Dermatologic Adverse Events Associated with Selective Fibroblast Growth Factor Receptor Inhibitors: Overview, Prevention, and Management Guidelines

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

PURPOSE

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

EXPERIMENTAL DESIGN

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

RESULTS

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

CONCLUSION

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

SIGNIFICANCE

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

Safety Profile and Adverse Event Management for Futibatinib, An Irreversible FGFR1-4 Inhibitor: Pooled Safety Analysis of 469 Patients

PURPOSE

Futibatinib, a covalently-binding inhibitor of fibroblast growth factor receptor (FGFR)1-4 gained approval for the treatment of refractory, advanced intrahepatic cholangiocarcinoma (iCCA) harboring an FGFR2 fusion/other rearrangement. An integrated analysis was performed to evaluate safety and provide guidance on the management of futibatinib-associated adverse events (AEs) in patients with unresectable/metastatic tumors, including iCCA.

PATIENTS AND METHODS

Data from three global phase I or II studies of futibatinib (NCT02052778; JapicCTI-142552) were pooled. AEs were graded per NCI CTCAE v4.03, where applicable. Safety was analyzed for patients receiving any futibatinib starting dose (overall population) and in those receiving the approved starting dose of 20 mg once every day.

RESULTS

In total, 469 patients with one of 33 known tumor types were analyzed, including 318 patients who received futibatinib 20 mg every day. AEs of clinical interest (AECI; any grade/grade ≥3) in the overall population included hyperphosphatemia (82%/19%), nail disorders (27%/1%), hepatic AEs (27%/11%), stomatitis (19%/3%), palmar-plantar erythrodysesthesia syndrome (PPES; 13%/3%), rash (9%/0%), retinal disorders (8%/0%), and cataract (4%/1%). Median time to onset of grade ≥3 AECIs ranged from 9 days (hyperphosphatemia) to 125 days (cataract). Grade ≥3 hyperphosphatemia, hepatic AEs, PPES, and nail disorders resolved to grade ≤2 within a median of 7, 7, 8, and 28 days, respectively. Discontinuations due to treatment-related AEs were rare (2%), and no treatment-related deaths occurred. AE management included phosphate-lowering medication and dose adjustments.

CONCLUSIONS

Futibatinib showed a consistent and manageable safety profile across patients with various tumor types. AECIs were mostly reversible with appropriate clinical management.

Lack of pharmacokinetic interaction between derazantinib and naringin in rats

CONTEXT

Derazantinib-an orally bioavailable, ATP competitive, multikinase inhibitor-has strong activity against fibroblast growth factor receptors (FGFR)2, FGFR1, and FGFR3 kinases. It has preliminary antitumor activity in patients with unresectable or metastatic FGFR2 fusion-positive intrahepatic cholangiocarcinoma (iCCA).

OBJECTIVE

This experiment validates a novel sensitive and rapid method for the determination of derazantinib concentration in rat plasma by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), and applies it to the study of drug-drug interaction between derazantinib and naringin in vivo.

MATERIALS AND METHODS

A Xevo TQ-S triple quadrupole tandem mass spectrometer was used for mass spectrometry monitoring in selective reaction monitoring (SRM) mode with transitions of m/z 468 96 → 382.00 for derazantinib and m/z 488.01 → 400.98 for pemigatinib, respectively. The pharmacokinetics of derazantinib (30 mg/kg) was investigated in Sprague-Dawley (SD) rats divided into two groups (with the oral pretreatment of 50 mg/kg naringin or not).

RESULTS

The newly optimized UPLC-MS/MS method was suitable for the determination of derazantinib in rat plasma. It was also successfully employed to evaluate the effect of naringin on derazantinib metabolism in rats. After pretreatment with naringin, there was no significant difference in the pharmacokinetic parameters (AUC_0→t, AUC_0→∞, t_1/2, CLz/F, and C_max) of derazantinib when compared with derazantinib alone.

CONCLUSION

Co-administration of naringin with derazantinib was not associated with significant changes in pharmacokinetic parameters. Thus, this study suggests that the combination of derazantinib with naringin can safely be administered concomitantly without dose adjustment.

Pharmacovigilance Study of Infigratinib: A Safety Analysis of the FDA Adverse Event Reporting System

BACKGROUND

Infigratinib is a fibroblast growth factor receptor (FGFR)-specifc tyrosine kinase inhibitor indicated for the treatment of patients with previously treated, unresectable, locally advanced or metastatic cholangiocarcinoma. However, few studies have been conducted to evaluated the safety of infigratinib in the real world. In this study, we conducted a pharmacovigilance study to evaluate the adverse events (AEs) of infigratinib by using the Food and Drug Administration Adverse Event Reporting System (FAERS) database.

