Clinical pharmacology of axitinib

Non-kinase off-target inhibitory activities of clinically-relevant kinase inhibitors

Protein kinases are responsible for a myriad of cellular functions, such as cell cycle, apoptosis, and proliferation. Because of this, kinases make excellent targets for therapeutics. During the process to identify clinical kinase inhibitor candidates, kinase selectivity profiles of lead inhibitors are typically obtained. Such kinome selectivity screening could identify crucial kinase anti-targets that might contribute to drug toxicity and/or reveal additional kinase targets that potentially contribute to the efficacy of the compound via kinase polypharmacology. In addition to kinome panel screening, practitioners also obtain the inhibition profiles of a few non-kinase targets, such as ion-channels and select GPCR targets to identify compounds that might possess potential liabilities. Often ignored is the possibility that identified kinase inhibitors might also inhibit or bind to the other proteins (greater than 20,000) in the cell that are not kinases, which may be relevant to toxicity or even additional mode of drug action. This review highlights various inhibitors, which have been approved by the FDA or are currently undergoing clinical trials, that also inhibit other non-kinase targets. The binding poses of the drugs in the binding sites of the target kinases and off-targets are analyzed to understand if the same features of the compounds are critical for the polypharmacology.

Cabozantinib Induces Isolated Hyperbilirubinemia in Renal Cell Carcinoma Patients carrying the UGT1A1*28 Polymorphism

BACKGROUND

Genetic variants of UGT1A1, involved in glucuronidation and clearance of bilirubin, are associated with reduced bilirubin metabolization and drug-induced isolated hyperbilirubinemia. We studied the impact of the UGT1A1*28 polymorphism on drug-induced isolated hyperbilirubinemia in metastatic renal cell carcinoma patients treated with pazopanib, cabozantinib, and axitinib.

METHODS

We genotyped the UGT1A1*28 TA6/TA6-TA6/TA7-TA7/TA7 polymorphism and correlated with median baseline, on-treatment and peak bilirubin levels during therapy, incidence of grade-1- or -2 (G1/2)-hyperbilirubinemia and time-to-G1-hyperbilirubinemia.

RESULTS

Of the 66 patients treated with pazopanib, 29 received axitinib and 28 cabozantinib upon progression. Median baseline bilirubin was higher in TA7/TA7-carriers versus TA6/TA6+TA6/TA7-carriers at start of pazopanib (P < .0001), cabozantinib (P < .0001), and axitinib (P = .007). During pazopanib therapy, median bilirubin increased 1.4-fold in TA7/TA7+TA6/TA7-carriers but not in TA6/TA6-carriers. On cabozantinib, bilirubin increased 1.5-fold in TA7/TA7-carriers but not in TA6/TA6+TA6/TA7-carriers. Axitinib did not increase bilirubin in any genotype. Peak bilirubin in TA7/TA7- versus TA6/TA6+TA6/TA7-carriers was higher on pazopanib (P < .0001) or cabozantinib (P < .0001). With pazopanib, G1-hyperbilirubinemia occurred in 57% of TA7/TA7- and 12% of TA6/TA6+TA6/TA7-carriers (P = .0009) and G2-hyperbilirubinemia in 36% and 6% of the patients, respectively (P = .004). On cabozantinib, G1-hyperbilirubinemia occurred in 100% of TA7/TA7- and 5% of TA6/TA6+TA6/TA7-carriers (P < .0001) and G2-hyperbilirubinemia in 33% and 0% of the patients, respectively (P = .04). On axitinib, no correlation between the genotypes and G1/2-hyperbilirubinemia was observed.

CONCLUSION

We validate the previously described impact of the UGT1A1*28 polymorphism on isolated bilirubin increase on pazopanib. We report for the first time that cabozantinib also interferes with UGT1A1 and causes isolated bilirubin increase.

Kinome expression profiling improves risk stratification and therapeutic targeting in myelodysplastic syndromes

ABSTRACT

The human kinome, which comprises >500 kinases, plays a critical role in regulating numerous essential cellular functions. Although the dysregulation of kinases has been observed in various human cancers, the characterization and clinical implications of kinase expressions in myelodysplastic syndromes (MDS) have not been systematically investigated. In this study, we evaluated the kinome expression profiles of 341 adult patients with primary MDS and identified 7 kinases (PTK7, KIT, MAST4, NTRK1, PAK6, CAMK1D, and PRKCZ) whose expression levels were highly predictive of compromised patient survival. We then constructed the kinase stratification score (KISS) by combining the weighted expressions of the 7 kinases and validated its prognostic significance in 2 external MDS cohorts. A higher KISS was associated with older age, higher peripheral blood and marrow blast percentages, higher Revised International Prognostic Scoring System (IPSS-R) risks, complex karyotype, and mutations in several adverse-risk genes in MDS, such as ASXL1, EZH2, NPM1, RUNX1, STAG2, and TP53. Multivariate analysis confirmed that a higher KISS was an independent unfavorable risk factor in MDS. Mechanistically, the KISS-high patients were enriched for gene sets associated with hematopoietic and leukemic stem cell signatures. By investigating the Genomics of Drug Sensitivity in Cancer database, we identified axitinib and taselisib as candidate compounds that could potentially target the KISS-high myeloblasts. Altogether, our findings suggest that KISS holds the potential to improve the current prognostic scheme of MDS and inform novel therapeutic opportunities.

An Investigation in the Comparability of the Exposure and Recommended Dose of Selected Pfizer Drugs in East Asian Countries: Is Mutual Usage of Clinical Data Among East Asian Countries Feasible?

The current regulatory path for new drug registration in East Asian countries has led to significant delay of the new medicines in these countries. A unified regulatory path and allowance of mutual usage of clinical data in East Asian countries would lead to cost saving in drug development and expedite the new drug registration in these countries. The objectives of the present analysis are to compare the approval dates of a selection of products developed by Pfizer in the United States and East Asian countries (China, Japan, Korea) and compare the pharmacokinetics and recommended doses of these products in East Asian countries. Eighteen products (20 drugs, 2 products with 2 combination drugs) with exposure data available in at least 2 of the 3 East Asian countries across different therapeutic areas were included in the analyses. The results showed that most products had delayed approval in East Asian countries (up to 8 years) after US or EU approval. No distinct differences were observed in the drug exposure and recommended doses for the selected products in East Asian countries. These results together with literature data of genetic similarity of the East Asian populations support the mutual usage of the clinical data in the East Asian countries for expedited regulatory submission and approval.

