Search

In the field of chronic myeloid leukemia (CML), new strategies are needed to increase the rate of successful treatment discontinuations, a crucial goal in this disease. Anti-PD-L1 checkpoint inhibitors are a promising therapeutic approach in CML after the demonstration of an increase of these inhibitory molecules in patients with CML. A phase Ib/II (NCT04793399, registration date March 11, 2021) open-label exploratory trial has been conducted to evaluate the safety of atezolizumab, a humanized anti-PD-L1 antibody, in combination with bosutinib in patients with newly diagnosed chronic phase CML. A total of 36 patients were planned to be enrolled, but the study had to be prematurely terminated due to safety concerns. Nine patients were included in the study, and only 8 went on to receive the combination with atezolizumab. There were a total of 44 adverse events (AEs) during the study period. The most frequent were gastrointestinal (50%), mostly mild (86% grade 1–2). The most serious AEs were hepatic. There were 17 hepatic AEs in 5 patients. Of the hepatic AEs 5 were during the bosutinib monotherapy phase and 12 during the combination phase (AST increase x4, ALT increase x4, blood bilirubin increase x1, alkaline phosphatase elevation x2, GGT increase x2), most of them grade 3–4. There were 2 patients who presented a dose-limiting toxicity; a grade 3 elevation of transaminases, that led to premature termination of the study. The combination of atezolizumab with bosutinib presents hepatotoxicity as a dose-limiting effect and therefore we do not recommend to explore this combination in future studies. [ABSTRACT FROM AUTHOR]

Introduction: Chronic myeloid leukemia is characterized by the dysregulated growth of granulocytes, driven by the Philadelphia chromosome translocation. The prevalence of CML is higher in men, with a median age of 57 years and a five-year survival rate of 85%. Tyrosine kinase inhibitors such as Imatinib have revolutionized CML treatment. However, resistance or intolerance to first-line Imatinib requires second-generation TKIs like Nilotinib and Dasatinib. This study aims to evaluate the response of patients treated with these TKIs at a hematology clinic. Methods: This retrospective study analyzed 100 randomly selected CML patients treated between 2020 and 2022. Data were collected on patient demographics, disease progression, treatment regimens, and response rates. Patients who started on Imatinib and later switched to second-line TKIs due to resistance or side effects were followed to assess treatment efficacy. Results: The cohort had a median age of 43 years, with 52% males and 48% females. Most patients (95%) initiated treatment with Imatinib, with 6% experiencing mild side effects and 4% severe side effects leading to treatment changes. In patients resistant to Imatinib, second-generation TKIs showed favorable responses: Dasatinib was effective in patients with advanced disease, while Nilotinib was useful for those intolerant to Imatinib. One patient resistant to both was successfully treated with Bosutinib, a third-generation TKI. Conclusion: Our findings highlight the efficacy of secondgeneration TKIs for managing Imatinib-resistant CML. Dasatinib and Nilotinib effectively managed disease progression, though side effects were a concern. The use of third-generation TKIs like Bosutinib provides additional therapeutic options for refractory cases. [ABSTRACT FROM AUTHOR]