METHODS

OpenVigil 2.1 was employed to extract the FAERS database. Descriptive analysis was used to describe the characteristics of infigratinib-associated AE reports. Disproportionality analysis was performed by calculating the proportional reporting ratio (PRR), reporting odds ratios (ROR), and Bayesian analysis confidence propagation neural network (BCPNN) to detect positive signals.

RESULTS

Our findings revealed 149 AE reports, among which 36 significant signals were identified. These significant AE signals were mainly observed in gastrointestinal disorders (N = 26, ROR = 26.03, PRR = 8.44, information component [IC] = 3.08) and skin and subcutaneous tissue disorders (N = 21, ROR = 92.13, PRR = 40.41, IC = 5.34). Notably, dehydration and skin exfoliation were unexpected AEs, but had relatively high signal intensities (ROR = 29.75, PRR = 26.64, IC = 4.74; ROR = 50.61, PRR = 45.24, IC = 5.50, respectively) despite not being listed on the drug label. Furthermore, our analysis showed that infigratinib dose differed statistically between severe and non-severe reports (113.82 ± 16.13 mg vs 125 ± 0.00 mg, t = - 4.28; p < 0.001). However, there were no significant differences in sex, age, and types of AEs between the two groups (p  = 0.06, p  = 0.86, and p = 0.93, respectively).

CONCLUSIONS

These findings suggest that gastrointestinal and skin toxicities are the most common adverse reactions for infigratinib. It is important to recognize skin exfoliation and dehydration in clinical practice, as they are unexpected AEs. Additionally, our study indicates that infigratinib dose may correlate with an increased risk of AE severity, highlighting the need for dose adjustment of infigratinib when exposure to the drug is increased due to internal or external factors.

The role of dermocosmetics in the management of cancer-related skin toxicities: international expert consensus

Skin toxicities are very common in patients undergoing cancer treatment and have been found to occur with all types of cancer therapeutic interventions (cytotoxic chemotherapy, targeted therapies, immunotherapy, and radiotherapy). Further, skin toxicities can lead to interruption or even discontinuation of anticancer treatment in some patients, translating to suboptimal outcomes. Dermocosmetics (or cosmeceuticals)-defined as skincare solutions incorporating dermatologically active ingredients (beyond vehicle effects) that directly improve symptoms of various skin conditions-are increasingly being used in cancer care to prevent and manage skin toxicities. The active ingredients in these products have a measurable biological action in skin; they typically improve skin integrity (barrier function/hydration and other factors) while relieving skin symptoms. The Association Francophone des Soins Oncologiques de Support (AFSOS) and Multinational Association of Supportive Care in Cancer (MASCC) partnered to select a multidisciplinary group of healthcare professionals involved in the management of patients with cancer and skin toxicities. The group reviewed existing literature and created a summary of recommendations for managing these toxicities through online meetings and communication. In this publication, the group (1) reviews new skin toxicities seen with oncology drugs and (2) evaluates the role of dermocosmetics in improving patient outcomes and minimizing cancer treatment interruptions. We provide general recommendations for initiation and selection of skin care in all oncology patients as well as recommendations for what factors should be considered when using dermocosmetics in specific types of skin toxicities.

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.

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.

The management of toxicities from immune, targeted and ADCs treatments in patients with urothelial cancer

Newly approved systemic treatment options for metastatic urothelial cancer (mUC) have diversified treatments and improved responses and survival for chemotherapy refractory disease. These systemic treatments have associated toxicities which need appropriate management for patients to stay on treatment and potentially have longer benefit from treatment. We review the expected toxicities of immune checkpoint inhibitors, FGFR inhibitors such as erdafitinib, and antibody drug conjugates such as enfortumab vedotin and sacituzumab govitecan.

Cutaneous adverse reactions resulting from targeted cancer therapies: histopathologic and clinical findings

Targeted cancer treatments-designed to interfere with specific molecular signals responsible for tumor survival and progression-have shown benefit over conventional chemotherapies but may lead to diverse cutaneous adverse effects. This review highlights clinically significant dermatologic toxicities and their associated histopathologic findings, resulting from various targeted cancer drugs. Case reports and series, clinical trials, reviews, and meta-analyses are included for analysis and summarized herein. Cutaneous side effects resulting from targeted cancer therapies were reported with incidences as high as 90% for certain medications, and reactions are often predictable based on mechanism(s) of action of a given drug. Common and important reaction patterns included: acneiform eruptions, neutrophilic dermatoses, hand-foot skin reaction, secondary cutaneous malignancies, and alopecia. Clinical and histopathologic recognition of these toxicities remains impactful for patient care.