Glycaemic abnormalities induced by small molecule tryosine kinase inhibitors: a review

In light of the expected increase in the prevalence of diabetes mellitus due to an aging population, sedentary lifestyles, an increase in obesity, and unhealthy diets, there is a need to identify potential pharmacological agents that can heighten the risk of developing diabetes. Similarly, it is equally important to also identify those agents that show blood glucose-lowering properties. Amongst these agents are tyrosine kinase inhibitors used to treat certain types of cancers. Over the last two decades, there has been an increase in the use of targeted chemotherapy for cancers such as renal cell carcinoma, chronic leukaemia, and gastrointestinal stromal tumours. Small molecule tyrosine kinase inhibitors have been at the forefront of targeted chemotherapy. Studies have shown that small molecule tyrosine kinase inhibitors can alter glycaemic control and glucose metabolism, with some demonstrating hypoglycaemic activities whilst others showing hyperglycaemic properties. The mechanism by which small molecule tyrosine kinase inhibitors cause glycaemic dysregulation is not well understood, therefore, the clinical significance of these chemotherapeutic agents on glucose handling is also poorly documented. In this review, the effort is directed at mapping mechanistic insights into the effect of various small molecule tyrosine kinase inhibitors on glycaemic dysregulation envisaged to provide a deeper understanding of these chemotherapeutic agents on glucose metabolism. Small molecule tyrosine kinase inhibitors may elicit these observed glycaemic effects through preservation of β-cell function, improving insulin sensitivity and insulin secretion. These compounds bind to a spectrum of receptors and proteins implicated in glucose regulation for example, non-receptor tyrosine kinase SRC and ABL. Then receptor tyrosine kinase EGFR, PDGFR, and FGFR.

The Role of Nurses in the Management of Adverse Events in Patients Receiving First-Line Axitinib Plus Immuno-Oncology Agents for Advanced Renal Cell Carcinoma

OBJECTIVES

The recent approval of first-line tyrosine kinase inhibitor plus immuno-oncology agent combination therapy for the treatment of advanced renal cell carcinoma offers substantially improved response rates and survival compared with the previous standard of care. This expansion of treatment options has also led to a greater range and complexity of potential treatment-related adverse events related to overlapping toxicities. The aim of this article is to discuss the management of common treatment-emergent adverse events (AEs) associated with axitinib plus immuno-oncology therapy, highlight the specific roles of oncology nurses in managing these events, and provide AE management resources to aid oncology nurses in their care of patients with advanced renal cell carcinoma.

DATA SOURCES

Author experience, journal articles, and treatment guidelines were used.

CONCLUSION

The use of oncology nurses and nurse-led innovations to monitor and assess treatments can have a positive impact on the management of AEs in cancer patients by identifying those who are most at risk, providing regular assessment, appropriate patient education, and supporting the monitoring of patient safety.

IMPLICATIONS FOR NURSING PRACTICE

Skilled oncology nurses should be a key part of a team that addresses the supportive care needs and management of AEs that are associated with novel cancer treatments. Early and ongoing communication between the patient and oncology nurses regarding the development of adverse events is a critical component of maximizing treatment outcomes and quality of life.

Exploring the Spectrum of VEGF Inhibitors' Toxicities from Systemic to Intra-Vitreal Usage in Medical Practice

The use of Vascular Endothelial Growth Factor inhibitors (VEGFi) has become prevalent in the field of medicine, given the high incidence of various pathological conditions necessitating VEGF inhibition within the general population. These conditions encompass a range of advanced neoplasms, such as colorectal cancer, non-small cell lung cancer, renal cancer, ovarian cancer, and others, along with ocular diseases. The utilization of VEGFi is not without potential risks and adverse effects, requiring healthcare providers to be well-prepared for identification and management. VEGFi can be broadly categorized into two groups: antibodies or chimeric proteins that specifically target VEGF (bevacizumab, ramucirumab, aflibercept, ranibizumab, and brolucizumab) and non-selective and selective small molecules (sunitinib, sorafenib, cabozantinib, lenvatinib, regorafenib, etc.) designed to impede intracellular signaling of the VEGF receptor (RTKi, receptor tyrosine kinase inhibitors). The presentation and mechanisms of adverse effects resulting from VEGFi depend primarily on this distinction and the route of drug administration (systemic or intra-vitreal). This review provides a thorough examination of the causes, recognition, management, and preventive strategies for VEGFi toxicities with the goal of offering support to oncologists in both clinical practice and the design of clinical trials.

A review of emerging tyrosine kinase inhibitors as durable treatment of neovascular age-related macular degeneration

INTRODUCTION

Current treatment for age-related macular degeneration poses a large burden on patients and the inability of patients to adhere to this immense burden can lead to worse visual outcomes. Novel treatments have been proposed to extend treatment intervals and reduce visit burden.

AREAS COVERED

This review article summarizes phase I and phase II clinical trials of tyrosine kinase inhibitors as durable treatment options for patient with neovascular age-related macular degeneration.

EXPERT OPINION

Tyrosine kinase inhibitors have shown substantial promise in reducing treatment burden while maintaining visual acuity and anatomic outcomes with favorable safety profiles. Several platforms have shown positive outcomes in initial trials and are currently moving toward phase III clinical trials.

Antitumor Activity of Axitinib in Lung Carcinoids: A Preclinical Study

Lung carcinoids (LCs) comprise well-differentiated neuroendocrine tumors classified as typical (TCs) and atypical (ACs) carcinoids. Unfortunately, curative therapies remain elusive for metastatic LCs, which account for 25-30% of cases. This study evaluated the antitumor activity of axitinib (AXI), a second-generation tyrosine kinase inhibitor selectively targeting vascular endothelial growth factor receptors (VEGFR-1, VEGFR-2, VEGFR-3) in human lung TC (NCI-H727, UMC-11, NCI-H835) and AC (NCI-H720) cell lines. In vitro and in vivo (zebrafish) assays were performed following AXI treatment to gather several read-outs about cell viability, cell cycle, the secretion of proangiogenic factors, apoptosis, tumor-induced angiogenesis and migration. AXI demonstrated relevant antitumor activity in human LC cells, with pronounced effects observed in UMC-11 and NCI-H720, characterized by cell cycle perturbation and apoptosis induction. AXI significantly hindered tumor induced-angiogenesis in Tg(fli1a:EGFP)y1 zebrafish embryos implanted with all LC cell lines and also reduced the invasiveness of NCI-H720 cells, as well as the secretion of several proangiogenic factors. In conclusion, our study provides initial evidence supporting the potential anti-tumor activity of AXI in LC, offering a promising basis for future investigations in mammalian animal models and, eventually, progressing to clinical trials.

BR55 Ultrasound Molecular Imaging of Clear Cell Renal Cell Carcinoma Reflects Tumor Vascular Expression of VEGFR-2 in a Patient-Derived Xenograft Model

Standard imaging cannot reliably predict the nature of renal tumors. Among malignant renal tumors, clear cell renal cell carcinoma (ccRCC) is the most common histological subtype, in which the vascular endothelial growth factor 2 (VEGFR-2) is highly expressed in the vascular endothelium. BR55, a contrast agent for ultrasound imaging, consists of gas-core lipid microbubbles that specifically target and bind to the extracellular portion of the VEGFR-2. The specific information provided by ultrasound molecular imaging (USMI) using BR55 was compared with the vascular tumor expression of the VEGFR-2 by immunohistochemical (IHC) staining in a preclinical model of ccRCC. Patients' ccRCCs were orthotopically grafted onto Nod-Scid-Gamma (NSG) mice to generate patient-derived xenografts (PdX). Mice were divided into four groups to receive either vehicle or axitinib an amount of 2, 7.5 or 15 mg/kg twice daily. Perfusion parameters and the BR55 ultrasound contrast signal on PdX renal tumors were analyzed at D0, D1, D3, D7 and D11, and compared with IHC staining for the VEGFR-2 and CD34. Significant Pearson correlation coefficients were observed between the area under the curve (AUC) and the CD34 (0.84, p < 10-4), and between the VEGFR-2-specific signal obtained by USMI and IHC (0.72, p < 10-4). USMI with BR55 could provide instant, quantitative information on tumor VEGFR-2 expression to characterize renal masses non-invasively.