New generation BCR-ABL1 TKIs raised attention regarding their adverse effects, including hepatotoxicity. Indeed, bosutinib and nilotinib were associated with severe hepatotoxicity compared with imatinib. Moreover, ponatinib has a boxed warning due to its potential to cause inflammatory liver damage, even death. However, the underlying mechanisms remain unclear. This study aimed to investigate the role of NLRP3 inflammasome activation in the underlying mechanism of ponatinib and bosutinib-induced hepatotoxicity. Furthermore, we determined the initiating event of this adverse outcome pathway by measuring the levels of reactive oxygen species as well as mitochondrial membrane potential in AML12 cells. The results demonstrated that ponatinib or bosutinib markedly inhibited cell viability and caused cytosolic membrane damage in cells. Moreover, drugs (IC 50) dramatically induced oxidative stress and mitochondrial membrane potential disruption, which led to upregulation in the expression levels of NLRP3 inflammasome-related genes and proteins, activation of NLRP3 inflammasomes, cleavage of gasdermin-D and caspase-1, secretion of IL-1β, and cytosolic membrane damage. Furthermore, MCC950, a well-known specific inhibitor of NLRP3 inflammasome, and antioxidant N-acetyl-l-cysteine reversed the effects of drugs on the NLRP3 signaling pathway and cytosolic membranes. In summary, NLRP3 inflammasome activation is involved in new-generation BCR-ABL1 TKIs-triggered hepatotoxicity. Mitochondrial damage and reactive oxygen species accumulation were significant upstream signaling events in this signaling pathway. [Display omitted] • NLRP3 signaling pathway is a promising therapeutic target for the prevention of drug toxicity. • NLRP3 inflammasome activation might contribute to the hepatotoxicity effects of ponatinib and bosutinib. • Oxidative stress might be initiating event of ponatinib and bosutinib-induced NLRP3 inflammasome activation. [ABSTRACT FROM AUTHOR]

Although bosutinib is generally safe and effective, drug-related toxicities (DRTs) such as diarrhea or increased transaminase levels often lead to treatment discontinuation. To clarify whether a lower initial dose of bosutinib (i.e., starting at 200 mg) would reduce rates of discontinuation due to DRTs, we conducted a phase 2 study of BOsutinib Gradual Increase (BOGI trial, UMIN 000032282) as a second/third-line treatment for chronic myeloid leukemia (CML). Between February 4, 2019 and May 24, 2022, 35 patients were enrolled. The rate of bosutinib discontinuation at 12 months was 25.7% vs. 35.9% in a historical control study (Japanese phase 1/2 study) (p = 0.102). The rate of bosutinib discontinuation due to DRTs was significantly lower, at 11.4% vs. 28.2% (p = 0.015). The incidence of grade 3/4 transaminase elevation was 20% vs. 29% (p = 0.427), while the incidence of diarrhea was 3% vs. 25% (p = 0.009). The median dose intensity of bosutinib was higher (391.7 mg/day vs. 353.9 mg/day). Pharmacokinetic analysis of bosutinib showed that patients who achieved a major molecular response tended to have high trough concentrations. Thus, a low initial dose of bosutinib followed by dose escalation reduced discontinuation due to severe DRTs while maintaining high dose intensity and efficacy. [ABSTRACT FROM AUTHOR]

Introduction: Up to 30% of CML patients will require a therapeutic change during follow-up due to intolerance and/or resistance to first-line tyrosine kinase inhibitor (TKI) approach. In this context, bosutinib (BOS) has not only demonstrated its efficacy, but also presents a favorable safety profile, without comorbid conditions representing an absolute contraindication to its use. Methods: To gain further into BOS treatment in real life, we conducted a retrospective analysis on the outcome of CML patients receiving BOS in 18 hematological centers, all belonging to the “REL” (Lombard Hematology Network). Results: Of 546 regularly followed CML cases, a total of 132 patients were reported as being treated with BOS, most frequently (62.9%) in second line. Interestingly, most patients (63.6%) switched to BOS due to intolerance to the previous TKI, while resistance to the last treatment was reported in the remaining 36.4% of patients. Despite a permanent discontinuation rate of 18.9%, over 80% of patients achieved at least a major molecular response and seven cases were able to attempt treatment-free remission. Conclusion: Although in this survey BOS represented the preferred option especially in patients intolerant rather than resistant to previous TKIs, we confirmed that BOS represents a safe and effective therapeutic option beyond the first line in the real-life setting. [ABSTRACT FROM AUTHOR]

