Cost in the United States of FDA-approved small molecule protein kinase inhibitors used in the treatment of neoplastic and non-neoplastic diseases.

Because genetic alterations including mutations, overexpression, translocations, and dysregulation of protein kinases are involved in the pathogenesis of many illnesses, this enzyme family is the target of many drug discovery programs worldwide. The FDA has approved 80 small molecule protein kinase inhibitors with 77 drugs orally bioavailable. The data indicate that 69 of these medicinals are approved for the management of neoplasms including solid tumors such as breast and lung cancer as well as non-solid tumors such as leukemia. Moreover, the remaining 11 drugs target non-neoplastic diseases including psoriasis, rheumatoid arthritis, and ulcerative colitis. The cost of drugs was obtained from www.pharmacychecker.com using the FDA label to determine the dosage and number of tablets required per day. This methodology excludes any private or governmental insurance coverage, which would cover the entire cost or more likely a fraction of the stated price. The average monthly cost for the treatment of neoplastic diseases was $17,900 with a price of $44,000 for futibatinib (used to treat cholangiocarcinomas with FGFR2 fusions) and minimum of $5100 for binimetinib (melanoma). The average monthly cost for the treatment of non-neoplastic diseases was $6800 with a maximum of $17,000 for belumosudil (graft vs. host disease) and a minimum of $200 for netarsudil eye drops (glaucoma). There is a negative correlation of the cost of the drugs and the incidence of the targeted disease. Many of these agents are or were designated as orphan drugs meaning that there are fewer than 200,000 potential patients in the United States.

Plain language summary of the FOENIX-CCA2 study: futibatinib for people with advanced bile duct cancer.

WHAT IS THIS SUMMARY ABOUT?: This summary describes the results from a phase 2 study called FOENIXCCA2. The study evaluated treatment with futibatinib in people with a rare form of advanced bile duct cancer called intrahepatic cholangiocarcinoma (or iCCA), where the tumors have changes in the structure of a gene called FGFR2. These changes include FGFR2 gene fusions. Bile duct cancer often returns after surgery or cannot be treated by surgery because the tumor has spread, so it requires treatment with chemotherapy. People live for a median of 1 year after their first chemotherapy treatment and 6 months after their second treatment. This study included people whose cancer had grown/spread after one or more chemotherapy treatments. The aims of the study were to see if futibatinib could shrink the size of tumors and stop the cancer from growing/spreading and to see how long people lived when treated with futibatinib. Clinicians also looked at side effects from taking futibatinib and at how it affected people's quality of life. WHAT WERE THE RESULTS?: Futibatinib treatment shrank tumors in over 80% of people who received treatment. Tumors shrank by at least 30% in 42% of people. Futibatinib stopped tumors from growing/spreading for a median of 9.7 months. People who took the medicine lived for a median of 21.7 months, and 72% of people were still alive after 1 year. Side effects from taking futibatinib were like those reported for similar medicines, and clinicians considered the side effects to be manageable by adjusting the dose of futibatinib or treating the side effects. Most people reported that their quality of life stayed the same or improved during the first 9 months of taking futibatinib. WHAT DO THE RESULTS MEAN?: The results support the use of futibatinib for treating people with advanced bile duct cancer. Based on the results of this study, futibatinib is now approved in the US, Europe, and Japan. Futibatinib is approved for treating adults with advanced bile duct cancer who have received previous treatment for their cancer, and whose tumors have a gene fusion or other change in the FGFR2 gene.Clinical Trial Registration: NCT02052778 (FOENIX-CCA2).

Phase I study of the irreversible fibroblast growth factor receptor 1-4 inhibitor futibatinib in Japanese patients with advanced solid tumors.