Nerve trunk healing and neuroma formation after nerve transection injury

The nerve trunk healing process of a transected peripheral nerve trunk is composed of angiogenesis, nerve fiber regeneration, and scarring. Nerve trunk healing and neuroma formation probably share identical molecular mediators and similar regulations. At the nerve transection site, angiogenesis is sufficient and necessary for nerve fiber regeneration. Angiogenesis and nerve fiber regeneration reveal a positive correlation in the early time. Scarring and nerve fiber regeneration show a negative correlation in the late phase. We hypothesize that anti-angiogenesis suppresses neuromas. Subsequently, we provide potential protocols to test our hypothesis. Finally, we recommend employing anti-angiogenic small-molecule protein kinase inhibitors to investigate nerve transection injuries.

Cellular and Molecular Players in the Tumor Microenvironment of Renal Cell Carcinoma

Globally, clear-cell renal cell carcinoma (ccRCC) represents the most prevalent type of kidney cancer. Surgery plays a key role in the treatment of this cancer, although one third of patients are diagnosed with metastatic ccRCC and about 25% of patients will develop a recurrence after nephrectomy with curative intent. Molecular-target-based agents, such as tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs), are recommended for advanced cancers. In addition to cancer cells, the tumor microenvironment (TME) includes non-malignant cell types embedded in an altered extracellular matrix (ECM). The evidence confirms that interactions among cancer cells and TME elements exist and are thought to play crucial roles in the development of cancer, making them promising therapeutic targets. In the TME, an unfavorable pH, waste product accumulation, and competition for nutrients between cancer and immune cells may be regarded as further possible mechanisms of immune escape. To enhance immunotherapies and reduce resistance, it is crucial first to understand how the immune cells work and interact with cancer and other cancer-associated cells in such a complex tumor microenvironment.

The multikinase inhibitor axitinib in the treatment of advanced hepatocellular carcinoma: the current clinical applications and the molecular mechanisms

Advanced hepatocellular carcinoma (HCC) is a formidable public health problem with limited curable treatment options. Axitinib, an oral tyrosine kinase inhibitor, is a potent and selective second-generation inhibitor of vascular endothelial growth factor receptor (VEGFR) 1, 2, and 3. This anti-angiogenic drug was found to have promising activity in various solid tumors, including advanced HCC. At present, however, there is no relevant review article that summarizes the exact roles of axitinib in advanced HCC. In this review, 24 eligible studies (seven studies in the ClinicalTrials, eight experimental studies, and nine clinical trials) were included for further evaluation. The included randomized or single-arm phase II trials indicated that axitinib could not prolong the overall survival compared to the placebo for the treatment of advanced HCC, but improvements in progression free survival and time to tumor progression were observed. Experimental studies showed that the biochemical effects of axitinib in HCC might be regulated by its associated genes and affected signaling cascades (e.g. VEGFR2/PAK1, CYP1A2, CaMKII/ERK, Akt/mTor, and miR-509-3p/PDGFRA). FDA approved sorafenib combined with nivolumab (an inhibitor of PD-1/PD-L1) as the first line regimen for the treatment of advanced HCC. Since both axitinib and sorafenib are tyrosine kinase inhibitors as well as the VEGFR inhibitors, axitinib combined with anti-PDL-1/PD-1 antibodies may also exhibit tremendous potential in anti-tumoral effects for advanced HCC. The present review highlights the current clinical applications and the molecular mechanisms of axitinib in advanced HCC. To move toward clinical applications by combining axitinib and other treatments in advanced HCC, more studies are still warranted in the near future.

Therapeutic sequencing in advanced renal cell carcinoma: How to choose considering clinical and biological factors

In the last fifteen years a better understanding of the biological processes promoting tumour growth and progression led to an impressive revolution in metastatic renal cell carcinoma (mRCC) treatment landscape. Angiogenesis plays a critical role in the pathogenesis of RCC. These biological evidences led to targeted therapies interfering with vascular endothelial growth factor and mammalian target of rapamycin pathway. Another big step in the RCC therapeutic landscape was recently made because of the understanding of the interplay between angiogenesis and immune cells. Dual immune checkpoint inhibitors (ICIs) and ICIs plus tyrosine kinase inhibitors (TKI) combinations have been approved considering overall survival benefit compared to targeted therapies as first line treatment. We summarize the activity and the biological rationale of ICIs combinations as mRCC first line therapy. Additionally, we review the clinical and biological criteria useful to guide clinicians in the choice of treatment sequencing focusing on ICIs combinations resistance mechanisms.

Pyrazoline Containing Compounds as Therapeutic Targets for Neurodegenerative Disorders

Pyrazolines are a significant class of heterocyclic compounds with essential biological activities. They are quite stable, which has inspired medicinal chemists to experiment with the ring's structure in many different ways to create a variety of pharmacological activities. The structures of numerous commercially available therapeutic agents contain a pyrazoline ring. Pyrazolines are well-known for their ability to treat neurodegenerative diseases. The neurodegenerative diseases that affect huge populations globally include Alzheimer's disease (AD), Parkinson's disease (PD), and psychiatric disorders. The neuroprotective properties of pyrazolines published since 2003 are covered in the current review. Structure-activity relationships (SARs), molecular docking simulation, anticholinesterase (anti-AChE), and monoamine oxidase (MAO A/B) inhibitory actions are all covered in this article. Pyrazolines were discovered to have beneficial effects in the management of AD and were revealed to be inhibitors of acetylcholine esterase (AChE) and beta-amyloid (Aβ) plaques. They were discovered to be efficient against PD and also targeted MAO B and COMT. It was discovered that the pyrazolines block MAO A to treat psychiatric diseases. Pyrazolines are significant heteroaromatic scaffolds with a variety of biological functions. They were discovered to be remarkably stable and serve as an indispensable anchor for the development of new drugs. By blocking AChE and MAOs, they may be used to treat neurodegenerative diseases. The discussion outlined here is an essential and helpful resource for medicinal chemists who are investigating and applying pyrazolines in neurodegenerative research initiatives as well as to expedite future research programs on neurodegenerative disorders.

Review of potential medical treatments for middle ear cholesteatoma

Middle ear cholesteatoma (MEC), is a destructive, and locally invasive lesion in the middle ear driven by inflammation with an annual incidence of 10 per 100,000. Surgical extraction/excision remains the only treatment strategy available and recurrence is high (up to 40%), therefore developing the first pharmaceutical treatments for MEC is desperately required. This review was targeted at connecting the dysregulated inflammatory network of MEC to pathogenesis and identification of pharmaceutical targets. We summarized the numerous basic research endeavors undertaken over the last 30+ years to identify the key targets in the dysregulated inflammatory pathways and judged the level of evidence for a given target if it was generated by in vitro, in vivo or clinical experiments. MEC pathogenesis was found to be connected to cytokines characteristic for Th1, Th17 and M1 cells. In addition, we found that the inflammation created damage associated molecular patterns (DAMPs), which further promoted inflammation. Similar positive feedback loops have already been described for other Th1/Th17 driven inflammatory diseases (arthritis, Crohn’s disease or multiple sclerosis). A wide-ranging search for molecular targeted therapies (MTT) led to the discovery of over a hundred clinically approved drugs already applied in precision medicine. Based on exclusion criteria designed to enable fast translation as well as efficacy, we condensed the numerous MTTs down to 13 top drugs. The review should serve as groundwork for the primary goal, which is to provide potential pharmaceutical therapies to MEC patients for the first time in history.

