Bosutinib: a review of its use in patients with Philadelphia chromosome-positive chronic myelogenous leukemia

Bosutinib: Pediatric First Approval

Bosutinib (BOSULIF®), an orally administered BCR-ABL tyrosine kinase inhibitor (TKI) developed by Pfizer Inc., is well established in the EU and the USA as a treatment for adults with newly diagnosed (ND) chronic phase (CP) Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia (CML), and for CP, accelerated phase and blast phase Ph+ CML that is resistant or intolerant (R/I) to prior therapy. In September 2023, based on clinical data from patients aged ≥ 1 to < 18 years, bosutinib was approved in the USA for the treatment of pediatric patients aged ≥ 1 year with CP Ph+ CML that is ND or R/I to prior therapy. This article summarizes the milestones in the development of bosutinib leading to this first pediatric approval.

Current Progress on the Influence Human Genetics Has on the Efficacy of Tyrosine Kinase Inhibitors Used to Treat Chronic Myeloid Leukemia

The use of tyrosine kinase inhibitors (TKIs) has become the mainstay of treatment in patients suffering from chronic myeloid leukemia (CML), an adult leukemia caused by a reciprocal translocation between chromosomes 9 and 22, which creates an oncogene resulting in a myeloproliferative neoplasm. These drugs function by inhibiting the ATP-binding site on the fusion oncoprotein and subsequently halting proliferative activity. The goal of this work is to investigate the current state of research into genetic factors that influence the efficacy of four FDA-approved TKIs used to treat CML. This overview attempts to identify genetic criteria that could be considered when choosing one drug over the others and to identify where more research is needed. Our results suggest that the usual liver enzymes impacting patient response may not be a major factor affecting the efficacy of imatinib, nilotinib, and bosutinib, and yet, that is where most of the past research has focused. More research is warranted on the impact that human polymorphisms of the CYP enzymes have on dasatinib. The impact of polymorphisms in UGT1A1 should be investigated thoroughly in other TKIs, not only nilotinib. The role of influx and efflux transporters has been inconsistent thus far, possibly due to failures to account for the multiple proteins that can transport TKIs and the impact that tumors have on transporter expression. Because physicians cannot currently use a patient's genetic profile to better target their treatment with TKIs, it is critical that more research be conducted on auxiliary pathways or off-target binding effects to generate new leads for further study. Hopefully, new avenues of research will help explain treatment failures and improve patient outcomes.

Can pharmacy students use Wikipedia as a learning resource? Critical assessment of articles on chemotherapeutic drugs

Pharmacy students tend to use Wikipedia as a quick resource of knowledge. This study aimed to evaluate the accuracy of content and readability level of Wikipedia articles on chemotherapeutics, using quality and readability tools. Using the British National Formulary (BNF-2018) and ClinicalTrials.gov, we identified 188 chemotherapeutic drugs. We randomly selected 100 drugs with an Excel randomization program. The English Wikipedia was searched for the selected 100 drugs, and prints of the identified articles were obtained. Readability was calculated with an online instrument (http://www.readabilityformulas.com/). Articles were independently scored by two researchers using the modified DISCERN tool for content assessment. The modified DISCERN scores had a median value of 24 [interquartile range (IQR) = 7.5]. Two articles (2%) had good quality (DISCERN score 36-40), thirty-eight (38%) were moderate (DISCERN 26-35), and sixty (60%) were poor in score (DISCERN ≤25). The articles covered drug indications and most side effects. However, the majority lacked information on the routes of administration, contraindications, pharmacokinetics, and mechanisms of action. We found a correlation between DISCERN scores and number of edits (P value = 0.00033, R² = 0.1238). The number of references varied from 2 to 150 (median= 17, IQR = 17). Several problems were identified in the lists of references and citations. Most articles lacked tables and figures. The readability of the articles was 14.35 ± 3.13, consistent with the readability level of university students. In conclusion, the Wikipedia articles on chemotherapeutic drugs were not written for professional pharmacy students. Although they matched the expected readability level of university students, most were incomplete and lacked essential information.NEW & NOTEWORTHY Pharmacy students use Wikipedia as a quick resource of knowledge. However, Wikipedia articles are not written for professional pharmacy students. The study shows that although Wikipedia articles on chemotherapeutic drugs matched the expected readability level of university students, most needed to be completed and lacked essential information.

