RLY-4008, the First Highly Selective FGFR2 Inhibitor with Activity across FGFR2 Alterations and Resistance Mutations

FGFR2 residence in primary cilia is necessary for epithelial cell signaling

Primary cilium projects from cells to provide a communication platform with neighboring cells and the surrounding environment. This is ensured by the selective entry of membrane receptors and signaling molecules, producing fine-tuned and effective responses to the extracellular cues. In this study, we focused on one family of signaling molecules, the fibroblast growth factor receptors (FGFRs), their residence within cilia, and its role in FGFR signaling. We show that FGFR1 and FGFR2, but not FGFR3 and FGFR4, localize to primary cilia of the developing mouse tissues and in vitro cells. For FGFR2, we demonstrate that the ciliary residence is necessary for its signaling and expression of target morphogenic genes. We also show that the pathogenic FGFR2 variants have minimal cilium presence, which can be rescued for the p.P253R variant associated with the Apert syndrome by using the RLY-4008 kinase inhibitor. Finally, we determine the molecular regulators of FGFR2 trafficking to cilia, including IFT144, BBS1, and the conserved T429V430 motif within FGFR2.

Selective degradation of FGFR1/2 overcomes antiestrogen resistance in ER+ breast cancer with FGFR1/2 alterations

FGFR1 amplification and FGFR1/2 activating mutations have been associated with antiestrogen resistance in estrogen receptor-positive (ER+) breast cancer. However, there are no approved FGFR1-targeted therapies for breast cancers harboring these alterations. In this study, we investigated the selective degradation of FGFR1/2 using the proteolysis-targeting chimera (PROTAC) DGY-09-192 as a novel therapeutic strategy in ER + breast cancers harboring FGFR1/2 somatic alterations. Treatment of ER+/FGFR1-amplified breast cancer cells and patient-derived xenografts with DGY-09-192 resulted in sustained degradation of FGFR1 in a proteasome-dependent manner and suppressed downstream signal transduction. The combination of DGY-09-192 and the ERα degrader fulvestrant resulted in complete cell growth arrest and tumor regression of ER+/FGFR1-amplified patients-derived xenografts. In addition, we tested the effect of DGY-09-192 on breast cancer cells expressing FGFR1N546K and FGFR2K659E hotspot kinase domain mutations as well as ER-negative breast cancer cells harboring FGFR2 gene amplification. Treatment with DGY-09-192 resulted in the degradation of mutant FGFR1/2 and blocked mutant receptor-induced signal transduction and antiestrogen resistance. Collectively, our study suggests that degradation of FGFR1/2, in combination with antiestrogens, can be leveraged as a therapeutic strategy in ER + breast cancers harboring FGFR1/2 driver alterations.

Targeting fibroblast growth factor receptor (FGFR) with inhibitors in head and neck cancers: Their roles, mechanisms and challenges

Head and neck squamous cell carcinoma (HNSCC) is a common and aggressive type of cancer with significant rates of morbidity and mortality. Traditional treatment options, including radiotherapy, chemotherapy, and surgery, are widely used, but their effectiveness can be uncertain. As research in cancer therapies evolves, molecular-targeted therapies are increasingly recognized as promising alternatives for managing malignant tumors. Fibroblast growth factor receptors (FGFRs) have been shown to be one of the essential components in the pathways in the progression of HNSCC. This review aims to summarize and discuss the structure, functions, signaling pathways, abnormal alterations of FGFRs, and their roles in tumorigenesis and development. We have accumulated information from in vitro, in vivo, and clinical studies regarding FGFR inhibitors in HNSCC. However, the efficacy of FGFR inhibitors as a cancer therapy is limited, which may be due to the resistance to FGFR inhibitors. In this review we also discuss the potential mechanisms of FGFR inhibitor resistance in HNSCC. By enriching our understanding of the treatment with and resistance of FGFR inhibitors in HNSCC, researchers may unveil new therapeutic targets or strategies to enhance the efficacy of FGFR inhibitors in this context.

Residue-Selective Inhibitors Discovery via Covalent DNA-Encoded Chemical Libraries with Diverse Warheads

Covalent small molecule drugs have emerged as a crucial support in precision therapy due to their high selectivity and robust potency. Covalent DNA-encoded chemical library (CoDEL) technology is an advanced platform for covalent drug discovery. However, the application of CoDELs is constrained by a single-residue focus and limited warhead diversity. Here we report a method to identify residue-selective inhibitors using CoDELs with diverse warheads targeting multiple distinct residues. We systematically evaluated the reactivity of 17 warheads with 9 nucleophilic amino acids of FGFR2 and then constructed CoDELs comprising 24.8 million compounds. These CoDELs enabled the identification of active covalent inhibitors targeting cysteine, lysine, arginine, or glutamic acid. The lysine-targeting inhibitor engaged a novel reactive site. The arginine-targeting inhibitor demonstrated subtype selectivity and overcame drug resistance. The glutamic acid-targeting inhibitor validated the druggability of this unconventional covalent residue site. These findings suggest that our work could potentially expand the target space of covalent drugs and promote precision therapy by harnessing the power of the CoDELs.

Genomic landscape of biliary tract cancer and corresponding targeted treatment strategies

Biliary tract cancers (BTCs) are classified on the basis of their anatomical origin, and the feasibility of surgical resection depends on the tumor location and extent of progression. However, for unresectable BTCs, systemic therapy has been uniformly applied. Gemcitabine and cisplatin (GC) therapy and GC-based therapies were established as the first-line standard BTC treatment. However, no highly effective second-line therapy has been established, and the prognosis remains poor, highlighting the need for further therapeutic advancements. Meanwhile, the era of precision medicine has expanded the use of genetic testing, leading to the identification of actionable molecular targets in BTC. Several targeted therapies, including FGFR inhibitors and IDH1 inhibitors, have been developed, offering new second-line treatment options and the potential for first-line use in appropriate cases. Notably, the frequency of these genetic alterations varies depending on the tumor location, demonstrating the molecular heterogeneity of BTC. Therefore, it has been recognized that a tailored treatment approach for each BTC patient may be more effective than uniform systemic therapy. Consequently, although routine genetic testing before initiating systemic treatment is currently limited by the medical environment (e.g., cost, accessibility, regional differences), it is recommended in ESMO guideline and might be increasingly advocated. However, BTC harbors a wide range of genetic alterations, and numerous targeted therapies are being developed accordingly. This review provides an overview of the reported genetic alterations in BTC, the frequencies of these alterations, and the corresponding targeted therapies, emphasizing the evolving role of precision medicine in BTC treatment.

Identification of potent biparatopic antibodies targeting FGFR2 fusion-driven cholangiocarcinoma

Translocations involving FGFR2 gene fusions are common in cholangiocarcinoma and predict response to FGFR kinase inhibitors. However, response rates and durability are limited due to the emergence of resistance, typically involving FGFR2 kinase domain mutations, and to suboptimal dosing, relating to drug adverse effects. Here, we develop biparatopic antibodies targeting the FGFR2 extracellular domain (ECD) as candidate therapeutics. Biparatopic antibodies can overcome drawbacks of bivalent monospecific antibodies, which often show poor inhibitory or even agonist activity against oncogenic receptors. We show that oncogenic transformation by FGFR2 fusions requires an intact ECD. Moreover, by systematically generating biparatopic antibodies targeting distinct epitope pairs in FGFR2 ECD, we identified antibodies that effectively block signaling and malignant growth driven by FGFR2 fusions. Importantly, these antibodies demonstrate efficacy in vivo, synergy with FGFR inhibitors, and activity against FGFR2 fusions harboring kinase domain mutations. Thus, we believe that biparatopic antibodies may serve as an innovative treatment option for patients with FGFR2-altered cholangiocarcinoma.