A review on synthetic strategy, molecular pharmacology of indazole derivatives, and their future perspective

With different nitrogen-containing heterocyclic moieties, Indazoles earn one of the places among the top investigated molecules in medicinal research. Indazole, an important fused aromatic heterocyclic system containing benzene and pyrazole ring with a chemical formula of C₇ H₆ N₂ , is also called benzopyrazole. Indazoles consist of three tautomeric forms in which 1H-tautomers (indazoles) and 2H-tautomers (isoindazoles) exist in all phases. The tautomerism in indazoles greatly influences synthesis, reactivity, physical and even the biological properties of indazoles. The thermodynamic internal energy calculation of these tautomers points view 1H-indazole as the predominant and stable form over 2H-indazole. The natural source of indazole is limited and exists in alkaloidal nature (i.e., nigellidine, nigeglanine, nigellicine, etc.) found from Nigella plants. Some of the FDA-approved drugs like Axitinib, Entrectinib, Niraparib, Benzydamine, and Granisetron are being used to treat renal cell cancer, non-small cell lung cancer (NSCLC), epithelial ovarian cancer, chronic inflammation, chemotherapy-induced nausea, vomiting, and many more uses. Besides all these advantages regarding its biological activity, the main issue about indazoles is the less abundance in plant sources, and their synthetic derivatives also often face problems with low yield. In this review article, we discuss its chemistry, tautomerism along with their effects, different schematics for the synthesis of indazole derivatives, and their different biological activities.

Population Pharmacokinetic Modeling of Lucitanib in Patients with Advanced Cancer

Background

Lucitanib is an oral, potent, selective inhibitor of the tyrosine kinase activity of vascular endothelial growth factor receptors 1‒3, fibroblast growth factor receptors 1‒3, and platelet-derived growth factor receptors alpha/beta.

Objective

We aimed to develop a population pharmacokinetics (PopPK) model for lucitanib in patients with advanced cancers.

Methods

PopPK analyses were based on intensive and sparse oral pharmacokinetic data from 5 phase 1/2 clinical studies of lucitanib in a total of 403 patients with advanced cancers. Lucitanib was administered at 5‒30 mg daily doses as 1 of 2 immediate-release oral formulations: a film-coated tablet or a hard gelatin capsule.

Results

Lucitanib pharmacokinetics were best described by a 2-compartment model with zero-order release into the dosing compartment, followed by first-order absorption and first-order elimination. Large between-subject pharmacokinetic variability was partially explained by body weight. No effects of demographics or tumor type on lucitanib pharmacokinetics were observed. The model suggested that the formulation impacted release duration (tablet, 0.243 h; capsule, 0.814 h), but the effect was not considered clinically meaningful. No statistically significant effects were detected for concomitant cytochrome P450 (CYP) 3A4 inhibitors or inducers, CYP2C8 or P-glycoprotein inhibitors, serum albumin, mild/moderate renal impairment, or mild hepatic impairment. Concomitant proton pump inhibitors had no clinically significant effect on lucitanib absorption.

Conclusions

The PopPK model adequately described lucitanib pharmacokinetics. High between-subject pharmacokinetic variability supports a safety-based dose-titration strategy currently being used in an ongoing clinical study of lucitanib to optimize drug exposure and clinical benefit.

Trial Registration

ClinicalTrials.gov Identifier: NCT01283945, NCT02053636, ISRCTN23201971, NCT02202746, NCT02109016.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13318-022-00773-w.

A Profile of Avelumab Plus Axitinib in the Treatment of Renal Cell Carcinoma

Until recently, the approved first-line treatment for metastatic RCC (mRCC) consisted of tyrosine kinase inhibitors (TKI) targeting the vascular endothelial growth factor receptors (VEGFR) monotherapy. The landscape of first-line treatment has been transformed in the last few years with the advent of immune checkpoint inhibitors (ICI) or VEGFR TKI plus ICI combinations. This article focuses on the profile of one of these ICI plus VEGFR TKI combination, avelumab plus axitinib. We detail the characteristics of each drug separately, and then we explore the rationale for their association, its efficacy and the resulting toxicity. Finally, we examine the factors associated with avelumab plus axitinib outcomes, and their impact on therapeutic strategy.

Inhibition of Axitinib on Buspirone Metabolism in vitro and in vivo

Objective

To evaluate the effect of axitinib on buspirone metabolism in vitro and in vivo.

Methods

A microsome incubation assay was performed to study the effect and mechanism of axitinib on buspirone metabolizing. In vivo, buspirone was administered with or without axitinib to Sprague–Dawley rats. Plasma samples were collected and subjected to ultra-performance liquid chromatography–tandem mass spectrometry.

Results

In both human liver microsomes (HLMs) and rat liver microsomes (RLMs), axitinib (100 μM) decreased buspirone hydroxylation and N-dealkylation by >85%. Axitinib inhibited buspirone hydroxylation and N-dealkylation, with an IC₅₀ of 15.76 and 9.74 for RLMs, and 10.63 and 9.902 for HLMs. Axitinib showed noncompetitive inhibition of both 6′-hydroxylation and N-dealkylation. Moreover, coadministration of axitinib and buspirone led to an increase in the maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC) of buspirone by 4.3- and 5.3-fold, respectively, compared with the control group.

Conclusion

Axitinib inhibited buspirone metabolism in vivo and in vitro, which increases the risk of the side effects of buspirone in the clinic. When coadministered with axitinib, a lower dosage of buspirone should be defined to avoid a toxic response. Axitinib is suspected to function as an inhibitor of CYP3A4.

Predicting Approximate Clinically Effective Doses in Oncology Using Preclinical Efficacy and Body Surface Area Conversion: A Retrospective Analysis

The correlation between efficacious doses in human tumor-xenograft mouse models and the human clinical doses of approved oncology agents was assessed using published preclinical data and recommended clinical doses. For 90 approved small molecule anti-cancer drugs, body surface area (BSA) corrected mouse efficacious doses were strongly predictive of human clinical dose ranges with 85.6% of the predictions falling within three-fold (3×) of the recommended clinical doses and 63.3% within 2×. These results suggest that BSA conversion is a useful tool for estimating human doses of small molecule oncology agents from mouse xenograft models from the early discovery stage. However, the BSA based dose conversion poorly predicts for the intravenous antibody and antibody drug conjugate anti-cancer drugs. For antibody-based drugs, five out of 30 (16.7%) predicted doses were within 3× of the recommended clinical dose. The body weight-based dose projection was modestly predictive with 66.7% of drugs predicted within 3× of the recommended clinical dose. The correlation was slightly better in ADCs (77.7% in 3×). The application and limitations of such simple dose estimation methods in the early discovery stage and in the design of clinical trials are also discussed in this retrospective analysis.

