The efficacy of immune checkpoint inhibitors in biliary tract cancer with KRAS mutation

KRAS Mutations in Cancer: From Molecular Insights to Therapeutic Strategies

The global burden of cancer remains a major public health challenge, with Kirsten rat sarcoma viral oncogene homolog (KRAS) emerging as the most common mutated oncogene across diverse malignancies. Once considered "undruggable" due to its unique structure, KRAS has garnered intense research focus, resulting in significant advancements. This paper aims to review recent developments in our understanding of KRAS biology, including its structural and functional aspects, and to explore the latest insights into its mutations across various cancer types. Emphasis is placed on prognosis, predictive roles, and emerging therapeutic strategies targeting KRAS. This review aspires to deepen our comprehension of KRAS and potentially enhance treatment outcomes for cancer patients harboring KRAS mutations in the future.

Advances in target drugs and immunotherapy for biliary tract cancer

INTRODUCTION

After years of treatment stagnation in biliary tract cancers (BTC), there has been a notable shift with the emergence of targeted therapies and immunotherapy, leading to substantial progress in tackling this aggressive disease.

AREAS COVERED

We provide a comprehensive overview of the target therapies that are already part of the treatment algorithm for BTC, such as FGFR, IDH, and HER2 inhibitors. Additionally, we delve into some less known targets that are being explored, such as KRAS proto-oncogene, MAPK cascade, PI3K/AKT/mTOR pathway and novel molecules directed against P53, claudin, histones, and mitochondrial metabolism. Furthermore, we discuss agnostic drugs and analyze the efficacy data available for BTC specifically. We also examine the expanding world of immunotherapy, with an eye on predictive factors of response for immune checkpoint inhibitors, and on novel immune drugs such as chimeric antigen receptor (CAR)-T and vaccines.

EXPERT OPINION

In the expert opinion, we discuss the problem of the scarcity of patients eligible for target therapies and how can clinical trials be designed to overcome this challenge. We also summarize the most promising trials that have the potential to change clinical practice both for immunotherapies and target drugs.

Focusing on the Immune Cells: Recent Advances in Immunotherapy for Biliary Tract Cancer

Biliary tract cancer (BTC) represents a challenging malignancy characterized by aggressive behavior, high relapse rates, and poor prognosis. In recent years, immunotherapy has revolutionized the treatment landscape for various cancers, but its efficacy in BTC remains limited. This article provides a comprehensive overview of the advances in preclinical and clinical studies of immunotherapy for BTC. We explore the potential of immune checkpoint inhibitors in reshaping the management of BTC. Despite disappointing results thus far, ongoing clinical trials are investigating the combination of immunotherapy with other treatment modalities. Furthermore, research on the tumor microenvironment has unveiled novel targets for immunotherapeutic interventions. By understanding the current state of immunotherapy in BTC and highlighting future directions, this article aims to fuel further exploration and ultimately improve patient outcomes in this challenging disease.

KRAS Allelic Variants in Biliary Tract Cancers

Importance

Biliary tract cancers (BTCs) contain several actionable molecular alterations, including FGFR2, IDH1, ERBB2 (formerly HER2), and KRAS. KRAS allelic variants are found in 20% to 30% of BTCs, and multiple KRAS inhibitors are currently under clinical investigation.

Objectives

To describe the genomic landscape, co-sequence variations, immunophenotype, genomic ancestry, and survival outcomes of KRAS-mutated BTCs and to calculate the median overall survival (mOS) for the most common allelic variants.

Design, Setting, and Participants

This retrospective, multicenter, pooled cohort study obtained clinical and next-generation sequencing data from multiple databases between January 1, 2017, and December 31, 2022. These databases included Princess Margaret Cancer Centre, MD Anderson Cancer Center, Foundation Medicine, American Association for Cancer Research Project GENIE, and cBioPortal for Cancer Genomics. The cohort comprised patients with BTCs who underwent genomic testing.

Main Outcome and Measure

The main outcome was mOS, defined as date of diagnosis to date of death, which was measured in months.

Results

A total of 7457 patients (n = 3773 males [50.6%]; mean [SD] age, 63 [5] years) with BTCs and genomic testing were included. Of these patients, 5813 had clinical outcome data available, in whom 1000 KRAS-mutated BTCs were identified. KRAS allelic variants were highly prevalent in perihilar cholangiocarcinoma (28.6%) and extrahepatic cholangiocarcinoma (36.1%). Thirty-six KRAS allelic variants were identified, and the prevalence rates in descending order were G12D (41%), G12V (23%), and Q61H (8%). The variant G12D had the highest mOS of 25.1 (95% CI, 22.0-33.0) months compared with 22.8 (95% CI, 19.6-31.4) months for Q61H and 17.8 (95% CI, 16.3-23.1) months for G12V variants. The majority of KRAS-mutated BTCs (98.9%) were not microsatellite instability-high and had low tumor mutational burden (ranging from a median [IQR] of 1.2 (1.2-2.5) to a mean [SD] of 3.3 [1.3]). Immune profiling through RNA sequencing of KRAS and NRAS-mutated samples showed a pattern toward a more immune-inflamed microenvironment with higher M1 macrophage activation (0.16 vs 0.12; P = .047) and interferon-γ expression compared with wild-type tumors. The G12D variant remained the most common KRAS allelic variant in all patient ancestries. Patients with admixed American ancestry had the highest proportion of G12D variant (45.0%).

