Targeting the FGFR signaling pathway in cholangiocarcinoma: promise or delusion?

Human Biodistribution and Radiation Dosimetry of the Targeting Fibroblast Growth Factor Receptor 1-Positive Tumors Tracer [68Ga]Ga-DOTA-FGFR1-Peptide

Objective: [68Ga]Ga-DOTA-FGFR1-peptide is a novel positron emission tomography (PET) radiotracer targeting fibroblast growth factor receptor 1 (FGFR1). This study evaluated the safety, biodistribution, radiation dosimetry, and imaging potential of [68Ga]Ga-DOTA-FGFR1-peptide. Methods: The FGFR1-targeting peptide DOTA-(PEG2)-KAEWKSLGEEAWHSK was synthesized by manual solid-phase peptide synthesis with high-performance liquid chromatography purification, and labeled with 68Ga with DOTA as chelating agent. We recruited 14 participants and calculated the radiation dose of 4 of these pathologically confirmed nontumor subjects using OLINDA/EXM 2.2.0 software. At the same time, the imaging potential in 10 of these lung cancer patients was evaluated. Results: The biodistribution of [68Ga]Ga-DOTA-FGFR1-peptide in 4 subjects showed the highest uptake in the bladder and kidney. Dosimetry analysis indicated that the bladder wall received the highest effective dose (3.73E-02 mSv/MBq), followed by the lungs (2.36E-03 mSv/MBq) and red bone marrow (2.09E-03 mSv/MBq). No normal organs were found to have excess specific absorbed doses. The average systemic effective dose was 4.97E-02 mSv/MBq. The primary and metastatic tumor lesions were clearly visible on PET/computed tomography (CT) images in 10 patients. Conclusion: Our results indicate that [68Ga]Ga-DOTA-FGFR1-peptide has a good dosimetry profile and can be used safely in humans, and it has significant potential value for clinical PET/CT imaging.

Intrahepatic cholangiocarcinoma with FGFR alterations: A series of Chinese cases with an emphasis on their clinicopathologic and genetic features

Intrahepatic Cholangiocarcinoma (iCCA) with FGFR alterations is relatively rare, and its identification is important in the era of targeted therapy. We collected a large series of FGFR-altered cases in the Chinese population and characterized their clinicopathological and genetic features. Among the 18 FGFR-altered cases out of 260 iCCAs, 10 were males and 8 were females, ranging in age from 35 to 74 years (mean, 57.3 years; median, 58 years). Pathologically, they include 9 cases of large duct (LD, 50 %) and small duct (SD, 50 %) types each. All of them (100 %, 18/18) showed microsatellite stable (MSS) and low tumor mutation burden (TMB). Genetically, FGFR alterations involved FGFR1 (20 %), FGFR2 (70 %), and FGFR3 (10 %), with FGFR2 rearrangement accounting for the most (11/18). The most frequently altered genes/biological processes were development/proliferation-related pathways (44 %), chromatin organization (20 %), and tumor suppressors (32 %). Our study further revealed the clinicopathological and genetic features of FGFR-altered iCCA and demonstrated that its occurrence may show regional or ethnic variability and is less common in the Chinese population. A significant number of LD-type iCCA cases also have FGFR alterations rather than the SD type.

Buparlisib and ponatinib inhibit aggressiveness of cholangiocarcinoma cells via suppression of IRS1-related pathway by targeting oxidative stress resistance

