Tasurgratinib in patients with cholangiocarcinoma or gastric cancer: Expansion part of the first‐in‐human phase I study

Goyal L., Meric-Bernstam F., Hollebecque A., Valle J.W., Morizane C., Karasic T.B., Abrams T.A., Furuse J., Kelley R.K., Cassier P.A., Klümpen H., Chang H., Chen L., Tabernero J., Oh D., et. al.

Alterations in fibroblast growth factor receptor 2 (FGFR2) have emerged as promising drug targets for intrahepatic cholangiocarcinoma, a rare cancer with a poor prognosis. Futibatinib, a next-generation, covalently binding FGFR1-4 inhibitor, has been shown to have both antitumor activity in patients with FGFR-altered tumors and strong preclinical activity against acquired resistance mutations associated with ATP-competitive FGFR inhibitors.In this multinational, open-label, single-group, phase 2 study, we enrolled patients with unresectable or metastatic FGFR2 fusion-positive or FGFR2 rearrangement-positive intrahepatic cholangiocarcinoma and disease progression after one or more previous lines of systemic therapy (excluding FGFR inhibitors). The patients received oral futibatinib at a dose of 20 mg once daily in a continuous regimen. The primary end point was objective response (partial or complete response), as assessed by independent central review. Secondary end points included the response duration, progression-free and overall survival, safety, and patient-reported outcomes.Between April 16, 2018, and November 29, 2019, a total of 103 patients were enrolled and received futibatinib. A total of 43 of 103 patients (42%; 95% confidence interval, 32 to 52) had a response, and the median duration of response was 9.7 months. Responses were consistent across patient subgroups, including patients with heavily pretreated disease, older adults, and patients who had co-occurring TP53 mutations. At a median follow-up of 17.1 months, the median progression-free survival was 9.0 months and overall survival was 21.7 months. Common treatment-related grade 3 adverse events were hyperphosphatemia (in 30% of the patients), an increased aspartate aminotransferase level (in 7%), stomatitis (in 6%), and fatigue (in 6%). Treatment-related adverse events led to permanent discontinuation of futibatinib in 2% of the patients. No treatment-related deaths occurred. Quality of life was maintained throughout treatment.In previously treated patients with FGFR2 fusion or rearrangement-positive intrahepatic cholangiocarcinoma, the use of futibatinib, a covalent FGFR inhibitor, led to measurable clinical benefit. (Funded by Taiho Oncology and Taiho Pharmaceutical; FOENIX-CCA2 ClinicalTrials.gov number, NCT02052778.).

Abou-Alfa G.K., Sahai V., Hollebecque A., Vaccaro G., Melisi D., Al-Rajabi R., Paulson A.S., Borad M.J., Gallinson D., Murphy A.G., Oh D., Dotan E., Catenacci D.V., Van Cutsem E., Ji T., et. al.

