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PURPOSE Precision oncology has transformed the management of advanced cancers through implementation of advanced molecular profiling technologies to identify increasingly defined subsets of patients and match them to appropriate therapy. We report outcomes of a prospective molecular profiling study in a high-volume Asian tertiary cancer center. PATIENTS AND METHODS Patients with advanced cancer were enrolled onto a prospective protocol for genomic profiling, the Individualized Molecular Profiling for Allocation to Clinical Trials Singapore study, at the National Cancer Center Singapore. Primary objective was to identify molecular biomarkers in patient's tumors for allocation to clinical trials. The study commenced in February 2012 and is ongoing, with the results of all patients who underwent multiplex next-generation sequencing (NGS) testing until December 2018 presented here. The results were discussed at a molecular tumor board where recommendations for allocation to biomarker-directed trials or targeted therapies were made. RESULTS One thousand fifteen patients were enrolled with a median age of 58 years (range 20-83 years). Most common tumor types were lung adenocarcinoma (26%), colorectal cancer (15%), and breast cancer (12%). A total of 1,064 NGS assays were performed, on fresh tumor tissue for 369 (35%) and archival tumor tissue for 687 (65%) assays. TP53 (39%) alterations were most common, followed by EGFR (21%), KRAS (14%), and PIK3CA (10%). Of 405 NGS assays with potentially actionable alterations, 111 (27%) were allocated to a clinical trial after molecular tumor board and 20 (4.9%) were enrolled on a molecularly matched clinical trial. Gene fusions were detected in 23 of 311 (7%) patients tested, including rare fusions in new tumor types and known fusions in rare tumors. CONCLUSION Individualized Molecular Profiling for Allocation to Clinical Trials Singapore demonstrates the feasibility of a prospective broad molecular profiling program in an Asian tertiary cancer center, with the ability to develop and adapt to a dynamic landscape of precision oncology.

3603 Background: Debio 1347 is a selective oral inhibitor of FGFR 1-3 tyrosine kinases. It exhibited high antitumor activity in in vitro and in vivo tumor models with FGFR1-3 gene fusions. Here we report the results of the expansion portion of a Phase 1 study of advanced solid tumors patients (pts) harboring an FGFR1-3 gene fusion. Methods: Pts with advanced refractory solid tumors harboring an FGFR1-3 gene fusion were enrolled. Based on results from the dose escalation portion, pts received Debio1347 80 mg once daily (qd) in 28-day cycles. Pharmacokinetics (PK) and pharmacodynamics were evaluated. The data cut-off was October 8, 2019. Results: Among 18 pts enrolled, 5 had primary brain tumors (PBT), 5 had cholangiocarcinoma, 2 had urothelial cancer, 2 had colon cancer, 1 patient each lung neoplasm, gastric cancer, endometrial cancer and squamous cell carcinoma of the chest wall. Tumors harbored fusions with FGFR1 (n = 1), FGFR2 (n = 8), and FGFR3 (n = 9). All had prior systemic therapy (median 3 lines; range 1-4). The most common treatment emergent adverse events were fatigue (50%), hyperphosphatemia (44.4%), anemia (38.9%), alopecia (33.3%), nausea (33.3%), vomiting (33.3%), constipation (33.3%), and palmar-plantar erythrodysesthesia syndrome (22.2%). Blurred vision was reported in 1 pt. There were no findings on ocular exams compatible with retinal detachment. No grade 3 AE related to study drug were reported. One patient needed dose reduction due to grade 2 nails toxicity. In PK analysis, plasma steady-state was rapidly achieved and serum phosphate increase correlated with Debio 1347 plasma exposure, confirming target engagement at 80 mg qd. Median follow-up was 18 weeks. Partial responses were observed in 3 pts harboring an FGFR2 fusion: 1 out of 2 colon cancer and 2 out 5 cholangiocarcinoma. Median duration of response was 16.1 weeks (range: 8.4-22.8+). Overall disease control was observed in 11 out of 14 pts without PBT (79%). Median PFS was 18.3 weeks. No signs of activity were observed in the 5 patients with PBT, all with an FGFR3-TACC3 fusion. Conclusions: Debio 1347 at the recommended dose of 80 mg qd was generally well tolerated and showed signs of activity in solid tumors harboring an FGFR fusion. The FUZE phase 2 clinical trial of Debio 1347 is recruiting FGFR fusion-positive advanced solid tumors irrespectively of tumor histology, excluding PBT. Clinical trial information: NCT01948297 .