This phase I study was designed to: (1) determine the maximum tolerated dose (MTD) and recommended dose (RD) of the fibroblast growth factor receptor (FGFR) inhibitor futibatinib in Japanese patients with advanced solid tumors, and (2) examine the antitumor activity of the RD in patients with gastric cancer (GC) or other advanced solid tumors who have FGFR or FGF/FGFR abnormalities, respectively. In the dose-escalation phase, patients were assigned to 21-day cycles of oral futibatinib 8-160 mg three times a week (TIW) or 16 or 20 mg once daily (QD). In the expansion phase, patients received oral futibatinib 56, 80, or 120 mg TIW, or 16 or 20 mg QD. Eighty-three patients received futibatinib TIW (n = 40) or QD (n = 43). No dose-limiting toxicities were observed according to the final study protocol definition, and the MTD was not reached. The most common adverse events with both regimens were hyperphosphatemia (TIW, 82.5%; QD, 100.0%) and decreased appetite (TIW, 40.0%; QD, 58.1%). Hyperphosphatemia was asymptomatic, not leading to futibatinib discontinuation. The overall response rate (ORR) was 11.5% in patients with FGF/FGFR abnormalities. Notably, in GC patients harboring FGFR2 copy number (CN) ≥10, the ORR was 36.4% versus 0 in patients with CN <10. Therefore, futibatinib had a generally predictable and manageable safety profile in patients with advanced solid tumors. Antitumor activity was seen in patients with FGF/FGFR abnormalities, particularly those with GC and high FGFR2 CNs. Thus, futibatinib 20 mg QD was chosen as the RD for phase II studies.

Futibatinib, an Irreversible FGFR1-4 Inhibitor for the Treatment of FGFR-Aberrant Tumors.

Fibroblast growth factor receptors (FGFR) are emerging as an important therapeutic target for patients with advanced, refractory cancers. Most selective FGFR inhibitors under investigation show reversible binding, and their activity is limited by acquired drug resistance. This review summarizes the preclinical and clinical development of futibatinib, an irreversible FGFR1-4 inhibitor. Futibatinib stands out among FGFR inhibitors because of its covalent binding mechanism and low susceptibility to acquired resistance. Preclinical data indicated robust activity of futibatinib against acquired resistance mutations in the FGFR kinase domain. In early-phase studies, futibatinib showed activity in cholangiocarcinoma, and gastric, urothelial, breast, central nervous system, and head and neck cancers harboring various FGFR aberrations. Exploratory analyses indicated clinical benefit with futibatinib after prior FGFR inhibitor use. In a pivotal phase II trial, futibatinib demonstrated durable objective responses (42% objective response rate) and tolerability in previously treated patients with advanced intrahepatic cholangiocarcinoma harboring FGFR2 fusions or rearrangements. A manageable safety profile was observed across studies, and patient quality of life was maintained with futibatinib treatment in patients with cholangiocarcinoma. Hyperphosphatemia, the most common adverse event with futibatinib, was well managed and did not lead to treatment discontinuation. These data show clinically meaningful benefit with futibatinib in FGFR2-rearrangement-positive cholangiocarcinoma and provide support for further investigation of futibatinib across other indications. Future directions for this agent include elucidating mechanisms of resistance and exploration of combination therapy approaches.

Properties of FDA-approved small molecule protein kinase inhibitors: A 2023 update.

Owing to the dysregulation of protein kinase activity in many diseases including cancer, this enzyme family has become one of the most important drug targets in the 21st century. There are 72 FDA-approved therapeutic agents that target about two dozen different protein kinases and three of these drugs were approved in 2022. Of the approved drugs, twelve target protein-serine/threonine protein kinases, four are directed against dual specificity protein kinases (MEK1/2), sixteen block nonreceptor protein-tyrosine kinases, and 40 target receptor protein-tyrosine kinases. The data indicate that 62 of these drugs are prescribed for the treatment of neoplasms (57 against solid tumors including breast, lung, and colon, ten against nonsolid tumors such as leukemia, and four against both solid and nonsolid tumors: acalabrutinib, ibrutinib, imatinib, and midostaurin). Four drugs (abrocitinib, baricitinib, tofacitinib, upadacitinib) are used for the treatment of inflammatory diseases (atopic dermatitis, psoriatic arthritis, rheumatoid arthritis, Crohn disease, and ulcerative colitis). Of the 72 approved drugs, eighteen are used in the treatment of multiple diseases. The following three drugs received FDA approval in 2022 for the treatment of these specified diseases: abrocitinib (atopic dermatitis), futibatinib (cholangiocarcinomas), pacritinib (myelofibrosis). All of the FDA-approved drugs are orally effective with the exception of netarsudil, temsirolimus, and trilaciclib. This review summarizes the physicochemical properties of all 72 FDA-approved small molecule protein kinase inhibitors including lipophilic efficiency and ligand efficiency.