Discovery of BW710 as a potent, selective and orally bioavailable fibroblast growth factor receptor 2 (FGFR2) inhibitor

While fibroblast growth factor receptor 2 (FGFR2) emerges as an appealing cancer therapeutic target, so far there is no selective FGFR2 inhibitor on the market. Here, we report the discovery of a series of new selective, irreversible FGFR2 inhibitors with compound BW710 being the representative. Compound BW710 potently inhibited the proliferation of BaF3-FGFR2 cells with an IC50 value of 2.8 nM, and was much less active against BaF3-FGFR1 and parental BaF3 cells with IC50 values of >1000 nM. Kinase selectivity profiling revealed that BW710 completely abolished FGFR2 enzymatic activity and was selective against other 75 tyrosine kinases including FGFR1, FGFR3, and FGFR4 at 1 μM. The covalent binding mode between BW710 and FGFR2 was confirmed by MS spectrometry. Further evaluation showed that BW710 potently suppressed the FGFR2 signaling and selectively inhibited FGFR2-driven cancer cell proliferation. Additionally, BW710 also displayed reasonable pharmacokinetic properties with an oral bioavailability of 29 % in mice. Taken together, this study provides a potent, selective and orally bioavailable FGFR2 inhibitor for further development of FGFR2-targeted therapeutic agents.

Safety and Activity of Fibroblast Growth Factor Receptor Inhibitors in Advanced Malignancies: A Pooled Analysis of Early-Phase Clinical Trials

PURPOSE

Aberrant signaling through the fibroblast growth factor receptor (FGFR) due to activating somatic alterations has been associated with multiple malignancies. FGFR inhibitors (FGFRi) with distinct profiles recently entered standard of care. This work summarizes the experience of a dedicated clinical trial unit with FGFRi developed in the last decade within the context of clinical trials.

METHODS

Demographic and clinical data were collected for patients enrolled in FGFR-targeting phase I to II trials conducted at Sarah Cannon Research Institute, United Kingdom between January 2012 and August 2023.

RESULTS

Fifty-four patients across seven trials were identified: 50% male; median age 55 years. An FGFR alteration was present in 81% of cases; rearrangements, amplifications, and mutations were present in 59%, 43%, and 9.1% of the cases, respectively, with coexisting alterations in 27%. The most frequent primary tumors were cholangiocarcinomas (31%), urothelial (15%), and colorectal (15%); 85% of the patients were FGFRi-naïve. The most common adverse events (AEs) were hyperphosphatemia (42%), dry mouth (35%), fatigue (24%), mucositis (24%), nail changes (22%), and palmar-plantar erythrodysesthesia (20%), with significant differences between pan-FGFRi and FGFR-2i. The rate of G3 AEs was 22%; no G4-5 events were observed. The median time on treatment was 3.5 months (0.2-72.8). Higher disease control rate was observed in the presence of any FGFR alteration, compared with all-comers (odds ratio [OR], 7; P = .0226). The objective response rate was 38%, 25%, and 25% in patients with gene rearrangements, amplification, and mutations, respectively. The median duration of response was 2.3 months (1.6-7.7). After a median follow-up time of 20 months (95% CI, 12.9 to 71.8), median progression-free survival (mPFS) was 3.2 months (95% CI, 1.9 to 4.6) and median overall survival was 13 months (95% CI, 6.4 to 19.6). PFS was significantly different by response, FGFR status, and tumor type. Patients who experienced a G2-3 AE were more likely to achieve a response (OR, 5.24; P = .0256).

CONCLUSION

FGFRi are effective treatment strategies for patients with advanced solid tumors harboring FGFR alterations, with manageable toxicities in most patients.

Current status and prospects of targeted therapy for cholangiocarcinoma based on molecular characteristics

Cholangiocarcinoma (CCA) is a serious public health issue due to its insidious onset and dismal prognosis. The past few years have witnessed and highlighted the development of understanding and management of CCA. The combination of gemcitabine and cisplatin (GP) chemotherapy regimen with immunotherapy using immune checkpoint inhibitors has been considered the new standard first-line treatment alternative for advanced CCA. Notably, the proportion of patients with advanced CCA with targetable genetic mutations is approximately 40 %, and these patients may be considered for molecularly targeted therapy in the second-line treatment. In this review, we highlight the advances and progress in targeted therapies for advanced CCA, with special attention to data from Asian populations, including Chinese. In addition, we present in detail the phosphatase tension homolog (PTEN), a novel biomarker for both of first-line chemotherapy and second-line targeted therapy in advanced CCA, and its ability to forecast prognosis in patients with CCA. The mechanisms of rapid resistance to targeted agents warrant further investigation and address in light of the development of new targeted therapies. Precision medicine is gradually playing an increasing role in achieving optimal therapeutic outcomes.

Specific inhibition of fibroblast growth factor receptor 1 signaling by a DNA aptamer

Impaired fibroblast growth factor receptor (FGFR) signaling is associated with many human conditions, including growth disorders, degenerative diseases, and cancer. Current FGFR therapeutics are based on chemical inhibitors of FGFR tyrosine kinase activity (TKIs). However, FGFR TKIs are limited in their target specificity as they generally inhibit all FGFRs and other receptor tyrosine kinases. In the search for specific inhibitors of human FGFR1, we identified VZ23, a DNA aptamer that binds to FGFR1b and FGFR1c with a KD of 55 nM and 162 nM, respectively, but not to the other FGFR variants (FGFR2b, FGFR2c, FGFR3b, FGFR3c, FGFR4). In cells, VZ23 inhibited the activation of downstream FGFR1 signaling and FGFR1-mediated regulation of cellular senescence, proliferation, and extracellular matrix homeostasis. Consistent with the specificity toward FGFR1 observed in vitro, VZ23 did not inhibit FGFR2-4 signaling in cells. We show that the VZ23 inhibits FGFR1 signaling in the presence of cognate fibroblast growth factor (FGF) ligands and its inhibitory activity is linked to its capacity to form unusual G-quadruplex structure. Our data suggest that targeting FGFR1 with DNA aptamers could be an effective alternative to TKIs for treating impaired FGFR1 signaling in human craniosynostoses.

Update for: New developments in systemic therapy for advanced biliary tract cancer

Biliary tract cancer, carcinoma of the extrahepatic bile ducts, carcinoma of the gallbladder, ampullary carcinoma, and intrahepatic cholangiocarcinoma are often identified at advanced stages. The standard therapy for advanced biliary tract cancer has been a combination of cytotoxic agents. Globally, gemcitabine plus cisplatin has been the standard first-line regimen, whereas gemcitabine plus cisplatin plus S-1 and gemcitabine plus S-1 have also been the standard regimens in Japan. Recently, treatment strategies have been updated. As first-line systemic therapy, the addition of an immune checkpoint inhibitor, such as durvalumab or pembrolizumab, to gemcitabine plus cisplatin has been shown to prolong overall survival compared with gemcitabine plus cisplatin. These combined immunotherapies are widely used in clinical practice as internationally standard first-line regimens. Regarding second-line treatment after a gemcitabine-based regimen, fluorouracil and folinic acid plus oxaliplatin have been the standard regimen. Additionally, FGFR2 fusion gene/rearrangement, mutations of IDH1/2, KRAS, and BRAF, and overexpression of HER2 are promising therapeutic targets for which the effectiveness of each targeted therapy has been reported, at this time, as a second-line or later treatment.