4590 Background: Nivolumab (N) and Y90-radioembolization (RE) are both therapeutic options in advanced hepatocellular carcinoma (aHCC). Increasing evidence suggests that radiotherapy synergizes with immune checkpoint inhibitors to augment anti-tumour effects. Methods: Eligible Child-Pugh A aHCC patients (pts) were treated with Y90-RE followed by N 240mg, 21 days after Y90-RE and every 2 weeks thereafter. Pre- and on-treatment tumor biopsies together with circulating biomarkers were obtained. Primary end-point was overall response rate (ORR) (per RECIST v 1.1). Overall response was defined as the composite overall response observed for the lesions within Y90-RE field and outside Y90-RE field. Key secondary end points included disease control rate (DCR), progression free survival (PFS), overall survival (OS), and safety. 36 evaluable pts were needed to assess whether the addition of N improved the ORR of Y90-RE from 21% to 41% as determined by Simon two-stage optimal design with 80% power and one sided significance level of 0.05. Results: Forty pts were enrolled of which 36 were evaluable. At baseline: 63.9% were HepB in aetiology; 63.9% BCLC stage C; 47.2% had AFP > 400ng/mL; number of liver lesions – median 5 (range 1- 20); size of largest liver lesion – median 80mm (range 14-177mm); 27.8% had prior TACE; and 13.9% had prior systemic therapy. ORR was 31% (95% CI 16.4 - 48.1%). Eight out of 11 responders had not progressed at study cut-off. DCR was 58.3%. 81% of target lesions within Y90-RE field regressed. With a median follow up of 16.4 months, median PFS and OS were 4.6 months (95% CI 2.3m - 8.4m) and 15.1 months (95% CI 7.8m - NE) respectively. Six- and 12-month PFS rates were 44.2% (95% CI 27.3% - 59.9%) and 26.1% (95% CI 11.2% - 43.8%) respectively. Overall, N+ Y90-RE was well tolerated and safe; only 11% had grade 3/4 treatment related adverse events (AEs). Responders demonstrated significant alterations of LIF, MIG and Eotaxin3 levels in the pre-treatment cytokine analyses. Conclusions: Combination N+Y90-RE resulted in an encouraging ORR of 31% (95% CI 16.4 - 48.1%) in aHCC. 81% of target lesions within Y90-RE field regressed suggesting synergy in combining Y90-RE with nivolumab. This combination is safe and tolerable with low G3/4 treatment related AEs of 11%. Further biomarker analyses will be presented at the meeting. Clinical trial information: NCT03033446 .

730 Background: Tumoral KRAS mutations (KRAS mt) are detected in ~80% of APC and associated with a negative prognosis. Digital droplet PCR (ddPCR) has high sensitivity for circulating KRASmtbut narrower gene coverage. NGS using hybrid-capture methods has reported ctDNA KRASmtin ~30% of patients (pt). We previously presented clinical results of the Phase I trial of OXIRI (GI ASCO 18 #411). We now present the first prospective evaluation of ctDNA in APC by an amplicon-based NGS approach in this Phase I trial. Methods: Paired ctDNA and CA19-9 samples were taken at baseline, C2D1, C3D1 and end of trial. A targeted panel with error-correction (Lucence Diagnostics) was used to detect for mtin KRAS, TP53, SMAD4, CDKN2A, CTNNB1, GNAS, APC and MYC. CT scans were performed every 2 cycles. Survival curves by Kaplan Meier were compared by mutational status, ctDNA and CA19-9 response using the log-rank test. Spearman correlation of ctDNA and CA19-9 changes was performed. Results: ctDNA mtwas detected at baseline in 19/23 (83%) samples, comprising KRAS 17/23 (73%), TP53 (61%), SMAD4 (48%) and CDKN2A (30%). KRAS mtand SMAD4 mt conferred a negative prognosis for overall survival with a hazard ratio of 4.2 (CI: 1.6-10.4; p = 0.01) and 2.8 (CI: 0.9-8.65; p = 0.01) respectively. Drop in ctDNA and CA19-9 was associated with a trend for longer progression free survival at C2D1 (both) and C3D1 (ctDNA only). Radiological partial response (PR) was associated with lower ctDNA in 5/5 pt and CA 19-9 in 4/5 pt. Decrease in ctDNA and CA19-9 was associated with disease control (PR/SD) at C2D1 in 11/14 pt and 10/10 pt; at C3D1 in 11/12 pt and 6/7 respectively. No significant correlation between the amplitude of CA19-9 and ctDNA changes was found. Conclusions: ctDNA could be detected in 83% of pts of whom KRAS mtrates were similar to reports using tissue NGS. Determination of RAS mtand SMAD4 mtin ctDNA may aid in the prognostication of pts and decrease in ctDNA levels may predict for treatment benefit, similar in extent to CA 19-9. This may be particularly useful in non-CA19-9 secreting APC as an adjunct to imaging. Clinical trial information: NCT02368860.