Phase I, first-in-human study of futibatinib, a highly selective, irreversible FGFR1-4 inhibitor in patients with advanced solid tumors.

BACKGROUND: Futibatinib is an oral, irreversible, highly selective fibroblast growth factor receptor (FGFR)1-4 inhibitor with potent preclinical activity against tumors harboring FGFR aberrations. This first-in-human, phase I dose-escalation trial (NCT02052778) evaluates the safety and pharmacokinetics/pharmacodynamics of futibatinib in advanced solid tumors. PATIENTS AND METHODS: Following a standard 3+3 dose-escalation design, eligible patients with advanced solid tumors refractory to standard therapies received 8-200 mg futibatinib three times a week (t.i.w.) or 4-24 mg once daily (q.d.). RESULTS: A total of 86 patients were enrolled in the nine t.i.w. (n = 42) and five q.d. cohorts (n = 44); 71 patients (83%) had tumors harboring FGF/FGFR aberrations. Three of nine patients in the 24-mg q.d. cohort experienced dose-limiting toxicities, including grade 3 increases in alanine transaminase, aspartate transaminase, and blood bilirubin (n = 1 each). The maximum tolerated dose (MTD) was determined to be 20 mg q.d.; no MTD was defined for the t.i.w. schedule. Across cohorts (n = 86), the most common treatment-emergent adverse events (TEAEs) were hyperphosphatemia (59%), diarrhea (37%), and constipation (34%); 48% experienced grade 3 TEAEs. TEAEs led to dose interruptions, dose reductions, and treatment discontinuations in 55%, 14%, and 3% of patients, respectively. Pharmacokinetics were dose proportional across all q.d. doses but not all t.i.w. doses evaluated, with saturation observed between 80 and 200 mg t.i.w. Serum phosphorus increased dose dependently with futibatinib on both schedules, but a stronger exposure-response relationship was observed with q.d. dosing, supporting 20 mg q.d. as the recommended phase II dose (RP2D). Overall, partial responses were observed in five patients [FGFR2 fusion-positive intrahepatic cholangiocarcinoma (n = 3) and FGFR1-mutant primary brain tumor (n = 2)], and stable disease in 41 (48%). CONCLUSIONS: Futibatinib treatment resulted in manageable safety, pharmacodynamic activity, and preliminary responses in patients with advanced solid tumors. The results of this phase I dose-escalation trial support 20 mg q.d. futibatinib as the RP2D. CLINICAL TRIAL REGISTRATION: FOENIX-101 (ClinicalTrials.gov, NCT02052778).

Prolonged Clinical Benefit with Futibatinib in a Patient with FGFR Inhibitor-Pretreated FGFR2 Fusion-Positive Intrahepatic Cholangiocarcinoma: Case Report.

Multiple FGFR inhibitors have demonstrated significant activity in pretreated advanced FGFR2 fusion-positive intrahepatic cholangiocarcinoma. The irreversible pan-FGFR inhibitor futibatinib has the potential to overcome acquired resistance to ATP-competitive FGFR inhibitors in a subset of patients. We present a case of prolonged clinical benefit using FGFR inhibitors sequentially, initially an ATP-competitive inhibitor followed by futibatinib upon progression, for a total of 36 months of FGFR-targeting therapy. This case supports sequential FGFR-targeting therapies for FGFR2 fusion-positive cholangiocarcinoma, with futibatinib acting as rescue therapy after failure of ATP-competitive inhibitors.

Spectrofluorometric determination of futibatinib in human plasma and pharmaceutical formulations.

