Erdafitinib in Asian patients with advanced solid tumors: an open-label, single-arm, phase IIa trial.

BACKGROUND: FGFR genomic aberrations occur in approximately 5-10% of human cancers. Erdafitinib has previously demonstrated efficacy and safety in FGFR-altered advanced solid tumors, such as gliomas, thoracic, gastrointestinal, gynecological, and other rare cancers. However, its efficacy and safety in Asian patients remain largely unknown. We conducted a multicenter, open-label, single-arm phase IIa study of erdafitinib to evaluate its efficacy in Asian patients with FGFR-altered advanced cholangiocarcinoma, non-small cell lung cancer (NSCLC), and esophageal cancer. METHODS: Patients with pathologically/cytologically confirmed, advanced, or refractory tumors who met molecular and study eligibility criteria received oral erdafitinib 8 mg once daily with an option for pharmacodynamically guided up-titration to 9 mg on a 28-day cycle, except for four NSCLC patients who received erdafitinib 10 mg (7 days on/7 days off) as they were recruited before the protocol amendment. The primary endpoint was investigator-assessed objective response rate per RECIST v1.1. Secondary endpoints included progression-free survival, duration of response, disease control rate, overall survival, safety, and pharmacokinetics. RESULTS: Thirty-five patients (cholangiocarcinoma: 22; NSCLC: 12; esophageal cancer: 1) were enrolled. At data cutoff (November 19, 2021), the objective response rate for patients with cholangiocarcinoma was 40.9% (95% CI, 20.7-63.6); the median progression-free survival was 5.6 months (95% CI, 3.6-12.7) and median overall survival was 40.2 months (95% CI, 12.4-not estimable). No patient with RET/FGFR-altered NSCLC achieved objective response and the disease control rate was 25.0% (95% CI, 5.5-57.2%), with three patients with stable disease. The single patient with esophageal cancer achieved partial response. All patients experienced treatment-emergent adverse events, and grade ≥ 3 treatment-emergent adverse events were reported in 22 (62.9%) patients. Hyperphosphatemia was the most frequently reported treatment-emergent adverse event (all-grade, 85.7%). CONCLUSIONS: Erdafitinib demonstrated efficacy in a population of Asian patients in selected advanced solid tumors, particularly in those with advanced FGFR-altered cholangiocarcinoma. Treatment was tolerable with no new safety signals. TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov (NCT02699606); study registration (first posted): 04/03/2016.

Discovery of novel FGF trap small molecules endowed with anti-myeloma activity.

Fibroblast growth factors (FGFs) act as proangiogenic and mitogenic cytokines in several cancers, including multiple myeloma (MM). Indeed, corrupted FGF autocrine and paracrine secretion induces an aberrant activation of the FGF receptor (FGFR) signaling sustaining cancer cell spreading and resistance to pharmacological treatments. Thus, FGF traps may represent a promising anti-cancer strategy to hamper the ligand-dependent activation of the FGF/FGFR system. We previously identified NSC12 as the first orally available small molecule FGF trap able to inhibit the growth and progression of several FGF-dependent tumor models. NSC12 is a pregnenolone derivative carrying a 1,1-bis-trifluoromethyl-1,3-propanediol chain in position 17 of the steroid nucleus. Investigation of structure-activity relationships (SARs) provided more potent and specific NSC12 steroid derivatives and highlighted that the C17-side chain is pivotal for the FGF trap activity. Here, a scaffold hopping approach allowed to obtain two FGF trap compounds (22 and 57) devoid of the steroid nucleus and able to efficiently bind FGF2 and to inhibit FGFR activation in MM cells. Accordingly, these compounds exert a potent anti-tumor activity on MM cell lines both in vitro and in vivo and on MM patient-derived primary cells, strongly affecting the survival of both proteasome-inhibitor sensitive and resistant MM cells. These results propose a new therapeutic option for relapsed/refractory MM patients and set the bases for the development of novel FGF traps prone to chemical diversification to be used in the clinic for the treatment of those tumors in which the FGF/FGFR system plays a pivotal role, including MM.

Open-label, dose-escalation FIGHT-101 study of pemigatinib combined with targeted therapy, chemotherapy, or immunotherapy in patients with advanced malignancies.