331 Background: Varlitinib is a nanomolar inhibitor of EGFR, HER2, and HER4 and has shown potent anti-tumor activity as monotherapy in preclinical BTC models. During Phase (Ph) 1 development, significant tumor shrinkage was observed in biliary tract cancer (BTC) patients (pts). Tissue microarray analysis has revealed that ~70% of BTC pts exhibit HER overexpression, suggesting varlitinib could be beneficial in BTC. Methods: Data from BTC pts were pooled from 3 Ph1 trials of varlitinib (dosed 200-500 mg BID) in combination with cisplatin and 5-FU/capecitabine (cape) (Study 002); oxaliplatin and 5-FU/cape (Study 002SG); cisplatin and gemcitabine (Study 007). The depth of tumor response, disease control rate (DCR), and treatment-related adverse events (TRAEs) were analysed. Results: As of 12 June 2018, 43 pts were recruited: 12 (27.9%); 10 (23.3%) and 21 (48.8%) from study 002; 002SG and 007 respectively. 002SG and 007 were still ongoing at data cut-off. 20 (46.5%) pts were male and the median age was 62 years (range 42-82). Most tumors were cholangiocarcinoma (74.4%), followed by gallbladder cancer (16.3%) and carcinoma of the Ampulla of Vater (9.3%). 14 (32.6%) pts had received ≥ 1 prior lines of treatment. Of the 37 pts evaluable for efficacy (those with measurable disease and received ≥ 1 dose of treatment), partial responses were observed in 10 (27.0%) pts and stable disease in 16 (43.2%) pts, with a DCR of 70.3%. The median depth of tumor response was -10.8% (range 49.5% to -87.1%). Of 43 pts, the most frequent (≥ 30%) TRAE (any grade) were fatigue (37%), decreased appetite (34%), and nausea (32%) and the most common Grade ≥ 3 TRAE were hyperbilirubinemia (12%), increased AST (9%), and neutropenia (9%). The median PFS data is not matured and will be provided if evaluable at the time of presentation. Conclusions: Varlitinib with platinum-based chemotherapy has a promising efficacy and safety profile in BTC. A Ph2/3 randomised study of varlitinib and cape in 2nd line BTC and a Ph1b/2 study of varlitinib with platinum-based chemotherapy in 1st line BTC are ongoing. Clinical trial information: NCT02648425, NCT02435927, and NCT02992340.

65 Background: Trastuzumab (T) + chemo is standard first-line therapy (tx) for HER2+ gastroesophageal adenocarcinoma (GEA) pts, though progression ensues in 6-8 months. The approved second-line tx is ramucirumab +/- paclitaxel (R+PAC). Pts with GC are less responsive to R+PAC than gastroesophageal junction (GEJ) pts, in particular HER2+ GC, and no anti-HER2 agents are approved in post-T setting. We report results of combination M+P in HER2+ GC pts and describe a biological rationale for this population. M is an anti-HER2 mAb Fc optimized for enhanced binding to activating FcgRIIIa (CD16A) and decreased binding to inhibitory FcgRIIb (CD32B). M demonstrated an enhanced Fc-dependent MoA, including enhanced ADCC. Methods: HER2+, PD-L1-unselected, second-line GEA pts post T progression received M (15 mg/kg) + P (200 mg) Q3wk. Safety, objective response rate (ORR), median overall & progression-free survival (mOS, mPFS), disease control rate (DCR), circulating tumor DNA, & tumor PD-L1 expression were assessed. Results: To date, 66 GEA pts were dosed; 35 (53%) GC and 31 (47%) GEJ. Overall, 12/66 (18.2%) had tx-related adverse events ≥ grade 3; 5 had drug-related SAEs: dehydration, diabetic ketoacidosis, hypotension and pneumonitis, each a single event, and 2 events of autoimmune hepatitis. Eligibility was based on archival HER2 expression; an exploratory endpoint measured retention of HER2 expression post-T by ERBB2 ctDNA. HER2 expression was lost in 23/56 (41.1%) of pts tested post T. HER2 retention was higher in pts with GC versus GEJ (65.8% vs. 44.8%) and in GEA pts with IHC 3+ vs 2+ archival tumors (61.7% vs 47.4%, respectively). Furthermore, GC had higher PD-L1 expression than GEJ, 53.3 vs. 33.3%, respectively. This coincided with more responses in IHC3+ GC pts, ORR 12/29 (41.4%; 95% CI 23.5-61.1), DCR 21/29 (72.4%; 95% CI 52.8-87.3), mPFS 5.5 months (95% CI 2.3-7.6), mOS not reached, with lower bound of 9.1 months for 95% CI. Enrollment of an additional 25 pts enriched for IHC3+ GC is ongoing. Conclusions: Results suggest that M+P, a chemo-free regimen, demonstrates acceptable tolerability and has encouraging preliminary activity in second-line HER2+ GEA, specifically in GC pts who retain ERBB2 amp prior to second-line tx. Clinical trial information: NCT02689284.