Cholangiocarcinoma (CCA) is an oxidative stress-driven liver cancer with bile duct epithelial cell phenotypes and currently lacks effective treatments, making targeted drug therapy urgently needed. Oxidative stress plays a critical role in CCA carcinogenesis, involving cells with oxidative stress resistance via upregulation of the PI3K and MEKK3 signaling pathways. In this study, we investigated the antineoplastic efficacy of a PI3K inhibitor (buparlisib) and a multi-tyrosine kinase inhibitor (ponatinib) on CCA. The cytotoxicity of the drug combination was studied in vitro using CCA cell lines and in vivo using CCA xenograft models. It was found that the drug combination suppressed growth, colony formation, and migration abilities of CCA cells and induced oxidative damage, cell cycle arrest, and autophagy by suppressing MEKK3 and YAP1 through inhibition of insulin receptor substrate 1 (IRS1) signaling. Moreover, the drugs would potentially bind to the IRS1 protein, significanly decreasing IRS1 phosphorylation. Additionally, the drug combination significantly diminished the expression of YAP1, the cell proliferation marker and an antioxidant regulator, and increased oxidative stress-responsive markers in the xenograft model. In conclusion, targeting oxidative stress resistance with combined buparlisib and ponatinib suppressed tumor growth and migration by repressing IRS1-related pathways and ultimately inducing oxidative damage, suggesting the potential for targeted therapy and clinical trials in CCA patients over the use of a single drug.

Resistance mechanism to fibroblast growth factor receptor (FGFR) inhibitors in cholangiocarcinoma

Precision medicine is a major achievement that has impacted on management of patients diagnosed with advanced cholangiocarcinoma (CCA) over the last decade. Molecular profiling of CCA has identified targetable alterations, such as fibroblast growth factor receptor-2 (FGFR-2) fusions, and has thus led to the development of a wide spectrum of compounds. Despite favourable response rates, especially with the latest generation FGFRi, there are still a proportion of patients who will not achieve a radiological response to treatment, or who will have disease progression as the best response. In addition, for patients who do respond to treatment, secondary resistance frequently develops and mechanisms of such resistance are not fully understood. This review will summarise the current state of development of FGFR inhibitors in CCA, their mechanism of action, activity, and the hypothesised mechanisms of resistance.

Past, present, and future of FGFR inhibitors in cholangiocarcinoma: from biological mechanisms to clinical applications

INTRODUCTION

Biliary tract carcinoma (BTC) is a heterogenous group of aggressive hepatic malignancies, second to hepatocellular carcinoma per prevalence. Despite clinical research advancement, the overall 5-year survival rate is just above 2%. With the identification of somatic core mutations in half of cholangiocarcinomas. In the intrahepatic subtype (iCCA), it is possible to target mutational pathways of pharmacological interest.

AREAS COVERED

Major attention has been drawn to fibroblast growth factor receptor (FGFR), especially the type 2 (FGFR2), found mutated in 10-15% of iCCAs. FGFR2 fusions became the target of novel tyrosine-kinase inhibitors investigated in clinical studies, showing promising results so as to gain regulatory approval by American and European committees in recent years. Such drugs demonstrated a better impact on the quality of life compared to standard chemotherapy; however, side effects including hyperphosphatemia, gastrointestinal, eye, and nail disorders are common although mostly manageable.

EXPERT OPINION

As FGFR inhibitors may soon become the new alternative to standard chemotherapy in FGFR-mutated cholangiocarcinoma, accurate molecular testing and monitoring of acquired resistance mechanisms will be essential. The possible application of FGFR inhibitors in first-line treatment, as well as in combination with current standard treatments, remains the next step to be taken.

To Investigate Growth Factor Receptor Targets and Generate Cancer Targeting Inhibitors

Receptor tyrosine kinase (RTK) regulates multiple pathways, including Mitogenactivated protein kinases (MAPKs), PI3/AKT, JAK/STAT pathway, etc. which has a significant role in the progression and metastasis of tumor. As RTK activation regulates numerous essential bodily processes, including cell proliferation and division, RTK dysregulation has been identified in many types of cancers. Targeting RTK is a significant challenge in cancer due to the abnormal upregulation and downregulation of RTK receptors subfamily EGFR, FGFR, PDGFR, VEGFR, and HGFR in the progression of cancer, which is governed by multiple RTK receptor signalling pathways and impacts treatment response and disease progression. In this review, an extensive focus has been carried out on the normal and abnormal signalling pathways of EGFR, FGFR, PDGFR, VEGFR, and HGFR and their association with cancer initiation and progression. These are explored as potential therapeutic cancer targets and therefore, the inhibitors were evaluated alone and merged with additional therapies in clinical trials aimed at combating global cancer.

