Remarkable Response to Olaparib in a Patient with Combined Hepatocellular-Cholangiocarcinoma Harboring a Biallelic BRCA2 Mutation

Off-label use of olaparib in uncommon tumor locations in patients with impaired homologous recombination genes

OBJECTIVE

To describe the effectiveness and safety of olaparib off-label indications in patients with impaired homologous recombination genes and solid tumors different than those authorized.

METHODS

A single-center, observational and retrospective study including patients treated with olaparib for off-label use. The main variables were patient characteristics, prior therapies, response to therapy, progression-free survival, overall survival and adverse events.

RESULTS

A total of 6 patients were included. All patients had metastases and received 3 or more lines of prior treatment. The primary tumor locations and mutations were partner and localizer of BRCA2 (PALB2) intrahepatic cholangiocarcinoma, ataxia telangiectasia mutated (ATM) non-small cell lung adenocarcinoma, somatic breast cancer gene (sBRCA2) colorectal cancer, germinal breast cancer gene 2 (gBRCA2) breast neuroendocrine tumor, gBRCA2 ampullary cancer and gBRCA2 pancreatic neuroendocrine tumor. At the end of the study, one patient was still receiving olaparib showing more than 25 months of sustained stable disease response. No novel toxicities were observed besides those included in the product information.

CONCLUSIONS

There is limited published evidence on the use of olaparib in patients harboring pathogenic variants other than breast cancer genes, like PALB2 and ATM and conditions different than those authorized such as digestive tract, neuroendocrine and lung tumors. Further research is to assess the efficacy of olaparib in these patients.

Current and Future Therapeutic Targets for Directed Molecular Therapies in Cholangiocarcinoma

We conducted a comprehensive review of the current literature of published data, clinical trials (MEDLINE; ncbi.pubmed.com), congress contributions (asco.org; esmo.org), and active recruiting clinical trains (clinicaltrial.gov) on targeted therapies in cholangiocarcinoma. Palliative treatment regimens were analyzed as well as preoperative and perioperative treatment options. We summarized the current knowledge for each mutation and molecular pathway that is or has been under clinical evaluation and discussed the results on the background of current treatment guidelines. We established and recommended targeted treatment options that already exist for second-line settings, including IDH-, BRAF-, and NTRK-mutated tumors, as well as for FGFR2 fusion, HER2/neu-overexpression, and microsatellite instable tumors. Other options for targeted treatment include EGFR- or VEGF-dependent pathways, which are known to be overexpressed or dysregulated in this cancer type and are currently under clinical investigation. Targeted therapy in CCA is a hallmark of individualized medicine as these therapies aim to specifically block pathways that promote cancer cell growth and survival, leading to tumor shrinkage and improved patient outcomes based on the molecular profile of the tumor.

Current advances and future directions in combined hepatocellular and cholangiocarcinoma

The low incidence of combined hepatocellular cholangiocarcinoma (cHCC-CCA) is an important factor limiting research progression. Our study extensively included nearly three decades of relevant literature and assembled the most comprehensive database comprising 5,742 patients with cHCC-CCA. We summarized the characteristics, tumor markers, and clinical features of these patients. Additionally, we present the evolution of cHCC-CCA classification and explain the underlying rationale for these classification standards. We reviewed cHCC-CCA diagnostic advances using imaging features, tumor markers, and postoperative pathology, as well as treatment options such as surgical, adjuvant, and immune-targeted therapies. In addition, recent advances in more effective chemotherapeutic regimens and immune-targeted therapies were explored. Furthermore, we described the molecular mutation features and potential specific markers of cHCC-CCA. The prognostic value of Nestin has been proven, and we speculate that Nestin will also play a role in classification and diagnosis. However, further research is needed. Moreover, we believe that the possibility of using machine learning liquid biopsy for preoperative diagnosis and establishing a scoring system are directions for future research.

Hepatocellular-Cholangiocarcinoma Collision Tumors: An Update of Current Management Practices

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare form of primary hepatic collision tumor, with an incidence ranging from 0.4 to 14.2%. Given the diagnostic challenges and lack of randomized trials, standardized treatment has yet to be established. We aim to review the literature to summarize the diagnosis, molecular characteristics, current treatment modalities, and challenges for cHCC-CC. A literature review was performed using PubMed. We included studies investigating and describing cHCC-CC, focusing on surgical, medical, and radiologic treatments. Overall prognosis is poor, with a 5-year survival rate under 30%. Minor or major hepatectomy with R0 resection is the only curative treatment; however, recurrence is likely (as high as 50% within 5 years). The role of liver transplantation is also highly debated given the biliary nature of these tumors, with cHCC-CC as a relative contraindication for liver transplantation. Although gemcitabine-based treatments had higher progression-free survival over sorafenib, there is no standard chemotherapy regimen. Treatment with gemcitabine and platinum demonstrates improved disease control rates compared to gemcitabine in conjunction with 5-fluorouracil (78.4% verse 38.5% respectively). Additionally, platinum-containing chemotherapy regimens exhibit a higher overall response rate than non-platinum regimens (21.4% verse 7.0% respectively). These molecular-directed therapies have prolonged survival for HCC, but further investigation needs to be done to assess their utility in patients with cHCC-CC. cHCC-CC is a rare and complex subset of primary hepatic neoplasms with a dismal prognosis and unstandardized treatment options. Further trials need to be performed to investigate systemic chemotherapy and immunotherapy options for patients with unresectable disease.