Conclusions and Relevance

This cohort study found that KRAS allelic variants were relatively common and may be potentially actionable genomic alterations in patients with BTCs, especially perihilar cholangiocarcinoma and extrahepatic cholangiocarcinoma. The findings add to the growing data on genomic and immune landscapes of KRAS allelic variants in BTCs and are potentially of value to the planning of specific therapies for this heterogeneous patient group.

The predictive value of PD-L1 expression in response to anti-PD-1/PD-L1 therapy for biliary tract cancer: a systematic review and meta-analysis

BACKGROUND

Recently, anti-programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) immunotherapy offers promising results for advanced biliary tract cancer (BTC). However, patients show highly heterogeneous responses to treatment, and predictive biomarkers are lacking. We performed a systematic review and meta-analysis to assess the potential of PD-L1 expression as a biomarker for treatment response and survival in patients with BTC undergoing anti-PD-1/PD-L1 therapy.

METHODS

We conducted a comprehensive systematic literature search through June 2023, utilizing the PubMed, EMBASE, and Cochrane Library databases. The outcomes of interest included objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) according to PD-L1 expression. Subgroup analyses and meta-regression were performed to identify possible sources of heterogeneity.

RESULTS

A total of 30 studies was included in the final analysis. Pooled analysis showed no significant differences in ORR (odds ratio [OR], 1.56; 95% confidence intervals [CIs], 0.94-2.56) and DCR (OR, 1.84; 95% CIs, 0.88-3.82) between PD-L1 (+) and PD-L1 (-) patients. In contrast, survival analysis showed improved PFS (hazard ratio [HR], 0.54, 95% CIs, 0.41-0.71) and OS (HR, 0.58; 95% CI, 0.47-0.72) among PD-L1 (+) patients compared to PD-L1 (-) patients. Sensitivity analysis excluding retrospective studies showed no significant differences with the primary results. Furthermore, meta-regression demonstrated that drug target (PD-1 vs. PD-L1), presence of additional intervention (monotherapy vs. combination therapy), and PD-L1 cut-off level (1% vs. ≥5%) significantly affected the predictive value of PD-L1 expression.

CONCLUSION

PD-L1 expression might be a helpful biomarker for predicting PFS and OS in patients with BTC undergoing anti-PD-1/PD-L1 therapy. The predictive value of PD-L1 expression can be significantly influenced by diagnostic or treatment variables.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023434114.

Current Standards, Multidisciplinary Approaches, and Future Directions in the Management of Extrahepatic Cholangiocarcinoma

OPINION STATEMENT

Biliary tract cancers are molecularly and anatomically diverse cancers which include intrahepatic cholangiocarcinoma, extrahepatic (perihilar and distal) cholangiocarcinoma, and gallbladder cancer. While recognized as distinct entities, the rarer incidence of these cancers combined with diagnostic challenges in classifying anatomic origin has resulted in clinical trials and guideline recommended strategies being generalized patients with all types of biliary tract cancer. In this review, we delve into the unique aspects, subtype-specific clinical trial outcomes, and multidisciplinary management of patients with extrahepatic cholangiocarcinoma. When resectable, definitive surgery followed by adjuvant chemotherapy (sometimes with selective radiation/chemoradiation) is current standard of care. Due to high recurrence rates, there is growing interest in the use of upfront/neoadjuvant therapy to improve surgical outcomes and to downstage patients who may not initially be resectable. Select patients with perihilar cholangiocarcinoma are being successfully treated with novel approaches such as liver transplant. In the advanced disease setting, combination gemcitabine and cisplatin remains the standard base for systemic therapy and was recently improved upon with the addition of immune checkpoint blockade to the chemotherapy doublet in the recently reported TOPAZ-1 and KEYNOTE-966 trials. Second-line all-comer treatments for these patients remain limited in both options and efficacy, so clinical trial participation should be strongly considered. With increased use of molecular testing, detection of actionable mutations and opportunities to receive indicated targeted therapies are on the rise and are the most significant driver of improved survival for patients with advanced stage disease. Though these targeted therapies are currently reserved for the second or later line, future trials are looking at moving these to earlier treatment settings and use in combination with chemotherapy and immunotherapy. In addition to cross-disciplinary management with surgical, medical, and radiation oncology, patient-centered care should also include collaboration with advanced endoscopists, palliative care specialists, and nutritionists to improve global patient outcomes.