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

Oncogenic activation of fibroblast growth factor receptor 2 (FGFR2) drives multiple cancers and represents a broad therapeutic opportunity, yet selective targeting of FGFR2 has not been achieved. Although the clinical efficacy of pan-FGFR inhibitors (pan-FGFRi) validates FGFR2 driver status in FGFR2 fusion-positive intrahepatic cholangiocarcinoma, their benefit is limited by incomplete target coverage due to FGFR1- and FGFR4-mediated toxicities (hyperphosphatemia and diarrhea, respectively) and the emergence of FGFR2 resistance mutations. RLY-4008 is a highly selective, irreversible FGFR2 inhibitor designed to overcome these limitations. In vitro, RLY-4008 demonstrates >250- and >5,000-fold selectivity over FGFR1 and FGFR4, respectively, and targets primary alterations and resistance mutations. In vivo, RLY-4008 induces regression in multiple xenograft models-including models with FGFR2 resistance mutations that drive clinical progression on current pan-FGFRi-while sparing FGFR1 and FGFR4. In early clinical testing, RLY-4008 induced responses without clinically significant off-isoform FGFR toxicities, confirming the broad therapeutic potential of selective FGFR2 targeting.

SIGNIFICANCE

Patients with FGFR2-driven cancers derive limited benefit from pan-FGFRi due to multiple FGFR1-4-mediated toxicities and acquired FGFR2 resistance mutations. RLY-4008 is a highly selective FGFR2 inhibitor that targets primary alterations and resistance mutations and induces tumor regression while sparing other FGFRs, suggesting it may have broad therapeutic potential. See related commentary by Tripathi et al., p. 1964. This article is featured in Selected Articles from This Issue, p. 1949.

ESMO/ASCO Recommendations for a Global Curriculum in Medical Oncology Edition 2023

The European Society for Medical Oncology (ESMO) and ASCO are publishing a new edition of the ESMO/ASCO Global Curriculum (GC) with contributions from more than 150 authors. The purpose of the GC is to provide recommendations for the training of physicians in medical oncology and to establish a set of educational standards for trainees to qualify as medical oncologists. This edition builds on prior ones in 2004, 2010, and 2016 and incorporates scientific advances and input from an ESMO ASCO survey on GC adoption conducted in 2019, which revealed that GC has been adopted or adapted in as many as two thirds of the countries surveyed. To make GC even more useful and applicable, certain subchapters were rearranged into stand-alone chapters, that is, cancer epidemiology, diagnostics, and research. In line with recent progress in the field of multidisciplinary cancer care new (sub)chapters, such as image-guided therapy, cell-based therapy, and nutritional support, were added. Moreover, this edition includes an entirely new chapter dedicated to cancer control principles, aiming to ensure that medical oncologists are able to identify and implement sustainable and equitable cancer care, tailored to local needs and resources. Besides content renewal, modern didactic principles were introduced. GC content is presented using two chapter templates (cancer-specific and non-cancer-specific), with three didactic points (objectives, key concepts, and skills). The next step is promoting GC as a contemporary and comprehensive document applicable all over the world, particularly due to its capacity to harmonize education in medical oncology and, in so doing, help to reduce global disparities in cancer care.

Safety analysis of pemigatinib leveraging the US Food and Drug administration adverse event reporting system

Background: Cholangiocarcinoma (CCA) is a highly lethal and aggressive epithelial tumor of the hepatobiliary system. A poor prognosis, propensity for relapse, low chance of cure and survival are some of its hallmarks. Pemigatinib, the first targeted treatment for CCA in the United States, has been demonstrated to have a significant response rate and encouraging survival data in early-phase trials. The adverse events (AEs) of pemigatinib must also be determined. Objective: To understand more deeply the safety of pemigatinib in the real world through data-mining of the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS). Methods: Disproportionality analysis was employed in a retrospective pharmacovigilance investigation to identify the AEs linked to pemigatinib use as signals. Data were collected between 1 January 2020 to 30 June 2022. Four data-mining methods (proportional reporting odds ratio; proportional reporting ratio; Bayesian confidence propagation neural networks of information components; empirical Bayes geometric means) were used to calculate disproportionality. Results: A total of 203 cases using pemigatinib as the prime-suspect medication were found in our search, which involved 99 preferred terms (PTs). Thirteen signals of pemigatinib-induced AEs in seven System Organ Classes were detected after confirming the four algorithms simultaneously. Nephrolithiasis was an unexpected significant AE not listed on the drug label found in our data-mining. Comparison of the differences between pemigatinib and platinum drugs in terms of 33 PTs revealed that 13 PTs also met the criteria of the four algorithms. Ten of these PTs were identical to those compared with all other drugs, in which (excluding a reduction in phosphorus in blood) other PT signal values were higher than those of all other drugs tested. However, comparison of the differences between pemigatinib and infigratinib in terms of the 33 PTs revealed no significant signals in each algorithm method. Conclusion: Some significant signals were detected between pemigatinib use and AEs. PTs with apparently strong signals and PTs not mentioned in the label should be taken seriously.