Futibatinib is a powerful inhibitor of fibroblast growth factor receptors that impedes its phosphorylation and subsequently leading to a reduction in in cell viability across various cell lines. Futibatinib was approved for initial use as an effective treatment for several diseases, including non-small cell lung cancer and breast cancer. Herein, a novel selective fluorescence probe was created for futibatinib quantification in various matrices, including pharmaceutical formulation and human plasma. The technique primarily depends on futibatinib's chemical conversion into a fluorescent product through a reaction with trimethylamine and bromoacetyl bromide. The created fluorescent probe exhibits maximum emission peak at 338 nm upon excitation at 248 nm. The method provided a low detection limit of 0.120 ng/mL and maintained a linear concentration-dependent relationship across the range of 1-200 ng/mL. High sensitivity, accuracy and precision were demonstrated for futibatinib quantification in pharmaceutical formulation and spiked plasma matrix by the method, which was validated in accordance with ICH requirements.

A comprehensive overview of selective and novel fibroblast growth factor receptor inhibitors as a potential anticancer modality.

The arrival of comprehensive genome sequencing has accelerated the understanding of genetically aberrant advanced cancers and target identification for possible cancer treatment. Fibroblast growth factor receptor (FGFR) gene alterations are frequent findings in various rare and advanced cancers refractive to mainstay chemo-therapy or surgical interventions. Several FGFR inhibitors have been developed for addressing these genetically altered FGFR-harboring malignancies, and some have performed well in clinical trials. In contrast, others are still being investigated in different phases of clinical trials. FDA has approved four anticancer agents such as erdafitinib, pemigatinib, infigratinib, and futibatinib, for clinical use in oncogenic FGFR-driven malignancies. These include cholangiocarcinoma, urothelial carcinoma, and myeloid/lymphoid malignancies. Pemigatinib is the only FGFR inhibitor globally approved (USA, EU, and Japan) and available as a targeted therapy for two types of cancer, including FGFR2 fusion or other rearrangements harboring cholangiocarcinoma and relapsed/refractory myeloid/lymphoid neoplasms with FGFR1 rearrangements. Myeloid/lymphoid neoplasm is the latest area of application added to the therapeutic armamentarium of FGFR inhibitors. Furthermore, futibatinib is the first-in-class covalent or irreversible pan-FGFR inhibitor that has received FDA approval for locally advanced or metastatic intrahepatic cholangiocarcinoma harboring FGFR2 gene aberrations. This review highlights the current clinical progress concerning the safety and efficacy of all the approved FGFR-TKIs (tyrosine kinase inhibitors) and their ongoing investigations in clinical trials for other oncogenic FGFR-driven malignancies.

Response of FGFR-2 Positive Adenoid Cystic Carcinoma to Futibatinib: A Case Report.

Adenoid cystic carcinoma (ACC) is an uncommon and aggressive head and neck cancer mainly affecting minor salivary glands. It affects more women than men in their 60s and 70s. The tumor is typically locally aggressive and has a high rate of distant metastatic disease. This report unveils a potential avenue for targeted therapy for the management of metastatic disease: a patient with ACC who harbored a specific fibroblast growth factor receptor 2 (FGFR-2) mutation and responded significantly to a novel FGFR-2 inhibitor. This finding could pave the way for personalized treatment options for ACC patients with similar genetic alterations. Nevertheless, the use of futibatinib requires further investigation to optimize treatment protocols, including exploring combination therapies, identifying predictive biomarkers for treatment response, and developing strategies to overcome potential resistance.

Effect of Futibatinib on Cardiac Repolarization: Results of a Randomized, Controlled, Double-Blind, QT/QTc, Phase 1 Study in Healthy Subjects.