SummaryBackground Fibroblast growth factor receptor (FGFR) 2 gene alterations are involved in the pathogenesis of cholangiocarcinoma. Pemigatinib is a selective, potent, oral inhibitor of FGFR1, 2, and 3. This study evaluated the safety and antitumour activity of pemigatinib in patients with previously treated, locally advanced or metastatic cholangiocarcinoma with and without FGFR2 fusions or rearrangements. Methods In this multicentre, open-label, single-arm, multicohort, phase 2 study (FIGHT-202), patients aged 18 years or older with disease progression following at least one previous treatment and an Eastern Cooperative Oncology Group (ECOG) performance status of 0–2 recruited from 146 academic or community-based sites in the USA, Europe, the Middle East, and Asia were assigned to one of three cohorts: patients with FGFR2 fusions or rearrangements, patients with other FGF/FGFR alterations, or patients with no FGF/FGFR alterations. All enrolled patients received a starting dose of 13·5 mg oral pemigatinib once daily (21-day cycle; 2 weeks on, 1 week off) until disease progression, unacceptable toxicity, withdrawal of consent, or physician decision. The primary endpoint was the proportion of patients who achieved an objective response among those with FGFR2 fusions or rearrangements, assessed centrally in all patients who received at least one dose of pemigatinib. This study is registered with ClinicalTrials.gov, NCT02924376, and enrolment is completed. Findings Between Jan 17, 2017, and March 22, 2019, 146 patients were enrolled: 107 with FGFR2 fusions or rearrangements, 20 with other FGF/FGFR alterations, 18 with no FGF/FGFR alterations, and one with an undetermined FGF/FGFR alteration. The median follow-up was 17·8 months (IQR 11·6–21·3). 38 (35·5% [95% CI 26·5–45·4]) patients with FGFR2 fusions or rearrangements achieved an objective response (three complete responses and 35 partial responses). Overall, hyperphosphataemia was the most common all-grade adverse event irrespective of cause (88 [60%] of 146 patients). 93 (64%) patients had a grade 3 or worse adverse event (irrespective of cause); the most frequent were hypophosphataemia (18 [12%]), arthralgia (nine [6%]), stomatitis (eight [5%]), hyponatraemia (eight [5%]), abdominal pain (seven [5%]), and fatigue (seven [5%]). 65 (45%) patients had serious adverse events; the most frequent were abdominal pain (seven [5%]), pyrexia (seven [5%]), cholangitis (five [3%]), and pleural effusion (five [3%]). Overall, 71 (49%) patients died during the study, most frequently because of disease progression (61 [42%]); no deaths were deemed to be treatment related. Interpretation These data support the therapeutic potential of pemigatinib in previously treated patients with cholangiocarcinoma who have FGFR2 fusions or rearrangements. Funding Incyte Corporation.

Koyama T., Shimizu T., Iwasa S., Fujiwara Y., Kondo S., Kitano S., Yonemori K., Shimomura A., Iizumi S., Sasaki T., Furuse J., Yamamoto N.

Fibroblast growth factor receptors (FGFR) are a family of transmembrane receptor tyrosine kinases involved in regulating cellular processes. FGFR mutations are implicated in oncogenesis, representing therapeutic potential in the form of FGFR inhibitors. This phase I, first-in-human study in Japan evaluated safety and tolerability of E7090, a potent selective FGFR1-3 inhibitor, in patients with advanced solid tumors. Dose escalation (daily oral dose of 1-180 mg) was carried out to assess dose-limiting toxicity (DLT), maximum tolerated dose, and pharmacokinetics. Pharmacodynamic markers (serum phosphate, fibroblast growth factor 23, and 1,25-(OH)2 -vitamin D) were also evaluated. A total of 24 patients refractory to standard therapy or for whom no appropriate treatment was available were enrolled. No DLT were observed up to the 140-mg dose; one patient in the 180-mg cohort experienced a DLT (increased aspartate aminotransferase/alanine aminotransferase, grade 3). The maximum tolerated dose was not reached. Dose-dependent increases in the maximum concentration and area under the curve from time 0 to the last measurable concentration were observed up to 180 mg. Dose-dependent increases were observed in all pharmacodynamic markers and plateaued at 100-140 mg, indicating sufficient FGFR pathway inhibition at doses ≥100 mg. In conclusion, E7090 showed a manageable safety profile with no DLT at doses ≤140 mg. Maximum tolerated dose was not determined. The recommended dose for the follow-up expansion part, restricted to patients with tumors harboring FGFR alterations, was determined as 140 mg, once daily.

Hollebecque A., Silverman I., Owens S., Féliz L., Lihou C., Zhen H., Newton R., Burn T., Melisi D.