Naturally occurring, natural product inspired and synthetic heterocyclic anti-cancer drugs

This chapter describes the importance and activity of a huge number of commercially available naturally occurring, natural product derived or synthetic heterocyclic anti-cancer drugs.

A Novel Eye Drop Formulation for Potential Treatment of Neovascular Age-Related Macular Degeneration

Purpose

Drug delivery to posterior ocular tissues via topical eye drop administration is arduous due to the unique anatomy and physiology of the eye. Therefore, treatments for posterior eye disease have to be administered via intravitreal injection or systemic route, both of which have their drawbacks. Herein, the objective of this work was to demonstrate that a specially designed eye drop formulation could effectively deliver small-molecule vascular endothelial growth factor (VEGF) inhibitor to posterior ocular tissues for antiangiogenic therapy.

Methods

The unique eye drop formulation, termed ITRI AXN eye drops, was obtained from self-assembly of (2-hydroxypropyl)-β-cyclodextrin with a VEGF tyrosine kinase inhibitor, a hydrophilic polymer, hypromellose, and a complex stabilizer, caffeine. In vivo ocular pharmacokinetics studies were performed with New Zealand White (NZW) rabbits and Non Human Primates (NHP). The antiangiogenesis effect was evaluated on the Long-Evans rat with laser-induced choroidal neovascularization and pigmented Dutch-Belted rabbits with VEGF-induced retinal neovascularization.

Results

The successful drug transport from ocular surface to posterior ocular cavity was indicated by a drug biodistribution pattern in pharmacokinetic studies. Excellent drug exposure in the choroid and retina with the concentrations of 900- and 750-fold greater than drug IC50 0.5 hours post the eye drop administration (drug level: 0.8%) was observed on the NHP study. The obtained formulation also demonstrated a comparable antiangiogenic outcome with the intravitreal injection of anti-VEGF antibody on rat and rabbit disease models.

Conclusions

Our eye drop formulation has demonstrated great promise in antiangiogenic therapy against retinal and choroidal neovascularization in animal models. The results suggest that the aim of this work can be successfully achieved by the novel eye drop formulation.

Translational Relevance

The preclinical results provide evidence that ITRI AXN eye drops could effectively deliver therapeutics to the choroid and retina for antiangiogenic therapy.

Antiangiogenic Therapy in Clear Cell Renal Carcinoma (CCRC): Pharmacological Basis and Clinical Results

Simple Summary

In the last 15 years, a deep improvement in the knowledge regarding the biological mechanisms responsible for neoplastic cell development and progression has led to a dramatic change in the treatment landscape of metastatic clear cell renal carcinoma. Nowadays, it is known that neo-angiogenesis is a key player in tumor growth and metastatic spread. In particular, the crucial role of the mutation of the von Hippel–Lindau (VHL) tumor suppressor gene, leading to angiogenesis through the transcription of multiple pro-angiogenic factors, is clearly recognized. On the basis of this biological evidence, three classes of targeted therapies with antiangiogenetic activity have received approval for the treatment of advanced disease: tyrosine kinase inhibitors (TKIs); a monoclonal antibody that interferes with vascular endothelial growth factor (VEGF); and two mammalian target of rapamycin (mTOR) inhibitors. These drugs showed impressive results in terms of progression-free survival and objective response rate. In addition, a “second therapeutic revolution” has recently started, due to the latest information on the immunogenic characteristics of renal cell carcinoma and the interplay between angiogenesis and immune surveillance systems. Consequently, immune checkpoint inhibitors, alone or in combination with TKIs, have been approved. In this review, we analyze the pharmacological characteristics and activity of antiangiogenic drugs approved for the treatment of metastatic clear cell renal carcinoma.

Abstract

Angiogenesis has a direct stimulatory effect on tumor growth, duplication, invasion and metastatic development. A significant portion of conventional renal cell carcinomas are angiogenesis-dependent tumors and the pathways supporting this process have been thoroughly investigated over the last 20 years. As a consequence, many tyrosine kinase inhibitors (TKIs) (sunitinib, sorafenib, pazopanib, axitinib, and cabozantinib), one monoclonal antibody (bevacizumab), and two mammalian target of rapamycin (mTOR) inhibitors (temsirolimus and everolimus) have been investigated and approved for the treatment of advanced or metastatic clear cell renal carcinoma (metastatic CCRC) in first-line, as well as second-line, therapy, with impressive results in progression-free survival and in the objective response rate compared with previously available therapies or placebo. Recently, a new type of drug has been approved for metastatic CCRC: immunomodulatory checkpoint inhibitors (ICIs), alone or in combination with TKIs. However, many questions and areas to be explored still remain with regard to clear cell renal carcinoma (CCRC) treatment: research on predictive biomarkers, the best patient selection, how to overcome the mechanisms of resistance, and the best sequence of therapies in daily clinical practice. This review focuses on the pharmacological properties and anticancer activities of these drugs. The toxicity profile and clinical limitations of these therapies are also discussed.

Clinical Factors Associated With Long-Term Benefit in Patients With Metastatic Renal Cell Carcinoma Treated With Axitinib: Real-World AXILONG Study

BACKGROUND

Axitinib monotherapy obtained approval in pre-treated mRCC patients and recently in combination with pembrolizumab or avelumab in the first-line setting. However, patient profiles that may obtain increased benefit from this drug and its combinations still need to be identified.

PATIENTS AND METHODS

Retrospective multicentre analysis describing clinical characteristics associated with axitinib long-responder (LR) population by comparing two extreme-response sub-groups (progression-free survival [PFS] ≥9 months vs. disease progression/refractory patients [RP]). A multivariate logistic-regression model was used to analyse clinical factors. Efficacy and safety were also analysed.

RESULTS

In total, 157 patients who received axitinib in second or subsequent line were evaluated (91 LR and 66 RP). Older age at start of axitinib and haemoglobin levels > LLN were independent predictive factors for LR in multivariate analyses. In LR patients, median (m) PFS was 18.1 months, median overall survival was 36.0 months and objective response rate (ORR) was 45.5%. In 59 LR patients receiving axitinib in second-line, mPFS was 18.7 months, mOS was 44.8 months and ORR was 43.9%. mOS was significantly longer in second line compared to subsequent lines (44.8 vs. 26.5 months; P = .009). In LR vs. RP, mPFS with sunitinib in first-line was correlated with mPFS with axitinib in second-line (27.2 vs. 10.9 months P < .001). The safety profile was manageable and consistent with known data.

CONCLUSIONS

This study confirms the long-term benefits of axitinib in a selected population, helping clinicians to select the best sequential approach and patients who could obtain a greater benefit from axitinib.

Model-based comparative analysis of rifampicin and rifabutin drug-drug interaction profile

Rifamycins are widely used for treating mycobacterial and staphylococcal infections. Drug-drug interactions (DDI) caused by rifampicin (RIF) is a major issue. We used a model-based approach to predict the magnitude of DDI with RIF and rifabutin (RBT) for 217 cytochrome P450 (CYP) substrates. On average, DDI caused by low-dose RIF were twice more potent than those caused by RBT. Contrary to RIF, RBT appears unlikely to cause severe DDI, even with sensitive CYP substrates.

