Bendell, Johanna C.

TPS545 Background: Advanced cholangiocarcinoma (CC) is a life-threatening disease with limited effective chemotherapy options. Mutations in isocitrate dehydrogenase 1 (mIDH1) occur in 13–15% of CC cases, and up to 25% of intrahepatic CC cases, leading to epigenetic and genetic changes that promote oncogenesis via production of the oncometabolite 2-hydroxyglutarate (2-HG). AG-120 (ivosidenib), a first-in-class oral mIDH1 inhibitor, displayed a favorable safety profile and clinical activity in a phase 1 study enrolling 73 mIDH1 CC patients who had received ≥1 prior systemic regimen. As of 10 Mar 2017, 4/73 (5%) had a partial response and 41/73 (56%) stable disease. Progression free survival (PFS) rates at 6 months and 12 months were 38.5% and 20.7%, respectively. The 500 mg once daily dose level of AG-120 was selected for further development in mIDH1 CC. Methods: ClarIDHy is a global, phase 3, multicenter, double-blind, randomized (2:1) study of AG-120 (500 mg once daily) vs. matched placebo in 186 mIDH1 CC patients (ClinicalTrials.gov NCT02989857). Key eligibility criteria: non-resectable or metastatic CC, documented mIDH1 by central laboratory testing, ECOG performance status 0–1, measurable disease (RECIST v1.1), documented disease progression after ≤2 prior systemic therapies in the advanced setting including at least 1 gemcitabine- or 5-fluorouracil-containing regimen, and no prior mIDH inhibitor therapy. Crossover from placebo to AG-120 will be allowed at time of radiographic disease progression. Primary endpoint: PFS assessed by independent radiologists. Secondary endpoints: safety, tolerability, overall response rate (RECIST 1.1), overall survival, pharmacokinetic/pharmacodynamic analyses, and quality of life (EORTC QLQ-C30 and QLQ-BIL21 scales). An independent data monitoring committee will monitor the data during study conduct. The ClarIDHy study is currently activated at participating sites in the US, UK, EU, and S. Korea. R eused with permission from the American Society of Clinical Oncology (ASCO). This abstract was accepted and previously presented at the 2017 ASCO Annual Meeting. All rights reserved. Clinical trial information: NCT02989857.

TPS4142 Background: Advanced cholangiocarcinoma (CC) is a life-threatening disease for which there are limited therapeutic options. Mutations in isocitrate dehydrogenase 1 (mIDH1) occur in up to 25% of intrahepatic CC cases. mIDH1 lead to epigenetic and genetic changes that promote oncogenesis via production of the oncometabolite, D-2-hydroxyglutarate (2-HG). AG-120 is a first-in-class oral inhibitor of the mIDH1 enzyme, and is being tested in a phase 1 study that enrolled 73 patients (pts) with mIDH1 CC who had received a median of 2 prior therapies (range 1–5). AG-120 has demonstrated a favorable safety profile and clinical activity in this study. Among the 72 efficacy evaluable pts (≥1 post-baseline response assessment or discontinued prematurely), 6% (n = 4) had a confirmed partial response and 56% (n = 40) had stable disease. Progression-free survival (PFS) rate at 6 months was 40% as of Dec 16, 2016. The 500 mg once daily (QD) dose of AG-120 was selected for the ongoing phase 3 study in mIDH1 CC described here. Methods: ClarIDHy is a global, phase 3, multicenter, double-blind study randomizing 186 pts with mIDH1 CC in a 2:1 ratio to AG-120 (500 mg QD) or matched placebo (NCT02989857). Key eligibility criteria: nonresectable or metastatic CC; documented mIDH1 based on central laboratory testing; ECOG 0–1; measurable disease (RECIST v1.1); documented disease progression following ≤2 prior systemic therapies in the advanced setting, including at least 1 gemcitabine- or 5-fluorouracil-containing regimen; and no prior mIDH inhibitor therapy. Crossover from the placebo arm to the AG-120 arm will be permitted. The primary endpoint is PFS as assessed by an independent review. Secondary endpoints include safety, tolerability, overall response rate, overall survival, pharmacokinetic and pharmacodynamic analyses on plasma, and quality of life as assessed by the EORTC QLQ-C30, EORTC QLQ-BIL21, and EQ-5D-5L instruments. An independent data monitoring committee will monitor the data throughout the study. The ClarIDHy study is currently activated at participating sites in the US and will be activated in centers throughout Europe and in South Korea. Clinical trial information: NCT02989857.