Pancreatic ductal adenocarcinoma (PDAC): clinical progress in the last five years

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal malignancy with limited therapeutic options and poor overall survival. In recent years, advances in genomic profiling have revealed the complex molecular and cellular heterogeneity of PDAC, offering new avenues for therapeutic intervention.

AREAS COVERED

This review explores emerging therapeutic strategies targeting dysregulated molecular pathways, along with the tumor microenvironment, that have shown promise in overcoming drug resistance. Novel immunotherapy strategies, such as immune checkpoint inhibitors and CAR T-cell therapies, are currently being explored in an attempt to modulate PDAC immugnosuppressive microenvironment. Additionally, we highlight recent clinical trials over the last 5 years and innovative therapeutic strategies aiming to improve outcomes in PDAC.

EXPERT OPINION

Significant progress in genomic profiling, targeted therapies, and immunotherapy is shaping the treatment of PDAC. Despite challenges posed by its dense stroma and immune suppressive microenvironment, novel strategies such as IL 6 and CD137 inhibitors, CAR-T, and therapeutic cancer vaccines are promising. KRAS targeted therapies are expanding beyond G12C inhibitors, with novel drugs in development that will further improve treatment options. Additionally, tumor treating fields (TTF) are being investigated in locally advanced PDAC, with the PANOVA-3 trial potentially integrating this modality into future treatment strategies. Continued advancements in these areas will significantly enhance PDAC outcomes.

Cholangiocarcinoma Targeted Therapies: Mechanisms of Action and Resistance

Cholangiocarcinoma is an aggressive bile duct malignancy with heterogeneous genomic features. Although most patients receive standard-of-care chemotherapy/immunotherapy, genomic changes that can be targeted with established or emerging therapeutics are common. Accordingly, precision medicine strategies are transforming the next-line treatment for patient subsets. Hotspot IDH1 mutations and activating fibroblast growth factor receptor 2 fusions occur frequently, and small-molecule inhibitors against these alterations are US Food and Drug Administration approved. Translational and basic science studies have elucidated the mechanisms of response and resistance in cholangiocarcinoma, providing insights into these targets that extend to other cancers. Additional US Food and Drug Administration-approved and National Comprehensive Cancer Network guideline-recommended treatments for recurrent genomic changes include BRAF inhibition (BRAF-V600E) and trastumazab deruxtecan (human epidermal growth factor receptor 2 amplification). Furthermore, ongoing clinical trials show promising results with KRAS inhibition (KRAS-codon 12 mutations), PRTM5 inhibition, alone or with methylthioadenosine inhibition (5-methylthioadenosine phosphorylase deletion), and murine double minute 2 inhibition (murine double minute 2 amplification). Despite these advances, the rate, depth, and duration of response to each treatment need improvement. Moreover, many patients do not have currently targetable genotypes. This review examines the clinical efficacy and mechanisms of resistance associated with these treatments, as well as insights into the molecular and biological effects of pathway activation and inhibition, based on study of patient samples and preclinical models. It also explores strategies to overcome resistance and possible precision medicine approaches for additional patient subsets.

Resistance to immunotherapy in non-small cell lung cancer: Unraveling causes, developing effective strategies, and exploring potential breakthroughs

Over the last two decades, advancements in deciphering the intricate interactions between oncology and immunity have fueled a meteoric rise in immunotherapy for non-small cell lung cancer, typified by an explosive growth of immune checkpoint inhibitors. However, resistance to immunotherapy remains inevitable. Herein we unravel the labyrinthine mechanisms of resistance to immunotherapy, characterized by their involvement of nearly all types of cells within the body, beyond the extrinsic cancer cells, and importantly, such cells are not only (inhibitory or excitatory, or both) signal recipients but also producers, acting in a context-dependent manner. At the molecular level, these mechanisms underlie genetic and epigenetic aberrations, which are regulated by or regulate various protein kinases, growth factors, and cytokines with inherently dynamic and spatially heterogeneous properties. Additionally, macroscopic factors such as nutrition, comorbidities, and the microbiome within and around organs or tumor cells are involved. Therefore, developing therapeutic strategies combined with distinct action informed by preclinical, clinical, and real-world evidence, such as radiotherapy, chemotherapy, targeted therapy, antibody-drug conjugates, oncolytic viruses, and cell-based therapies, may stand as a judicious reality, although the ideality is to overcome resistance point-by-point through a novel drug. Notably, we highlight a realignment of treatment aims, moving the primary focus from eliminating cancer cells -- such as through chemotherapy and radiotherapy -- to promoting immune modulation and underscore the value of regulating various components within the host macro- or micro-environment, as their effects, even if seemingly minimal, can cumulatively contribute to visible clinical benefit when applied in combination with ICIs. Lastly, this review also emphasizes the current hurdles scattered throughout preclinical and clinical studies, and explores evolving directions in the landscape of immunotherapy for NSCLC.

Discovery of Pyrrolopyrazine Carboxamide Derivatives as Potent and Selective FGFR2/3 Inhibitors that Overcome Mutant Resistance

Fibroblast growth factor receptors (FGFRs) are established oncogenic drivers in various solid tumors. However, the approved FGFR inhibitors face challenges with acquired resistance and dose-limiting adverse effects associated with FGFR1/4 inhibition, limiting therapeutic efficacy. Herein, we systematically explored linker and electrophile moieties based on the pyrrolopyrazine carboxamide core and identified aniline α-fluoroacrylamide as an effective covalent warhead. Compound 10 potently inhibited FGFR2 and FGFR3, even in the context of common inhibitor-resistance mutations, including in the gatekeeper, molecular brake, and activation loop regions. Compound 10 spared FGFR1/4 and other kinases without causing diarrhea and serum phosphate elevation in vivo. Oral administration of compound 10 induced tumor stasis or regression in the SNU-16 gastric cancer model with favorable pharmacokinetics and robust pharmacodynamic suppression.

Design of studies on neoadjuvant therapy for intrahepatic cholangiocarcinoma

The high recurrence rate and dismal prognosis of localized intrahepatic cholangiocarcinoma (ICC) indicate the unmet need for effective adjuvant and neoadjuvant therapy. In recent years, progress has been made in immunotherapy and targeted therapy for the treatment of advanced biliary tract cancer (BTC), leading to clinical exploration of the provision of these therapies in the perioperative period. Based on years of experience in clinical research on hepatobiliary cancers, the authors discuss the design of studies on neoadjuvant therapy for ICC, aiming to provide references for future neoadjuvant studies.

New Relevant Evidence in Cholangiocarcinoma Biology and Characterization

Among solid tumors, cholangiocarcinoma (CCA) emerges as one of the most difficult to eradicate. The silent and asymptomatic nature of this tumor, particularly in its early stages, as well as the high heterogeneity at genomic, epigenetic, and molecular levels delay the diagnosis, significantly compromising the efficacy of current therapeutic options and thus contributing to a dismal prognosis. Extensive research has been conducted on the molecular pathobiology of CCA, and recent advances have been made in the classification and characterization of new molecular targets. Both targeted therapy and immunotherapy have emerged as effective and safe strategies for various types of cancers, demonstrating potential benefits in advanced CCA. Furthermore, the deeper comprehension of the cellular and molecular components in the tumor microenvironment (TME) has opened up possibilities for new innovative treatment methods. This review discusses recent evidence in the characterization and molecular biology of CCA, highlighting novel possible druggable targets.