Futibatinib, a fibroblast growth factor receptor (FGFR) 1-4 inhibitor, is being investigated for FGFR-aberrant tumors. A 4-period, crossover, phase 1 thorough QT/QTc study compared effects on Fridericia heart rate-corrected QT (QTcF) interval of single doses of futibatinib 20 and 80 mg (therapeutic and supratherapeutic doses, respectively), placebo, and moxifloxacin (positive control) in healthy subjects. The study objective was to assess the time-matched difference in change from baseline in QTcF (ddQTcF) between futibatinib and placebo. In addition, changes from baseline in QTcF and other electrocardiogram (ECG) parameters, pharmacokinetics, ECG morphology, and safety were assessed. Forty-eight subjects were randomized. ddQTcF upper limits of 2-sided 90%CIs remained <10 milliseconds (clinical threshold) for both futibatinib doses at all time points (range, 2.0-4.5 milliseconds). Assay sensitivity was demonstrated by lower limits of 2-sided 97.5%CIs of the dQTcF difference between moxifloxacin and placebo of >5 milliseconds. Futibatinib exposure increased in a dose-dependent manner, and no significant relationship was detected between plasma futibatinib concentration and ddQTcF. There were no significant effects on heart rate, other ECG parameters, or ECG morphology. No serious adverse events occurred. Futibatinib did not prolong QTcF or affect other cardiac measures at therapeutic or supratherapeutic doses.

Evaluation of Potential Food Effects and Drug Interactions With Lansoprazole in Healthy Adult Volunteers Receiving Futibatinib.

Futibatinib, an oral, irreversible fibroblast growth factor receptor (FGFR) 1-4 inhibitor, is being evaluated for FGFR-aberrant tumors. Two open-label phase 1 studies evaluated the effects of high-fat, high-calorie food and concomitant proton pump inhibitors (PPIs; lansoprazole) on single-dose futibatinib (20 mg) pharmacokinetics and safety in healthy adults. In the food effect study (N  =  17), subjects received futibatinib under fed and fasted conditions, separated by a 7-day washout. In the PPI study (N  =  20), subjects received futibatinib alone, underwent a 2-day washout, and then received lansoprazole 60 mg once daily for 5 days, with futibatinib also administered on day 5. Under fed versus fasted conditions, futibatinib bioavailability was 11.2% lower (area under the plasma concentration-time curve from time 0 to infinity geometric mean ratio 88.8%; 90% confidence interval, 79.8%-98.9%), and median time to maximum plasma concentration was significantly delayed (4.0 vs 1.5 hours; P < .0001). There were no significant differences in futibatinib exposure between futibatinib plus lansoprazole and futibatinib alone. No serious adverse events occurred in either study. These findings suggest that food and PPIs are unlikely to have clinically meaningful impacts on futibatinib bioavailability. Thus, futibatinib may be used with or without food and concomitantly with acid-reducing agents.

Preclinical Evaluation of the FGFR-Family Inhibitor Futibatinib for Pediatric Rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma. Despite decades of clinical trials, the overall survival rate for patients with relapsed and metastatic disease remains below 30%, underscoring the need for novel treatments. FGFR4, a receptor tyrosine kinase that is overexpressed in RMS and mutationally activated in 10% of cases, is a promising target for treatment. Here, we show that futibatinib, an irreversible pan-FGFR inhibitor, inhibits the growth of RMS cell lines in vitro by inhibiting phosphorylation of FGFR4 and its downstream targets. Moreover, we provide evidence that the combination of futibatinib with currently used chemotherapies such as irinotecan and vincristine has a synergistic effect against RMS in vitro. However, in RMS xenograft models, futibatinib monotherapy and combination treatment have limited efficacy in delaying tumor growth and prolonging survival. Moreover, limited efficacy is only observed in a PAX3-FOXO1 fusion-negative (FN) RMS cell line with mutationally activated FGFR4, whereas little or no efficacy is observed in PAX3-FOXO1 fusion-positive (FP) RMS cell lines with FGFR4 overexpression. Alternative treatment modalities such as combining futibatinib with other kinase inhibitors or targeting FGFR4 with CAR T cells or antibody-drug conjugate may be more effective than the approaches tested in this study.

Evaluation of the Mass Balance and Metabolic Profile of Futibatinib in Healthy Participants.