29 Background: The incidence rates of gastric cancer in Asia are among the highest in the world. Gastric cancer is a heterogeneous disease. The Cancer Genome Atlas and Asian Cancer Research Group provide molecular classification of gastric cancers. Recently, immunotherapy was found to be effective in selected gastric cancer patients. Despite the molecular classification, a classification system based on immune microenvironment is in need to better stratify patients for ideal immunotherapy combinations. Methods: We have performed indexed-sorting single cell RNA-seq to analyze both CD45+ and CD45- cells from biopsy samples of 15 gastric cancer patients (5 Diffuse; 4 Intestinal; 5 Mixed; 1 unknown type). Using our ezsinglecell analytical pipeline, we have built a draft Asian Single-cell Immune Atlas (ASIA) of human gastric cancers. Results: We were able to probe fibroblast, epithelial cells and various subtypes of immune cells. Interestingly, we observed that fibroblast and mast cells were more enriched in diffuse type. In addition, we have profiled single immune cells in tumor and normal adjacent tissues to distinguish tissue-induced versus tumor-driven immune signatures. Comparing tumor and normal tissues, we found that tumor site has less natural killer (NK) and CD8 T cells; more B, myeloid and CD4 T cells. Moreover, CD8 T cells and NK cells showed distinct phenotypes in tumor compared to normal tissues. In particular, inhibitory receptor Tim-3 and CTLA-4 were up-regulated in the tumor. Most interestingly, T Cell Receptor (TCR) reconstruction revealed clonal expansion of CD8 T cells. Conclusions: Both immune (CD45+) and non-immune (CD45-) cell components of human gastric cancers are highly heterogeneous. Diffuse type showed differential tumor microenvironment compared to intestinal and mixed types. Tumor site presented an immune-suppressive phenotype compared to normal adjacent site. The clonal expansion of CD8 T cells suggested the role of adaptive immunity on recognizing tumor antigens. This discovery may determine the clinical applications of immunotherapy for gastric cancer in the future.

3612Background: Brain metastases (BM) from colorectal cancer (CRC) are a rare but increasing event as patients survive longer. While human epidermal growth factor receptor 2 (HER2) gene amplificati...

4030Background: T + chemo is standard 1st line therapy (tx) for HER2+ GEA patients (pts). However, pts typically progress within 6-8 months, with up to 30% demonstrating loss of HER2 positivity. No...

411 Background: The FOLFIRINOX regimen is highly active in APC, but its use is limited by toxicity. Irinotecan (IR) toxicity is correlated with UGT1A1 genotype status and chronomodulated delivery of fluoropyrimidines may reduce toxicity and increase efficacy. We have presented the dose escalation (DES) of OXIRI. In dose expansion (DXP), several pts required dose reduction after cycle 1 and we evaluated a lower starting dose. We now present data of the recommended Phase II dose (RP2D) and DES combined. Methods: Pts with APC and ECOG performance status ≤2, adequate organ function were enrolled. Previous OX or IR exposure was disallowed. During DES, APC pts homozygous for UGT1A1*6/*6 or UGT1A1*28/*28 were excluded. During DXP, only pts progressing on ≥ 1 line prior chemo was allowed and IR was dosed according to UGT1A1 genotype. At RP2D, pts received iv OX 37.5mg/m2 and IR 50mg/m2 on D1, 8 and po capecitabine 2650mg once at midnight on D1-14 every 21D until progression. Results: A total of 25 pts were enrolled, 17 in DES and 8 in DXP, 21 had metastatic and 4 had locally advanced APC. Male:Female 11:14, median (range) age and ECOG PS was 65yrs (50-77) and 0 (0-1) respectively. Pts with 0, 1 or 2 lines of prior chemo were 4 (16%) , 14 (56%) and 7(28%) respectively. Grade 3/4 AEs (≥5%) related to OXIRI were neutropenia (32%), anaemia (12%), diarrhoea (16%). No events of febrile neutropenia were reported. At data cut-off on 31 Aug 2017, 4 pts are on study. Median progression-free and overall survival was 22 and 35 wks respectively. Response rate (RR) was 5/25 (20%, overall); 5/20 (25%, evaluable pts) including 1 complete response and 1 unconfirmed partial response. Disease control rate for ≥ 12wks was 16/25 (64%) with 3 pts > 52wks. CA19-9 decrease of ≥ 20% was seen in 9/25 pts. Conclusions: OXIRI is an active regimen with RR of 20% despite 84% of pts having prior chemo, with disease control for ≥ 12wks in 64% of pts. Predominant toxicity was neutropenia. This study was supported by the National Medical Research Council Singapore. Clinical trial information: NCT02368860.