Fibroblast growth factor therapies in biliary tract cancers: current and future state

INTRODUCTION

Cholangiocarcinoma is the rare and aggressive tumor with poor prognosis and limited therapeutic options. Recently, there have been promising developments in molecular targeted therapies for patients following the progression of first-line chemotherapy and immunotherapy combinations. Dysregulation of fibroblast Growth Factor Receptor (FGFR) signaling is significantly associated with tumorigenesis of intrahepatic cholangiocarcinoma and has been identified as a targetable alteration. This was possible through the discovery of crucial insights into the biochemical mechanisms and pathophysiology of the FGFR pathway.

AREAS COVERED

This review summarizes the current state of FGFR targeted therapies, mechanisms of resistance, and future directions for FGFR-targeted therapies in patients with cholangiocarcinoma.

EXPERT OPINION

Currently, pemigatinib and futibatinib are FDA approved FGFR-targeted therapies that have demonstrated remarkable responses. However, there is still a significant proportion of patients whose disease remains intrinsically resistant to treatment and most patients eventually develop secondary resistance after an initial response. Additionally, unique side effects of FGFR inhibitors may limit their efficacy in clinical practice and can have detrimental effects on quality of life. Several novel FGFR inhibitors are currently being investigated to overcome resistance mechanisms and reduce toxicities.

Pharmacological and Biological Targeting of FGFR1 in Cancer

FGFR1 is a key member of the fibroblast growth factor receptor family, mediating critical signaling pathways such as RAS-MAPK and PI3K-AKT. which are integral to regulating essential cellular processes, including proliferation, differentiation, and survival. Alterations in FGFR1 can lead to constitutive activation of signaling pathways that drive oncogenesis by promoting uncontrolled cell division, inhibiting apoptosis, and enhancing the metastatic potential of cancer cells. This article reviews the activation mechanisms and signaling pathways of FGFR1 and provides a detailed exposition of the types of FGFR1 aberration. Furthermore, we have compiled a comprehensive overview of current therapies targeting FGFR1 aberration in cancer, aiming to offer new perspectives for future cancer treatments by focusing on drugs that address specific FGFR1 alterations.

Clinical advances and challenges in targeting FGF/FGFR signaling in lung cancer

Fibroblast growth factors (FGFs) and their receptors regulate numerous cellular processes, such as metabolism and signal transduction, but can also drive tumorigenesis. Specifically, in lung cancer, the overexpression of FGFs, as well as the amplification, mutation and fusion of FGFR genes, are closely linked to the initiation, progression and resistance of the disease, suggesting that targeting FGF/FGFR is an attractive therapeutic strategy for lung cancer treatment. Nintedanib, a multitarget tyrosine kinase inhibitor (TKI) used in combination with docetaxel, has shown some success as a second-line therapy for lung cancer. However, clinical trials evaluating other FGFR inhibitors have yielded mixed results, indicating substantial complexity in targeting aberrant FGF/FGFR signaling. In this review, we describe the aberrations in FGF/FGFR signaling in lung cancer and summarize the clinical efficacy of FGFR inhibitors, such as multitarget TKIs, selective FGFR-TKIs and biological agents. We also discuss various challenges associated with FGFR targeting in lung cancer, including precision patient selection, toxicity and resistance. Finally, we provide perspectives on future directions, namely, developing novel FGFR-targeting drugs, such as FGFR degraders and more specific FGFR-TKIs, adopting combination therapy and targeting FGFs.

Current Status of Computational Approaches for Small Molecule Drug Discovery

2024 has been an exciting year for computational sciences, with the Nobel Prize in Physics awarded for "artificial neural network" and the Nobel Prize in Chemistry presented for "protein structure prediction and design". Given the rapid advancements in Computer-Aided Drug Design (CADD) and Artificial Intelligence in Drug Discovery (AIDD), a document summarizing their current standing and future directions would be timely and relevant to the readership of Journal of Medicinal Chemistry. This piece of commentary aims to highlight recent developments, key challenges, and potential synergies between these fields, contributing to ongoing discussions in the literature and scientific blogs.

Lower FGFR2 mRNA Expression and Higher Levels of FGFR2 IIIc in HER2-Positive Breast Cancer

Fibroblast growth factor receptor 2 (FGFR2) has been associated with breast cancer. We performed in silico analyses to investigate the FGFR2 mRNA expression and splice variants associated with breast cancer subtypes. Online databases, including cBioPortal and TCGA SpliceSeq, were used to examine the association between the FGFR2 expression and splice variants with breast cancer subtypes. A higher FGFR2 mRNA was significantly associated with luminal, oestrogen receptor (ER)-positive breast cancers, and invasive lobular carcinomas, whereas a lower FGFR2 was associated with human epidermal growth factor receptor 2 (HER2)-positive breast cancer and invasive ductal carcinomas. The epithelial alternatively spliced FGFR2 IIIb isoform was significantly enriched in ER+ breast cancer, while the mesenchymal FGFR2 IIIc isoform was significantly prevalent in HER2+ cancer. Increased levels of FGFR2 and IIIb splice isoforms are associated with less aggressive breast cancer phenotypes, while decreased levels of FGFR2 and increased IIIc splice isoform are associated with more aggressive phenotypes.

Cancer-Associated Fibroblast-Derived FGF7 Promotes Clear Cell Renal Cell Carcinoma Progression and Macrophage Infiltration

As the predominant stromal cells in the ccRCC surrounding environment, cancer-associated fibroblasts (CAFs) have been established as supportive of tumor growth. However, the detailed molecular mechanisms underlying the supporting role of CAFs in ccRCC have not been well characterized. Evidence from the clustering consensus analysis, single-cell analysis, and the experimental results illustrate that CAF-derived FGF7 plays a crucial role as a signaling mediator between CAFs and ccRCC tumor cells. Mechanistically, CAF-derived FGF7 triggers AKT activation to promote cell growth and cell invasion of ccRCC tumor cells. As a response, ccRCC tumor cells stimulate STAT3-mediated transcriptional regulation, directly increasing FGF7 expression at the chromatin level in CAFs. Moreover, there exists a positive clinical correlation between the abundance of CAFs, FGF7 expression, and the infiltration of M2 type macrophages. The RENCA in vivo mouse model also confirmed that FGF7 depletion could impede RCC development by reducing the recruitment of M2 type macrophages. Overall, this study delineates a key signaling axis governing the crosstalk between CAFs and ccRCC tumor cells, highlighting FGF7 as a promising therapeutic target of ccRCC.

Understanding and Overcoming Resistance to Selective FGFR Inhibitors across FGFR2-Driven Malignancies

PURPOSE

Understanding resistance to selective FGFR inhibitors is crucial to improve the clinical outcomes of patients with FGFR2-driven malignancies.

EXPERIMENTAL DESIGN

We analyzed sequential ctDNA, ± whole-exome sequencing, or targeted next-generation sequencing on tissue biopsies from patients with tumors harboring activating FGFR2 alterations progressing on pan-FGFR-selective inhibitors, collected in the prospective UNLOCK program. FGFR2::BICC1 Ba/F3 and patient-derived xenograft models were used for functional studies.

RESULTS

Thirty-six patients were included. In cholangiocarcinoma, at resistance to both reversible inhibitors (e.g., pemigatinib and erdafitinib) and the irreversible inhibitor futibatinib, polyclonal FGFR2 kinase domain mutations were frequent (14/27 patients). Tumors other than cholangiocarcinoma shared the same mutated FGFR2 residues, but polyclonality was rare (1/9 patients). At resistance to reversible inhibitors, 14 residues in the FGFR2 kinase domain were mutated-after futibatinib, only the molecular brake N550 and the gatekeeper V565. Off-target alterations in PI3K/mTOR and MAPK pathways were found in 11 patients, often together with on-target mutations. At progression to a first FGFR inhibitor, 12 patients received futibatinib or lirafugratinib (irreversible inhibitors), with variable clinical outcomes depending on previous resistance mechanisms. Two patients with TSC1 or PIK3CA mutations benefited from everolimus. In cell viability assays on Ba/F3 and in pharmacologic studies on patient-derived xenografts, irreversible inhibitors retained better activity against FGFR2 kinase domain mutations, with lirafugratinib active against the recalcitrant V565L/F/Y.

