Citations

TPS532 Background: Recent studies have shown that FGFR2 fusions may represent recurrent (prevalence ~10-15% in larger cohorts) driver events amenable to therapeutic targeting in patients with advanced, intrahepatic cholangiocarcinoma. Methods: This single arm pilot study (NCT02265341) is being conducted at 3 centers (Mayo Clinic Arizona, Mayo Clinic Florida and Mayo Clinic Rochester; enrollment initiated December 2014). Next-generation sequencing based assays and a FISH-break apart assay are used to identify tumors with FGFR2 fusions. Patients must additionally have histologically/cytologically confirmed cholangiocarcinoma, ECOG performance score 0-2, measurable disease, preserved hematologic/renal and hepatic function and absence of cardiac events/stroke in the preceding 6 months. Ponatinib is administered at 45 mg once daily. Patients will be treated until disease progression, intolerable toxicity or patient decision to not pursue further therapy. The primary objective of the study is to estimate the clinical benefit rate (defined as composite of partial response rate, complete response rate and stable disease rate ≥ 4 months; as defined by RECIST criteria v1.1). Secondary endpoints include estimation of progression-free survival, overall survival, CA19-9 response rate (defined as > 50% reduction from baseline) and evaluation of the overall adverse event profile of ponatinib in this patient population. Translational objectives include serial circulating DNA (ct-DNA) monitoring, target knockdown assessments in tumor tissue (p-FGFR2, p-FRS2, p-Akt and p-ERK) and evaluation of mechanisms of resistance through comparison of baseline and progression biopsy samples using multi-platform sequencing (exome, RNA-Seq and methyl-Seq). Additionally, quality of life assessments will be evaluated using EORTC-QLQ-C30 and BIL21 tools. A total of 30 patients will be enrolled into the study (12 of 30 patients have been enrolled). The trial is designed using an underlying assumption of clinical benefit rate (CBR) of 5% with significance level of 0.15 and 80% power to detect a 20% CBR. Clinical trial information: NCT02265341.

328 Background: Patients with a history of solid organ transplants have been excluded from PD-1/PD-L1 inhibitor clinical trials due to concern for graft rejection. Only 2 case reports of PD-1 inhibitor use in patients with liver transplantation (LT) have been reported thus far. Here, we report our experience with using checkpoint inhibitors in metastatic cancer patients with LT. Methods: A single center pilot evaluation was conducted to evaluate the safety and efficacy of PD-1/PD-L1 inhibitors in patients with LT. PD-L1 staining on both the tumor and allograft were assessed if there was available tissue. The primary endpoint was evaluation of the risk for allograft rejection. Secondary endpoints included RECIST v1.1 and Immune-Related Response criteria (iRC) response rates, progression free survival (PFS) and overall survival (OS). Translational objectives included the relationship of PD-L1/PD-1 staining of tumor/allograft with response and rejection. Results: Six metastatic cancer patients with a history of LT received PD-1 inhibitor therapy (hepatocellular n=5, melanoma n=1). 3 patients were on mTOR inhibitor as immunosuppressive regimen and 3 on calcineurin inhibitor. Overall, allograft rejection was observed in 1/6 patients (on mTOR inhibitor). One patient achieved a CR (melanoma), 3 patients had PD and 2 patients discontinued therapy prior to restaging assessments. A single response (by both RECIST v1.1 and iRC) and rejection were reported in patients who received mTOR inhibitors (1 of 3). Three patients were tested for PD-L1 staining in the allograft tissue and all of them were negative (0% staining) with no graft rejections observed. Four patients had tumor PD-L1 evaluated (2 patients tested positive with 1 patient obtained a CR). The median OS, PFS and duration of therapy were 1.2, 1.8 and 1.2 months respectively. Conclusions: In this pilot evaluation of PD-1/PD-L1 inhibitors in LT patients both preliminary efficacy (1 of 4) and allograft rejection (1 of 6) was exhibited. Larger, prospective trials are needed to elucidate optimal patient and immunosuppressive regimen selection in these patients.

Aberrant hepatocyte Notch activation is required for development of NASH-associated fibrosis, and Notch inhibition ameliorates obesity-induced liver disease.

AimsBile salt export pump (BSEP) is a transporter expressed exclusively at hepatic canaliculi and drives bile‐salt efflux. Minimal data exist about BSEP expression in tumours. We hypothesized that BSEP immunohistochemistry would be specific for hepatocellular carcinoma (HCC).Methods and resultsTissue microarrays, including 48 HCC, 41 cholangiocarcinomas and 24 metastatic tumours in liver, were immunostained for BSEP. Expression was compared with common markers of hepatocytic differentiation including CD10, hepatocyte paraffin‐1 antigen (HepPar‐1), carcinoembryonic antigen, arginase‐1 (ARG) and glypican‐3 (GPC‐3). BSEP expression was assessed in normal tissues. Special attention was given to adrenal gland (normal and neoplasia). BSEP was easy to interpret and showed no background staining. Canalicular expression was seen in all normal livers, but not in other normal tissue. BSEP was 90% sensitive and 100% specific for HCC (canalicular in 33 of 43 positive cases). The sensitivity of ARG was slightly higher, but specificity was slightly lower (94% for both). HepPar‐1 was 90% sensitive and 97% specific. CD10, polyclonal carcinoembryonic antigen (pCEA) and GPC‐3 all had lower sensitivity (74, 81 and 54%, respectively).ConclusionsIn malignant tumours in the liver, BSEP marking was 100% specific and 90% sensitive for HCC. The specificity of BSEP for HCC obviates the need to identify a ‘canalicular’ pattern, which can limit the utility of other canalicular markers.