4073 Background: Durvalumab and tremelimumab, investigational monoclonal antibodies against PD-L1 and CTLA-4 immune checkpoints, respectively, have shown efficacy in monotherapy and offer promise in combination for patients (pts) with HCC. This is a phase I/II, open-label, randomized study of durvalumab combined with tremelimumab in unresectable HCC. Methods: Phase I part of this study is a safety run-in cohort treated at the recommended phase II doses of the durvalumab/tremelimumab combination (20 and 1 mg/kg IV Q4W respectively for 4 doses followed by 20 mg/kg Q4W durvalumab alone) in pts with unresectable HCC with or without concomitant HBV or HCV infection who progress on, are intolerant to, or have refused sorafenib therapy. Secondary objectives include evaluation of antitumor activity. Here we present results of a preplanned analysis from the completed phase I part of the study. Results: As of 10 January 2017, 40 pts have been enrolled (11 HBV+, 9 HCV+, 20 uninfected). 30% had no prior systemic therapy; 93% were Child Pugh Class A. 24 (60%) had ≥1 treatment-related AE; 20% had ≥1 grade ≥3 related AE. Most common (≥15%) treatment-related AEs: fatigue (20%), increased ALT (18%), pruritus (18%), and increased AST (15%). Most common grade ≥3 related AE was asymptomatic increased AST (10%). 24 pts have discontinued treatment: 3 due to treatment-related AEs (grade 3 pneumonitis, grade 3 colitis/diarrhea, asymptomatic grade 4 elevated AST and ALT), 16 due to progressive disease, 4 due to death unrelated to treatment (cardiac arrest, variceal bleed, progressive disease, probable HCC rupture), and 1 other (pt entered hospice care). 40 pts were evaluable for response at ≥16 weeks follow-up. Conclusions: No unexpected safety signals with durvalumab and tremelimumab were seen in this unresectable HCC population. Clinical activity observed predominantly in uninfected pts though interpretation limited by small subsets. Enrollment to the phase II portion of the study is ongoing. Clinical trial information: NCT02519348. [Table: see text]

3529 Background: Cancer stem cells are considered to be fundamentally important for resistance, recurrence and metastasis. Napabucasin is a first-in-class cancer stemness inhibitor in development identified by its ability to inhibit STAT3-driven gene transcription and spherogenesis of cancer stem cells (Li et al, PNAS 112(6):1839, 2015). Preclinically, napabucasin sensitizes cancer cells to chemotherapy and targeted agents. Methods: A phase Ib/II multi-center study in mCRC pts was done to confirm the RP2D and signs of anti-cancer activity of napabucasin in combination with FOLFIRI +/- Bev. Pts received napabucasin 240 mg PO BID with bi-weekly FOLFIRI IV +/- Bev 5 mg/kg until disease progression or other discontinuation criterion. Results: 82 pretreated mCRC pts were enrolled (ITT); including 32 (39%) previously treated with FOLFIRI +/- bev. Of the 82 pts, 48 received FOLFIRI and 34 FOLFIRI plus bev in combination with napabucasin. There was no dose-limiting or unexpected toxicity or significant PK interactions. Most common adverse events (AEs) included grade 1/2 diarrhea, cramping, nausea, vomiting, fatigue and anorexia with grade 4 diarrhea in 1 pt and 27 pts with grade 3 AEs including: diarrhea (15), fatigue (5), dehydration (1), electrolyte imbalance (4), abdominal pain (1), vomiting (1) and weight loss (1), which resolved with dose reduction and supportive care. Disease control (CR+PR+SD) was observed in 55 of 66 pts who received RECIST evaluation (83%), with 1 CR (1.5%), 13 PR (20%) (33-100% regression) and 27 SD with tumor regression (41%). Conclusions: This phase Ib/II study confirmed that napabucasin can be safely combined with FOLFIRI +/- bev, and shows encouraging signs of efficacy in pretreated mCRC pts, including pts previously treated with FOLFIRI +/- bev. Clinical trial information: NCT02024607. [Table: see text]