Chronic myeloid leukemia (CML), characterized by the presence of the BCR::ABL1 fusion gene, has undergone a transformative shift with the introduction of tyrosine kinase inhibitors (TKIs). The current availability of six different TKIs (imatinib, dasatinib, nilotinib, bosutinib, ponatinib, and asciminib) in clinical practicemakes it important to know their efficacy and toxicity profile for treatment optimization. This review examines the latest insights regarding the use of bosutinib in CML treatment. Clinical trials have demonstrated the effectiveness of bosutinib, positioning it as a first-line treatment that can induce sustained molecular responses. Importantly, it can also be effective in patients who have experienced treatment failure or intolerance with prior TKIs, revealing the potential of bosutinib also in secondand later-line settings. Even in the advanced phase of CML, bosutinib has demonstrated its capacity to achieve molecular responses, expanding its usefulness. Real-world evidence studies echo these findings, emphasizing bosutinib's effectiveness in achieving deep molecular responses, maintaining remissions, and serving as an alternative for patients intolerant or resistant to other TKIs as a second-line therapy. Notably, one of the greatest strengths of bosutinib is its favorable safety profile, in particular the low incidence of vascular complications with its use, which is undoubtedly a comparative advantage over other TKIs. In summary, the latest research highlights the versatility of bosutinib in CML treatment and underscores its pivotal role in optimizing patient management in challenging cases. Continuing research and investigation will further establish bosutinib's place in the evolving landscape of CML therapy, offering an alternative for CML patients across different treatment stages. [ABSTRACT FROM AUTHOR]

Bosutinib is a second-generation tyrosine kinase inhibitor indicated for the treatment of patients with newly diagnosed Philadelphia chromosome–positive chronic phase chronic myeloid leukemia (CML), and for patients with Ph + chronic phase, accelerated phase, or blast phase CML resistant or intolerant to prior therapy. As is the case for all TKIs approved for treatment of CML, bosutinib is associated with adverse events (AEs) that require appropriate management to ensure adherence to treatment and optimized outcomes. The aim of this review is to provide physicians with updated practical information for the prevention and management of AEs occurring during treatment with bosutinib, including dosing strategies, based on the latest published evidence and clinical experience. Clinical studies and real-world evidence have shown bosutinib has a generally favorable safety profile, which has remained consistent across lines of therapy and in long-term reports. Adjusting the starting dose and/or modifying the dose during treatment with bosutinib are important strategies to manage AEs and improve tolerability, which are recognized within the label and in treatment guidelines. Dosing adjustment strategies to manage AEs are a recognized management approach for other TKIs in the treatment of CML and are not exclusive to bosutinib. In summary, long-term results from clinical trials and emerging real-world evidence demonstrate bosutinib has a safety profile that can largely be managed with treatment modifications and/or supportive care. Increased experience in managing toxicities and by using a personalized dosing approach may further improve adherence and outcomes with bosutinib. [ABSTRACT FROM AUTHOR]

Management of chronic myeloid leukemia (CML) has been transformed by the use of tyrosine kinase inhibitors (TKIs). Presently in India, five TKIs are approved for the management of CML with distinct safety profiles. The selection of TKIs for chronic phase (CP)-CML patients is based on treatment goals, underlying comorbidities, and specific TKI toxicity profiles. Bosutinib is one of five TKIs indicated for the first-line treatment of CP-CML and patients with intolerance or resistance to prior TKI therapy. It possesses a distinct safety profile among other TKIs, with less cardiovascular adverse events (AEs), albeit the liver-related and gastrointestinal AEs have higher occurrence. The safety and efficacy of bosutinib have been examined in clinical trials; however, there is a paucity of data from Asia. A virtual expert panel meeting was convened to gather expert opinion from India on the selection of bosutinib as a treatment choice for patients with CP-CML. This is a white paper document drafted with the help of an expert panel of 14 oncologists and hematooncologists from India on bosutinib use in CP-CML. The experts concurred that bosutinib has proven efficacy for CP-CML in global randomized clinical trials and is well suited for CP-CML patients with existing cardiovascular comorbidities. However, it was not recommended for patients with gastrointestinal, pancreatic, or renal abnormalities. This review aims to put forth expert opinion and guidance document on key considerations for CP-CML clinical decision-making in India. [ABSTRACT FROM AUTHOR]