Pyrazole ring-containing isolongifolanone derivatives as potential CDK2 inhibitors: Evaluation of anticancer activity and investigation of action mechanism

Isolongifolanone is a high value-added sustainable natural product. Recent studies have demonstrated that isolongifolanone possesses anticancer activities. In this study, a series of novel pyrazole ring-containing isolongifolanone derivatives was designed, synthesized, and their anti-proliferative activities in three cancer cell lines were evaluated. Among them, compound 3b exhibited strongest antiproliferative ability on MCF-7 cancer cells and induced the generation of intracellular ROS and mitochondrial depolarization. More importantly, compound 3b still maintained antitumor activity in MCF-7 3D culture systems. The study on molecular mechanism suggested that compound 3b induced apoptosis via activation of caspase-3 and PARP, also via decreasing of Bcl-2 and increasing of Bax and p53. Moreover, compound 3b down-regulated the level of CDK2, a crucial cyclin-dependent kinase which is necessary for the progression of the cells out of the G1 phase of the cell cycle. Docking results showed that compound 3b could bind well with CDK2 by forming hydrogen bonds with amino acid residues (LYS89 and HIS84). These results suggested that compound 3b could be taken as a lead compound for anticancer agents.

Pembrolizumab plus axitinib for the treatment of advanced renal cell carcinoma

Introduction: The dominant paradigm of sequential therapy of metastatic renal cell carcinoma (mRCC) with single agents has recently been challenged by improved outcomes obtained with combined regimens with immune checkpoint inhibitors. These combined regimens include the combination of pembrolizumab plus axitinib.Areas covered: Here, we provide a brief overview of the current clinical data on the pembrolizumab plus axitinib combination including mechanism of action, pharmacokinetics, efficacy and safety profile.Expert opinion: Both agents targeting the vascular endothelial growth factor (VEGF) pathway and immune checkpoint inhibitors are active as single agents in mRCC. Improved outcomes have been demonstrated in phase 3 trials in comparison with sunitinib for the combinations of axitinib plus pembrolizumab, axitinib plus avelumab, bevacizumab plus atezolizumab, and ipilimumab plus nivolumab. Among these combinations, an OS benefit has, so far, demonstrated only for the combinations of axitinib with pembrolizumab and ipilimumab with nivolumab. Although there are currently no prospective data comparing the combination of ipilimumab and nivolumab with the combination of immune checkpoint inhibitors and VEGF inhibitors, currently available retrospective analyses indicate that these two approaches achieve comparable outcomes.

Symptomatic methemoglobinemia in a patient with metastatic clear cell renal cell carcinoma treated with pembrolizumab and axitinib combination therapy: a case report

Background

Combination regimens that include immune checkpoint (ICI) and vascular endothelial growth factor (VEGF) inhibition have opened the door to new treatment opportunities for patients with metastatic renal cell carcinoma (mRCC). While these treatment options have provided improved tolerability and better outcomes compared to older regimens, many patients still experience a myriad of treatment-related adverse events. Given that these regimens were recently approved for mRCC, the complete side effect profile may not be fully elucidated yet.

Case presentation

We report a case of a 73-year old White male with mRCC who was managed with an ICI-VEGF inhibitor combination regimen. He experienced a partial response (Fig. 1) but had side effects including symptomatic cyanosis diagnosed as methemoglobinemia which led to treatment discontinuation. Upon holding his therapy, his methemoglobinemia and cyanosis resolved.

Conclusions

Combination VEGF-ICI therapy provide novel regimens for advanced solid tumor malignancies including mRCC. While shown to have improved efficacy in clinical trials, it is crucial that oncologists uncover the full side effect profile of these novel agents especially as their use becomes more standard in the management of advanced malignancies. To our knowledge, this is the first reported case of a patient experiencing symptomatic methemoglobinemia as an adverse event associated with a VEGF-ICI combination regimen. While the cause of this side effect is unclear, in this paper we attempt to elucidate a process that is in line with the mechanism of action of these therapies to explain how these agents, specifically the axitinib, could have caused the methemoglobin to rise to a symptomatic level.

Optimized Combination of HDACI and TKI Efficiently Inhibits Metabolic Activity in Renal Cell Carcinoma and Overcomes Sunitinib Resistance

Clear cell renal cell carcinoma (ccRCC) is characterized by high histone deacetylase (HDAC) activity triggering both cell motility and the development of metastasis. Therefore, there is an unmet need to establish innovative strategies to advance the use of HDAC inhibitors (HDACIs). We selected a set of tyrosine kinase inhibitors (TKIs) and HDACIs to test them in combination, using the validated therapeutically guided multidrug optimization (TGMO) technique based on experimental testing and in silico data modeling. We determined a synergistic low-dose three-drug combination decreasing the cell metabolic activity in metastatic ccRCC cells, Caki-1, by over 80%. This drug combination induced apoptosis and showed anti-angiogenic activity, both in original Caki-1 and in sunitinib-resistant Caki-1 cells. Through phosphoproteomic analysis, we revealed additional targets to improve the translation of this combination in 3-D (co-)culture systems. Cell-cell and cell-environment interactions increased, reverting the invasive and metastatic phenotype of Caki-1 cells. Our data suggest that our optimized low-dose drug combination is highly effective in complex in vitro settings and promotes the activity of HDACIs.

Absorption of the orally active multikinase inhibitor axitinib as a therapeutic index to guide dose titration in metastatic renal cell carcinoma

Purpose Axitinib is an orally active multikinase inhibitor currently used to treat patients with metastatic renal cell carcinoma (RCC). This study examined the pharmacokinetics of axitinib and the relationship between peak drug concentration (C_max) and clinical outcomes in real-world practice. Methods Twenty patients with metastatic RCC treated with axitinib monotherapy were enrolled. Post-dose (1-4 h) blood samples were obtained, and axitinib C_max in plasma was measured by liquid chromatography-tandem mass spectrometry. Efficacy endpoints were best overall response (per RECIST 1.1) and progression-free survival (PFS). The safety endpoint was the cumulative incidence of dose-limiting toxicities (DLTs). Results Large inter- and intra-individual variability in dose-adjusted C_max was observed (0.02-11.2 ng/mL/mg). Axitinib absorption was significantly influenced by glucuronidation activity (P = 0.040). C_max at steady state was significantly higher in responders than in non-responders (P = 0.013). The optimal C_max cutoff to predict a clinical response was 12.4 ng/mL. The median PFS was significantly longer in patients who achieved an average steady state C_max above the threshold than in those who did not (799 vs. 336 days; P = 0.047). The cumulative incidence of DLTs was significantly higher in patients with C_max ≥ 40.2 ng/mL than in other patients (sub-hazard ratio, 4.13; 95% confidence interval, 1.27-13.5; P = 0.019). Conclusions The potential therapeutic window of axitinib C_max in metastatic RCC was estimated at 12.4-40.2 ng/mL. Pharmacokinetically guided dose titration using therapeutic drug monitoring may improve the efficacy and safety of axitinib, warranting further investigation in a larger patient population.