BACKGROUND: Pemigatinib is an oral, potent, selective fibroblast growth factor receptor (FGFR) 1-3 inhibitor. FIGHT-101, a three-part, open-label, first-in-human, phase I/II study (NCT02393248), evaluated pemigatinib in patients with advanced solid tumors. In parts 1 and 2, pemigatinib monotherapy had a manageable safety profile and antitumor activity in FGFR-altered tumors. Part 3 (pemigatinib combination therapies) results are presented here. PATIENTS AND METHODS: Patients received 9, 13.5, or 20 mg oral once-daily pemigatinib on continuous or intermittent schedules with gemcitabine and cisplatin (pemi/gem/cis), docetaxel (pemi/doc), trastuzumab (pemi/tras), pembrolizumab (pemi/pembro), or retifanlimab (pemi/reti) irrespective of whether the tumor was confirmed as FGFR altered. Primary endpoints were safety and pharmacodynamics. Secondary endpoints were investigator-assessed tumor objective response rates (ORRs) and pharmacokinetics (PK). RESULTS: Of 65 enrolled patients (pemi/gem/cis, n = 8; pemi/doc, n = 7; pemi/tras, n = 6; pemi/pembro, n = 26; pemi/reti, n = 18), all discontinued. Treatment-emergent adverse events (TEAEs) were generally consistent with individual drug AEs. Serious and grade ≥3 TEAEs occurred in 0%-85.7% and 33.3%-100.0% of patients across treatment groups, respectively. All pemigatinib combinations demonstrated steady-state PK comparable to monotherapy. Pharmacodynamic effects in all pemigatinib combinations, except pemi/gem/cis, were consistent with monotherapy. Less inhibition of FGFR2α phosphorylation was observed with this combination. ORRs (95% confidence interval) were 37.5% [8.5% to 75.5% (pemi/gem/cis)], 14.3% [0.4% to 57.9% (pemi/doc)], 0% (pemi/tras), 26.9% [11.6% to 47.8% (pemi/pembro)], and 11.1% [1.4% to 34.7% (pemi/reti)]. All groups had instances of tumor shrinkage. ORRs in assessable patients with FGFR rearrangements and mutations were 50% and 33%, respectively. CONCLUSIONS: Pemigatinib combination therapy showed no unexpected toxicities. PK and pharmacodynamics were mostly consistent with pemigatinib monotherapy. Pemi/gem/cis (37.5%) and pemi/pembro (26.9%) had the highest ORR; most responders had FGFR alterations.

Combined targeted therapy with PI3K and CDK4/6, or FGFR inhibitors show synergistic effects in a neuroblastoma spheroid culture model.

AIM: Neuroblastoma (NB) is, in spite of current intensive therapy with severe side effects, still not cured so new therapies are needed. Recently, we showed combining phosphoinositide 3-kinase (PI3K) (BYL719), fibroblast growth factor receptor (FGFR) (JNJ-42756493) and cyclin-dependent kinase 4/6 (CDK4/6) (PD-0332991) inhibitors, in vitro in NB cell lines grown as monolayers had synergistic effects. However, there were variations depending on the combinations used and the targeted NB cell lines. To obtain further information and to mimic more natural circumstances, we investigated the effects of single and combined administrations of the above inhibitors in spheroid NB-cultures. MATERIAL AND METHODS: Spheroid cultures of NB cell lines SK-N-AS, SK-N-BE(2)-C, SK-N-FI and SK-N-SH were established and treated with single and combined administrations of BYL719, JNJ-42756493, and PD-0332991 and followed for growth, viability, proliferation, cytotoxicity and migration. KEY FINDINGS: Single inhibitor administrations gave dose dependent responses with regard to growth and viability and their combinations were efficient and resulted in a range of additive and synergistic effects. The responses to individual drugs and their various combinations were predominantly alike regardless of whether the cells were cultivated in monolayer or D spheroid NB models. However, in general, slightly higher drug concentrations were necessary in spheroidcultures. SIGNIFICANCE: This study provides pre-clinical evidence that single PI3K, FGFR, and CDK4/6, inhibitors exhibit promising anti-NB activity and when combined lower doses of the drugs could be also used in spheroid NB-cultures, supporting the pursuit of further in vitro and in vivo studies in preparation for future potential clinical use.

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.

