in BTC has been reported to be 5-20%, and clinical trials suggested the clinical benefit of HER2-targeted treatment in this disease subpopulation. In a global collaboration, we investigated the comprehensive clinico-molecular characterization as well as the efficacy of anti-HER2 therapy in HER2-amplified BTC. Methods: Patients with advanced BTC who received systemic therapy were included from the GOZILA and MONSTAR studies in Japan and from the COLOMATE trial in the US. Genomic alterations were detected by tissue next-generation sequencing (NGS), including FoundationOne CDx and TempuslxT, and plasma circulating tumor DNA NGS including Guardant360 and FoundationOne Liquid CDx. The clinico-molecular characteristics were evaluated in an exploratory cohort comprised of patients from Japan, whereas the efficacy of anti-HER2 therapy was assessed in a biomarker selected cohort with patients from both Japan and the US. Results: Of 439 patients included in the exploratory cohort, 43 (10%) had HER2 amplification. BTC with primary tumor location in the gallbladder accounted for 58% of primary sites of patients with HER2 amplification. TP53 mutation (84% vs 61%, p=0.003) and BRAF amplification (9% vs 2%, p=0.030) were significantly more frequent in patients with HER2 amplification compared to those without, and no KRAS mutation co-occurred with HER2 amplification. There was no significant difference in overall survival (OS) between patients with and without HER2 amplification (17.7 months [M] vs 16.9 M, hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.65-1.40, p=0.799). Of 58 patients with HER2-amplified BTC included in the biomarker selected cohort (43 Japan, 15 US), 27 (47%) received anti-HER2 therapy. The median OS of patients treated with anti-HER2 therapy was significantly longer than that of patients who did not receive anti-HER2 therapy (24.3 M vs. 12.1 M, HR 0.43, 95% CI 0.23-0.82, p=0.011). Multivariate analysis also identified anti-HER2 therapy as an independent prognostic factor for OS (HR 0.42, 95% CI 0.20-0.85, p=0.015). Conclusions: HER2 amplifications were found in 10% of advanced BTC and did not represent an independent predictive factor for OS. Of clinical significance, patients with HER2-amplified BTC derive a significant benefit from anti-HER2 therapy.

4086 Background: Abnormalities in the MAPK pathway are potential therapeutic targets in various cancers. However, the clinical impact of alterations in the MAPK pathway in BTC have not been elucidated, especially outside of canonical mutations in KRAS and BRAF. We investigated the clinical outcomes of advanced BTC with MAPK pathway alterations treated with chemotherapy in Japan and the United States. Methods: Patients with advanced BTC who received gemcitabine plus cisplatin as first-line therapy were included from the GOZILA study in Japan and Duke Molecular Registry of Tumors in the US. Genetic abnormalities were detected by Guardant360, a cell-free DNA assay, in Japan and by blood or tissue-based next-generation sequencing (NGS) at Duke University. Two hundred and seven patients with BTC from Japan were included in an exploratory cohort to evaluate the association of MAPK alterations with overall survival (OS) according to MAPK alteration status. One hundred and ten patients with BTC from both Japan and the US harboring oncogenic alterations in the MAPK pathway were included in a biomarker selected cohort to assess the association of specific MAPK alterations with OS. Multivariate analysis was performed using a Cox regression model based on a univariate p-value < 0.2. Results: MAPK pathway-related oncogenic alterations detected in each cohort are shown in the table below. In the exploratory cohort, median OS was shorter for patients with MAPK alterations vs. no MAPK alteration (15.9 m vs. 24.9 m, log-rank p = 0.001). Based on univariate analysis, the following covariates were selected for multivariate analyses: age, prior resection, and MAPK pathway alteration in the exploratory cohort; country, the timing of NGS, distant metastasis, KRAS amplification, and BRAF class 2 mutation in the biomarker selected cohort. In the exploratory cohort, multivariate analysis identified MAPK pathway alterations as an independent predictor of shorter OS with a HR of 1.92 (95% CI = 1.28-2.87, p = 0.001). In the biomarker selected cohort, multivariate analysis identified BRAF class 2 mutations and KRAS amplification as independent predictors of shorter OS with a HR of 16.2 (95% CI = 3.26-80.8, p = 0.001) and 5.97 (95% CI = 1.74-19.3, p = 0.002) respectively. Conclusions: MAPK pathway alterations, especially BRAF class 2 mutation and KRAS amplification, had a significant negative impact on clinical outcomes in BTC receiving first-line chemotherapy. These results are newly confirmed in BTC. [Table: see text]