Background Fight-202 is a phase 2 study (NCT02924376) of pemigatinib (INCB054828), a selective, potent, oral inhibitor of FGFR1, 2, and 3 in pts with advanced CCA. Interim results from the first 47 FGFR2+ CCA pts with ≥8 months (mo) of follow-up demonstrated an objective response rate (ORR) of 40.4%, disease control rate (DCR) of 85%, median progression-free survival (mPFS) of 9.2 mo, and median overall survival (mOS) of 15.8 mo, based on independent central review. Here we report the frequency of FGFR2 rearrangement partners and co-occurring alterations and their impact on clinical outcomes. Methods Comprehensive genomic profiling was performed in all pts prescreened and/or enrolled in fight-202 using FoundationOne. Clinical data were reported previously. Results Among 118 FGFR2+ pts identified, 54 unique FGFR2 rearrangement partners were observed, of which 74.1% (n = 40) were unique to a single patient. BICC1 was the most frequent FGFR2 rearrangement partner (29.7% [n = 35]). FGFR2+ pts had fewer genomic alterations (3.36 alterations/pt) than unaltered pts (4.6 alterations/pt). The most frequently co-altered gene, BAP1, was altered in 39.8% (n = 47) of FGFR2+ pts. As of the data cutoff date (July 24, 2018), 47 FGFR2+ pts were treated with pemigatinib and followed for ≥8 mo. There were no meaningful differences in ORR (42.9% vs 39.4%), mPFS (8.9 mo vs 9.6 mo), or mOS (not reached [NR] vs 15.8 mo) in patients with FGFR2-BICC1 (n = 14) versus other FGFR2 rearrangements. Similarly, no meaningful difference in ORR (53.3% vs 34.4%), mPFS (8.9 mo vs NR), or mOS (NR vs 15.8 mo) was observed in pts with BAP1 loss-of-function mutations (n = 15). Among other co-occurring genomic alterations, pts with TP53 alterations (n = 5) had no objective responses (0% vs 45.2%) and shorter mPFS (6.2 mo vs NR) and mOS (10.5 mo vs NR). Conclusions Despite myriad FGFR2 rearrangement partners identified in the study, an interim analysis did not indicate a difference in ORR, mPFS, or mOS between the most common rearrangement partner (BICC1) and other partner genes. Alterations in TP53, but not BAP1, were associated with decreased clinical benefit. Editorial acknowledgement Simon J. Slater, PhD, CMPP, of Envision Pharma Group (Philadelphia, PA), funded by Incyte Corporation. Legal entity responsible for the study Incyte Corporation. Funding Incyte Corporation. Disclosure A. Hollebecque: Consulting/Advisory Role, Travel/Accommodation/Expenses, Courses/Trainings: Amgen; Consulting/Advisory Role: Spectrum Pharmaceuticals; Consulting/Advisory Role, Travel/Accommodation/Expenses: Lilly; Consulting/Advisory Role, Travel/Accommodation/Expenses: Debiopharm; Travel/Accommodation/Expenses: Servier; Travel/Accommodation/Expenses: Incyte; Courses/Trainings: Bayer; Courses/Trainings: Eisai; Research grant/Funding (institution): AstraZeneca; Research grant/Funding (institution): BMS; Research grant/Funding (institution): Boehringer Ingelheim; Research grant/Funding (institution): Janssen Cilag; Research grant/Funding (institution): Merck; Research grant/Funding (institution): Novartis; Research grant/Funding (institution): Pfizer; Research grant/Funding (institution): Roche; Research grant/Funding (institution): Sanofi. I.M. Silverman: Shareholder / Stockholder / Stock options, Full / Part-time employment: ): Incyte Research Institute, Incyte Corporation. S. Owens: Shareholder / Stockholder / Stock options, Full / Part-time employment: ): Incyte Research Institute, Incyte Corporation. L. Feliz: Shareholder / Stockholder / Stock options, Full / Part-time employment: Incyte Corporation. C.F. Lihou: Shareholder / Stockholder / Stock options, Full / Part-time employment: Incyte Corporation. H. Zhen: Shareholder / Stockholder / Stock options, Full / Part-time employment: Incyte Corporation. R.C. Newton: Shareholder / Stockholder / Stock options, Full / Part-time employment: ): Incyte Research Institute, Incyte Corporation. T.C. Burn: Shareholder / Stockholder / Stock options, Full / Part-time employment: ): Incyte Research Institute, Incyte Corporation. D. Melisi: Research Grants (Institution), Advisory/Consultancy Role: Shire; Research Grants (Institution), Advisory/Consultancy Role: Incyte; Research Grants (Institution), Advisory/Consultancy Role: Evotec; Research Grants (Institution): Celgene; Advisory/Consultancy Role: Eli Lilly; Advisory/Consultancy: Baxter. All other authors have declared no conflicts of interest.