Management of Locally Advanced or Metastatic Combined Hepatocellular Cholangiocarcinoma

Combined hepatocellular cholangiocarcinoma (cHCC-CC) is a rare primary liver malignancy that comprises features of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). Due to the rarity of this tumor, the treatment of choice has not yet been defined. For resectable disease, liver resection is the mainstay treatment. However, most patients relapse or display advanced disease and were not surgical candidates. Although the majority of patients are either primarily or secondarily treated in palliative intent, no guideline recommendations or prospective trial reports exist to allow reliable evaluation of debated treatment options. We review different locoregional or medical treatment options for advanced combined hepatocellular cholangiocarcinoma (cHCC-CC) in the neoadjuvant, adjuvant, or palliative setting and discuss the possibility of predictive biomarker-guided therapeutic options.

Human Metastatic Cholangiocarcinoma Patient-Derived Xenografts and Tumoroids for Preclinical Drug Evaluation

PURPOSE

Cholangiocarcinoma (CCA) is usually diagnosed at advanced stages, with limited therapeutic options. Preclinical models focused on unresectable metastatic CCA are necessary to develop rational treatments. Pathogenic mutations in IDH1/2, ARID1A/B, BAP1, and BRCA1/2 have been identified in 30%-50% of patients with CCA. Several types of tumor cells harboring these mutations exhibit homologous recombination deficiency (HRD) phenotype with enhanced sensitivity to PARP inhibitors (PARPi). However, PARPi treatment has not yet been tested for effectiveness in patient-derived models of advanced CCA.

EXPERIMENTAL DESIGN

We have established a collection of patient-derived xenografts from patients with unresectable metastatic CCA (CCA_PDX). The CCA_PDXs were characterized at both histopathologic and genomic levels. We optimized a protocol to generate CCA tumoroids from CCA_PDXs. We tested the effects of PARPis in both CCA tumoroids and CCA_PDXs. Finally, we used the RAD51 assay to evaluate the HRD status of CCA tissues.

RESULTS

This collection of CCA_PDXs recapitulates the histopathologic and molecular features of their original tumors. PARPi treatments inhibited the growth of CCA tumoroids and CCA_PDXs with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1. In line with these findings, only CCA_PDX and CCA patient biopsy samples with mutations of BRCA2 showed RAD51 scores compatible with HRD.

CONCLUSIONS

Our results suggest that patients with advanced CCA with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1, are likely to benefit from PARPi therapy. This collection of CCA_PDXs provides new opportunities for evaluating drug response and prioritizing clinical trials.

Unraveling the actin cytoskeleton in the malignant transformation of cholangiocyte biology

Correct actin cytoskeleton organization is vital in the liver organ homeostasis and disease control. Rearrangements of the actin cytoskeleton may play a vital role in the bile duct cells cholangiocytes. An abnormal actin network leads to aberrant cell morphology, deregulated signaling networks and ultimately triggering the development of cholangiocarcinoma (CCA) and paving the route for cancer cell dissemination (metastasis). In this review, we will outline alterations of the actin cytoskeleton and the potential role of this dynamic network in initiating CCA, as well as regulating the course of this malignancy. Actin rearrangements not only occur because of signaling pathways, but also regulate and modify cellular signaling. This emphasizes the importance of the actin cytoskeleton itself as cause for aberrant signaling and in promoting tumorigenic phenotypes. We will highlight the impact of aberrant signaling networks on the actin cytoskeleton and its rearrangement as potential cause for CCA. Often, these exact mechanisms in CCA are limited understood and still must be elucidated. Indeed, focusing future research on how actin affects and regulates other signaling pathways may provide more insights into the mechanisms of CCA development, progression, and metastasis. Moreover, manipulation of the actin cytoskeleton organization highlights the potential for a novel therapeutic area.

Role of molecular genetics in the clinical management of cholangiocarcinoma

The incidence of cholangiocarcinoma (CCA) has steadily increased during the past 20 years, and mortality is increasing. The majority of patients with CCA have advanced or metastatic disease at diagnosis, and treatment options for unresectable disease are limited, resulting in poor prognosis. However, recent identification of targetable genomic alterations has expanded treatment options for eligible patients. Given the importance of early and accurate diagnosis in optimizing patient outcomes, this review discusses best practices in CCA diagnosis, with a focus on categorizing molecular genetics and available targeted therapies. Imaging and staging of CCAs are discussed, as well as recommended biopsy collection techniques, and molecular and genomic profiling methodologies, which have become increasingly important as molecular biomarker data accumulate. Approved agents targeting actionable genomic alterations specifically in patients with CCA include ivosidenib for tumors harboring IDH1 mutations, and infigratinib and pemigatinib for those with FGFR2 fusions. Other agents currently under development in this indication have shown promising results, which are presented here.