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.

A phase 1/1b, open-label, dose-escalation study of PD-1 inhibitor, cetrelimab alone and in combination with FGFR inhibitor, erdafitinib in Japanese patients with advanced solid tumors.

Immune checkpoint inhibitors are the leading approaches in tumor immunotherapy. The aim of the study was to establish recommended phase 2 doses (RP2Ds) of intravenous cetrelimab, a checkpoint inhibitor, alone and with oral erdafitinib in Japanese patients with advanced solid tumors. This open-label, non-randomized, dose-escalation phase 1/1b study enrolled adults with advanced solid tumors who were ineligible for standard therapy. Study was conducted in two parts: phase 1a assessed cetrelimab at three dosing levels (80 mg every 2 weeks [Q2W], 240 mg Q2W, and 480 mg Q4W); phase 1b assessed cetrelimab+erdafitinib at two dosing levels (240 mg Q2W + 6 mg once daily [QD] and 240 mg Q2W + 8 mg QD). Primary endpoint was frequency and severity of dose-limiting toxicities (DLTs) of cetrelimab ± erdafitinib. In total 22 patients (phase 1a, n = 9; phase 1b, n = 13) were enrolled. Median duration of follow-up was 8.64 months in phase 1a and 2.33 months in phase 1b. In phase 1a, DLTs weren't reported while in phase 1b, 1 patient who received 240 mg cetrelimab + 6 mg erdafitinib reported Stevens-Johnson syndrome (grade 3, immune-related). Overall, 88.9% patients in phase 1a (grade ≥ 3: 44.4%) and 100.0% in phase 1b (grade ≥ 3: 53.8%) experienced ≥ 1 treatment-related adverse events (TEAEs); 33.3% in phase 1a and 38.5% in phase 1b reported serious TEAEs, of which 11.1% patients in phase 1a and 15.4% in phase 1b had TEAEs which led to treatment discontinuation. Cetrelimab alone and in combination with erdafitinib showed manageable safety in Japanese patients with advanced solid tumors. RP2Ds were determined as 480 mg cetrelimab Q4W for monotherapy, and cetrelimab 240 mg Q2W + erdafitinib 8 mg QD for combination therapy.

Effect of Carbamazepine on the Pharmacokinetics of Erdafitinib in Healthy Participants.

Erdafitinib, a selective and potent oral pan-FGFR inhibitor, is metabolized mainly through CYP2C9 and CYP3A4 enzymes. This phase 1, open-label, single-sequence, drug-drug interaction study evaluated the pharmacokinetics, safety, and tolerability of a single oral dose of erdafitinib alone and when co-administered with steady state oral carbamazepine, a dual inducer of CYP3A4 and CYP2C9, in 13 healthy adult participants (NCT04330248). Compared with erdafitinib administration alone, carbamazepine co-administration decreased total and free maximum plasma concentrations of erdafitinib (Cmax) by 35% (95% CI 30%-39%) and 22% (95% CI 17%-27%), respectively. The areas under the concentration-time curve over the time interval from 0 to 168 hours, to the last quantifiable data point, and to time infinity (AUC168h, AUClast, AUCinf), were markedly decreased for both total erdafitinib (56%-62%) and free erdafitinib (48%-55%). The safety profile of erdafitinib was consistent with previous clinical studies in healthy participants, with no new safety concerns when administered with or without carbamazepine. Co-administration with carbamazepine may reduce the activity of erdafitinib due to reduced exposure. Concomitant use of strong CYP3A4 inducers with erdafitinib should be avoided.

Effect of FGFR alteration on prognosis in 1963 urothelial carcinoma patients with immune checkpoint inhibitors: Implying combination of FGFR inhibitor and immunotherapy for FGFR-altered urothelial carcinoma.

Immune checkpoint inhibitors (ICIs) are essential for urothelial carcinoma (UC) treatment. Fibroblast growth factor receptor (FGFR) alterations, as common oncogenic drivers in UC, have been reported to drive T cell depletion of UC immune microenvironment via up-regulating FGFR signaling, which indicated FGFR alterations potentially result in reduced response to ICIs. In addition, the selective pan-FGFR inhibitor showed better clinical benefit in clinical trials, indicating FGFR has emerged as critical therapeutic target via inhibiting FGFR signaling. The present study aims to evaluate prognosis and response to ICIs between FGFR-altered UC patients and FGFR-wildtype UC patients via 1963 UC patients and offers new insights into personalized precision therapy and combination therapy for UC.