Application of drug–metal ion interaction principle in conductometric determination of imatinib, sorafenib, gefitinib and bosutinib

An analytical method for the quantification of anticancer agents such as imatinib, sorafenib, gefitinib and bosutinib using conductometry was developed. Each drug solution was mixed with measured concentration of metal ion (Cu2+) solution resulting in drug–metal ion complexation in the titration cell. Conductance was progressively decreased on addition of the analyte solution up to a point of maximum reduction, that is, the end point. Corrected conductance values were calculated from the observed conductance and used to plot a graph against the volume of drug solution added. No interferences were observed from blank and placebo as they gave no clear inflection in the conductivity during titration. The precision and the accuracy of the developed method was established by the analysis of quality control samples; %RSD of corrected conductance values <2% and recovery results within 100 ± 2% were achieved. The calibration graphs obtained were linear over the concentrations 1.0–1.4 mM for all the drugs (R2 > 0.99). The drugs were successfully analyzed in their respective dosage forms prepared in-house. The method has offered easier, faster and cost-effective analysis of the selected drugs and can be used for routine determinations in the quality control laboratories. More importantly, it is an environmental friendly procedure, as no organic solvent was used throughout the analysis.

Application of Physiologically Based Pharmacokinetic Modeling in Understanding Bosutinib Drug-Drug Interactions: Importance of Intestinal P-Glycoprotein

Bosutinib is an orally available Src/Abl tyrosine kinase inhibitor indicated for the treatment of patients with Ph+ chronic myelogenous leukemia at a clinically recommended dose of 500 mg once daily. Clinical results indicated that increases in bosutinib oral exposures were supraproportional at the lower doses (50-200 mg) and approximately dose-proportional at the higher doses (200-600 mg). Bosutinib is a substrate of CYP3A4 and P-glycoprotein and exhibits pH-dependent solubility with moderate intestinal permeability. These findings led us to investigate the factors influencing the underlying pharmacokinetic mechanisms of bosutinib with physiologically based pharmacokinetic (PBPK) models. Our primary objectives were to: 1) refine the previously developed bosutinib PBPK model on the basis of the latest oral bioavailability data and 2) verify the refined PBPK model with P-glycoprotein kinetics on the basis of the bosutinib drug-drug interaction (DDI) results with ketoconazole and rifampin. Additionally, the verified PBPK model was applied to predict bosutinib DDIs with dual CYP3A/P-glycoprotein inhibitors. The results indicated that 1) the refined PBPK model adequately described the observed plasma concentration-time profiles of bosutinib and 2) the verified PBPK model reasonably predicted the effects of ketoconazole and rifampin on bosutinib exposures by accounting for intestinal P-glycoprotein inhibition/induction. These results suggested that bosutinib DDI mechanism could involve not only CYP3A4-mediated metabolism but also P-glycoprotein-mediated efflux on absorption. In summary, P-glycoprotein kinetics could constitute an element in the PBPK models critical to understanding the pharmacokinetic mechanism of dual CYP3A/P-glycoprotein substrates, such as bosutinib, that exhibit nonlinear pharmacokinetics owing largely to a saturation of intestinal P-glycoprotein-mediated efflux.

Risk of Infectious Complications in Hemato-Oncological Patients Treated with Kinase Inhibitors

Infectious complications are a major cause of morbidity and mortality in patients with hemato-oncological diseases. Although disease-related immunosuppression represents one factor, aggressive treatment regimens, such as chemotherapy, stem cell transplantation, or antibody treatment, account for a large proportion of infectious side effects. With the advent of targeted therapies affecting specific kinases in malignant diseases, the outcome of patients has further improved. Nonetheless, dependent on the specific pathway targeted or off-target activity of the kinase inhibitor, therapy-associated infectious complications may occur. We review the most common and approved kinase inhibitors targeting a variety of hemato-oncological malignancies for their immunosuppressive potential and evaluate their risk of infectious side effects based on preclinical evidence and clinical data in order to raise awareness of the potential risks involved.

