This study is registered at ClinicalTrials.gov (NCT01267344). All patients gave written informed consent.

BackgroundGastrointestinal stromal tumors (GISTs) are caused by the constitutive activation of KIT or platelet-derived growth factor receptor alpha (PDGFRA) mutations. Imatinib selectively inhibits KIT and PDGFR, leading to disease control for 80%–90% of patients with metastatic GIST. Imatinib resistance can occur within a median of 2–3 years due to secondary mutations in KIT. According to preclinical studies, both imatinib and sunitinib are ineffective against exon 17 mutations. However, the treatment efficacy of regorafenib for patients with GIST with exon 17 mutations is still unknown.Patients and MethodsDocumented patients with GIST with exon 17 mutations were enrolled in this study. Patients received 160 mg of oral regorafenib daily on days 1–21 of a 28-day cycle. The primary end point of this trial was the clinical benefit rate (CBR; i.e., complete or partial response [PR], as well as stable disease [SD]) at 16 weeks. The secondary end points of this study included progression free survival (PFS), overall survival, and safety.ResultsBetween June 2014 to May 2016, 18 patients were enrolled (15 of which were eligible for response evaluation). The CBR at 16 weeks was 93.3% (14 of 15; 6 PR and 8 SD). The median PFS was 22.1 months. The most common grade 3 toxicities were hand-and-foot skin reactions (10 of 18; 55.6%), followed by hypertension (5 of 18; 27.8%).ConclusionRegorafenib significantly prolonged PFS in patients with advanced GIST harboring secondary mutations of exon 17. A phase III trial of regorafenib versus placebo is warranted.Trial registrationThis trial is registered atClinicalTrials.gov in November 2015, number NCT02606097.Key messageThis phase II trial was conducted to assess the efficacy and safety of regorafenib in patients with GIST with exon 17 mutations. The results provide strong evidence that regorafenib significantly prolonged PFS in patients with advanced GIST harboring secondary mutations of exon 17.

Non-random gains of chromosome 5p have been observed in clinically aggressive gastrointestinal stromal tumors, whereas the driving oncogenes on 5p remain to be characterized. We used an integrative genomic and functional approach to identify amplified oncogenes on 5p and to evaluate the relevance of AMACR amplification at 5p13.3 and its overexpression in gastrointestinal stromal tumors. Thirty-seven tumor samples, imatinib-sensitive GIST882 cell line, and imatinib-resistant GIST48 cell line were analyzed for DNA imbalances using array-based genomic profiling. Forty-one fresh tumor samples of various risk categories were enriched for pure tumor cells by laser capture microdissection and quantified for AMACR mRNA expression. AMACR-specific fluorescence in situ hybridization and immunohistochemistry were both informative in tissue microarray sections of 350 independent primary gastrointestinal stromal tumors, including 213 cases with confirmed KIT /PDGFRA genotypes. To assess the oncogenic functions of AMACR, GIST882 and GIST48 cell lines were stably silenced against their endogenous AMACR expression. In 59% of cases featuring 5p gains, two major amplicons encompassed discontinuous chromosomal regions that were differentially overrepresented in high-risk cases, including the one harboring the mRNA-upregulated AMACR gene. Gene amplification was detected in 19.7% of cases (69/350) and strongly related to protein overexpression (p<0.001), although 52% of AMACR-overexpressing cases exhibited no amplification. Both gene amplification and protein overexpression were significantly associated with epithelioid histology, larger size, increased mitoses, higher risk levels, and unfavorable genotypes (all p≤0.03). They were also independently predictive of decreased disease-free survival (overexpression, p<0.001; amplification, p=0.020) in the multivariate analysis. Concomitant with downregulated cyclin D1, cyclin E, and CDK4, AMACR knockdown suppressed cell proliferation and induced G1-phase arrest, but did not affect apoptosis in both GIST882 and GIST48 cells. In conclusion, AMACR amplification is a mechanism driving increased mRNA and protein expression and conferring aggressiveness through heightened cell proliferation in gastrointestinal stromal tumors.