Outcomes following FGFR Inhibitor Therapy in Patients with Cholangiocarcinoma

BACKGROUND

Sequencing efforts in patients with cholangiocarcinoma (CCA) have provided insights into molecular mechanisms including fibroblast growth factor receptor (FGFR) alterations. There is a lack of data on outcomes of patients following cessation of FGFR inhibitor (FGFRi) therapy.

OBJECTIVE

We describe the clinical outcomes following initial FGFRi treatment in CCA harboring FGFR alterations.

PATIENTS AND METHODS

We conducted a multicentric, retrospective analysis of patients with FGFR-altered CCA diagnosed between 2010 and 2021. Median overall survival (OS) and progression-free survival (PFS) analyses were performed using the Kaplan-Meier method.

RESULTS

We identified 88 advanced or metastatic CCA patients, 28 males (31.8%) and 60 females (68.2%), harboring FGFR alterations who received FGFRi. Median PFS on initial FGFRi was 6.6 months (95% confidence interval (CI): 5.5-8.3). Following cessation of first FGFRi therapy, 55% patients received systemic therapy as next line: 67% received chemotherapy or targeted treatment and 33% received another FGFRi. Median PFS for patients who received chemotherapy or targeted agent was 2.1 months (95% CI 1.6-5.7) and for patients who received a second FGFRi was 3.7 months (95% CI 1.5-not evaluable). OS was 2.0 months for patients who did not receive any therapy compared to 8.7 months with chemotherapy and 8.6 months with another FGFRi. In addition, one patient treated with pemigatinib developed FGFR2 M540_I541insMM alteration at time of resistance, which has not been functionally characterized and its effect on protein function remains unknown.

CONCLUSIONS

Understanding the mechanisms of resistance with FGFRi is essential to understand sequencing of treatments. In this study, patients received standard chemotherapy in the first line and were fit enough to be considered for subsequent therapy with an FGFRi. Almost half of the patients become ineligible to receive further systemic therapy following progression on FGFRi. As more agents are being introduced, detailed understanding of outcomes following treatment with an FGFRi, including subsequent FGFRi, is essential.

Intrahepatic cholangiocyte regeneration from an Fgf-dependent extrahepatic progenitor niche in a zebrafish model of Alagille Syndrome

BACKGROUND AND AIMS

Alagille Syndrome (ALGS) is a congenital disorder caused by mutations in the Notch ligand gene JAGGED1, leading to neonatal loss of intrahepatic duct (IHD) cells and cholestasis. Cholestasis can resolve in certain patients with ALGS, suggesting regeneration of IHD cells. However, the mechanisms driving IHD cell regeneration following Jagged loss remains unclear. Here, we show that cholestasis due to developmental loss of IHD cells can be consistently phenocopied in zebrafish with compound jagged1b and jagged2b mutations or knockdown.

APPROACH AND RESULTS

Leveraging the transience of jagged knockdown in juvenile zebrafish, we find that resumption of Jagged expression leads to robust regeneration of IHD cells through a Notch-dependent mechanism. Combining multiple lineage tracing strategies with whole-liver three-dimensional imaging, we demonstrate that the extrahepatic duct (EHD) is the primary source of multipotent progenitors that contribute to the regeneration, but not to the development, of IHD cells. Hepatocyte-to-IHD cell transdifferentiation is possible but rarely detected. Progenitors in the EHD proliferate and migrate into the liver with Notch signaling loss and differentiate into IHD cells if Notch signaling increases. Tissue-specific mosaic analysis with an inducible dominant-negative Fgf receptor suggests that Fgf signaling from the surrounding mesenchymal cells maintains this extrahepatic niche by directly preventing premature differentiation and allocation of EHD progenitors to the liver. Indeed, transcriptional profiling and functional analysis of adult mouse EHD organoids uncover their distinct differentiation and proliferative potential relative to IHD organoids.