Futibatinib, a selective, irreversible fibroblast growth factor receptor 1-4 inhibitor, was recently approved for FGFR2 rearrangement-positive cholangiocarcinoma. This Phase I study evaluated the mass balance and metabolic profile of 14 C-futibatinib single oral 20-mg dose in healthy participants (n = 6). Futibatinib was rapidly absorbed; median time to peak drug concentration was 1.0 hours. The mean elimination half-life in plasma was 2.3 hours for futibatinib, and 11.9 hours for total radioactivity. Mean recovery of total radioactivity was 70% of the dose, with 64% recovered in feces and 6% in urine. The major excretion route was fecal; negligible levels were excreted as parent futibatinib. Futibatinib was the most abundant plasma component, comprising 59% of circulating radioactivity (CRA). The most abundant metabolites were cysteinylglycine-conjugated futibatinib in plasma (13% CRA) and reduction of desmethyl futibatinib in feces (17% of dose). In human hepatocytes, 14 C-futibatinib metabolites included glucuronide and sulfate of desmethyl futibatinib, whose formation was inhibited by 1-aminobenzotriazole (a pan-cytochrome P450 inhibitor), and glutathione- and cysteine-conjugated futibatinib. These data indicate the primary metabolic pathways of futibatinib are O-desmethylation and glutathione conjugation, with cytochrome P450 enzyme-mediated desmethylation as the main oxidation pathway. 14 C-futibatinib was well tolerated in this Phase 1 study.

Sustained response on sequential anti-FGFR therapy in metastatic gall bladder cancer: a case report and literature review.

PURPOSE: Advanced gall bladder cancer (GBC) is an aggressive disease, and there is no consensus on treatment options beyond first-line chemotherapy. We report a case of an elderly male with FGFR2-altered advanced adenocarcinoma of the gallbladder who failed two prior lines of chemotherapy but had sustained response and stable disease on sequential FGFR-directed targeted therapy. DESIGN: We describe a case of FGFR2-altered metastatic adenocarcinoma of the gallbladder who failed two prior lines of chemotherapy. The treatment was based on comprehensive genomic profiling when the patient was found to have FGFR2 single amino acid mutation (S252W) in one of his tissue samples. A novel therapeutic regimen with sequential anti-FGFR tyrosine kinase inhibitors was later initiated. RESULT: The patient tolerated the sequential targeted therapy very well and had a sustained response and stable disease. He had an overall survival of nearly five years. Unfortunately, GBC is an aggressive disease, and there is no consensus on treatment options beyond first-line chemotherapy. CONCLUSION: Through this patient, we demonstrate that advanced-metastatic GBC with FGFR alterations can be maintained on anti-FGFR therapy for prolonged periods of time, with improved survival. Therefore, we endorse the need for comprehensive genomic profiling in advanced-metastatic GBC and the need to study the role of FGFR inhibitors as a viable treatment option in these patients.

Evaluation of the Cytochrome P450 3A and P-glycoprotein Drug-Drug Interaction Potential of Futibatinib.

Futibatinib, a selective, irreversible fibroblast growth factor receptor 1-4 inhibitor, is being investigated for tumors harboring FGFR aberrations and was recently approved for the treatment of FGFR2 fusion/rearrangement-positive intrahepatic cholangiocarcinoma. In vitro studies identified cytochrome P450 (CYP) 3A as the major CYP isoform in futibatinib metabolism and indicated that futibatinib is likely a P-glycoprotein (P-gp) substrate and inhibitor. Futibatinib also showed time-dependent inhibition of CYP3A in vitro. Phase I studies investigated the drug-drug interactions of futibatinib with itraconazole (a dual P-gp and strong CYP3A inhibitor), rifampin (a dual P-gp and strong CYP3A inducer), or midazolam (a sensitive CYP3A substrate) in healthy adult participants. Compared with futibatinib alone, coadministration of futibatinib with itraconazole increased futibatinib mean peak plasma concentration and area under the plasma concentration-time curve by 51% and 41%, respectively, and coadministration of futibatinib with rifampin lowered futibatinib mean peak plasma concentration and area under the plasma concentration-time curve by 53% and 64%, respectively. Coadministration of midazolam with futibatinib had no effect on midazolam pharmacokinetics compared with midazolam administered alone. These findings suggest that concomitant use of dual P-gp and strong CYP3A inhibitors/inducers with futibatinib should be avoided, but futibatinib can be concomitantly administered with other drugs metabolized by CYP3A. Drug-drug interaction studies with P-gp-specific substrates and inhibitors are planned.

Clinical development and management of adverse events associated with FGFR inhibitors.