4117 Background: Patients (pts) with advanced CCA who progressed on or after first line chemotherapy have no approved treatment options. Fibroblast growth factor receptor (FGFR) gene alterations are observed in many tumor types including 14-17% in CCA. Erdafitinib, an orally bioavailable, selective pan-FGFR kinase inhibitor, has shown clinical activity against solid tumors with FGFR alterations. Methods: LUC2001 is an open-label, multicenter, Ph2a study in advanced CCA pts with FGFR alterations (FoundationOne), who progressed after ≥ 1 prior treatment. The primary endpoint is objective response rate (ORR; RECIST 1.1). The secondary endpoints are disease control rate (DCR), progression free survival (PFS), duration of response (DOR), safety and pharmacokinetics (PK). Disease is evaluated every 8 weeks until disease progression (PD). Results: As of 3 Dec 2018, 222 CCA pts were molecularly screened; 34 had FGFR alterations, of whom 14 (8 FGFR2 fusion, 3 FGFR2 mutation, 1 FGFR3 fusion, 2 FGFR3 mutation) were dosed 8 mg once daily with up titration option. Median age was 51.5 years. 13/14 and 12/14 pts had prior platinum or gemcitabine based therapy respectively, 7/14 pts got re-treated with platinum or gemcitabine based therapy, and 9/14 pts had ≥2 prior lines of therapy. Median number of treatment cycles was 5.0 (range: 1; 22) and treatment duration was 4.83 (range: 0.5; 20.3) months. In 12 evaluable pts, there were 6 confirmed partial response (PR), 4 stable disease (SD) and 2 PD; ORR (CR+PR) was 6/12 (50.0%), DCR (CR+PR+uCR+uPR+SD) was 10/12 (83.3%); median DOR was 6.83 months (95% CI: 3.65; 12.16); median PFS was 5.59 months (95% CI: 1.87, 13.67). In 10 evaluable FGFR2+ pts, ORR was 6/10 (60.0%); DCR was 10/10(100%); median PFS was 12.35 months (95% CI: 3.15, 19.38). The most common TEAEs ( > 30%) were hyperphosphatemia, dry mouth, stomatitis, and dry skin. 9 pts had ≥ Grade 3 AEs (8 Grade 3,1 Grade 5), of which 7 drug related. TEAE led to treatment 1 discontinuation, 6 dose reductions and 1 death (not drug related). The results of PK and PK/PD relationship were consistent with other erdafitinib studies in different ethnic background pts. Conclusions: Asian advanced CCA pts with FGFR alterations treated with erdafitinib had encouraging efficacy and acceptable safety profile similar to experience in other tumor types and populations. Clinical trial information: NCT02699606.

To explore the implications of lipid catabolism-associated genes in gastrointestinal stromal tumors, we reappraised transcriptomic and genomic datasets and identified copy-gained and differentially upregulated PLCB4 gene associated with tumor progression. On full sections, PLCB4 mRNA abundance and PLCß4 immunoexpression were validated in 70 cases. On tissue microarrays, PLCB4 gene copies and PLCß4 immunoexpression were both informative in 350 cases with KIT/PDGFRA/BRAF genotypes noted in 213. In GIST48 cell line, we stably silenced PLCB4 and YAP1 to characterize their functional effects and regulatory link. Compared with normal tissue, PLCB4 mRNA abundance significantly increased across tumors of various risk levels (p<0.001), and was strongly correlated with immunoexpression level (p<0.001, r=0.468). Including polysomy (12.6%) and amplification (17.4%), PLCB4 copy gain was detected in 105 (30%) cases and significantly more frequent (p<0.001) in cases exhibiting higher PLCß4 immunoexpression (82/175). Copy gain and protein overexpression were modestly associated with unfavorable genotypes (both p<0.05), strongly associated with increased size, mitosis, and risk levels defined by both the NIH and NCCN schemes (all p<0.001), and univariately predictive of shorter disease-free survival (both p<0.0001). In PLCß4-overexpressing cases, PLCB4 copy gain still predicted worse prognosis (p<0.0001). In a multivariate comparison, both overexpression (p=0.007, hazard ratio: 2.454) and copy gain (p=0.031, hazard ratio: 1.892) exhibited independent impact. In vitro, YAP1 increased PLCB4 mRNA and protein expression, and both molecules significantly promoted cell proliferation. Being driven by copy gain or YAP1, PLCß4 is a novel overexpressed enzyme regulating lipid catabolism that promotes cell proliferation and independently confers a worse prognosis.