CONCLUSIONS

At progression to FGFR inhibitors, FGFR2-driven malignancies are characterized by high intra- and interpatient molecular heterogeneity, particularly in cholangiocarcinoma. Resistance to FGFR inhibitors can be overcome by sequential, molecularly oriented treatment strategies across FGFR2-driven tumors.

Ductal pancreatic cancer interception by FGFR2 abrogation

Activating KRAS mutations are a key feature of pancreatic ductal adenocarcinoma (PDA) and drive tumor initiation and progression. However, mutant KRAS by itself is weakly oncogenic. The pathways that cooperate with mutant KRAS to induce tumorigenesis are less-defined. Analyzing organoids and murine and human pancreatic specimens, we found that the receptor tyrosine kinase FGFR2 was progressively up-regulated in mutant KRAS-driven metaplasia, pre-neoplasia and Classical PDA. Using genetic mouse models, we showed that FGFR2 supported mutant KRAS-driven transformation of acinar cells by promoting proliferation and MAPK pathway activation. FGFR2 abrogation significantly delayed tumor formation and extended the survival of these mice. Furthermore, we discovered that FGFR2 collaborated with EGFR and dual blockade of these receptor signaling pathways significantly reduced mutant KRAS-induced pre-neoplastic lesion formation. Together, our data have uncovered a pivotal role for FGFR2 in the early phases of pancreatic tumorigenesis, paving the way for future therapeutic applications of FGFR2 inhibitors for pancreatic cancer interception.

STATEMENT OF SIGNIFICANCE

Mutant KRAS-expressing pancreatic intraepithelial neoplasias (PanINs), the precursor lesions of PDA, are prevalent in the average healthy adult but rarely advance to invasive carcinoma. Here, we discovered that FGFR2 promoted PDA progression by amplifying mutant KRAS signaling and that inactivation of FGFR2 intercepted disease progression.

Alchemical Transformations and Beyond: Recent Advances and Real-World Applications of Free Energy Calculations in Drug Discovery

Computational methods constitute efficient strategies for screening and optimizing potential drug molecules. A critical factor in this process is the binding affinity between candidate molecules and targets, quantified as binding free energy. Among various estimation methods, alchemical transformation methods stand out for their theoretical rigor. Despite challenges in force field accuracy and sampling efficiency, advancements in algorithms, software, and hardware have increased the application of free energy perturbation (FEP) calculations in the pharmaceutical industry. Here, we review the practical applications of FEP in drug discovery projects since 2018, covering both ligand-centric and residue-centric transformations. We show that relative binding free energy calculations have steadily achieved chemical accuracy in real-world applications. In addition, we discuss alternative physics-based simulation methods and the incorporation of deep learning into free energy calculations.

Biomolecular simulations at the exascale: From drug design to organelles and beyond

The rapid advancement in computational power available for research offers to bring not only quantitative improvements, but also qualitative changes in the field of biomolecular simulation. Here, we review the state of biomolecular dynamics simulations at the threshold to exascale resources becoming available. Both developments in parallel and distributed computing will be discussed, providing a perspective on the state of the art of both. A main focus will be on obtaining binding and conformational free energies, with an outlook to macromolecular complexes and (sub)cellular assemblies.

Identification of potent biparatopic antibodies targeting FGFR2 fusion driven cholangiocarcinoma

Translocations involving FGFR2 gene fusions are common in cholangiocarcinoma and predict response to FGFR kinase inhibitors. However, the rate and durability of response are limited due to the emergence of resistance, typically involving acquired FGFR2 kinase domain mutations, and to sub-optimal dosing, relating to drug adverse effects. Here, we report the development of biparatopic antibodies targeting the FGFR2 extracellular domain (ECD), as candidate therapeutics. Biparatopic antibodies can overcome drawbacks of standard bivalent monoparatopic antibodies, which often show poor inhibitory or even agonist activity against oncogenic receptors. We show that oncogenic transformation by FGFR2 fusions requires an intact ECD. Moreover, by systematically generating biparatopic antibodies that target distinct epitope pairs along the FGFR2 ECD, we identified antibodies that effectively block signaling and malignant growth driven by FGFR2-fusions. Importantly, these antibodies demonstrate efficacy in vivo, synergy with FGFR inhibitors, and activity against FGFR2 fusions harboring kinase domain mutations. Thus, biparatopic antibodies may serve as new treatment options for patients with FGFR2-altered cholangiocarcinoma.

Summary

We identify biparatopic FGFR2 antibodies that are effective against FGFR2 fusion driven cholangiocarcinoma.

Design, synthesis and biological evaluation of 5-amino-1H-pyrazole-4-carboxamide derivatives as pan-FGFR covalent inhibitors

The aberrant activation of FGFRs plays a critical role in various cancers, leading to the development of several FGFR inhibitors in clinic. However, the emergence of drug resistance, primarily due to gatekeeper mutations in FGFRs, has limited their clinical efficacy. To address the unmet medical need, a series of 5-amino-1H-pyrazole-4-carboxamide derivatives were designed and synthesized as novel pan-FGFR covalent inhibitors targeting both wild-type and the gatekeeper mutants. The representative compound 10h demonstrated nanomolar activities against FGFR1, FGFR2, FGFR3 and FGFR2 V564F gatekeeper mutant in biochemical assays (IC50 = 46, 41, 99, and 62 nM). Moreover, 10h also strongly suppressed the proliferation of NCI-H520 lung cancer cells, SNU-16 and KATO III gastric cancer cells with IC50 values of 19, 59, and 73 nM, respectively. Further X-ray co-crystal structure revealed that 10h irreversibly binds to FGFR1. The study provides a new promising point for anticancer drug development medicated by FGFRs.

Identifying Actionable Alterations in KRAS Wild-Type Pancreatic Cancer

The 5-year relative survival rate for pancreatic cancer is currently the lowest among all cancer types with a dismal 13%. A Kirsten rat sarcoma virus (KRAS) gene mutation is present in approximately 90% of patients with pancreatic cancer; however, KRAS-specific drugs are not yet widely used in clinical practice for pancreatic cancer, specifically the KRASG12D variant. Advances in genomic testing revealed an opportunity to detect genetic alterations in a subset of patients with no KRAS mutation termed KRAS wild-type. Patients with KRAS wild-type tumors have a propensity to express driver alterations, hence paving the way for utilizing a targeted therapy approach either via clinical trials or standard-of-care drugs. These alterations include fusions, amplifications, translocations, rearrangements and microsatellite instability-high tumors and can be as high as 11% in some studies. Here, we discuss some of the most notable alterations in KRAS wild-type and highlight promising clinical trials.