Approved fibroblast growth factor receptor (FGFR) inhibitors include erdafitinib, pemigatinib, and futibatinib. We review the most common toxicities associated with FGFR inhibitors and provide practical advice regarding their management. Hyperphosphatemia can be managed with careful monitoring, dose reduction or interruption, a prophylactic low-phosphate diet, and phosphate-lowering therapy. Ocular adverse events (AEs) are managed by withholding or adjusting the dose of the FGFR inhibitor. Dermatologic AEs include alopecia, which can be managed with minoxidil, and dry skin, which can be treated with moisturizers. Hand-foot syndrome can be prevented by lifestyle changes and managed with moisturizing creams, urea, or salicylic acid. Among gastrointestinal AEs, diarrhea may be managed with loperamide; stomatitis can be managed with baking soda rinses, mucosa-coating agents, and topical anesthetics; and dry mouth may be alleviated with salivary stimulants. Most FGFR inhibitor-associated toxicities are manageable with prophylactic measures and treatments; proactive monitoring is key to ensuring optimal clinical benefits.

Quantification of the irreversible fibroblast growth factor receptor inhibitor futibatinib by UPLC-MS/MS: Application to the metabolic stability assay in human liver microsomes for the estimation of its in vitro hepatic intrinsic clearance.

Futibatinib (FUT) is a potent irreversible inhibitor of fibroblast growth factor receptor 1-4 currently under clinical investigation for the treatment of cholangiocarcinoma. However, there remains a paucity of information pertaining to its hepatic metabolism. In this study, our overarching aims were to systematically develop and validate a novel ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) analytical method to quantify FUT for the subsequent application to the metabolic stability assay. Chromatographic separation was achieved on a C18 column and a gradient elution system comprising 0.1% formic acid in water (A) and acetonitrile (B). Positive electrospray ionization in conjunction with multiple reaction monitoring (MRM) mode was harnessed for the selective and sensitive quantification of FUT (m/z 419.2 → 296.0) and erdafitinib (m/z 447.0 → 362.0; internal standard). The retention time was 1.49 min for FUT and 1.29 min for erdafitinib. The calibration curve was linear from 0.003 to 3 µM (r2 > 0.99) and the lower limit of quantification was 0.003 µM. The intra-day and inter-day precision (% RSD) and accuracy (% bias) were all < 11.4% and < 11.3% respectively. Quality control samples were determined to be stable under several conditions routinely employed in sample preparation and UPLC-MS/MS analyses. Moreover, the liver microsomal matrix did not adversely affect the quantification of FUT. Following which, the in vitro microsomal intrinsic clearance (CLint) of FUT was calculated from our metabolic stability assay to be 29.3 µL/min/mg, thereby suggesting that it was a medium clearance drug. Finally, extrapolating the CLint with human scaling factors yielded an estimated in vitro hepatic intrinsic clearance value of 2075 mL/min. Our study reports the first UPLC-MS/MS method and offers a specific, sensitive and rapid means of determining FUT human liver microsomal stability.

Precision approaches for cholangiocarcinoma: progress in clinical trials and beyond.

INTRODUCTION: Although a relatively uncommon tumor, the incidence of intrahepatic cholangiocarcinoma is rising globally. Unfortunately, most patients are diagnosed with locally advanced or metastatic disease with poor prognosis. Strategies targeting genomic alterations and incorporation of precision medicine will represent a new therapeutic avenue for these patients. AREAS COVERED: In this review article, we addressed clinical trials in cholangiocarcinoma with FGFR, IDH, BRAF, and ErbB2 targeted therapies. We also reviewed mechanisms of resistance to precision medicine and possible future strategies to overcome clonal evolution. Articles selected for this review were based on reported studies indexed in PubMed (2010-2021). EXPERT OPINION: Pemigatinib, infigratinib and futibatinib could eventually be incorporated in the landscape of first-line systemic treatment for advanced cholangiocarcinoma with FGFR2 fusions or rearrangements after the ongoing phase III trials. Circulating tumor DNA could be used as a dynamic tool for evaluating mechanisms of resistance and prediction of response in patients treated with directed therapy.