Adverse effects of tyrosine kinase inhibitors in cancer therapy: pathophysiology, mechanisms and clinical management

Since their invention in the early 2000s, tyrosine kinase inhibitors (TKIs) have gained prominence as the most effective pathway-directed anti-cancer agents. TKIs have shown significant utility in the treatment of multiple hematological malignancies and solid tumors, including chronic myelogenous leukemia, non-small cell lung cancers, gastrointestinal stromal tumors, and HER2-positive breast cancers. Given their widespread applications, an increasing frequency of TKI-induced adverse effects has been reported. Although TKIs are known to affect multiple organs in the body including the lungs, liver, gastrointestinal tract, kidneys, thyroid, blood, and skin, cardiac involvement accounts for some of the most serious complications. The most frequently reported cardiovascular side effects range from hypertension, atrial fibrillation, reduced cardiac function, and heart failure to sudden death. The potential mechanisms of these side effects are unclear, leading to critical knowledge gaps in the development of effective therapy and treatment guidelines. There are limited data to infer the best clinical approaches for the early detection and therapeutic modulation of TKI-induced side effects, and universal consensus regarding various management guidelines is yet to be reached. In this state-of-the-art review, we examine multiple pre-clinical and clinical studies and curate evidence on the pathophysiology, mechanisms, and clinical management of these adverse reactions. We expect that this review will provide researchers and allied healthcare providers with the most up-to-date information on the pathophysiology, natural history, risk stratification, and management of emerging TKI-induced side effects in cancer patients.

Management of Fibroblast Growth Factor Inhibitor Treatment-emergent Adverse Events of Interest in Patients with Locally Advanced or Metastatic Urothelial Carcinoma

Background

Erdafitinib is indicated for the treatment of adults with locally advanced/metastatic urothelial carcinoma and susceptible FGFR3/2 alterations progressing on/after one or more lines of prior platinum-based chemotherapy.

Objective

To better understand the frequency and management of select treatment-emergent adverse events (TEAEs) to enable optimal fibroblast growth factor receptor inhibitor (FGFRi) treatment.

Design setting and participants

Longer-term efficacy and safety results of the BLC2001 (NCT02365597) trial in patients with locally advanced and unresectable or metastatic urothelial carcinoma were studied.

Intervention

Erdafitinib schedule of 8 mg/d continuous in 28-d cycles, with uptitration to 9 mg/d if serum phosphate level was <5.5 mg/dl and no significant TEAEs occurred.

Outcome measurements and statistical analysis

Adverse events were graded using National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. The Kaplan-Meier methodology was used for the cumulative incidence of the first onset of TEAEs by grade. Time to resolution of TEAEs was summarized descriptively.

Results and limitations

At data cutoff, the median treatment duration was 5.4 mo among 101 patients receiving erdafitinib. Select TEAEs (total; grade 3) were hyperphosphatemia (78%; 2.0%), stomatitis (59%; 14%), nail events (59%; 15%), non-central serous retinopathy (non-CSR) eye disorders (56%; 5.0%), skin events (55%; 7.9%), diarrhea (55%; 4.0%), and CSR (27%; 4.0%). Select TEAEs were mostly of grade 1 or 2, and were managed effectively with dose modifications, including dose reductions or interruptions, and/or supportive concomitant therapies, resulting in few events leading to treatment discontinuation. Further work is needed to determine whether management is generalizable to the nonprotocol/general population.

Conclusions

Identification of select TEAEs and appropriate management with dose modification and/or concomitant therapies resulted in improvement or resolution of most TEAEs in patients, allowing for continuation of FGFRi treatment to ensure maximum benefit.

Patient summary

Early identification and proactive management are warranted to mitigate or possibly prevent erdafitinib side effects to allow for maximum drug benefit in patients with locally advanced or metastatic bladder cancer.

Specific-class Skin Side-effects of Drugs Might Compromise Blinding in Randomized Controlled Trials

Abstract is missing (Short communication)

FGFR Inhibitors in Cholangiocarcinoma-A Novel Yet Primary Approach: Where Do We Stand Now and Where to Head Next in Targeting This Axis?