The combination of gemcitabine plus an anti-FGFR inhibitor can have a synergistic antitumor effect on FGF-activating cholangiocarcinoma.

Anti-FGFR treatment for cholangiocarcinoma (CCA) with fibroblast growth factor receptor (FGFR) alteration is a promising treatment option. Since the antitumor mechanisms of anti-FGFR inhibitors and conventional cytotoxic drugs differ, synergistic effects can be possible. This study aimed to evaluate the efficacy of the combined administration of gemcitabine (GEM) and pemigatinib in CCA cells with FGFR2 alterations. To simulate the treatment for patients with 3 kinds of CCA, chemonaïve CCA with activation of the FGF pathway, chemo-resistant CCA with activation of the FGF pathway, and CCA without FGF pathway activation (as controls), we evaluated 3 different CCA cell lines, CCLP-1 (with a FGFR2 fusion mutation), CCLP-GR (GEM-resistant cells established from CCLP-1), and HuCCT1 (without FGFR mutations). There was no significant difference between CCLP-1 and HuCCT1 in GEM suspensibility (IC50 = 19.3, 22.6 mg/dl, p = 0.1187), and the drug sensitivity to pemigatinib did not differ between CCLP-1 and CCLP-GR (IC50 = 7.18,7.60 nM, p = 0.3089). Interestingly, only CCLP-1 showed a synergistic effect with combination therapy consisting of GEM plus pemigatinib in vitro and in vivo. In a comparison of the reaction to GEM exposure, only CCLP-1 cells showed an increase in the activation of downstream proteins in the FGF pathway, especially FRS2 and ERK. In association with this reaction, cell cycle and mitosis were increased with GEM exposure in CCLP-1, but HuCCT1/CCLP-GR did not show this reaction. Our results suggested that combination therapy with GEM plus pemigatinib is a promising treatment for chemonaïve patients with CCA with activation of the FGF pathway.

From Tumor to Bone: Growth Factor Receptors as Key Players in Cancer Metastasis.

This review article explores the intricate correlation between growth factors and bone metastases, which play a crucial role in the development of several types of malignancies, namely breast, prostate, lung, and renal cancers. The focal point of our discussion is on crucial receptors for growth factors, including Epidermal Growth Factor Receptor (EGFR), Transforming Growth Factor-ß (TGFß), Vascular Endothelial Growth Factor Receptor (VEGFR), and Fibroblast Growth Factor Receptor (FGFR). These receptors, which are essential for cellular activities including growth, differentiation, and survival, have important involvement in the spread of cancer and the interactions between tumors and the bone environment. We discuss the underlying mechanisms of bone metastases, with a specific emphasis on the interaction between growth factor receptors and the bone microenvironment. EGFR signaling specifically enhances the process of osteoclast development and the formation of osteolytic lesions, especially in breast and lung malignancies. TGFß receptors have a role in both osteolytic and osteoblastic metastases by releasing TGFß, which attracts cancer cells and promotes bone remodeling. This is a crucial element in the spread of prostate cancer to the bones. The functions of FGFR and VEGFR in the processes of bone formation and tumor angiogenesis, respectively, highlight the complex and diverse nature of these interactions. The review emphasizes the possibility of targeted therapeutics targeting these receptors to interrupt the cycle of tumor development and bone degradation. Therapeutic approaches include focusing on the VEGF/VEGFR, EGF/EGFR, FGF/FGFR, and TGFß/TGFßR pathways. These include a variety of compounds, such as small molecule inhibitors and monoclonal antibodies, which have shown potential to interfere with tumor-induced alterations in bone. The text discusses clinical trials and preclinical models, offering insights into the effectiveness and constraints of various treatments. Ultimately, this study provides a succinct but thorough summary of the present knowledge and treatment strategies focused on growth factor receptors in bone metastases. This highlights the significance of comprehending the signaling of growth factor receptors in the microenvironment where tumors spread to the bones, as well as the possibility of using targeted therapies to enhance the results for cancer patients with bone metastases. The advancement of treating bone metastases hinges on the development of treatments that specifically target the intricate relationships between malignancies and bone.