4009 Background: Survival outcomes are historically poor in patients (pts) with advanced/metastatic iCCA, with median overall survival (mOS) times of approximately 1 year with first-line gemcitabine plus cisplatin and approximately 6 months with second-line chemotherapy. Futibatinib, a highly selective, irreversible FGFR1–4 inhibitor, demonstrated efficacy with durable responses in pts with iCCA harboring FGFR2 fusion/rearrangements in the pivotal FOENIX-CCA2 phase 2 study (NCT02052778). At the primary analysis of this trial (data cutoff: October 1, 2020), an objective response rate (ORR) of 41.7% was observed, with a median duration of response (mDOR) of 9.7 mo. Here, we report updated efficacy (including mature OS data) and safety data from the final analysis with an additional 8 mo of follow-up. Methods: FOENIX-CCA2 was a single-arm phase 2 study that enrolled pts with advanced/metastatic iCCA with FGFR2 fusion/rearrangement and progressive disease (PD) after ≥1 prior treatment (tx; including gemcitabine plus platinum-based chemotherapy). Pts received futibatinib 20 mg once daily until PD/intolerability. The primary endpoint was ORR per RECIST v1.1 by independent central review. Secondary endpoints were DOR, disease control rate (DCR), progression-free survival (PFS), OS, safety, and patient-reported outcomes. Results: At the time of the final data cutoff (May 29, 2021), median follow-up was 25.0 mo, and 96/103 pts (93%) had discontinued tx. The median number of tx cycles was 13.0 for a median tx duration of 9.1 mo. The confirmed ORR was 41.7% (43/103) and thereby the same as of the primary analysis, as was the DCR (at 82.5%). The ORR was consistent across pt subgroups. The mDOR was 9.5 mo, and 74% of responses lasted ≥6 mo. mPFS was 8.9 mo, with a 12-mo PFS rate of 35.4%. Mature mOS was 20.0 mo, with a 12-mo OS rate of 73.1% . No new safety signals were identified. Common tx-related adverse events (TRAEs) included hyperphosphatemia (85%), alopecia (33%), dry mouth (30%), diarrhea (28%), dry skin (27%), and fatigue (25%). TRAEs resulted in tx discontinuation in 4 pts (4%). No tx-related deaths occurred. Quality of life was maintained from baseline to tx cycle 13. Conclusions: Findings from the final analysis of FOENIX-CCA2 confirm the results of the primary analysis and reinforce the durable efficacy and continued tolerability of futibatinib in previously treated pts with advanced/metastatic iCCA harboring FGFR2 fusion/rearrangements. Mature OS data were consistent with data from the primary analysis and far exceed historical data in this patient population. Clinical trial information: NCT02052778.

Abstract Background FGFR2 fusions occur in ~15% of patients (pts) with iCCA, a rare cancer with a poor prognosis. Futibatinib, a highly selective, irreversible FGFR1-4 inhibitor, has shown activity across tumor types, including iCCA, in a phase 1 study. The pivotal phase 2 FOENIX-CCA2 trial (NCT02052778) is evaluating futibatinib in iCCA harboring FGFR2 fusions/rearrangements. Here, we report the first efficacy, safety, and quality of life (QoL) data for the complete FOENIX-CCA2 population. Methods Eligible pts had unresectable/metastatic iCCA with an FGFR2 fusion/rearrangement and progressive disease (PD) after ≥1 prior treatment (tx; excluding FGFR inhibitors). Pts received futibatinib 20 mg QD until PD/intolerability. The primary endpoint was objective response rate (ORR) per RECIST v1.1 by independent central review (target ORR: 20%). Secondary endpoints included duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), safety, and patient-reported outcomes (PROs). Subgroup analyses were performed by pt characteristic and molecular alteration. Results Among 103 pts (56% female), 53% had received ≥2 prior tx. FGFR2 fusions were present in 78% (23% had FGFR2-BICC1 fusions) and FGFR2 rearrangements in 22%. At data cutoff (Oct 1, 2020), 72 pts (70%) had discontinued tx. The study met its primary objective with a confirmed ORR of 41.7% (43/103). Responses were durable, with a median (m) DOR of 9.7 mo and 72% of responses ≥6 mo. DCR was 82.5%. mPFS was 9.0 mo; mOS was 21.7 mo, with a 12-mo OS rate of 72%. ORR was consistent across pt demographic subgroups (≥65 y: 65.2%; 2 prior tx: 38.7%). Common tx-related AEs (TRAEs) were hyperphosphatemia (85%), alopecia (33%), and dry mouth (30%). The most frequent grade 3 TRAE, hyperphosphatemia (30%), resolved with adequate management (median 7 d). Retinal disorders (all grade 1-2) were reported in 8% of pts. TRAEs were managed with dosing interruptions (50%)/reductions (54%); 2 pts discontinued tx due to TRAEs. No tx-related deaths occurred. ORRs were consistent in pts with dosing interruptions (40.2%) or reductions (46.8%). PROs were stable through 11.0 mo of tx. In exploratory biomarker analyses, ORR was consistent in pts with FGFR2 fusions (43.8%) and other FGFR2 rearrangements (34.8%) and in pts with BICC1 (41.7%) and non-BICC1 (44.6%) fusion partners. Notably, no obvious differences in ORR were observed in pts with co-occurring genetic alterations, including TP53 comutations (ORR, 38.5% [5/13]). Additional biomarker data will be presented. Conclusions Futibatinib resulted in frequent, durable objective responses in pts with iCCA harboring FGFR2 fusion/rearrangements, regardless of pt baseline characteristic, molecular alteration, or comutation. AEs were manageable with dosing modifications that did not impact response. QoL was maintained. Citation Format: Lipika Goyal, Funda Meric-Bernstam, Antoine Hollebecque, Chigusa Morizane, Juan W. Valle, Thomas B. Karasic, Thomas A. Abrams, Robin Kate Kelley, Philippe Cassier, Junji Furuse, Heinz-Josef Klümpen, Heung-Moon Chang, Li-Tzong Chen, Yoshito Komatsu, Kunihiro Masuda, Daniel Ahn, Yaohua He, Nital Soni, Karim A. Benhadji, John A. Bridgewater. Primary results of phase 2 FOENIX-CCA2: The irreversible FGFR1-4 inhibitor futibatinib in intrahepatic cholangiocarcinoma (iCCA) with FGFR2 fusions/rearrangements [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT010.