Cholangiocarcinomas (CCAs) are rare but aggressive tumours with poor diagnosis and limited treatment options. Molecular targeted therapies became a promising proposal for patients after progression under first-line chemical treatment. In light of an escalating prevalence of CCA, it is crucial to fully comprehend its pathophysiology, aetiology, and possible targets in therapy. Such knowledge would play a pivotal role in searching for new therapeutic approaches concerning diseases' symptoms and their underlying causes. Growing evidence showed that fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) pathway dysregulation is involved in a variety of processes during embryonic development and homeostasis as well as tumorigenesis. CCA is known for its close correlation with the FGF/FGFR pathway and targeting this axis has been proposed in treatment guidelines. Bearing in mind the significance of molecular targeted therapies in different neoplasms, it seems most reasonable to move towards intensive research and testing on these in the case of CCA. However, there is still a need for more data covering this topic. Although positive results of many pre-clinical and clinical studies are discussed in this review, many difficulties lie ahead. Furthermore, this review presents up-to-date literature regarding the outcomes of the latest clinical data and discussion over future directions of FGFR-directed therapies in patients with CCA.

FGF23 functions and disease

The main function of fibroblast growth factor 23 (FGF23) is the regulation of phosphate metabolism through its action on the sodium-dependent phosphate cotransporters in the proximal renal tubules. Additionally, FGF23 interacts with vitamin D and parathyroid hormone in a complex metabolic pathway whose detailed mechanisms are still not clear in human physiology and disease. More recently, research has also focused on the understanding of mechanisms of FGF23 action on organs and system other than the kidneys and bone, as well as on its interaction with other metabolic pathways. Collectively, the new evidence are successfully used for the clinical evaluation and management of FGF23-related disorders, for which new therapies with many potential applications are now available.

Pemigatinib in cholangiocarcinoma with a FGFR2 rearrangement or fusion

INTRODUCTION

Cholangiocarcinoma (CCA) accounts for approximately 3% of gastrointestinal malignancies and is associated with a high mortality rate. Recent progress in the understanding of cholangiocarcinoma tumorigenesis and molecular markers has led to the development of several targeted therapies applicable to this disease. Fibroblast growth factor receptor 2 (FGFR2) gene fusion or translocation, resulting in constitutive activation of the FGFR tyrosine kinase, has been identified as a driver of oncogenesis in 10-15% of intrahepatic CCA. Pemigatinib is an FGFR inhibitor that has demonstrated survival benefit in the second line setting for treatment of CCA with FGFR2 fusion or rearrangement refractory to chemotherapy. Pemigatinib was the first targeted therapy to be approved by the FDA for treatment of cholangiocarcinoma.

AREAS COVERED

This article reviews FGFR and its dysregulation in oncogenesis, FGFR inhibitors, especially pemigatinib, utilized in treatment of CCA, common adverse events associated with FGFR inhibitors, and future directions in the field of targeted drug development for CCA.

EXPERT OPINION

FGFR inhibitors, including pemigatinib, have shown promise in the management of CCA with FGFR2 fusion or rearrangement; however, acquired resistance remains a major barrier in the field of FGFR inhibitors and requires further study.

Dermatologic adverse events associated with IDH inhibitors ivosidenib and enasidenib for the treatment of acute myeloid leukemia

Two novel inhibitors of isocitrate dehydrogenase (IDHi), ivosidenib and enasidenib, significantly improve survival for AML patients with an IDH1 or IDH2 mutation, respectively; however, rash has been reported as a toxicity of IDHi. The objective of our study is to determine the incidence, grade, clinical, and histopathologic features of dermatologic adverse events (DAEs) secondary to IDHi. This study is a retrospective analysis of 169 patients who were treated with either ivosidenib or enasidenib as single agent or in combination with induction chemotherapy at Memorial Sloan Kettering Cancer Center from January 1, 2013 to April 1, 2021. DAEs thought to be possibly, probably, or definitely related to IDHi occurred in 55 of 169 patients [0.32, 95 % CI: 0.25 - 0.40]. Of a total 81 DAEs observed, the most common DAE types were inflammatory dermatoses (27 %); cutaneous vascular manifestations (8%); cutaneous infections (7%); and pruritus (2%). Notably, 50% of infections and 15.5% of rashes were high grade. Knowledge of these findings is critical to optimize the treatment and quality of life of patients with AML on IDHi.

An Emollient PLUS Balm Is Useful for the Management of Xerosis in Patients Treated for Cancer: A Real-World, Prospective, Observational, Multicenter Study

INTRODUCTION

Xerosis is a common skin side effect of current anticancer therapies, including chemotherapy, targeted therapy, radiotherapy, and hormonotherapy. We evaluated the effectiveness of an emollient PLUS containing an Aquaphilus dolomiae extract (ADE-G1) for the management of xerosis in adult patients treated for cancer.