TPS542 Background: In recent years, Yttrium-90 (Y90) trans-arterial radioembolization (TARE) has emerged as a therapeutic option for intermediate stage hepatocellular carcinoma (HCC). Cancer immunotherapy targeting tumour immune evasion has shown remarkable successes in various cancers. Nivolumab, an immune checkpoint inhibitor of programmed death 1 (PD1), has demonstrated encouraging activity in advanced stage HCC. Similarly, chronic hepatitis B virus (HBV) infection, a strong risk factor for HCC, is characterized by immune escape mechanisms. We hypothesize that TARE will stimulate tumor and/or HBV specific T cell responses that can be boosted using nivolumab. We thus propose an open label phase 2 trial investigating the combination of TARE with nivolumab in BCLC intermediate stage HCC. Methods: Eligible patients (pts) have ECOG performance status ≤ 2, Child-Pugh A score, intermediate stage HCC planned for TARE according to institutional practice with adequate organ function. Pts will be treated with TARE followed by nivolumab 240mg, 21 days after TARE and every 2 weeks thereafter. Pre- and on-treatment tumor biopsies will be taken. Primary end-point is response rate (RR) of combinational TARE and nivolumab. Key secondary end points are: progression free survival, overall survival, safety and quality of life using FACT-HEP score and EORTC QLQ-C30. Exploratory objectives are to evaluate how tumor PD L-1 expression, HCC mutational burden and blood lymphocyte activation/phenotypic profiles correlate with tumor response. Where possible, serial changes in antigen-specific T cell responses to HBV and/or tumour antigens will also be assessed. This study aims to enroll 40 pts as calculated using the Simon two-stage optimal design with 80% power and one sided significance level of 0.05. This will assess whether the addition of nivolumab improves the RR of TARE at 8 weeks from 21% to 41%. Patient accrual was initiated in December 2016 and as of September 2017, 9 pts have been treated. Clinical trial information: 03033446.

140 Background: Trastuzumab (T) + chemotherapy (ctx) is standard for 1st line advanced HER2+ GEA, yet subsequent targeted options are lacking. M is an anti-Her 2 monoclonal antibody with an optimized Fc domain to increase affinity for activating CD16A Fc-receptors (FcR) on NK cells. Outcomes for T-treated patients (pts) carrying the low-affinity CD16A-F allele are generally worse than pts homozygous for the high-affinity V allele. M is designed to be FcR genotype independent. Evidence of clinical activity of M alone has been seen in HER2+ GEA pts post T, while P has demonstrated durable activity. Loss of HER2 amplification may occur after T failure in a subset of initially HER2+ GEA pts. Preclinical studies suggest that engagement of innate and adaptive immunity with the combination of anti-HER-2 antibodies and T-cell checkpoint inhibition could achieve greater antitumor activity than either agent alone. Methods: Advanced HER2+, PD-L1-unselected GEA pts post T failure were eligible. Dose escalation evaluated 10 and 15 mg/kg M and 200 mg P for 2nd line or higher pts. Cohort expansion evaluates safety and objective response rate (ORR) by RECIST v1.1 in 2nd line pts. M + P is given every 21 days; response assessed every 6 weeks. HER2 amplification status was assessed in a subset of pts by plasma circulating tumor (ct) DNA analysis prior to Cycle 1 of M+P. Results: Dose escalation enrolled 9 pts; cohort expansion 48 pts at 15 mg/kg M: 30 in North America (NA) and 18 in Asia (A). Treatment was well tolerated, with 1 drug-related serious adverse event. Of 38 evaluable pts to date in expansion (24 NA and 14 A), the best overall responses include 7 pts (18.4%) with PR (4 confirmed and 3 unconfirmed) and 11 (28.9%) with SD. Higher ORR trends were observed in A vs NA (35.7% vs 8.3%) and G vs GEJ (31.6% vs 5.3%). Of 25 pts with ctDNA results, HER2 amplification detection was higher in GC than GEJ (80% vs 53%). Responses were independent of FcR genotype; CD16A genotype for evaluable pts with PR: 1 V/V, 2 V/F, 2 F/F with similar allelic distribution among non-responders. Conclusions: M+P is a well-tolerated ctx-free regimen that has shown preliminary antitumor activity in 2nd line pts with advanced/metastatic GEA. Clinical trial information: NCT02689284.