BACKGROUND: Chronic myeloid leukemia (CML) is a type of myeloproliferative neoplasm characterized by the excessive accumulation of malignant myeloid cells in the bone marrow and peripheral blood. This condition is primarily triggered by a specific chromosomal translocation known as t(9;22) (q34.13;q11.23), which leads to the formation of the BCR-ABL fusion gene. The treatment landscape for CML has undergone significant changes with the approval of tyrosine kinase inhibitors (TKIs) targeting the BCR-ABL1 kinase activity. One such inhibitor is bosutinib, which has been available for several years to treat patients with chronic, accelerated, and blast-phase CML who have shown resistance or intolerance to previous therapies. OBJECTIVES: The aim of this study was to assess efficacy and safety of Bosutinib as a 2nd line therapy in CML patients, in addition to effect of adherence to treatment on patients response. PATIENTS AND METHODS: Eighty-five patients with CML were enrolled in a prospective cohort study from October 2021 to October 2022 at Hematology Center in Medical City Complex – Baghdad. All patients failed to at least one TKI, and all of them started escalated dose of bosutinib. The patients were followed-up by assessing molecular and cytogenetic response at 3 and 6 months and monitored carefully for adverse events (AEs) which were graded by common terminology IX criteria for AEs version 5. Adherence to bosutinib was also monitored by a specific adherence scale to optimize the response rate to treatment. RESULTS: The mean age of patients was 47.3 ± 14.9 (range: 18–77), with male:female ratio 1.4:1. Status of CML patients showed that 89.4% were in the chronic phase, 5.8% in accelerated phase, and 4.7% in blast phase. Regarding the number of previous TKIs before bosutinib, 72.9% of patients failed to prior one TKI (imatinib). At 6 months (72.3%), patients achieve optimal response according to European Leukemia Net criteria 2013. Gastrointestinal symptoms and dermatological manifestations were the most common nonhematological AEs of bosutinib. According to 9-item Morisky Medication Adherence Scale, 42% of patients were adherent to medication which showed a significant association with a higher number of optimal response (P = 0.0001). CONCLUSION: Bosutinib is effective with a high and promising response as a subsequent line treatment in CML patients, and it is generally safe and associated with mild-to-moderate tolerable and manageable AEs. Adherence to the drug plays a significant role in optimal response to bosutinib.

Bosutinib (BOS) is a BCS class IV drug that shows low oral bioavailability and high fast-fed variability. Various pharmaceutical formulations have been explored thus far in order to improve its bioavailability while avoiding fast-fed variability. In the present study, we explored cyclodextrin (CD) complexation strategy to overcome the aforementioned disadvantages associated with BOS. CD complexation is a simple, versatile and economic approach that enables formation of inclusion complexes, thereby improving aqueous solubility while nullifying pH-dependent solubility and fast-fed variability for poorly soluble drugs. Initially, we performed molecular dynamics and docking studies to select appropriate CD derivative. The results of in silico studies revealed that sulfo-butyl ether β-cyclodextrin (SBE-CD) offered superior binding affinity with BOS. Further, Job's plot revealed that 1:1 stoichiometry of BOS and CD resulted in enhancement of BOS solubility up to ~ 132.6-folds. In vitro release studies in bio-relevant media (fasted and fed state simulated gastric and intestinal fluids) revealed higher drug release while overcoming its pH-dependent solubility. In vitro studies on K562 cells demonstrated a 1.83-fold enhancement in cytotoxicity due to enhanced ROS production and G2/M phase arrest.In vivo pharmacokinetic studies in Sprague-Dawley rats revealed insignificant fast-fed variability with AUCfast/fed 0.9493 and Cmaxfast/fed 0.8291 being closer to 1 in comparison with BOS. Hence, we conclude that SBE-CD complexation could be a promising approach in diminishing fast-fed variability of BOS. [ABSTRACT FROM AUTHOR]