METHODS

This real-world, prospective, observational, multicenter study involved 319 xerotic cancer patients, who were prescribed the study product according to the usual practice of their physician. The practitioner assessed xerosis severity and objective clinical signs, and the patients assessed subjective clinical signs and the impact of their skin condition on their quality of life, at inclusion and after around 4 weeks of use. Overall effectiveness and tolerance were assessed at the end of the study. Clinical success was defined by the combination of several of these effectiveness outcomes.

RESULTS

Daily application of the emollient PLUS reduced xerosis severity in 62.7% of patients (p < 0.0001). The mean total severity scores for objective and subjective clinical signs were reduced by 67.7% and 57.4% (p < 0.0001), respectively, compared with baseline. The mean Dermatology Life Quality Index (DLQI) score also significantly improved at the end of follow-up (-56.6%, p < 0.0001). The product was rated as "effective" or "very effective" by the physician for over 80% of patients, regardless of the initial severity grade of xerosis. Overall clinical success was achieved in 73.7% of patients. A trend toward higher effectiveness and clinical success was observed in patients under hormonotherapy. The study product was well tolerated, regardless of the anticancer therapy being received.

CONCLUSION

This study shows that the emollient PLUS containing ADE-G1 is an effective treatment for xerosis in cancer patients, regardless of the initial grade of xerosis and the anticancer treatment received.

Calciphylaxis Cutis Associated With Fibroblast Growth Factor Receptor (FGFR) Inhibitor Therapy: A New Challenge

Specific fibroblast growth factor receptor (FGFR) inhibitors have been developed to treat malignancies harboring fusions or rearrangements in FGFR2 or FGFR3. Here, we report a case of calciphylaxis cutis in association with FGFR inhibitor therapy in a patient with FGFR2 rearranged cholangiocarcinoma. Although calciphylaxis cutis typically arises in the setting of hyperphosphatemia and end-stage renal disease, this patient had preserved renal function, normal serum calcium, and only modestly elevated serum phosphorus levels, which is similar to other recent reports of calciphylaxis in patients receiving FGFR inhibitor therapy. Calciphylaxis cutis is a possible adverse event observed with FGFR inhibitor therapy, and the mechanism of calciphylaxis cutis in association with FGFR inhibitor therapy warrants further investigation.

Cutaneous toxicities from targeted therapies used in oncology: Literature review of clinical presentation and management

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Cutaneous toxicities are frequent with targeted therapies.

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Managing cutaneous toxicities is critical for life-saving treatment continuation.

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Dermatologists can provide a key input in preventing and managing these toxicities.

With the development of molecular targeted therapies, a wide array of dermatologic toxicities is appearing. Their prevention, recognition, and management by dermatologists is critical to ensure antineoplastic treatment continuation. The objective of this study was to provide a literature review of the most common dermatologic toxicities due to targeted therapies in oncologic patients, including their clinical presentation, prevention, and management.

Quality of Life and Symptom Management in Advanced Biliary Tract Cancers

Simple Summary

Patients with advanced BTC have poor prognosis and frequently experience symptoms that adversely impact their quality of life. In this review, we explore the potential complications of advanced BTC and its treatments. We also review the possible strategies and interventions available to manage these adverse events.

Abstract

Biliary tract carcinomas (BTCs) account for less than 1% of all cancers but are increasing in incidence. Prognosis is poor for BTC patients, with 5-year survival rates of less than 10%. While chemotherapy has been the mainstay treatment for patients with advanced BTC, immunotherapy and targeted therapies are being evaluated in numerous clinical trials and rapidly incorporated into clinical practice. As patients with BTC have reduced health-related quality of life (HRQoL) due to both tumor- and treatment-related symptoms, it is important for clinicians to recognize and manage these symptoms early. This review will highlight the anticipated complications from BTC and its systemic treatment, as well as their effects on HRQoL.

Diverse landscape of dermatologic toxicities from small-molecule inhibitor cancer therapy

BACKGROUND

Advances in molecular biology and genetics have contributed to breakthrough treatments directed at specific pathways associated with the development of cancer. Small-molecule inhibitors (Nibs) aimed at a variety of cellular pathways have been efficacious; however, they are associated with significant dermatologic toxicities.