Discovery of Aloperine as a Potential Antineoplastic Agent for Cholangiocarcinoma Harboring Mutant IDH1

Intrahepatic cholangiocarcinoma (ICC) is a universally lethal malignancy with increasing incidence. However, ICC patients receive limited benefits from current drugs; therefore, we must urgently explore new drugs for treating ICC. Quinolizidine alkaloids, as essential active ingredients extracted from Sophora alopecuroides Linn, can suppress cancer cell growth via numerous mechanisms and have therapeutic effects on liver-related diseases. However, the impact of quinolizidine alkaloids on intrahepatic cholangiocarcinoma has not been fully studied. In this article, the in vitro anti-ICC activities of six natural quinolizidine alkaloids were explored. Aloperine was the most potent antitumor compound among the tested quinolizidine alkaloids, and it preferentially inhibited RBE cells rather than HCCC-9810 cells. Mechanistically, aloperine can potentially decrease glutamate content by inhibiting the hydrolysis of glutamine, reducing D-2-hydroxyglutarate levels and, consequently, leading to preferential growth inhibition in isocitrate dehydrogenase (IDH)-mutant ICC cells. In addition, aloperine preferentially resensitizes RBE cells to 5-fluorouracil, AGI-5198 and olaparib. This article demonstrates that aloperine shows preferential antitumor effects in intrahepatic cholangiocarcinoma cells harboring the mutant IDH1 by decreasing D-2-hydroxyglutarate, suggesting that aloperine could be used as a lead compound or adjuvant chemotherapy drug to treat ICC harboring the mutant IDH.

Overcoming treatment resistance in cholangiocarcinoma: current strategies, challenges, and prospects

Significant advancements in our understanding and clinical treatment of cholangiocarcinoma (CCA) have been achieved over the past 5 years. Groundbreaking studies have illuminated the immune landscape and pathological characteristics of the tumor microenvironment in CCA. The development of immune- and metabolism-based classification systems has enabled a nuanced exploration of the tumor microenvironment and the origins of CCA, facilitating a detailed understanding of tumor progression modulation. Despite these insights, targeted therapies have not yet yielded satisfactory clinical results, highlighting the urgent need for innovative therapeutic strategies. This review delineates the complexity and heterogeneity of CCA, examines the current landscape of therapeutic strategies and clinical trials, and delves into the resistance mechanisms underlying targeted therapies. Finally, from a single-cell and spatial transcriptomic perspective, we address the challenge of therapy resistance, discussing emerging mechanisms and potential strategies to overcome this barrier and enhance treatment efficacy.

Molecular Differences With Therapeutic Implications in Early-Onset Compared With Average-Onset Biliary Tract Cancers

PURPOSE

Early-onset biliary tract cancer (eoBTC) is among the fast-growing subset of early-onset cancers, yet little is known about its biology. We sought to identify novel molecular characteristics of eoBTC in relation to average-onset BTC (aoBTC) using a real-world multiomics data set.

METHODS

The study comprised patients with BTC whose tumors underwent molecular analyses at Caris Life Sciences and were categorized by age (<50 years for eoBTC, ≥50 years for aoBTC). P values were adjusted for multiple testing and considered significant at Q < 0.05 (molecular comparisons) or Q < 0.25 (Gene Set Enrichment Analysis [GSEA]). Insurance claims data were used for survival analysis.

RESULTS

The study included 5,587 patients with BTC (453 eoBTC, median age = 44 years and 5,134 aoBTC, median age = 68 years). FGFR2 fusion (15.7% in eoBTC v 5.9% in aoBTC) and NIPBL fusion (1.1% v 0%) were significantly more prevalent in eoBTC (both Q < 0.001). The interferon gamma-IFG score (fold change [FC], 1.1; Q = 0.01) and T-cell inflammation score (FC, 17.3; Q = 0.03) were significantly higher in aoBTC. On GSEA, angiogenesis was enriched in eoBTC (normalized enrichment score [NES] = 1.51; Q = 0.16), whereas IFG (NES = -1.58; Q = 0.06) and inflammatory response (NES = -1.46; Q = 0.18) were enriched in aoBTC. The median overall survival (OS) was 16.5 (eoBTC) versus 13.3 months (aoBTC), hazard ratio = 0.86, P = .004. The median OS by FGFR2 fusion (with fusion v without) was 21.7 versus 15.0 months (P = .47) for eoBTC and 18.6 versus 12.2 months (P < .001) for aoBTC.

CONCLUSION

We identified crucial differences including higher prevalence of FGFR2 fusions in eoBTC and variations in immunotherapy-related markers. Better outcomes in eoBTC were affected by the FGFR2 fusion status. Our findings underscore the need for ensuring access to next-generation sequencing testing, including prompt identification of actionable targets.

Integrating Molecular Insights into Biliary Tract Cancer Management: A Review of Personalized Therapeutic Strategies

Biliary tract cancers (BTCs) are rare and aggressive malignancies with an increasing incidence and poor prognosis. The standard systemic treatment for BTCs has evolved to include immune checkpoint inhibitors associated with gemcitabine-cisplatin as first-line therapies. However, survival rates remain low, highlighting the critical need for personalized treatment strategies based on molecular profiling. Currently, significant advancements have been made in the molecular characterization of BTCs, where genetic alterations, such as IDH1 mutations and FGFR2 fusions, provide targets for therapy. Molecular profiling is crucial early in the management process to identify potential candidates for clinical trials and guide treatment strategy. The integration of these molecular insights into clinical practice has allowed for the development of targeted therapies, although many of them are still in the phase 2 trial stage without definitive survival benefits demonstrated in phase 3 trials. This integration of comprehensive molecular profile insights with traditional treatment approaches offers a new horizon in the personalized medicine landscape for BTCs, with the aim of significantly improving patient outcomes through precision oncology.

Discovery of LHQ490 as a highly selective fibroblast growth factor receptor 2 (FGFR2) inhibitor

Fibroblast growth factor receptor 2 (FGFR2) represents an appealing therapeutic target for multiple cancers, yet no selective FGFR2 inhibitors have been approved for clinical use to date. Here, we report the discovery of a series of new selective, irreversible FGFR2 inhibitors. The representative compound LHQ490 potently inhibited FGFR2 kinase activity with an IC50 of 5.2 nM, and was >61-, >34-, and >293-fold selective against FGFR1, FGFR3, and FGFR4, respectively. LHQ490 also exhibited high selectivity in a panel of 416 kinases. Cell-based studies revealed that LHQ490 efficiently suppressed the proliferation of BaF3-FGFR2 cells with an IC50 value of 1.4 nM, and displayed >70- and >714-fold selectivity against BaF3-FGFR1 and the parental BaF3 cells, respectively. More importantly, LHQ490 potently suppressed the FGFR2 signaling pathways, selectively inhibited FGFR2-driven cancer cell proliferation, and induced apoptosis of FGFR2-driven cancer cells. Taken together, this study provides a potent and highly selective FGFR2 inhibitor for further development of FGFR2-targeted therapeutic agents.

Targeting FGFR for cancer therapy

The FGFR signaling pathway is integral to cellular activities, including proliferation, differentiation, and survival. Dysregulation of this pathway is implicated in numerous human cancers, positioning FGFR as a prominent therapeutic target. Here, we conduct a comprehensive review of the function, signaling pathways and abnormal alterations of FGFR, as well as its role in tumorigenesis and development. Additionally, we provide an in-depth analysis of pivotal phase 2 and 3 clinical trials evaluating the performance and safety of FGFR inhibitors in oncology, thereby shedding light on the current state of clinical research in this field. Then, we highlight four drugs that have been approved for marketing by the FDA, offering insights into their molecular mechanisms and clinical achievements. Our discussion encompasses the intricate landscape of FGFR-driven tumorigenesis, current techniques for pinpointing FGFR anomalies, and clinical experiences with FGFR inhibitor regimens. Furthermore, we discuss the inherent challenges of targeting the FGFR pathway, encompassing resistance mechanisms such as activation by gatekeeper mutations, alternative pathways, and potential adverse reactions. By synthesizing the current evidence, we underscore the potential of FGFR-centric therapies to enhance patient prognosis, while emphasizing the imperative need for continued research to surmount resistance and optimize treatment modalities.