Pembrolizumab plus axitinib combination and the paradigm change in the treatment of advanced renal cell carcinoma

Sequential administration of single targeted agents has been challenged as the dominant treatment paradigm in patients with metastatic renal cell carcinoma by improved outcomes obtained with combination regimens based on immune checkpoint inhibitors. Most patients treated with sequential monotherapy eventually develop drug resistance and succumb to progressive disease, leading to the search for therapies that would overcome drug resistance and result in a more durable treatment response. Improved outcomes have been demonstrated in Phase III trials in comparison with sunitinib for the combinations of axitinib plus pembrolizumab, axitinib plus avelumab, bevacizumab plus atezolizumab and ipilimumab plus nivolumab. A statistically significant improvement of both progression-free and overall survival has been demonstrated for the axitinib plus pembrolizumab combination.

Recent advancements in the development of bioactive pyrazoline derivatives

Pyrazolines remain privileged heterocycles in drug discovery. 2-Pyrazoline scaffold has been proven as a ubiquitous motif which is present in a number of pharmacologically important drug molecules such as antipyrine, ramifenazone, ibipinabant, axitinib etc. They have been widely explored by the scientific community and are reported to possess wide spectrum of biological activities. For combating unprecedented diseases and worldwide increasing drug resistance, 2-pyrazoline has been tackled as a fascinating pharmacophore to generate new molecules with improved potency and lesser toxicity along with desired pharmacokinetic profile. This review aims to summarizes various recent advancements in the medicinal chemistry of pyrazoline based compounds with the following objectives: (1) To represent inclusive data on pyrazoline based marketed drugs as well as therapeutic candidates undergoing preclinical and clinical developments; (2) To discuss recent advances in the medicinal chemistry of pyrazoline derivatives with their numerous biological significances for the eradication of various diseases; (3) Summarizes structure-activity relationships (SAR) including in silico and mechanistic studies to afford ideas for the design and development of novel compounds with desired therapeutic implications.

Nanotechnology for angiogenesis: opportunities and challenges

Angiogenesis plays a critical role within the human body, from the early stages of life (i.e., embryonic development) to life-threatening diseases (e.g., cancer, heart attack, stroke, wound healing). Many pharmaceutical companies have expended huge efforts on both stimulation and inhibition of angiogenesis. During the last decade, the nanotechnology revolution has made a great impact in medicine, and regulatory approvals are starting to be achieved for nanomedicines to treat a wide range of diseases. Angiogenesis therapies involve the inhibition of angiogenesis in oncology and ophthalmology, and stimulation of angiogenesis in wound healing and tissue engineering. This review aims to summarize nanotechnology-based strategies that have been explored in the broad area of angiogenesis. Lipid-based, carbon-based and polymeric nanoparticles, and a wide range of inorganic and metallic nanoparticles are covered in detail. Theranostic and imaging approaches can be facilitated by nanoparticles. Many preparations have been reported to have a bimodal effect where they stimulate angiogenesis at low dose and inhibit it at higher doses.

Axitinib plus immune checkpoint inhibitor: evidence- and expert-based consensus recommendation for treatment optimisation and management of related adverse events

With the recent approval of the combinations of axitinib with the immune checkpoint inhibitor (ICI) pembrolizumab or avelumab for first-line treatment of advanced renal cell carcinoma, guidance on how to distinguish between immune-related adverse events (AEs) caused by ICI versus axitinib-related AEs is necessary to optimise therapy with axitinib–ICI combinations. The recommendations here are based on (1) systematic review of published evidence, (2) discussion among experts in the field and (3) a survey to obtain expert consensus on specific measures for therapy management with the combinations axitinib/avelumab and axitinib/pembrolizumab. The experts identified areas of AEs requiring unique management during treatment with axitinib–ICI combinations that were not covered by current recommendations. Diarrhoea, hepatic toxicity, fatigue and cardiovascular AEs were found to be applicable to such specialised management. Triage between immune-suppressive and supportive measures is a key component in therapy management. Clinical monitoring and experience with both classes of agents are necessary to manage this novel therapeutic approach. We focused on AEs with an overlap between axitinib and ICI therapy. Our recommendations address AE management of axitinib–ICI combinations with the aim to improve the safety of these therapies.

Decreased Disposition of Anticancer Drugs Predominantly Eliminated via the Liver in Patients with Renal Failure

Background:

Evidence has revealed that renal impairment can affect the systemic exposure of drugs which are predominantly eliminated via the liver. The modulation of drug-metabolizing enzymes and transporters expressed in the liver and/or small intestine by diverse entities, including uremic toxins, in systemic circulation of patients with severe renal failure is considered as the cause of atypical pharmacokinetics, which sometimes induce undesirable adverse events that are especially critical for drugs with narrow therapeutic window such as anticancer drugs. A dosing strategy for anticancer drugs in these patients needs to be established.

Methods:

The effects of renal impairment on the systemic exposure and safety of anticancer drugs were summarized. The proposed mechanisms for the alterations in the pharmacokinetics of these anticancer drugs were also discussed.

Results:

Changes in pharmacokinetics and clinical response were reported in 9 out of 10 cytotoxic anticancer drugs investigated, although available information was limited and sometimes controversial. Systemic exposure of 3 out of 16 tyrosine kinase inhibitors was higher in patients with severe renal failure than that in patients with normal kidney function. An increase in systemic exposure of anticancer drugs in patients with renal impairment is likely to be observed for substrates of OATP1B1, despite the limited evidence.

Conclusion:

The molecular basis for the effect of uremia on non-renal drug elimination still needed to be clarified with further studies to generate generalizable concepts, which may provide insights into establishing better clinical usage of anticancer drugs, i.e. identifying patients at risk and dose adjustment.

IL-10 knockdown with siRNA enhances the efficacy of Doxorubicin chemotherapy in EBV-positive tumors by inducing lytic cycle via PI3K/p38 MAPK/NF-kB pathway

High levels of IL-10 expression in Epstein-Barr virus (EBV) associated tumors have been reported and it is likely to be important for maintaining EBV latency and EBV-associated tumors. The switch from the latent form of EBV to the lytic form in tumor cells can lead to tumor cell lysis. Here, we found that knockdown of IL-10 induced EBV lytic replication. Subsequently, we demonstrated that IL-10 knockdown activated BZLF1 promoter through PI3K-p38 MAPK-NF-κB signaling pathway. Interestingly, we verified that VEGF-A was required for IL-10 knockdown to activate PI3K signaling and the accompanying EBV lytic induction. Exogenous recombinant human VEGF-A induced PI3K activation and EBV lytic infection, and inhibition of VEGF-A signaling prevented the PI3K/AKT phosphorylation and EBV reactivation responded to IL-10 knockdown. Most importantly, IL-10 knockdown synergized with chemotherapeutic agent Doxorubicin to kill EBV associated tumor cells in vitro and repress EBV-positive tumor growth in vivo. Our results suggest that inhibition of IL-10 has the potential to serve as a new supplemental strategy for the treatment of EBV-associated tumors.