METHODS

We conducted a comprehensive review of dermatologic toxicities associated with Nibs categorized into the following five groups: (a) mitogen-activated protein kinase; (b) growth factor/multi-tyrosine kinase; (c) cell division/DNA repair; (d) signaling associated with myeloproliferative neoplasms; and (e) other signaling pathways. Prospective phase I, II, or III clinical trials, retrospective literature reviews, systematic reviews/meta-analyses, and case reviews/reports were included for analysis.

RESULTS

Dermatologic toxicities reviewed were associated with every class of Nibs and ranged from mild to severe or life-threatening adverse skin reactions. Inflammatory reactions manifesting as maculopapular, papulopustular/acneiform, and eczematous lesions were frequent types of dermatologic toxicities seen with Nibs. Squamous cell carcinoma with keratoacanthoma-like features was associated with a subset of Nibs. Substantial overlap in dermatologic toxicities was found between Nibs.

CONCLUSIONS

Dermatologic toxicities from Nibs are diverse and may overlap between classes of Nibs. Recognition of the various types of toxicities from Nibs is critical for patient care in the era of "oncodermatology/dermatopathology."

Application of Topical Lidocaine for Pain Relief in the Setting of Targeted Therapy-Induced Onycholysis: A Case Report

Selective pan fibroblast growth factor receptor (FGFR) inhibitors have been linked to severe onycholysis, the uncomfortable separation of the nail plate from the nail bed. Recommendations to assist with FGFR inhibitor onycholysis vary based on the severity. We hypothesized that the application of topical lidocaine to mimic a digital nerve block would be beneficial in addition to traditional supportive care interventions and subsequently report its immediate and continued efficacy for targeted therapy-induced onycholysis.

Infigratinib (BGJ398) in previously treated patients with advanced or metastatic cholangiocarcinoma with FGFR2 fusions or rearrangements: mature results from a multicentre, open-label, single-arm, phase 2 study

BACKGROUND

Treatment options are sparse for patients with advanced cholangiocarcinoma after progression on first-line gemcitabine-based therapy. FGFR2 fusions or rearrangements occur in 10-16% of patients with intrahepatic cholangiocarcinoma. Infigratinib is a selective, ATP-competitive inhibitor of fibroblast growth factor receptors. We aimed to evaluate the antitumour activity of infigratinib in patients with locally advanced or metastatic cholangiocarcinoma, FGFR2 alterations, and previous gemcitabine-based treatment.

METHODS

This multicentre, open-label, single-arm, phase 2 study recruited patients from 18 academic centres and hospitals in the USA, Belgium, Spain, Germany, Singapore, Taiwan, and Thailand. Eligible participants were aged 18 years or older, had histologically or cytologically confirmed, locally advanced or metastatic cholangiocarcinoma and FGFR2 fusions or rearrangements, and were previously treated with at least one gemcitabine-containing regimen. Patients received 125 mg of oral infigratinib once daily for 21 days of 28-day cycles until disease progression, intolerance, withdrawal of consent, or death. Radiological tumour evaluation was done at baseline and every 8 weeks until disease progression via CT or MRI of the chest, abdomen, and pelvis. The primary endpoint was objective response rate, defined as the proportion of patients with a best overall response of a confirmed complete or partial response, as assessed by blinded independent central review (BICR) according to Response Evaluation Criteria in Solid Tumors, version 1.1. The primary outcome and safety were analysed in the full analysis set, which comprised all patients who received at least one dose of infigratinib. This trial is registered with ClinicalTrials.gov, NCT02150967, and is ongoing.

FINDINGS

Between June 23, 2014, and March 31, 2020, 122 patients were enrolled into our study, of whom 108 with FGFR2 fusions or rearrangements received at least one dose of infigratinib and comprised the full analysis set. After a median follow-up of 10·6 months (IQR 6·2-15·6), the BICR-assessed objective response rate was 23·1% (95% CI 15·6-32·2; 25 of 108 patients), with one confirmed complete response in a patient who only had non-target lesions identified at baseline and 24 partial responses. The most common treatment-emergent adverse events of any grade were hyperphosphataemia (n=83), stomatitis (n=59), fatigue (n=43), and alopecia (n=41). The most common ocular toxicity was dry eyes (n=37). Central serous retinopathy-like and retinal pigment epithelial detachment-like events occurred in 18 (17%) patients, of which ten (9%) were grade 1, seven (6%) were grade 2, and one (1%) was grade 3. There were no treatment-related deaths.

INTERPRETATION

Infigratinib has promising clinical activity and a manageable adverse event profile in previously treated patients with locally advanced or metastatic cholangiocarcinoma harbouring FGFR2 gene fusions or rearrangements, and so represents a potential new therapeutic option in this setting.

FUNDING

QED Therapeutics and Novartis.