Goyal L., Shi L., Liu L.Y., Fece de la Cruz F., Lennerz J.K., Raghavan S., Leschiner I., Elagina L., Siravegna G., Ng R.W., Vu P., Patra K.C., Saha S.K., Uppot R.N., Arellano R., et. al.

AbstractATP-competitive fibroblast growth factor receptor (FGFR) kinase inhibitors, including BGJ398 and Debio 1347, show antitumor activity in patients with intrahepatic cholangiocarcinoma (ICC) harboring activating FGFR2 gene fusions. Unfortunately, acquired resistance develops and is often associated with the emergence of secondary FGFR2 kinase domain mutations. Here, we report that the irreversible pan-FGFR inhibitor TAS-120 demonstrated efficacy in 4 patients with FGFR2 fusion–positive ICC who developed resistance to BGJ398 or Debio 1347. Examination of serial biopsies, circulating tumor DNA (ctDNA), and patient-derived ICC cells revealed that TAS-120 was active against multiple FGFR2 mutations conferring resistance to BGJ398 or Debio 1347. Functional assessment and modeling the clonal outgrowth of individual resistance mutations from polyclonal cell pools mirrored the resistance profiles observed clinically for each inhibitor. Our findings suggest that strategic sequencing of FGFR inhibitors, guided by serial biopsy and ctDNA analysis, may prolong the duration of benefit from FGFR inhibition in patients with FGFR2 fusion–positive ICC.Significance:ATP-competitive FGFR inhibitors (BGJ398, Debio 1347) show efficacy in FGFR2-altered ICC; however, acquired FGFR2 kinase domain mutations cause drug resistance and tumor progression. We demonstrate that the irreversible FGFR inhibitor TAS-120 provides clinical benefit in patients with resistance to BGJ398 or Debio 1347 and overcomes several FGFR2 mutations in ICC models.This article is highlighted in the In This Issue feature, p. 983

Zhang J., Tang P.M., Zhou Y., Cheng A.S., Yu J., Kang W., To K.F.

Gastric cancer (GC) is one of the most wide-spread malignancies in the world. The oncogenic role of signaling of fibroblast growing factors (FGFs) and their receptors (FGFRs) in gastric tumorigenesis has been gradually elucidated by recent studies. The expression pattern and clinical correlations of FGF and FGFR family members have been comprehensively delineated. Among them, FGF18 and FGFR2 demonstrate the most prominent driving role in gastric tumorigenesis with gene amplification or somatic mutations and serve as prognostic biomarkers. FGF-FGFR promotes tumor progression by crosstalking with multiple oncogenic pathways and this provides a rational therapeutic strategy by co-targeting the crosstalks to achieve synergistic effects. In this review, we comprehensively summarize the pathogenic mechanisms of FGF-FGFR signaling in gastric adenocarcinoma together with the current targeted strategies in aberrant FGF-FGFR activated GC cases.

Voss M.H., Hierro C., Heist R.S., Cleary J.M., Meric-Bernstam F., Tabernero J., Janku F., Gandhi L., Iafrate A.J., Borger D.R., Ishii N., Hu Y., Kirpicheva Y., Nicolas-Metral V., Pokorska-Bocci A., et. al.