CONCLUSIONS

Our data show that IHD cells regenerate upon resumption of Jagged/Notch signaling, from multipotent progenitors originating from an Fgf-dependent extrahepatic stem cell niche. We posit that if Jagged/Notch signaling is augmented, through normal stochastic variation, gene therapy, or a Notch agonist, regeneration of IHD cells in patients with ALGS may be enhanced.

Cholangiocarcinoma: new perspectives for new horizons

INTRODUCTION

Biliary tract cancer represents a heterogeneous group of malignancies characterized by dismal prognosis and scarce therapeutic options.

AREA COVERED

In the last years, a growing interest in BTC pathology has emerged, thus highlighting a significant heterogeneity of the pathways underlying the carcinogenesis process, from both a molecular and genomic point of view. A better understanding of these differences is mandatory to deepen the behavior of this complex disease, as well as to identify new targetable target mutations, with the aim to improve the survival outcomes. The authors decided to provide a comprehensive overview of the recent highlights on BTCs, with a special focus on the genetic, epigenetic and molecular alterations, which may have an interesting clinical application in the next future.

EXPERT OPINION

In the last years, the efforts resulted from international collaborations have led to the identification of new promising targets for precision medicine approaches in the BTC setting. Further investigations and prospective trials are needed, but the hope is that these new knowledge in cooperation with the new technologies and procedures, including bio-molecular and genomic analysis as well radiomic studies, will enrich the therapeutic armamentarium thus improving the survival outcomes in a such lethal and complex disease.

Targeted genomic profiling revealed a unique clinical phenotype in intrahepatic cholangiocarcinoma with fibroblast growth factor receptor rearrangement

Genomic aberrations (GAs) in fibroblast growth factor receptors (FGFRs) are involved in the pathogenesis of intrahepatic cholangiocarcinoma (ICC), and clinical trials have shown efficacy of FGFR inhibitors in treating ICC patients with FGFR GAs such as FGFR2 rearrangement. To clarify the FGFRs GA profile and corresponding clinicopathological features in Chinese patients with ICC, a total of 257 cases were identified. Fourteen cases (5.45%) were positive for FGFR2 rearrangement. Further analysis on the 110 FGFR2 rearrangement negative cases showed that 13 patients present additional FGFRs GAs, including FGFR3 rearrangement (2.73%), and FGFRs mutations. When compared with patients without FGFRs GAs, those with FGFR2 or FGFR3 rearrangement presented more under the age of 58 years, female sex, HBsAb positivity, CD10 expression, and PD-L1 expression. The clinical characteristics between patients with FGFRs mutation and those without FGFRs GAs were similar, with the exception that cases with FGFRs mutation have more hepatolithiasis. We concluded that FGFR rearrangement is associated with unique clinical phenotypes in ICC.

FGFR Inhibitor Toxicity and Efficacy in Cholangiocarcinoma: Multicenter Single-Institution Cohort Experience

Cholangiocarcinomas (CCA) are a group of heterogeneous tumors arising from the biliary epithelia. Significant sequencing efforts have provided further insights into the molecular mechanisms of this disease including fibroblast growth factor receptor (FGFR) alterations, which occurs in approximately 15%-20% of intrahepatic CCAs. Herein, we describe the FGFR inhibitor (FGFRi)-associated treatment toxicity and cancer-specific outcomes from a multicenter single-institution cohort.

METHODS

This is a retrospective study of patients with CCA and known FGFR alterations treated with FGFRi. We describe the toxicity and efficacy in patients treated at Mayo Clinic between January 2010 and December 2020.