State-of-the-art and trends in fibroblast growth factor receptor-directed therapies in gastro-intestinal malignancies.

PURPOSE OF REVIEW: This review is timely and relevant due to the increasing recognition of the significance of the fibroblast growth factor receptor (FGFR) family in cancer biology. Understanding the role of FGFRs and their dysregulation in various cancers is crucial for developing targeted therapies and improving patient outcomes. RECENT FINDINGS: The review highlights the importance of the FGFR family in cellular processes such as growth, proliferation, and survival. It discusses how abnormalities in FGFR2, including overexpression, gene amplification, and other genetic alterations, contribute to cancer progression, particularly in gastro-intestinal cancers. The paper also emphasizes the promising results of FGFR-targeted therapies, especially tyrosine kinase inhibitors, in certain cancers such as cholangiocarcinoma and oesophagogastric cancers. SUMMARY: The findings underscore the potential of FGFR-targeted therapies in treating cancers with FGFR dysregulation. However, the review also addresses the challenges associated with these therapies, including toxicities and mechanisms of resistance. Understanding these complexities is essential for optimizing the efficacy of FGFR-targeted treatments and improving patient outcomes in clinical practice and research efforts.

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.

Genomic Profiling and Molecular Characterisation of Metastatic Urothelial Carcinoma.

The clinical management of metastatic urothelial carcinoma (mUC) is undergoing a major paradigm shift; the integration of immune checkpoint inhibitors (ICIs) and antibody-drug conjugates (ADCs) into the mUC therapeutic strategy has succeeded in improving platinum-based chemotherapy outcomes. Given the expanding therapeutic armamentarium, it is crucial to identify efficacy-predictive biomarkers that can guide an individual patient's therapeutic strategy. We reviewed the literature data on mUC genomic alterations of clinical interest, discussing their prognostic and predictive role. In particular, we explored the role of the fibroblast growth factor receptor (FGFR) family, epidermal growth factor receptor 2 (HER2), mechanistic target of rapamycin (mTOR) axis, DNA repair genes, and microsatellite instability. Currently, based on the available clinical data, FGFR inhibitors and HER2-directed ADCs are effective therapeutic options for later lines of biomarker-driven mUC. However, emerging genomic data highlight the opportunity for earlier use and/or combination with other drugs of both FGFR inhibitors and HER2-directed ADCs and also reveal additional potential drug targets that could change mUC management.

Dual FGFR-targeting and pH-activatable ruthenium-peptide conjugates for targeted therapy of breast cancer.

Dysregulation of Fibroblast Growth Factor Receptors (FGFRs) signaling has been associated with breast cancer, yet employing FGFR-targeted delivery systems to improve the efficacy of cytotoxic agents is still sparsely exploited. Herein, we report four new bi-functional ruthenium-peptide conjugates (RuPCs) with FGFR-targeting and pH-dependent releasing abilities, envisioning the selective delivery of cytotoxic Ru complexes to FGFR(+)-breast cancer cells, and controlled activation at the acidic tumoral microenvironment. The antiproliferative potential of the RuPCs and free Ru complexes was evaluated in four breast cancer cell lines with different FGFR expression levels (SKBR-3, MDA-MB-134-VI, MCF-7, and MDA-MB-231) and in human dermal fibroblasts (HDF), at pH 6.8 and pH 7.4 aimed at mimicking the tumor microenvironment and normal tissues/bloodstream pHs, respectively. The RuPCs showed higher cytotoxicity in cells with higher level of FGFR expression at acidic pH. Additionally, RuPCs showed up to 6-fold higher activity in the FGFR(+) breast cancer lines compared to the normal cell line. The release profile of Ru complexes from RuPCs corroborates the antiproliferative effects observed. Remarkably, the cytotoxicity and releasing ability of RuPCs were shown to be strongly dependent on the conjugation of the peptide position in the Ru complex. Complementary molecular dynamic simulations and computational calculations were performed to help interpret these findings at the molecular level. In summary, we identified a lead bi-functional RuPC that holds strong potential as a FGFR-targeted chemotherapeutic agent.

Erdafitinib or Chemotherapy in Advanced or Metastatic Urothelial Carcinoma.