Abstract Purpose: To investigate tolerability, efficacy, and pharmacokinetics/pharmacodynamics of Debio 1347, a selective FGFR inhibitor. Patients and Methods: This was a first-in-human, multicenter, open-label study in patients with advanced solid tumors harboring FGFR1–3 gene alterations. Eligible patients received oral Debio 1347 at escalating doses once daily until disease progression or intolerable toxicity. Dose-limiting toxicities (DLT) were evaluated during the first 4 weeks on treatment, pharmacokinetics/pharmacodynamics postfirst dose and after 4 weeks. Results: A total of 71 patients were screened and 58 treated with Debio 1347 at doses from 10 to 150 mg/day. Predominant tumor types were breast and biliary duct cancer, most common gene alterations were FGFR1 amplifications (40%) and mutations in FGFR2 (12%) and FGFR3 (17%); 12 patients (21%) showed FGFR fusions. Five patients at three dose levels had six DLTs (dry mouth/eyes, hyperamylasemia, hypercalcemia, hyperbilirubinemia, hyperphosphatemia, and stomatitis). The maximum tolerated dose was not reached, but dermatologic toxicity became sometimes dose limiting beyond the DLT period at ≥80 mg/day. Adverse events required dose modifications in 52% of patients, mostly due to dose-dependent, asymptomatic hyperphosphatemia (22%). RECIST responses were seen across tumor types and mechanisms of FGFR activation. Six patients, 3 with FGFR fusions, demonstrated partial responses, 10 additional patients' tumor size regressions of ≤30%. Plasma half-life was 11.5 hours. Serum phosphate increased with Debio 1347 plasma levels and confirmed target engagement at doses ≥60 mg/day. Conclusions: Preliminary efficacy was encouraging and tolerability acceptable up to 80 mg/day, which is now used in an extension part of the study.

Khan S.A., Tavolari S., Brandi G.

Cholangiocarcinoma (CCA) is a heterogeneous disease arising from a complex interaction between host-specific genetic background and multiple risk factors. Globally, CCA incidence rates exhibit geographical variation, with much higher incidence in parts of the Eastern world compared to the West. These differences are likely to reflect differences in geographical risk factors as well as genetic determinants. Of note, over the past few decades, the incidence rates of CCA appear to change and subtypes of CCA appear to show distinct epidemiological trends. These trends need to be interpreted with caution given the issues of diagnosis, recording and coding of subtypes of CCA. Epidemiological evidences suggest that in general population some risk factors are less frequent but associated with a higher CCA risk, while others are more common but associated with a lower risk. Moreover, while some risk factors are shared by intrahepatic and both extrahepatic forms, others seem more specific for one of the two forms. Currently some pathological conditions have been clearly associated with CCA development, and other conditions are emerging; however, while their impact in increasing CCA risk as single etiological factors has been provided in many studies, less is known when two or more risk factors co-occur in the same patient. Moreover, despite the advancements in the knowledge of CCA aetiology, in Western countries about 50% of cases are still diagnosed without any identifiable risk factor. It is therefore conceivable that other still undefined etiologic factors are responsible for the recent increase of CCA (especially iCCA) incidence worldwide.

Pavlović N., Goločorbin-Kon S., Ðanić M., Stanimirov B., Al-Salami H., Stankov K., Mikov M.