2584 Background: The Wnt signalling pathway is involved in cellular proliferation, differentiation, migration and implicated in stem cell function in several cancers. ETC-159 is a selective small molecule inhibitor of porcupine, an enzyme required for palmitoylation and secretion of all Wnt ligands. In preclinical studies, ETC-159 induced tumour regression in patient-derived xenograft models. Methods: Open-label, multi-centre study to determine safety, maximum tolerated dose, pharmacokinetics, pharmacodynamics (PD) of ETC-159 given orally, once every other day in a 28d cycle. PD was evaluated by AXIN2 mRNA levels in whole blood and hair follicles and bone turnover by radiological and serum markers. Dose escalation was by ordinal continual reassessment method with a dose-limiting toxicity (DLT) period of 28d. Results: As of 18 Jan 2017, 16 patients (pts) were treated in 6 cohorts at 1 mg (2pts), 2 mg (2pts), 4 mg (3pts), 8 mg (4pts); 16 mg (3pts), and 30 mg (2pts). 80% were male, median age (range) was 55yr (19-68). One DLT was seen at 16 mg due to hyperbilirubinaemia. Adverse events (≥ 20%) were vomiting (32%); anorexia and fatigue (31%); dysgeusia and constipation (25%). ETC-159 Cmax increased with dose with a mean t1/2 of 14 hr. Plasma levels of ETC-159 that inhibited colony formation in vitro were attained from 4 mg onwards. Reduction of whole blood and hair follicle AXIN2 mRNA levels and doubling of serum β-CTX levels was first observed at 4 mg and at C1D15 in some patients. PD modulation increased with dose, consistent with on-target modulation of Wnt signalling. Two pts had β-CTX rise > 1000 pg/mL (reference limit) and a ≥ 5% reduction in bone density by C3D1. Both took vitamin D and calcium supplements and were given i.v. bisphosphonates. No responses were seen but 2 pts (2 mg: colorectal and 4 mg: peritoneal carcinoma) had stable disease for 6 and 8 cycles respectively. Dose-escalation is ongoing at 30 mg. Conclusions: ETC-159 inhibits Wnt signalling at doses that are well tolerated. β-CTX levels increased early on, and in two pts were associated with reduced bone mineral density. Early and regular monitoring of bone turnover is indicated. This study was sponsored by D3 which is funded by NMRC, NRF and BMRC Singapore. Clinical trial information: NCT02521844.

48 Background: Theoxaliplatin/S-1 (SOX) and cisplatin/S-1 (SP) regimens are interchangeably used in the management of advanced gastric cancer (AGC). We previously developed a classification tool using gene expression signatures which successfully stratified gastric cancer cell lines and primary tumour samples according to their sensitivity to SOX or SP ( Tan et al, Gastroenterology 2011). We now report the first prospective study to evaluate the feasibility and efficacy of using a genomic classifier to tailor treatment in this setting. Methods: Pts with histologically-confirmed locally-advanced, metastatic and recurrent GC were recruited from 3 centres in Singapore and South Korea. Tumours were analysed using the Affymetrix HG-U133 Plus 2.0 array and results were used to classify pts as G1 (oxaliplatin-sensitive), G2 (cisplatin-sensitive) and G3 (status unclear or gene expression not available). G1 and G2 pts were matched to SOX and SP regimens respectively, while G3 pts were assigned SOX. The primary endpoint was best overall response; secondary endpoints were turnaround time and biomarker analyses. Results: Between July 2, 2010, and Apr 2, 2015, we screened 85 AGC pts. 74 pts received at least 1 cycle of treatment and were evaluable for analysis. Median turnaround time was 7 working days (IQR, 5–9). The misclassification rate was 6%. After an initial 30 pts in the G1 subgroup were treated with SOX, subsequent pts ( N = 13) classified as G1 received the SP regimen. The ORR were 44.8%, 8.3%, 26.7% and 55.6% for G1 SOX, G1 SP, G2 SP ( N = 19), G3 SOX ( N = 12) respectively; and was higher in G1 pts treated with SOX compared with SP ( P = 0.033). Post hoc genomic reclassification based on Lei et al (Gastroenterology 2013) confirmed the utility of the metabolic subtype as a predictive marker of benefit from chemotherapy (log rank P value for PFS = 0.004). Conclusions: This bench-to-bedside effort establishes that molecular profiling to direct choice of conventional chemotherapy for AGC is possible within a reasonable timeframe. The clinical utility of our genomic classifiers in question are promising but warrant further investigation. Clinical trial information: NCT01100801.