Investigation of the effects of axitinib on the pharmacokinetics of loperamide and its main metabolite N-demethylated loperamide in rats by UPLC-MS/MS

The epidemic of loperamide abuse and misuse in the patients for the alternative to opioids has become an increasing worldwide concern and has led to considerations about the potential for drug-drug interactions between loperamide and other combined drugs, especially inhibitors of cytochrome P450 (CYP450) enzymes, such as axitinib. This study assessed the effects of axitinib on the metabolism of loperamide and its main metabolite N-demethylated loperamide in rats and in rat liver microsomes (RLM), human liver microsomes (HLM) and recombinant human CYP3A4*1. The concentrations of both compounds were determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The exposures (AUC_(0-t), AUC_(0-∞) and C_max) of loperamide and N-demethylated loperamide showed a conspicuous increase when loperamide was co-administered with axitinib. The T_max of loperamide increased while CLz/F decreased under the influence of axitinib. In vitro, axitinib inhibited loperamide metabolism with the IC₅₀ of 18.34 μM for RLM, 1.705 μM for HLM and 1.604 μM for CYP3A4*1, and it was confirmed as a non-competitive inhibitor in all enzymes. Taken together, the results indicated that axitinib had an obvious inhibitory impact on loperamide metabolism both in vivo and in vitro. Thus, more attention should be paid to the concurrent use of loperamide and axitinib to reduce the risk of unexpected clinical outcomes.

Interaction between phytotherapy and oral anticancer agents: prospective study and literature review

Cancer is becoming more prevalent in elderly patient. Due to polypharmacy, older adults with cancer are predisposed to drug-drug interactions. There is also an increasing interest in the use of complementary and alternative medicine (CAM). Thirty to seventy percent of patients with cancer have used CAM. Through pharmaceutical counseling sessions, we can provide advices on herb-drug interactions (HDI). All the patients seen in pharmaceutical counseling sessions were prospectively included. Information was collected during these sessions: prescribed medication (oral anticancer agents (OAA) and other drugs), CAM (phytotherapy especially), and use of over-the-counter (OTC) drugs. If pharmacist considered an interaction or an intervention clinically relevant, the oncologist was notified. Then, a literature review was realized to identify the potential HDI (no interactions, precautions for use, contraindication). Among 201 pharmacist counseling sessions, it resulted in 104 interventions related to 46 HDI, 28 drug-drug interactions and 30 others (wrong dosage, omission…). To determine HDI, we review 73 medicinal plants which are used by our patients with cancer and 31 OAA. A total of 1829 recommendations were formulated about 59 (75%) medical plants and their interaction with an OAA. Herb-drug interactions should not be ignored by healthcare providers in their management of cancer patients in daily practice.

A study of axitinib, a VEGF receptor tyrosine kinase inhibitor, in children and adolescents with recurrent or refractory solid tumors: A Children's Oncology Group phase 1 and pilot consortium trial (ADVL1315)

BACKGROUND

Axitinib is an oral small molecule that inhibits receptor tyrosine kinases vascular endothelial growth factor receptors 1 to 3. A phase 1 and pharmacokinetic (PK) trial evaluating axitinib was conducted in children with refractory solid tumors.

METHODS

Axitinib was administered orally twice daily in continuous 28-day cycles. Dose levels (2.4 mg/m2 /dose and 3.2 mg/m2 /dose) were evaluated using a rolling 6 design. Serial PKs (cycle 1, days 1 and 8) and exploratory biomarkers were analyzed.

RESULTS

A total of 19 patients were enrolled; 1 patient was ineligible due to inadequate time having elapsed from prior therapy. The median age of the patients was 13.5 years (range, 5-17 years). Two of 5 patients who were treated at dose level 2 experienced dose-limiting toxicities (palmar-plantar erythryodysesthesia syndrome in 1 patient and intratumoral hemorrhage in 1 patient). Frequent (>20%) grade 1 to 2 toxicities during cycle 1 included anemia, anorexia, fatigue, diarrhea, nausea, and hypertension. Nonhematological toxicities of grade ≥3 in subsequent cycles included hypertension and elevated serum lipase. PK analysis demonstrated variability in axitinib exposure, the median time to peak plasma concentration was 2 hours, and the half-life ranged from 0.7 to 5.2 hours. Exposure and dose were not found to be significantly associated with hypertension. Five patients achieved stable disease for ≤6 cycles as their best response, including patients with malignant peripheral nerve sheath tumor (1 patient), Ewing sarcoma (1 patient), hepatocellular carcinoma (1 patient), and osteosarcoma (2 patients). One patient with alveolar soft part sarcoma achieved a partial response. Kidney injury biomarkers were found to be elevated at baseline; no trends were identified.

CONCLUSIONS

In children with refractory solid tumors, the maximum tolerated and recommended dose of axitinib appears to be 2.4 mg/m2 /dose, which provides PK exposures similar to those of adults.

Dynamic 18F-FLT PET imaging of spatiotemporal changes in tumor cell proliferation and vasculature reveals the mechanistic actions of anti-angiogenic therapy

Anti-angiogenic therapies target tumor vasculature and tumor cells, thus a concurrent assessment of these targets would lead to a greater understanding of therapeutic resistance and facilitate development of improved therapeutic strategies. We utilize dynamic 3'-deoxy-3'-¹⁸F-fluorothymidine positron emission tomography (¹⁸F-FLT PET) scanning to concurrently assess changes in tumor cell proliferation and vasculature during anti-angiogenic therapy, providing insight into how these therapies may be used effectively with combination chemotherapy. Thirty-three patients with advanced solid malignancies underwent treatment with vascular endothelial growth factor receptor inhibitor (VEGFR-TKI) axitinib on an intermittent schedule (two-weeks-on/one-week-off). Patients had up to three dynamic ¹⁸F-FLT PET/CT scans: at baseline, after two weeks of continuous VEGFR-TKI treatment, and following a one week treatment break. ¹⁸F-FLT kinetics were analyzed using a two-tissue compartment kinetic model. Kinetic parameters V _b and K ₁ were extracted to quantify changes in tumor vasculature and the ¹⁸F-FLT flux constant K _i was calculated to quantify changes in tumor cell proliferation. Two weeks of continuous axitinib exposure led to decreases in V _b (median -21%, P  =  0.07), K ₁ (median -39%, P  <  0.01), and K _i (median -37%, P  <  0.01), corresponding to diminished tumor vasculature and cell proliferation that may antagonize treatment with concurrent chemotherapy. Axitinib treatment breaks led to significant increases in V _b (median  +42%, P  <  0.01), K ₁ (median  +46%, P  <  0.01), and K _i (median  +39%, P  <  0.01) that is suggestive of an optimal time to schedule synergistic chemotherapy. Significant negative correlations (rho  ⩽  -0.70, P  <  0.01) were found between changes in tumor vasculature during axitinib exposure weeks and changes in tumor vasculature during treatment breaks. Imaging with dynamic ¹⁸F-FLT PET revealed new insights relating to the interplay of vascular and proliferative pharmacodynamics of axitinib therapy, facilitating a greater understanding of the mechanistic actions of VEGFR-TKIs. Increases in tumor vasculature and cell proliferation during VEGFR-TKI treatment breaks, suggests this period is an optimal time to schedule synergistic chemotherapy and warrants further investigation.