Bile acids have received considerable interest in the drug delivery research due to their peculiar physicochemical properties and biocompatibility. The main advantage of bile acids as drug absorption enhancers is their ability to act as both drug solubilizing and permeation-modifying agents. Therefore, bile acids may improve bioavailability of drugs whose absorption-limiting factors include either poor aqueous solubility or low membrane permeability. Besides, bile acids may withstand the gastrointestinal impediments and aid in the transporter-mediated absorption of physically complexed or chemically conjugated drug molecules. These biomolecules may increase the drug bioavailability also at submicellar levels by increasing the solubility and dissolution rate of non-polar drugs or through the partition into the membrane and increase of membrane fluidity and permeability. Most bile acid-induced effects are mediated by the nuclear receptors that activate transcriptional networks, which then affect the expression of a number of target genes, including those for membrane transport proteins, affecting the bioavailability of a number of drugs. Besides micellar solubilization, there are many other types of interactions between bile acids and drug molecules, which can influence the drug transport across the biological membranes. Most common drug-bile salt interaction is ion-pairing and the formed complexes may have either higher or lower polarity compared to the drug molecule itself. Furthermore, the hydroxyl and carboxyl groups of bile acids can be utilized for the covalent conjugation of drugs, which changes their physicochemical and pharmacokinetic properties. Bile acids can be utilized in the formulation of conventional dosage forms, but also of novel micellar, vesicular and polymer-based therapeutic systems. The availability of bile acids, along with their simple derivatization procedures, turn them into attractive building blocks for the design of novel pharmaceutical formulations and systems for the delivery of drugs, biomolecules and vaccines. Although toxic properties of hydrophobic bile acids have been described, their side effects are mostly produced when present in supraphysiological concentrations. Besides, minor structural modifications of natural bile acids may lead to the creation of bile acid derivatives with the reduced toxicity and preserved absorption-enhancing activity.

Shitara K., Doi T., Dvorkin M., Mansoor W., Arkenau H., Prokharau A., Alsina M., Ghidini M., Faustino C., Gorbunova V., Zhavrid E., Nishikawa K., Hosokawa A., Yalçın Ş., Fujitani K., et. al.

Trifluridine/tipiracil showed activity and was well tolerated in a phase 2 study of pretreated patients with advanced gastric cancer done in Japan. We investigated whether the treatment was efficacious compared with placebo in a global population.TAGS was a randomised, double-blind, placebo-controlled, phase 3 trial done in 110 academic hospitals in 17 countries. Patients aged 18 years or older with histologically confirmed, non-resectable, metastatic gastric adenocarcinoma (including adenocarcinoma of the gastroesophageal junction) as defined by the American Joint Committee on Cancer staging classification (7th edition) who had received at least two previous chemotherapy regimens and had experienced radiological disease progression were eligible for inclusion. Patients were randomly assigned (2:1) via dynamic randomisation from a centralised interactive voice-response system to receive either oral trifluridine/tipiracil (35 mg/m2 twice daily on days 1-5 and days 8-12 every 28 days) plus best supportive care or placebo plus best supportive care. Participants were allocated to groups by study-site personnel. Randomisation was stratified by region (Japan vs rest of world), ECOG performance status (0 vs 1), and previous treatment with ramucirumab (yes vs no). Both patients and investigators were masked to treatment allocation. The primary endpoint was overall survival. Efficacy was assessed in the intention-to-treat population and safety in all patients who received at least one dose of treatment. This trial is registered with ClinicalTrials.gov, number NCT02500043. The trial, including follow-up of all participants, has been completed.Between Feb 24, 2016, and Jan 5, 2018, 507 patients were enrolled and randomly assigned, 337 to the trifluridine/tipiracil group and 170 to the placebo group. Median overall survival was 5·7 months (95% CI 4·8-6·2) in the trifluridine/tipiracil group and 3·6 months (3·1-4·1) in the placebo group (hazard ratio 0·69 [95% CI 0·56-0·85]; one-sided p=0·00029, two-sided p=0·00058). Grade 3 or worse adverse events of any cause occurred in 267 (80%) patients in the trifluridine/tipiracil group and 97 (58%) in the placebo group. The most frequent grade 3 or worse adverse events of any cause were neutropenia (n=114 [34%]) and anaemia (n=64 [19%]) in the trifluridine/tipiracil group and abdominal pain (n=15 [9%]) and general deterioration of physical health (n=15 [9%]) in the placebo group. Serious adverse events of any cause were reported in 143 (43%) patients in the trifluridine/tipiracil group and 70 (42%) in the placebo group. One treatment-related death was reported in each group (because of cardiopulmonary arrest in the trifluridine/tipiracil group and because of toxic hepatitis in the placebo group).Trifluridine/tipiracil significantly improved overall survival compared with placebo and was well tolerated in this heavily pretreated population of patients with advanced gastric cancer. Trifluridine/tipiracil could be a new treatment option in this population who represent a high unmet medical need.Taiho Oncology and Taiho Pharmaceutical.