2500Background: Phosphatidylinositol-3-kinase (PI3K) and fibroblast growth factor receptor (FGFR) pathway dysregulation can co-occur in tumors. In this study (NCT01928459), safety, tolerability, and preliminary activity of the pan-FGFR (BGJ398) + α-specific PI3K (BYL719) inhibitors were evaluated and maximum tolerated dose (MTD) was established in pts w/ advanced solid tumors w/ PI3K catalytic subunit (PIK3CA) mutations ± FGFR alterations. Methods: Pts w/ solid tumors received once-daily (QD) BGJ on D1-D21 of each 28-D cycle (C) and BYL continuously during escalation (PIK3CA-mutant ± FGFR-altered) and expansion (arm 1, PIK3CA-mutant [n = 15]; arm 2, PIK3CA-mutant + FGFR-altered [n = 10]; arm 3, PIK3CA-mutant + FGFR-altered breast cancer [n = 10]). Results: Of 62 pts enrolled, 44% had ≥ 4 prior therapies. The MTD, 125 BGJ + 300 BYL, was determined based on 32 evaluable pts’ data during escalation. C1 dose-limiting toxicities (DLTs) occurred in 4 pts (table). During expansion, 24 pts in arms 1 (n = 12), 2 (...

127 Background: The addition of trastuzumab to cisplatin and 5-fluorouracil or capecitabine has been shown to have superior survival benefit. In this study, the addition of trastuzumab to chemotherapy combination, S-1 (tegafur, gimeracil, oteracil potassium; TS-ONER) and cisplatin, a standard first line therapy for advanced gastric cancer in Japan, was evaluated for efficacy and safety. Methods: This was a single-arm, phase II trial recruiting patients with advanced HER-2 positive (IHC 3+ or FISH +) gastric adenocarcinoma who had not had prior systemic therapy. Patients included had measurable disease, ECOG 0-2, creatinine clearance >60ml/min, LVEF at least 50%. Patients accrued received cisplatin at 60mg/m2 on day 1 of each cycle, trastuzumab at 8mg/kg as loading dose followed by 6mg/kg on day 1 of each cycle and oral S-1 for 14 days ( dosing based on BSA), every 3 weeks. Treatment continued till progressive disease or unbearable toxicity. Primary endpoint was response rate (ORR) and secondary endpoints were PFS, OS, CBR and safety. The study was designed to distinguish a favorable ORR of 55% from a null rate of 30% at 5% significance level and 80% power. Results: A total of 30 patients were recruited. Median age was 61.9 years, 73% were males and 90% had no prior resection of primary tumor. 56.7% were Chinese, 23.3% Japanese and 20% Korean. One patient achieved complete response, 16 had partial response and 2 had stable disease >24 weeks (ORR 63%; CBR 70.4%). Three patients did not have evaluable disease. With a median follow-up of 7.2 months, the median PFS was 7.4 months with 67.7% free of disease progression at the 6-month mark. Median OS was 14.6 months. The most common AEs were anorexia (50%), fatigue (47%), diarrhea ( 47%), nausea (37%), neutropenia (33%), anemia (27%) and mucositis ( 27%). LVEF decreased