Pemigatinib in previously treated solid tumors with activating FGFR1-FGFR3 alterations: phase 2 FIGHT-207 basket trial

Fibroblast growth factor receptor (FGFR) alterations drive oncogenesis in multiple tumor types. Here we studied pemigatinib, a selective, potent, oral FGFR1-FGFR3 inhibitor, in the phase 2 FIGHT-207 basket study of FGFR-altered advanced solid tumors. Primary end points were objective response rate (ORR) in cohorts A (fusions/rearrangements, n = 49) and B (activating non-kinase domain mutations, n = 32). Secondary end points were progression-free survival, duration of response and overall survival in cohorts A and B, and safety. Exploratory end points included ORR of cohort C (kinase domain mutations, potentially pathogenic variants of unknown significance, n = 26) and analysis of co-alterations associated with resistance and response. ORRs for cohorts A, B and C were 26.5% (13/49), 9.4% (3/32) and 3.8% (1/26), respectively. Tumors with no approved FGFR inhibitors or those with alterations not previously confirmed to be sensitive to FGFR inhibition had objective responses. In cohorts A and B, the median progression-free survival was 4.5 and 3.7 months, median duration of response was 7.8 and 6.9 months and median overall survival was 17.5 and 11.4 months, respectively. Safety was consistent with previous reports. The most common any-grade treatment-emergent adverse events were hyperphosphatemia (84%) and stomatitis (53%). TP53 co-mutations were associated with lack of response and BAP1 alterations with higher response rates. FGFR1-FGFR3 gatekeeper and molecular brake mutations led to acquired resistance. New therapeutic areas for FGFR inhibition and drug failure mechanisms were identified across tumor types. ClinicalTrials.gov identifier: NCT03822117 .

Basket Trials: Past, Present, and Future

Large-scale tumor molecular profiling has revealed that diverse cancer histologies are driven by common pathways with unifying biomarkers that can be exploited therapeutically. Disease-agnostic basket trials have been increasingly utilized to test biomarker-driven therapies across cancer types. These trials have led to drug approvals and improved the lives of patients while simultaneously advancing our understanding of cancer biology. This review focuses on the practicalities of implementing basket trials, with an emphasis on molecularly targeted trials. We examine the biologic subtleties of genomic biomarker and patient selection, discuss previous successes in drug development facilitated by basket trials, describe certain novel targets and drugs, and emphasize practical considerations for participant recruitment and study design. This review also highlights strategies for aiding patient access to basket trials. As basket trials become more common, steps to ensure equitable implementation of these studies will be critical for molecularly targeted drug development.

Treatment options for biliary tract cancer: unmet needs, new targets and opportunities from both physicians' and patients' perspectives

Biliary tract cancer (BTC) is a rare cancer with poor prognosis, characterized by considerable pathophysiological and molecular heterogeneity. While this makes it difficult to treat, it also provides targeted therapy opportunities. Current standard-of-care is chemotherapy ± immunotherapy, but several targeted agents have recently been approved. The current investigational landscape in BTC emphasizes the importance of biomarker testing at diagnosis. MDM2/MDMX are important negative regulators of the tumor suppressor p53 and provide an additional target in BTC (∼5-8% of tumors are MDM2-amplified). Brigimadlin (BI 907828) is a highly potent MDM2-p53 antagonist that has shown antitumor activity in preclinical studies and promising results in early clinical trials; enrollment is ongoing in a potential registrational trial for patients with BTC.

Clinical Developments and Challenges in Treating FGFR2-Driven Gastric Cancer

Recent advances in the treatment of gastric cancer (GC) with chemotherapy, immunotherapy, anti-angiogenic therapy and targeted therapies have yielded some improvement in survival outcomes; however, metastatic GC remains a lethal malignancy and amongst the leading causes of cancer-related mortality worldwide. Importantly, the ongoing molecular characterisation of GCs continues to uncover potentially actionable molecular targets. Among these, aberrant FGFR2-driven signalling, predominantly arising from FGFR2 amplification, occurs in approximately 3-11% of GCs. However, whilst several inhibitors of FGFR have been clinically tested to-date, there are currently no approved FGFR-directed therapies for GC. In this review, we summarise the significance of FGFR2 as an actionable therapeutic target in GC, examine the recent pre-clinical and clinical data supporting the use of small-molecule inhibitors, antibody-based therapies, as well as novel approaches such as proteolysis-targeting chimeras (PROTACs) for targeting FGFR2 in these tumours, and discuss the ongoing challenges and opportunities associated with their clinical development.

The Irreversible FGFR Inhibitor KIN-3248 Overcomes FGFR2 Kinase Domain Mutations

PURPOSE

FGFR2 and FGFR3 show oncogenic activation in many cancer types, often through chromosomal fusion or extracellular domain mutation. FGFR2 and FGFR3 alterations are most prevalent in intrahepatic cholangiocarcinoma (ICC) and bladder cancers, respectively, and multiple selective reversible and covalent pan-FGFR tyrosine kinase inhibitors (TKI) have been approved in these contexts. However, resistance, often due to acquired secondary mutations in the FGFR2/3 kinase domain, limits efficacy. Resistance is typically polyclonal, involving a spectrum of different mutations that most frequently affect the molecular brake and gatekeeper residues (N550 and V565 in FGFR2).

EXPERIMENTAL DESIGN

Here, we characterize the activity of the next-generation covalent FGFR inhibitor, KIN-3248, in preclinical models of FGFR2 fusion+ ICC harboring a series of secondary kinase domain mutations, in vitro and in vivo. We also test select FGFR3 alleles in bladder cancer models.

RESULTS

KIN-3248 exhibits potent selectivity for FGFR1-3 and retains activity against various FGFR2 kinase domain mutations, in addition to being effective against FGFR3 V555M and N540K mutations. Notably, KIN-3248 activity extends to the FGFR2 V565F gatekeeper mutation, which causes profound resistance to currently approved FGFR inhibitors. Combination treatment with EGFR or MEK inhibitors potentiates KIN-3248 efficacy in vivo, including in models harboring FGFR2 kinase domain mutations.

CONCLUSIONS

Thus, KIN-3248 is a novel FGFR1-4 inhibitor whose distinct activity profile against FGFR kinase domain mutations highlights its potential for the treatment of ICC and other FGFR-driven cancers.

FGFR inhibition blocks NF-ĸB-dependent glucose metabolism and confers metabolic vulnerabilities in cholangiocarcinoma

Genomic alterations that activate Fibroblast Growth Factor Receptor 2 (FGFR2) are common in intrahepatic cholangiocarcinoma (ICC) and confer sensitivity to FGFR inhibition. However, the depth and duration of response is often limited. Here, we conduct integrative transcriptomics, metabolomics, and phosphoproteomics analysis of patient-derived models to define pathways downstream of oncogenic FGFR2 signaling that fuel ICC growth and to uncover compensatory mechanisms associated with pathway inhibition. We find that FGFR2-mediated activation of Nuclear factor-κB (NF-κB) maintains a highly glycolytic phenotype. Conversely, FGFR inhibition blocks glucose uptake and glycolysis while inciting adaptive changes, including switching fuel source utilization favoring fatty acid oxidation and increasing mitochondrial fusion and autophagy. Accordingly, FGFR inhibitor efficacy is potentiated by combined mitochondrial targeting, an effect enhanced in xenograft models by intermittent fasting. Thus, we show that oncogenic FGFR2 signaling drives NF-κB-dependent glycolysis in ICC and that metabolic reprogramming in response to FGFR inhibition confers new targetable vulnerabilities.