FGFR Inhibitor Toxicity and Efficacy in Cholangiocarcinoma: Multicenter Single-Institution Cohort Experience

Cholangiocarcinomas (CCA) are a group of heterogeneous tumors arising from the biliary epithelia. Significant sequencing efforts have provided further insights into the molecular mechanisms of this disease including fibroblast growth factor receptor (FGFR) alterations, which occurs in approximately 15%-20% of intrahepatic CCAs. Herein, we describe the FGFR inhibitor (FGFRi)-associated treatment toxicity and cancer-specific outcomes from a multicenter single-institution cohort.

METHODS

This is a retrospective study of patients with CCA and known FGFR alterations treated with FGFRi. We describe the toxicity and efficacy in patients treated at Mayo Clinic between January 2010 and December 2020.

RESULTS

Our group identified 61 patients with advanced or metastatic CCA, 19 males (31%) and 42 females (69%), harboring FGFR alterations who received FGFRi. The most common grade 1 or higher adverse events for all patients included fatigue (92%), AST elevations (78%), anemia (80%), decreased platelet count (63%), and hyperphosphatemia (74%). Median progression-free survival on FGFRi was 5.8 months for all patients (95% CI, 4.9 to 9.0). Females had significantly longer progression-free survival at 6.9 months (95% CI, 5.2 to 11.8) on FGFRi compared with males at 4.9 months (95% CI, 2.8 to not estimable; P = .038).

CONCLUSION

FGFRi are well tolerated with clinical efficacy. With the recent approval of FGFRi by the US Food and Drug Administration and ongoing clinical trials for new FGFRi, understanding outcomes and toxicity associated with these medications is important for precision oncology.

FGFR Inhibitors in Oncology: Insight on the Management of Toxicities in Clinical Practice

Simple Summary

FGFR inhibitors evolved as therapeutic options in cholangiocarcinoma and urothelial malignancies. Given the implications of FGFR pathway in various physiological functions, FGFR inhibitors are known to cause unique toxicities. In this review, we summarized the physiology of FGF/FGFR signaling and briefly discussed the possible mechanisms that could lead to FGFR inhibitor resistance and side effects. In addition, we proposed treatment guidelines for the management of FGFR-inhibitor-associated toxicities.

Abstract

Fibroblast Growth Factor receptor (FGFR) pathway aberrations have been implicated in approximately 7% of the malignancies. As our knowledge of FGFR aberrations in cancer continues to evolve, FGFR inhibitors emerged as potential targeted therapeutic agents. The promising results of pemigatinib and infigratinib in advanced unresectable cholangiocarcinoma harboring FGFR2 fusions or rearrangement, and erdafitinib in metastatic urothelial carcinoma with FGFR2 and FGFR3 genetic aberrations, lead to their accelerated approval by the United States (USA) FDA. Along with these agents, many phase II/III clinical trials are currently evaluating the use of derazantinib, infigratinib, and futibatinib either alone or in combination with immunotherapy. Despite the encouraging results seen with FGFR inhibitors, resistance mechanisms and side effect profile may limit their clinical utility. A better understanding of the unique FGFR-inhibitor-related toxicities would invariably help us in the prevention and effective management of FGFR-inhibitor-induced adverse events thereby enhancing their clinical benefit. Herein, we summarized the physiology of FGF/FGFR signaling and briefly discussed the possible mechanisms that could lead to FGFR inhibitor resistance and side effects. In addition, we proposed treatment guidelines for the management of FGFR-inhibitor-associated toxicities. This work would invariably help practicing oncologists to effectively manage the unique toxicities of FGFR inhibitors.

Advantages and Disadvantages of Different Treatment Methods in Achondroplasia: A Review

Achondroplasia (ACH) is a disease caused by a missense mutation in the FGFR3 (fibroblast growth factor receptor 3) gene, which is the most common cause of short stature in humans. The treatment of ACH is necessary and urgent because untreated achondroplasia has many complications, both orthopedic and neurological, which ultimately lead to disability. This review presents the current and potential pharmacological treatments for achondroplasia, highlighting the advantages and disadvantages of all the drugs that have been demonstrated in human and animal studies in different stages of clinical trials. The article includes the potential impacts of drugs on achondroplasia symptoms other than short stature, including their effects on spinal canal stenosis, the narrowing of the foramen magnum and the proportionality of body structure. Addressing these effects could significantly improve the quality of life of patients, possibly reducing the frequency and necessity of hospitalization and painful surgical procedures, which are currently the only therapeutic options used. The criteria for a good drug for achondroplasia are best met by recombinant human growth hormone at present and will potentially be met by vosoritide in the future, while the rest of the drugs are in the early stages of clinical trials.