2566 Background: BAL101553, a pro-drug of the small molecule BAL27862, is a novel microtubule targeting agent (MTA) with cytotoxic and vascular disrupting properties. Pre-clinical data showed anti-proliferative activity in several in vitro and xenograft tumour models, including tumours refractory to conventional MTAs through diverse resistance mechanisms. Primary objectives of this FIH study were determination of the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT). Secondary objectives included the evaluation of PK, PD and anti-tumour activity. Methods: An accelerated titration dose-escalation design was used. Eligible patients (pts) with advanced solid tumours, who had failed standard therapy, received BAL101553 as a 2-h intravenous infusion on days 1, 8 and 15 of a 28-day cycle. Adverse events (AEs) were assessed according to CTCAEv4. Disease response was assessed by RECIST 1.1 every 2 cycles. Results: 16 pts (7 male; median age 52 years; range 29-80) with solid tumours were treated at 4 dose levels (15, 30, 45 and 60 mg/m2). DLTs were observed at 60 mg/m2 and included rapidly reversible grade (G) 3 hypertension (HTN) and G3 reduced mobility/ dizziness. DLT criteria for HTN were subsequently modified. Frequent drug-related AEs were injection site reactions, nausea, vomiting (all G1-2), and G2-3 HTN (transient during the infusion; responding to nifedipine). One pt experienced G2 peripheral neuropathy at 60 mg/m2. PK analyses indicated conversion of BAL101553 to the active BAL27862, dose proportional exposure for both compounds and a half-life of BAL27862 in a range of 11 to 27 h. Preliminary tumour PD data comparing pre/post biopsies showed loss of CD34+ capillaries and focally decreased proliferation. A confirmed partial response was demonstrated in 1 pt with ampullary (pancreaticobiliary) cancer maintained on treatment for >16 cycles with intra-pt dose escalation. 2 pts (laryngeal and rectal cancer) demonstrated stable disease >16 weeks. Conclusions: BAL101553 is well tolerated up to 60 mg/m2 with evidence of anti-tumour activity. Dose escalation continues to determine the MTD. Clinical trial information: NCT01397929.

2608 Background: AR-12 (OSU-03012) is an oral celecoxib analogue lacking COX-2 inhibitory activity that inhibits pyruvate dehydrogenase kinase isoenzyme 1 (PDK-1), AKT and impacts the endoplastic reticulum stress pathway. Preclinical studies indicate antitumor activity of AR-12 in various models and enhanced activity in combination. We completed a first in human clinical trial to determine its safety and tolerability, maximum tolerated dose (MTD) and recommended phase II dose (RD). Secondary objectives included assessment of tumor response, pharmacokinetics (PK) and pharmacodynamics (PD) including food effect. Methods: Patients (pts) with advanced solid tumors, ECOG PS 0-1, and adequate organ function were recruited in a modified 3+3 dose-escalation study. Pts received a run-in dose of AR-12 to analyze PK-PD and food effect, followed by continuous daily (QD) dosing in 28-day cycles. A twice daily (BID) cohort was initiated based on safety data. PD analysis was performed in platelet-rich plasma (PRP) and paired tumor biopsies when feasible. Results: 35 pts received at least one dose of study drug; 30 were evaluable for dose limiting toxicities (DLT) at dose ranges 100-3200mg QD and 800-1600mg BID. No DLT were observed in the QD cohort; DLT in the BID cohort are listed in table 1. Drug-related events (NCI-CTCAE v3) included rash (G2-2pts; G3-1pt), fatigue (G2-2pts; G3-4pts), nausea (G2-7pts; G3-1pt) and bloating (G2-1pt). Cmax after single dose was dose-proportional but high PK variability was observed, likely due to inadequate disintegration and dissolution of the formulation in the stomach. At RD, partial GSK3ß inhibition in PRP after 4 hours suggests AKT-pathway modulation. Best response (RECIST v1.0) was stable disease >6 cycles for 2 pts. Conclusions: The RD based on safety data is 800mg BID. Signs of pathway modulation were observed in concordance with the expected mechanism of action but were short-lasting. Considering limited drug absorption and PK variability, a new formulation of the drug will be developed to overcome these limitations. Clinical trial information: NCT00978523. [Table: see text]

6 Background: Previous studies suggest that tumoral cfDNA is a potential biomarker in cancer. Methods: Prospective collection of samples from patients (pts) referred to a phase I trials unit, in 2 cohorts: “A”(manual isolation of cfDNA, Sep09-Dec10) and “B”(robotic isolation, Jan11-Sep11) and from 41 healthy volunteers (HV). CfDNA and tumor DNA from matched formalin-fixed paraffin-embedded (FFPE) tissue were isolated, quantified and analyzed for 238 oncogenic mutations (OM) in 19 oncogenes using Sequenom OncoCarta Panel 1.0. Mutation data were used for trial allocation when available. Statistical analyses used Pearson’s Chi-squared test and Mann-Whitney test. Results: 280 pts were included: breast (60; 21%), ovarian (44; 16%), and colorectal (42; 15%). 265 (95%) plasma and 194 (69%) FFPE samples were suitable for analysis. In 181 pts (65%) both samples were available for comparison. Median turnover time for cfDNA 7 days (range 5-14). Median [cfDNA] (concentration; ng/ml) in pts was higher than in HV (“A” 21 v 6.4;p