Background: Few studies have reported the epidemiology and clinical outcome of venous thromboembolism (VTE) in Asian patients with pancreatic cancer. This study investigated the incidence, risk factors, and clinical outcome of VTE in patients with pancreatic cancer following palliative chemotherapy. Methods: The medical records of 838 patients with newly diagnosed locally advanced or metastatic pancreatic cancer who underwent palliative chemotherapy between 2010 and 2016 at four institutes in Taiwan were retrospectively reviewed. The clinical characteristics of all patients were analyzed to identify independent predictors of VTE and their effects on survival outcome. Results: During the median follow-up period of 7.7 months (range, 0.6–55.6), VTE occurred in 67 (8.0%) of the 838 patients. Leukocyte count > 11,000/μL and presence of liver metastases were the independent predictors of VTE. Patients with VTE did not show significantly poorer survival outcomes than those without VTE. However, early-onset VTE that occurred within 1.5 months after chemotherapy initiation was an independent negative prognosticator for overall survival. Conclusion: VTE incidence was found to be lower in Asian patients with pancreatic cancer than in their Western counterparts. Early-onset VTE, but not late-onset VTE, is a negative prognosticator for survival outcomes.

BackgroundLenvatinib is approved for patients with advanced hepatocellular carcinoma (HCC) due to its non-inferiority to sorafenib of overall survival (OR) in clinical trials. This study was to compare the effectiveness and safety of lenvatinib and sorafenib in the real world.MethodsWe retrospectively evaluated 338 patients with unresectable HCC who had undergone lenvatinib or sorafenib treatment between January 2018 and August 2020. Propensity-score matching analysis was performed with a 1:2 ratio to reduce the real-life baseline difference between the two groups.ResultsA total of 210 patients (Male/Female: 150/60, mean age: 65.8 years) were recruited including 70 patients in the Lenvatinib group and 140 patients in the Sorafenib group. Compared with sorafenib, lenvatinib had significantly longer progression-free survival (PFS) (5.2 vs 3.3 months, p=0.019) but similar OR (13.3 vs 11.8 months, p=0.714). Additionally, lenvatinib had better disease control rates (62.3 vs 48.6%, p=0.029) and equivalent incidences of treatment-related adverse events over sorafenib. In multivariate analysis, lenvatinib was associated with better PFS over sorafenib (hazard ratio: 0.49, 95% confidence interval: 0.3–0.79, p=0.004) after adjustments of albumin-bilirubin grade and alpha-fetoprotein level; however, different agents using lenvatinib or sorafenib did not contribute to OS, whether in univariate or multivariate analysis. Patients who failed lenvatinib had a lower proportion of having sequential systemic therapies compared with the Sorafenib group (36.2 vs 47.8%, p=0.02). The most frequently used sequential therapy following lenvatinib and sorafenib was chemotherapy (n=9, 42.8%) and regorafenib (n=33, 50.8%), respectively.ConclusionsIn clinical real-life practice, lenvatinib illustrated promising survival benefits and acceptable safety for patients with unresectable HCC, while reducing the risk of progression disease compared with sorafenib. Additionally, lack of approved post-lenvatinib systemic therapies is a serious issue in the real world.

Although imatinib mesylate (IM) has revolutionized the management of gastrointestinal stromal tumors (GISTs), drug resistance remains a challenge. Previous studies have shown that the expression of aurora kinase A (AURKA) predicts recurrence in patients with primary, surgically resected GISTs. The current study aimed to evaluate the significance of AURKA expression as an unfavorable prognostic marker for advanced GISTs, and provide evidence that AURKA could be a potential therapeutic target in GISTs. The prognostic significance of the expression of AURKA, along with other clinicopathological factors, was analyzed in a cohort of 99 IM-treated patients with advanced GISTs. The potential use of an inhibitor of AURKA as a therapeutic agent against GISTs was also tested in GIST cell lines. Among 99 enrolled patients, poor performance status, large tumor size, drug response, and AURKA overexpression were independent prognostic factors for poor progression-free survival (PFS). For overall survival (OS), only large tumor size and AURKA overexpression were identified as independent unfavorable factors. In an in vitro study, MLN8237, an AURKA inhibitor, inhibited growth of both IM-sensitive and IM-resistant GIST cells in a concentration-dependent manner, and exhibited synergistic cytotoxicity with IM in GIST cells. The inhibitory effect of MLN8237 in GIST cells could be attributed to the induction of G2/M arrest, apoptosis, and senescence. Our study shows that AURKA expression independently predicted poor PFS and OS in patients with advanced GISTs who were treated with IM. An AURKA inhibitor may have potential as a therapeutic agent for both IM-sensitive and IM-resistant GISTs.