Javle M., Lowery M., Shroff R.T., Weiss K.H., Springfeld C., Borad M.J., Ramanathan R.K., Goyal L., Sadeghi S., Macarulla T., El-Khoueiry A., Kelley R.K., Borbath I., Choo S.P., Oh D., et. al.

Purpose No standard treatment exists for patients with cholangiocarcinoma for whom first-line gemcitabine-based therapy fails. Fibroblast growth factor receptor 2 ( FGFR2) fusions/translocations are present in 13% to 17% of intrahepatic cholangiocarcinomas. BGJ398, an orally bioavailable, selective pan-FGFR kinase inhibitor, has shown preliminary clinical activity against tumors with FGFR alterations. Methods A multicenter, open-label, phase II study ( ClinicalTrials.gov identifier: NCT02150967) evaluated BGJ398 antitumor activity in patients age ≥ 18 years with advanced or metastatic cholangiocarcinoma containing FGFR2 fusions or other FGFR alterations whose disease had progressed while receiving prior therapy. Patients received BGJ398 125 mg once daily for 21 days, then 7 days off (28-day cycles). The primary end point was investigator-assessed overall response rate. Results Sixty-one patients (35 women; median age, 57 years) with FGFR2 fusion (n = 48), mutation (n = 8), or amplification (n = 3) participated. At the prespecified data cutoff (June 30, 2016), 50 patients had discontinued treatment. All responsive tumors contained FGFR2 fusions. The overall response rate was 14.8% (18.8% FGFR2 fusions only), disease control rate was 75.4% (83.3% FGFR2 fusions only), and estimated median progression-free survival was 5.8 months (95% CI, 4.3 to 7.6 months). Adverse events included hyperphosphatemia (72.1% all grade), fatigue (36.1%), stomatitis (29.5%), and alopecia (26.2%). Grade 3 or 4 treatment-related adverse events occurred in 25 patients (41%) and included hyperphosphatemia (16.4%), stomatitis (6.6%), and palmar-plantar erythrodysesthesia (4.9%). Conclusion BGJ398 is a first-in-class FGFR kinase inhibitor with manageable toxicities that shows meaningful clinical activity against chemotherapy-refractory cholangiocarcinoma containing FGFR2 fusions. This promising antitumor activity supports continued development of BGJ398 in this highly selected patient population.

Nti A.A., Serrano L.W., Sandhu H.S., Uyhazi K.E., Edelstein I.D., Zhou E.J., Bowman S., Song D., Gangadhar T.C., Schuchter L.M., Mitnick S., Huang A., Nichols C.W., Amaravadi R.K., Kim B.J., et. al.

Purpose:To assess the potential ocular toxicity of a combined BRAF inhibition (BRAFi) + MEK inhibition (MEKi) + hydroxychloroquine (HCQ) regime used to treat metastatic BRAF mutant melanoma.Methods:Patients with stage IV metastatic melanoma and BRAF V600E mutations (n = 11, 31–68 years of age) were

Hierro C., Alsina M., Sánchez M., Serra V., Rodon J., Tabernero J.