Bcr-Abl tyrosine kinase inhibitors: a patent review

INTRODUCTION

Breakpoint cluster region Abelson (Bcr-Abl) tyrosine kinase (TK) is a constitutively activated cytoplasmic TK and is the underlying cause of chronic myeloid leukemia (CML). To date, imatinib represents the frontline treatment for CML therapy. The development of resistance has prompted the search for novel Bcr-Abl inhibitors.

AREAS COVERED

This review presents a short overview of drugs already approved for CML therapy and of the compounds that are in clinical trials. The body of the article deals with Bcr-Abl inhibitors patented since 2008, focusing on their chemical features.

EXPERT OPINION

The search for Bcr-Abl inhibitors is very active. We believe that a number of patented compounds could enter clinical trials and some could be approved for CML therapy in the next few years. Overall, Bcr-Abl inhibitors constitute a very appealing research field that can be expected to expand further.

Synergism between bosutinib (SKI-606) and the Chk1 inhibitor (PF-00477736) in highly imatinib-resistant BCR/ABL⁺ leukemia cells

Interactions between the dual BCR/ABL and Src inhibitor bosutinib and the Chk1 inhibitor PF-00477736 were examined in BCR/ABL(+) leukemia cells, particularly imatinib-resistant cells, including those with the T315I mutation. Bosutinib blocked PF-00477736-induced ERK1/2 activation and sharply increased apoptosis in association with Mcl-1 inhibition, p34(cdc2) dephosphorylation, BimEL up-regulation, and DNA damage in imatinib-resistant CML or Ph(+) ALL cell lines. Inhibition of Src or MEK1 by shRNA significantly enhanced PF-0047736 lethality. Bosutinib/PF-00477736 co-treatment also potentiated cell death in CD34(+) CML patient samples, including dasatinib-resistant blast crisis cells exhibiting both T315I and E355G mutations, but was minimally toxic to normal CD34(+) cells. Finally, combined in vivo treatment significantly suppressed BaF3/T315I tumor growth and prolonged survival in an allogeneic mouse model. Together, these findings suggest that this targeted combination strategy warrants attention in IM-resistant CML or Ph(+) ALL.

Novel targeted therapies for eosinophil-associated diseases and allergy

Eosinophil-associated diseases often present with life-threatening manifestations and/or chronic organ damage. Currently available therapeutic options are limited to a few drugs that often have to be prescribed on a lifelong basis to keep eosinophil counts under control. In the past 10 years, treatment options and outcomes in patients with clonal eosinophilic and other eosinophilic disorders have improved substantially. Several new targeted therapies have emerged, addressing different aspects of eosinophil expansion and inflammation. In this review, we discuss available and currently tested agents as well as new strategies and drug targets relevant to both primary and secondary eosinophilic diseases, including allergic disorders.

Clinical advances in the management of chronic myelogenous leukemia: focus on bosutinib and patient considerations

The treatment for chronic myeloid leukemia has changed significantly over the past 15 years, and as of now, there are five BCR-ABL1 (breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1) tyrosine kinase inhibitors that have gained approval for treatment of this disease. All five are very effective drugs, and the decision surrounding which to use in specific patients is based on numerous factors. Bosutinib is one of the newer tyrosine kinase inhibitors to gain approval, and has been studied in the first-line setting as well as after failure of other tyrosine kinase inhibitors. It is an SRC-ABL1 (steroid receptor co-activator-ABL1) inhibitor that works in the presence of most kinase domain mutations. The primary side effects of bosutinib are gastrointestinal upsets. In the appropriate clinical setting, bosutinib can be considered a valuable addition to the armamentarium of treatments available for chronic myeloid leukemia.