BACKGROUND: Erdafitinib is a pan-fibroblast growth factor receptor (FGFR) inhibitor approved for the treatment of locally advanced or metastatic urothelial carcinoma in adults with susceptible FGFR3/2 alterations who have progression after platinum-containing chemotherapy. The effects of erdafitinib in patients with FGFR-altered metastatic urothelial carcinoma who have progression during or after treatment with checkpoint inhibitors (anti-programmed cell death protein 1 [PD-1] or anti-programmed death ligand 1 [PD-L1] agents) are unclear. METHODS: We conducted a global phase 3 trial of erdafitinib as compared with chemotherapy in patients with metastatic urothelial carcinoma with susceptible FGFR3/2 alterations who had progression after one or two previous treatments that included an anti-PD-1 or anti-PD-L1. Patients were randomly assigned in a 1:1 ratio to receive erdafitinib or the investigator's choice of chemotherapy (docetaxel or vinflunine). The primary end point was overall survival. RESULTS: A total of 266 patients underwent randomization: 136 to the erdafitinib group and 130 to the chemotherapy group. The median follow-up was 15.9 months. The median overall survival was significantly longer with erdafitinib than with chemotherapy (12.1 months vs. 7.8 months; hazard ratio for death, 0.64; 95% confidence interval [CI], 0.47 to 0.88; P = 0.005). The median progression-free survival was also longer with erdafitinib than with chemotherapy (5.6 months vs. 2.7 months; hazard ratio for progression or death, 0.58; 95% CI, 0.44 to 0.78; P<0.001). The incidence of grade 3 or 4 treatment-related adverse events was similar in the two groups (45.9% in the erdafitinib group and 46.4% in the chemotherapy group). Treatment-related adverse events that led to death were less common with erdafitinib than with chemotherapy (in 0.7% vs. 5.4% of patients). CONCLUSIONS: Erdafitinib therapy resulted in significantly longer overall survival than chemotherapy among patients with metastatic urothelial carcinoma and FGFR alterations after previous anti-PD-1 or anti-PD-L1 treatment. (Funded by Janssen Research and Development; THOR ClinicalTrials.gov number, NCT03390504.).

Identification of a novel extracellular inhibitor of FGF2/FGFR signaling axis by combined virtual screening and NMR spectroscopy approach.

The aberrant activation of the fibroblast growth factor 2 (FGF2)/fibroblast growth factor receptor (FGFR) signalling pathway drives severe pathologies, including cancer development and angiogenesis-driven pathologies. The perturbation of the FGF2/FGFR axis via extracellular allosteric small inhibitors is a promising strategy for developing FGFR inhibitors with improved safety and efficacy for cancer treatment. We have previously investigated the role of new extracellular inhibitors, such as rosmarinic acid (RA), which bind the FGFR-D2 domain and directly compete with FGF2 for the same binding site, enabling the disruption of the functional FGF2/FGFR interaction. To select ligands for the previously identified FGF2/FGFR RA binding site, NMR data-driven virtual screening has been performed on an in-house library of non-commercial small molecules and metabolites. A novel drug-like compound, a resorcinol derivative named RBA4 has been identified. NMR interaction studies demonstrate that RBA4 binds the FGF2/FGFR complex, in agreement with docking prediction. Residue-level NMR perturbations analysis highlights that the mode of action of RBA4 is similar to RA in terms of its ability to target the FGF2/FGFR-D2 complex, inducing perturbations on both proteins and triggering complex dissociation. Biological assays proved that RBA4 inhibited FGF2 proliferative activity at a level comparable to the previously reported natural product, RA. Identification of RBA4 chemical groups involved in direct interactions represents a starting point for further optimization of drug-like extracellular inhibitors with improved activity.

Developments in FGFR and IDH inhibitors for cholangiocarcinoma therapy.