593 Background: Cancer stem cells or stemness-high cancer cells are considered to be fundamentally important for resistance to therapy, recurrence and metastasis. Napabucasin, a first-in-class cancer stemness inhibitor in clinical development, suppresses cancer stemness by targeting Stat3-driven gene transcription. Preclinical studies suggest that napabucasin sensitizes heterogeneous cancer cells to chemotherapeutics and targeted agents. Methods: This study was performed to assess signs of anti-tumor activity of napabucasin in combination with FOLFIRI +/- Bev in CRC pts. Napabucasin was administered at 240 mg BID. FOLFIRI (5-FU 400 mg/m2 bolus with 2400 mg/m2, irinotecan 180 mg/m2, and leucovorin 400 mg/m2 infusion) +/- Bev 5 mg/kg was administered biweekly until disease progression or other discontinuation criterion. pSTAT3 status of archival tumor tissue was assayed by immunohistochemistry using the H-score with pSTAT3highdefined as ≥ 5% pSTAT3+ cancer cells and tumor stroma staining at ≥ 2+ intensity. Results: 63 CRC pts with an average of >2 prior therapy lines were enrolled. No pharmacokinetic interactions or dose-limiting toxicity was observed. Most common adverse events (AEs) included grade 1/2 diarrhea, nausea, vomiting and fatigue. 25 pts had grade 3 AEs, including diarrhea (14), fatigue (4), dehydration (2), electrolyte imbalance (4), nausea (1) and weight loss (1) resolved with dose reduction and supportive care. Among 63 pts enrolled who received RECIST evaluation, disease control (CR+PR+SD) was observed in 49 pts (86%) with an overall response (CR+PR) of 28% with 1 pt achieving CR. Clinical trial information: NCT02024607. Conclusions: This phase Ib/II study suggests napabucasin may sensitize chemorefractory CRC to FOLFIRI +/- Bev. Encouraging signs of synergistic activity between napabucasin and FOLFIRI was observed in CRC pts regardless of pSTAT3 status.[Table: see text]

514 Background: Randomized trials and OCSs have demonstrated that BV treatment in 1st-line (1L), in 2L, and across multiple lines is associated with longer survival in patients (pts) with mCRC. This analysis was aimed at comparing the effectiveness of BV after 1st disease progression (PD) between male and female mCRC pts who received 1L BV-containing therapy in a real-world setting. Methods: ARIES is a large, prospective OCS that enrolled pts who received BV and chemotherapy (CT) for 1L mCRC. Post-PD effectiveness was assessed for men and women characterizing BV use by cumulative and dichotomous approaches. The primary analysis treated BV exposure as cumulative BV doses after 1st PD and post-progression overall survival (ppOS) as the time from 1st PD to death. A time-dependent Cox regression model was fitted to assess the effect of cumulative BV exposure on ppOS, while controlling for potential confounders. A dichotomous secondary analysis characterized BV exposure as receipt of CT + BV (BBP) or CT alone (No BBP) within 2 months after PD and ppOS as time from 1st PD + 2 months to death. Results: Among the 1,550 1L mCRC pts enrolled, 1,199 (532 women) had PD. In the primary analysis, hazard ratios (HRs) for ppOS decreased, on average, by 1.2% with each additional BV dose. When stratified by sex, the average risk reduction per BV dose over 15 doses was 1.8% in women and 0.7% in men. In the secondary analysis that included 331 women (BBP, 180; No BBP, 151) and 417 men (BBP, 245, No BBP, 172) who received BV ± CT within 2 months post-PD, the HRs for ppOS with BBP treatment were 0.46 (95% CI, 0.35–0.59) in women and 0.52 (95% CI, 0.41–0.67) in men. Statistical interaction tests for differences in the effectiveness of BV between men and women were negative for primary and secondary analyses (P of 0.58 and 0.77). Protocol-specified adverse events occurred in 17.8% of women and 10.2% of men in the BBP population; this difference was largely related to rates of hypertension (8.3% vs 2.4%, respectively). Conclusions: In ARIES, the effectiveness of BV after first PD was not statistically different between women and men with mCRC. Clinical trial information: NCT00388206.