348 Background: The proportion of females in medicine is increasing (approx. 50% in medical school/workforce), but disparities in female authorship in oncology research publications exist; female corresponding authorship reportedly ranges from 7.2-39.1% in oncology clinical trials (Ludmir et al 2019). This study aimed to describe and assess factors associated with female first and senior authorship in later phase systemic clinical trials in BTC and to identify any changes over time. Methods: Embase/Medline were used to identify final primary trial publications in BTC (2000-2020) (excluding phase I (PI) (expected to move to later phase), mixed tumour site trials, reviews, editorials and trial-in-progress publications). Gender was determined by inspection of names, google search and author communication. Chi-square tests and log regression were used to assess factors associated with female first and senior authorship, including changes over time (STATA16). Results: Of 501 publications, 163 met inclusion criteria; 80% single-arm PII and 15% and 5% randomised PII and PIII respectively; 73% enrolled ≤50 patients. Tumour primary sites were all BTC: 86%, cholangiocarcinoma: 8%, gallbladder cancer: 6%; 80% involved chemotherapy, 13% targeted therapy and 5% localised/systemic combinations; 65% were in first-line (1L) advanced setting, 17% post 1L, 13% advanced non-specified and 5% neo-adjuvant/adjuvant. Forty-eight percent received industry funding and 65% met primary end-point. Sixty-four percent were published post ABC-02 (Valle et al 2010). Publication impact factor (IF) was ≤5 in 50% and >20 in 12%. Median number of authors in all publications was 11. Geographic location of all first and senior authors were Asia (42%/42%), Europe (29%/29%), USA (24%/22%) and other (4%/6%), respectively. Median individual trial female author representation was 25%; there were no female authors in 12% of trials. Overall, female first and senior author representation was 21% and 11%, respectively. Median position of first female author was second. In publications with IF ≤20 and >20, there were 22% and 16% female first and 13% and 0% female senior authors, respectively. The phase of trial, journal IF, industry funding, or whether met primary end-point did not impact female first or senior author representation (all P>.05). There were more female senior authors associated with “other” geographic locations (40% in 10 trials) (P=.016) vs Asia (7%), Europe (8%) and USA (14%). There were no significant changes in female first or senior author representation over time (‘00-05: 21%/18%, ‘06-10: 27%/5%, ‘11-15: 15%/15%, ‘16-20: 22%/9%, P=.738, and P=.508 respectively). Conclusions: Female first and senior author representation in later phase systemic clinical trial publications in BTC is low and has not changed significantly over time. The underlying reasons for this imbalance need to be better understood and addressed.

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.

TPS468 Background: Intrahepatic cholangiocarcinoma (iCCA) is a cancer arising from the intrahepatic bile duct. Standard treatment of unresectable, recurrent, or metastatic iCCA is with cytotoxic chemotherapy. FGFR2 gene fusions have been identified as oncogenic drivers in 10–20% of iCCA tumors, but no targeted agents have been established to date. TAS-120 is an investigational irreversible FGFR1–4 inhibitor in development as a once-daily oral treatment for iCCA. Based on initial studies in multiple tumor types expressing FGFR abnormalities, iCCA was identified as a tumor type with potential susceptibility to FGFR inhibition and high unmet need. A phase I portion of the trial with an iCCA expansion cohort demonstrated tolerability and preliminary evidence of clinical efficacy with TAS-120 as a continuous, once-daily oral treatment in patients with iCCA. The most common AEs in the phase I portion of the trial were hyperphosphatemia, a mechanism-based on-target side effect, cutaneous AEs, and gastrointestinal AEs. The phase I portion of the study is continuing to enroll, and final results are anticipated in early 2019. Based on preliminary findings, a phase II portion of the study (FOENIX-101; clinicaltrials.gov registration NCT02052778) has been initiated. Methods: The phase II portion of the trial is a global, single-arm study of TAS-120 in patients with iCCA harboring FGFR2 gene rearrangements. The study will enroll approximately 100 adult patients with locally advanced or metastatic iCCA that progressed after ≥ 1 systemic therapies and with an ECOG PS of 0 or 1. Prior systemic therapy must include gemcitabine plus platinum-based chemotherapy. Screening for FGFR2 gene rearrangements will be performed at a central laboratory. The primary endpoint is objective response rate based on RECIST v1.1. Secondary endpoints include duration of response, disease control rate, overall survival, progression-free survival, safety, and health-related quality of life. Clinical trial information: NCT02052778.