Exploring FGFR signaling inhibition as a promising approach in breast cancer treatment

As our grasp of cancer genomics deepens, we are steadily progressing towards the domain of precision medicine, where targeted therapy stands out as a revolutionary breakthrough in the landscape of cancer therapeutics. The fibroblast growth factor receptors (FGFR) pathway has been unveiled as a fundamental instigator in the pathophysiological mechanisms underlying breast carcinoma, paving the way for the exhilarating development of precision-targeted therapeutics. In the pursuit of exploring inhibitors that specifically target the FGFR signaling pathways, a multitude of kinase inhibitors targeting FGFR has been assiduously engineered to address the heterogeneous landscape of human malignancies. This review offers an exhaustive exploration of aberrations within the FGFR pathway and their functional implications in breast cancer. Additionally, we delve into cutting-edge therapeutic approaches for the treatment of breast cancer patients bearing FGFR alterations and the management of toxicity associated with FGFR inhibitors. Furthermore, our contemplation of the evolution of cutting-edge FGFR inhibitors foresees their potential to spearhead innovative therapeutic approaches in the ongoing combat against cancer.

Are FGFR Fusions and Mutations the Next Tumor-Agnostic Targets in Oncology?

Gong et al present two NCI-MATCH tumor-agnostic trials evaluating erdafitinib for FGFR-altered cancers, marking steppingstones in precision oncology.

A Phase I Study of KIN-3248, an Irreversible Small-molecule Pan-FGFR Inhibitor, in Patients with Advanced FGFR2/3-driven Solid Tumors

PURPOSE

Despite efficacy of approved FGFR inhibitors, emergence of polyclonal secondary mutations in the FGFR kinase domain leads to acquired resistance. KIN-3248 is a selective, irreversible, orally bioavailable, small-molecule inhibitor of FGFR1-4 that blocks both primary oncogenic and secondary kinase domain resistance FGFR alterations.

EXPERIMENTAL DESIGN

A first-in-human, phase I study of KIN-3248 was conducted in patients with advanced solid tumors harboring FGFR2 and/or FGFR3 gene alterations (NCT05242822). The primary objective was determination of MTD/recommended phase II dose (RP2D). Secondary and exploratory objectives included antitumor activity, pharmacokinetics, pharmacodynamics, and molecular response by circulating tumor DNA (ctDNA) clearance.

RESULTS

Fifty-four patients received doses ranging from 5 to 50 mg orally daily across six cohorts. Intrahepatic cholangiocarcinoma (48.1%), gastric (9.3%), and urothelial (7.4%) were the most common tumors. Tumors harbored FGFR2 (68.5%) or FGFR3 (31.5%) alterations-23 (42.6%) received prior FGFR inhibitors. One dose-limiting toxicity (hypersensitivity) occurred in cohort 1 (5 mg). Treatment-related, adverse events included hyperphosphatemia, diarrhea, and stomatitis. The MTD/RP2D was not established. Exposure was dose proportional and concordant with hyperphosphatemia. Five partial responses were observed; 4 in FGFR inhibitor naïve and 1 in FGFR pretreated patients. Pretreatment ctDNA profiling confirmed FGFR2/3 alterations in 63.3% of cases and clearance at cycle 2 associated with radiographic response.

CONCLUSION

The trial was terminated early for commercial considerations; therefore, RP2D was not established. Preliminary clinical data suggest that KIN-3248 is a safe, oral FGFR1-4 inhibitor with favorable pharmacokinetic parameters, though further dose escalation was required to nominate the MTD/RP2D.

SIGNIFICANCE

KIN-3248 was a rationally designed, next generation selective FGFR inhibitor, that was effective in interfering with both FGFR wild-type and mutant signaling. Clinical data indicate that KIN-3248 is safe with a signal of antitumor activity. Translational science support the mechanism of action in that serum phosphate was proportional with exposure, paired biopsies suggested phospho-ERK inhibition (a downstream target of FGFR2/3), and ctDNA clearance may act as a RECIST response surrogate.

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.

FGFR-targeted therapeutics: clinical activity, mechanisms of resistance and new directions

Fibroblast growth factor (FGF) signalling via FGF receptors (FGFR1-4) orchestrates fetal development and contributes to tissue and whole-body homeostasis, but can also promote tumorigenesis. Various agents, including pan-FGFR inhibitors (erdafitinib and futibatinib), FGFR1/2/3 inhibitors (infigratinib and pemigatinib), as well as a range of more-specific agents, have been developed and several have entered clinical use. Erdafitinib is approved for patients with urothelial carcinoma harbouring FGFR2/3 alterations, and futibatinib and pemigatinib are approved for patients with cholangiocarcinoma harbouring FGFR2 fusions and/or rearrangements. Clinical benefit from these agents is in part limited by hyperphosphataemia owing to off-target inhibition of FGFR1 as well as the emergence of resistance mutations in FGFR genes, activation of bypass signalling pathways, concurrent TP53 alterations and possibly epithelial-mesenchymal transition-related isoform switching. The next generation of small-molecule inhibitors, such as lirafugratinib and LOXO-435, and the FGFR2-specific antibody bemarituzumab are expected to have a reduced risk of hyperphosphataemia and the ability to overcome certain resistance mutations. In this Review, we describe the development and current clinical role of FGFR inhibitors and provide perspective on future research directions including expansion of the therapeutic indications for use of FGFR inhibitors, combination of these agents with immune-checkpoint inhibitors and the application of novel technologies, such as artificial intelligence.

Pemigatinib for patients with previously treated, locally advanced or metastatic cholangiocarcinoma harboring FGFR2 fusions or rearrangements: A joint analysis of the French PEMI-BIL and Italian PEMI-REAL cohort studies

BACKGROUND

Pemigatinib is approved for patients with pretreated, locally advanced or metastatic CCA harboring FGFR2 rearrangements or fusions. We aim to assess the effectiveness and safety of pemigatinib in real-world setting.

MATERIAL AND METHODS

A joint analysis of two multicentre observational retrospective cohort studies independently conducted in France and Italy was performed. All consecutive FGFR2-positive patients affected by CCA and treated with pemigatinib as second- or further line of systemic treatment in clinical practice, within or outside the European Expanded Access Program, were included.

RESULTS

Between July 2020 and September 2022, 72 patients were treated with pemigatinib in 14 Italian and 25 French Centres. Patients had a median age of 57 years, 76% were female, 81% had ECOG-PS 0-1, 99% had intrahepatic CCA, 74% had ≥ 2 metastatic sites, 67% had metastatic disease at diagnosis, while 38.8% received ≥ 2 previous lines of systemic treatment. At data cut-off analysis (April 2023), ORR and DCR were 45.8% and 84.7%, respectively. Median DoR was 7 months (IQR: 5.8-9.3). Over a median follow-up time of 19.5 months, median PFS and 1-year PFS rate were 8.7 months and 32.8%. Median OS and 1-year OS rate were 17.1 months and 60.6%. Fatigue (69.4%), ocular toxicity (68%), nail toxicities (61.1%), dermatologic toxicity (41.6%) hyperphosphataemia (55.6%), stomatitis (48.6%), and diarrhea (36.1%) were the most frequent, mainly G1-G2 AEs. Overall incidence of G3 AEs was 22.2%, while no patient experienced G4 AE. Dose reduction and temporary discontinuation were needed in 33.3% and 40.3% of cases, with 1 permanent discontinuation due to AEs.

CONCLUSIONS

These results confirm the effectiveness and safety of pemigatinib in a real-world setting.