702 Background: Median overall survival (OS) in mCRC has significantly improved over the past 20 yrs, but the observed range of OS in pts remains wide; a large percentage of pts have OS <1 yr or >4 yrs. ARIES was a prospective OCS conducted from 2006–2012 that evaluated outcomes in pts receiving BV + chemotherapy (CT) for mCRC in general clinical practice. The objective of this analysis is to examine clinical characteristics of pts with long vs short OS. Methods: This analysis included 1,417/1,550 first-line (1L) BV-treated mCRC pts who died or had complete follow-up on study. Long OS was defined as OS within the upper quartile of the analysis population (range 42–67 mos); short OS was defined as OS within the lower quartile (range 0.3–12 mos). Progression-free survival (PFS) was estimated using Kaplan-Meier methods. Pt and disease characteristics and treatment patterns were described using summary statistics. Results: Pt and disease characteristics are shown in the Table. Median PFS was 22.3 mos (95% CI, 19.9–23.3) vs. 4.9 mos (95% CI, 4.6–5.4), in the long-OS vs. short-OS groups. More pts with long OS received any second-line (2L) therapy (71% vs. 46%), and were exposed to 5-fluorouracil, oxaliplatin, and irinotecan throughout the course of their disease (53% vs. 32%) compared with pts with short OS. KRAS/BRAF mutation status was not collected. Conclusions: Pts with long OS had better baseline performance status, primary tumors more likely to have been resected, and were more likely to have received 2L CT. Additional analyses of detailed treatment patterns and safety are ongoing. Clinical trial information: NCT00388206. [Table: see text]

535 Background: Prior ARIES analyses showed that BV-treated mCRC patients (pts) receiving chemotherapy (CT)/biologics + BV within 2 months (mo) after 1st progressive disease (PD) had longer post-progression survival (PPS) than pts receiving only CT/biologics. The present analysis evaluated whether this effect of BV was consistent when used with common 2L CT regimens— irinotecan- (iri-) and oxaliplatin- (ox-) based—in mCRC pts exposed to 1L BV in ARIES. Methods: ARIES enrolled mCRC pts receiving 1L CT + BV. No tx regimens or assessments were protocol specified. This analysis evaluated 1L BV-treated mCRC pts who had PD, survived ≥2 mo after PD, and received 2L iri- or ox-based tx. PPS was estimated by Kaplan-Meier methods. Cox regression was used to estimate hazard ratios (HRs), while adjusting for covariates (eg, 1L time to progression). Results: Of 1550 1L pts in ARIES, 1074 had 1st PD and survived ≥2 mo after PD. Of these 1074, 390 and 114 received 2L iri- and ox-based tx, respectively, ± BV ( table ). Baseline characteristics were generally similar between groups. The incidence of targeted adverse events (TAEs) was as expected and similar between the BV and No BV groups over time. In pts receiving 2L iri- or ox-based CT tx, PPS in BV-treated pts was longer compared to those not on BV. Analyses may be limited by small pt numbers in some groups. Conclusions: Consistent with prior ARIES analyses, the continued use of BV after 1st PD was associated with prolonged PPS regardless of the 2L CT backbone used. [Table: see text]

480 Background: COs associated with varying Tx patterns in mCRC pts are poorly understood because patterns diverge from the randomized trials (RCT). The RCTs of BV (Avastin) plus chemotherapy (CT) in mCRC pts continued BV until progressive disease (PD), even if CT was stopped/changed. Some RCTs of BV+CT in mCRC show ∼50% of pts stopping Tx early for reasons other than PD with possible lessening of benefit. It is unclear if this is due to use of a particular CT regimen or other practice pattern. While the beneficial effect of post-PD BV Tx has been shown in ARIES (HR 0.52 BBP vs No BBP) [A Cohn, ASCO 2010], the effect of stopping BV or CT before PD is unclear. ARIES, a community based observational study with a large cohort of 1st line BV-treated mCRC pts, will assess the COs associated with different 1st line Tx patterns (BV and CT) based on real world practice. Methods: ARIES enrolled mCRC pts receiving first- or second-line CT+BV. No Tx regimens or assessments are protocol specified. Data are collected prospectively at baseline (BL) and quarterly. Analyses included first-line pts with PD. Tx patterns of pts initially treated with FOLFOX/BV or FOLFIRI/BV are described and preliminary COs (PFS and OS) are estimated from K-M curves. Tx duration is calculated from enrollment date. Results: As of 2/5/10, 1,548 first-line mCRC pts enrolled (median follow up = 21 m); 1,133 pts had PD. Of 1,133 pts with PD, most had FOLFOX/BV (63%) or FOLFIRI/BV (16%) as first CT. BL characteristics were similar, but the FOLFOX/BV group had more stage 4 pts (74%). Main reasons for stopping BV include AE, max benefit achieved and CT holiday. Tx patterns and COs are in the table. Conclusions: ARIES first-line mCRC pts treated with FOLFOX/BV or FOLFIRI/BV had similar Tx patterns and COs despite the common opinion that they may differ in tolerability and possibly effectiveness. Additional analyses will assess the impact of stopping BV and/or CT before PD. [Table: see text] [Table: see text]