INTRODUCTION: Cholangiocarcinoma (CCA) is an uncommon malignancy originating from epithelial cells of the biliary tract. Regardless of the site of origin within the biliary tree, CCAs are generally aggressive with a poor survival. Surgical resection remains the only chance for cure, yet a majority of patients are not surgical candidates at presentation. Unfortunately, systemic therapies are often ineffective and complicated by side effects. As such, more effective targeted therapies are required in order to improve survival. AREA COVERED: Genetic analysis of CCA has allowed for a better understanding of the genomic landscape of CCA. Isocitrate dehydrogenase (IDH) and fibroblast growth factor receptor (FGFR) mutations have emerged as the most promising molecular targets for CCA. Inhibitors of IDH and FGFR have proven to have therapeutic benefit with an acceptable safety profile. However, patients often develop resistance rendering the therapy ineffective. EXPERT OPINION: Understanding the molecular pathways of IDH and FGFR may lead to a better understanding of the mechanisms of resistance. Thus, novel therapies may be developed to improve the efficacy of these therapies. Developing novel biomarkers may improve patient selection and further enhance effectiveness of targeted therapies.

The fibroblast growth factor receptor inhibitor, derazantinib, has strong efficacy in human gastric tumor models and synergizes with paclitaxel in vivo.

Derazantinib (DZB) is an inhibitor of fibroblast growth factor receptors 1-3 (FGFR1-3), with additional activity against colony-stimulating-factor-1 receptor (CSF1R). We have profiled the activity of DZB in gastric cancer (GC) as monotherapy and combined with paclitaxel, and explored means of stratifying patients for treatment. The antiproliferative potency of DZB in vitro was quantified in 90 tumor cell lines and shown to correlate significantly with FGFR expression (<0.01) but not with FGFR DNA copy-number (CN) or FGFR mutations. In four GC cell lines in vitro , little or no synergy was observed with paclitaxel. In athymic nude mice, bearing cell-line derived xenografts (CDX) or patient-derived xenograft (PDX) GC models, DZB efficacy correlated highly significantly with FGFR gene expression ( r2 = 0.58; P = 0.0003; n = 18), but not FGFR mutations or DNA-CN. In FGFR-driven GC models, DZB had comparable efficacy to three other FGFR inhibitors and was more efficacious than paclitaxel. DZB had dose-dependent plasma pharmacokinetics but showed low brain penetration at all doses. GC models (one CDX and six PDX) were tested for sensitivity to the combination of DZB and paclitaxel and characterized by immunohistochemistry. The combination showed synergy (5) or additivity (2), and no antagonism, with synergy significantly associated ( P < 0.05) with higher levels of M2-type macrophages. The association of strong efficacy of the combination in vivo with M2 macrophages, which are known to express CSF1R, and the absence of synergy in vitro is consistent with the tumor microenvironment also being a factor in DZB efficacy and suggests additional means by which DZB could be stratified for cancer treatment in the clinic.

Deciphering the molecular mechanisms of selective non-covalency demonstrated differentially by 9-Allylnaphtho[1,8-ef]isoindole-7,8,10(9H)-trione (C11) against fibroblast growth factor receptors 1-4.

The specific inhibition of aberrant Fibroblast Growth Factor Receptors (FGFRs) has been identified as a feasible strategy to therapeutically ameliorate their respective carcinogenic involvements. High homology among these proteins has however limited efforts towards the discovery of selective small-molecule compounds due to undesirable effects elicited by pan-FGFR inhibitors. A recent study showed the selective activity of a new compound C11 which was >52 times more potent against FGFR1 than FGFR2 and FGFR3, and 4 times than FGFR4. This C11 selective non-covalency was investigated in this study using computational methods since it has remained unresolved. Structural findings revealed that C11 enhanced structural perturbations in FGFR1 with less prominent effects in other FGFRs. High deviations also characterized the C11-bound active pocket of FGFR1 with notable fluctuations across the constituent P-loop, αC helix, hinge region, catalytic, and activation loops. These induced motions were essential for optimal C11 motion an d positioning of its phenalenone ring and prop-2-en-l-yl moiety at the FGFR1 active pocket to interact stably and strongly with A564FGFR1, L484FGFR1, Y563FGFR1, and E562FGFR1 which as well had high energy contributions. C11 exhibited highly unstable binding in F GFRs2-3 with a more steady interaction with FGFR4. Free binding energy (ΔGbind) analyses further estimated the highest interaction energy for C11-FGFR1 with favorable desolvation energy that indicated a deep hydrophobic pocket binding for C11 in FGFR1 compared to other FGFRs. We believe rational insights from this study will contribute to the structure-based design of highly specific FGFR1 inhibitors.Communicated by Ramaswamy H. Sarma.