Gastric cancer is the third leading cause of death from cancer worldwide. Systemic chemotherapy remains the mainstay therapeutic option for this poor prognosis cancer. Trastuzumab, the epidermal growth factor receptor 2 (ERBB2 or HER2)-antibody, is the only biological agent approved for the molecularly selected population of HER2-positive gastric cancer patients. Over the last decade, several groups have been working for deepening into the molecular characterization of gastric cancer, shedding some light into the heterogeneity of this tumour. The published data have broadened the landscape towards a future molecular classification into several subtypes of gastric cancer, enabling a better selection of the optimal therapeutic strategy. The fibroblast growth factor receptor (FGFR) pathway plays a key role in gastric cancer pathogenesis, with 1.2%-9% of gastric cancer patients harbouring FGFR2 amplifications. Several selective FGFR inhibitors have been developed in the last years, with promising efficacy signals. However, there is still scarce evidence of the most reliant molecular determinants of response to these targeted agents. Homogeneous high-level clonal FGFR2-amplification, high FGFR2 mRNA or protein levels, specific FGFR2 C3 isoform expression, FGF ligand co-overexpression or detection of FGFR2 copy number in plasma circulating tumour DNA, are considered some of the potential predictive biomarkers to the FGFR inhibition. The successful development of highly specific FGFR inhibitors will rely on our capacity of establishing new personalized strategies, based on a deeper knowledge of the key alterations that drive oncogenesis in gastric cancer. Further efforts seem mandatory in order to implement accurate predictive biomarkers in the next stages of the FGFR inhibitors development.

Babina I.S., Turner N.C.

Deregulation of fibroblast growth factor (FGF) signalling is observed in several types of cancer, which makes this pathway a highly promising potential therapeutic target. However, aberrant FGF receptor (FGFR) signalling can be challenging. In this Review, Babinaet al. discuss the differences between diverse mechanisms of oncogenic activation of FGFR, and the factors that determine response and resistance to FGFR targeting. Fibroblast growth factors (FGFs) and their receptors (FGFRs) regulate numerous cellular processes. Deregulation of FGFR signalling is observed in a subset of many cancers, making activated FGFRs a highly promising potential therapeutic target supported by multiple preclinical studies. However, early-phase clinical trials have produced mixed results with FGFR-targeted cancer therapies, revealing substantial complexity to targeting aberrant FGFR signalling. In this Review, we discuss the increasing understanding of the differences between diverse mechanisms of oncogenic activation of FGFR, and the factors that determine response and resistance to FGFR targeting.

Goyal L., Saha S.K., Liu L.Y., Siravegna G., Leshchiner I., Ahronian L.G., Lennerz J.K., Vu P., Deshpande V., Kambadakone A., Mussolin B., Reyes S., Henderson L., Sun J.E., Van Seventer E.E., et. al.

Abstract Genetic alterations in the fibroblast growth factor receptor (FGFR) pathway are promising therapeutic targets in many cancers, including intrahepatic cholangiocarcinoma (ICC). The FGFR inhibitor BGJ398 displayed encouraging efficacy in patients with FGFR2 fusion–positive ICC in a phase II trial, but the durability of response was limited in some patients. Here, we report the molecular basis for acquired resistance to BGJ398 in three patients via integrative genomic characterization of cell-free circulating tumor DNA (cfDNA), primary tumors, and metastases. Serial analysis of cfDNA demonstrated multiple recurrent point mutations in the FGFR2 kinase domain at progression. Accordingly, biopsy of post-progression lesions and rapid autopsy revealed marked inter- and intralesional heterogeneity, with different FGFR2 mutations in individual resistant clones. Molecular modeling and in vitro studies indicated that each mutation led to BGJ398 resistance and was surmountable by structurally distinct FGFR inhibitors. Thus, polyclonal secondary FGFR2 mutations represent an important clinical resistance mechanism that may guide the development of future therapeutic strategies. Significance: We report the first genetic mechanisms of clinical acquired resistance to FGFR inhibition in patients with FGFR2 fusion–positive ICC. Our findings can inform future strategies for detecting resistance mechanisms and inducing more durable remissions in ICC and in the wide variety of cancers where the FGFR pathway is being explored as a therapeutic target. Cancer Discov; 7(3); 252–63. ©2016 AACR. See related commentary by Smyth et al., p. 248. This article is highlighted in the In This Issue feature, p. 235