RESULTS

Our group identified 61 patients with advanced or metastatic CCA, 19 males (31%) and 42 females (69%), harboring FGFR alterations who received FGFRi. The most common grade 1 or higher adverse events for all patients included fatigue (92%), AST elevations (78%), anemia (80%), decreased platelet count (63%), and hyperphosphatemia (74%). Median progression-free survival on FGFRi was 5.8 months for all patients (95% CI, 4.9 to 9.0). Females had significantly longer progression-free survival at 6.9 months (95% CI, 5.2 to 11.8) on FGFRi compared with males at 4.9 months (95% CI, 2.8 to not estimable; P = .038).

CONCLUSION

FGFRi are well tolerated with clinical efficacy. With the recent approval of FGFRi by the US Food and Drug Administration and ongoing clinical trials for new FGFRi, understanding outcomes and toxicity associated with these medications is important for precision oncology.

FGFR Inhibitors: Clinical Activity and Development in the Treatment of Cholangiocarcinoma

PURPOSE OF REVIEW

Cholangiocarcinoma is an aggressive cancer with a poor prognosis and limited treatment. Gene sequencing studies have identified genetic alterations in fibroblast growth factor receptor (FGFR) in a significant proportion of cholangiocarcinoma (CCA) patients. This review will discuss the FGFR signaling pathway's role in CCA and highlight the development of therapeutic strategies targeting this pathway.

RECENT FINDINGS

The development of highly potent and selective FGFR inhibitors has led to the approval of pemigatinib for FGFR2 fusion or rearranged CCA. Other selective FGFR inhibitors are currently under clinical investigation and show promising activity. Despite encouraging results, the emergence of resistance is inevitable. Studies using circulating tumor DNA and on-treatment tissue biopsies have elucidated underlying mechanisms of intrinsic and acquired resistance. There is a critical need to not only develop more effective compounds, but also innovative sequencing strategies and combinations to overcome resistance to selective FGFR inhibition. Therapeutic development of precision medicine for FGFR-altered CCA is a dynamic process of involving a comprehensive understanding of tumor biology, rational clinical trial design, and therapeutic optimization. Alterations in FGFR represent a valid therapeutic target in CCA and selective FGFR inhibitors are treatment options for this patient population.

Pemigatinib-induced nail changes - A case report

INTRODUCTION

Pemigatinib is an FGFR inhibitor that is one of few second-line treatment options for cholangiocarcinoma. Nail toxicities were common in the phase 2 study evaluating the safety and efficacy of pemigatinib.

CASE REPORT

We describe a 54-year-old female with a history of stage IV cholangiocarcinoma presenting for a follow-up visit after completing Cycle 4 of pemigatinib. The patient had been having significant nail changes to her fingernails and toenails, which has led to her great toenails falling off.Management and outcome: The patient was prescribed betamethasone dipropionate 0.05% cream to help with her nail changes and instructed to continue vinegar and hot water soaks that she had already been doing. It was discussed that if this did not help with her nail changes, treatment may have to be held for 2 weeks to allow her nails to heal.

DISCUSSION

Nail changes are a common side effect with pemigatinib and should be monitored closely for the need for temporary disruption in therapy.

Drug Discovery in Liver Disease Using Kinome Profiling

The liver is one of the most important organs, playing critical roles in maintaining biochemical homeostasis. Accordingly, disease of the liver is often debilitating and responsible for untold human misery. As biochemical nexus, with kinases being master regulators of cellular biochemistry, targeting kinase enzymes is an obvious avenue for treating liver disease. Development of such therapy, however, is hampered by the technical difficulty of obtaining comprehensive insight into hepatic kinase activity, a problem further compounded by the often unique aspects of hepatic kinase activities, which makes extrapolations from other systems difficult. This consideration prompted us to review the current state of the art with respect to kinome profiling approaches towards the hepatic kinome. We observe that currently four different approaches are available, all showing significant promise. Hence we postulate that insight into the hepatic kinome will quickly increase, leading to rational kinase-targeted therapy for different liver diseases.