Chronic myeloid leukemia (CML), characterized by the presence of the BCR::ABL1 fusion gene, has undergone a transformative shift with the introduction of tyrosine kinase inhibitors (TKIs). The current availability of six different TKIs (imatinib, dasatinib, nilotinib, bosutinib, ponatinib, and asciminib) in clinical practice makes it important to know their efficacy and toxicity profile for treatment optimization. This review examines the latest insights regarding the use of bosutinib in CML treatment. Clinical trials have demonstrated the effectiveness of bosutinib, positioning it as a first-line treatment that can induce sustained molecular responses. Importantly, it can also be effective in patients who have experienced treatment failure or intolerance with prior TKIs, revealing the potential of bosutinib also in second- and later-line settings. Even in the advanced phase of CML, bosutinib has demonstrated its capacity to achieve molecular responses, expanding its usefulness. Real-world evidence studies echo these findings, emphasizing bosutinib’s effectiveness in achieving deep molecular responses, maintaining remissions, and serving as an alternative for patients intolerant or resistant to other TKIs as a second-line therapy. Notably, one of the greatest strengths of bosutinib is its favorable safety profile, in particular the low incidence of vascular complications with its use, which is undoubtedly a comparative advantage over other TKIs. In summary, the latest research highlights the versatility of bosutinib in CML treatment and underscores its pivotal role in optimizing patient management in challenging cases. Continuing research and investigation will further establish bosutinib’s place in the evolving landscape of CML therapy, offering an alternative for CML patients across different treatment stages.

We present the case of a man with a history of recurrent pleural effusion as the only and first clinical manifestation of bosutinib toxicity in which medical thoracoscopy played a decisive role. [ABSTRACT FROM AUTHOR]

While tyrosine kinase inhibitors (TKI)-associated cerebral vascular stenosis (CVS) exhibit distinct mechanisms compared to conventional stroke in basic research, the clinical strategy remains nearly the same other than TKI-switching. We present the case of a 22-year-old female with chronic myeloid leukemia without stroke risk factors, who developed ponatinib-associated CVS. Three potential characteristics of TKI-associated CVS were identified: a heightened threshold for infarction, an atypical infarct area, and vascular recoverability. Specifically, brain computed tomography remained normal despite 20 h of severe hemiplegia. The ischemic distribution was confined in gray matter and the anterior cerebral artery territory on magnetic resonance imaging, despite severe stenosis of the internal carotid artery. Ischemic changes resolved within 10 days and arterial stenosis improved after ponatinib withdrawal. These unique features, distinct from typical stroke, could lead to misdiagnosis as non-organic neurological disorders or other conditions in ponatinib-treated patients.

Globally, endometrial cancer (EC) is the six most common cancers related to female reproductive. EC incidence and mortality rates have increased over the last decade. Cytotoxic therapy with carboplatin or paclitaxel is the recommended first-line treatment for EC patients. However, the options for following therapy are limited. The latest advances in molecular studies have uncovered the nature of genetic alterations in EC, compelling methods for further research into the treatment of EC since they may disclose to tailored pharmacological therapy. The aim of this study was to identify novel drug candidates in treating EC using genomics variants and biological pathway. The genomic variants of EC were downloaded from cBioportal database. We established connection between the biological EC risk genes from cBioportal database and the DrugBank database. Finally, we used Connectivity Map (CMap) analysis to identify possible drugs whose mechanisms coincided with therapeutic targets and rank them in accordance to scoring criteria. We identified novel conceivable candidate drugs for EC, they are Bosutinib, Acitretin and Nilutamide. These drugs exhibit robust scores in the CMap analysis compare to paclitaxel. We also discovered BCR-ABL1 and AR as potential biomarker-driven therapy in EC. This study demonstrates the possibility of using genetic network analysis combined with bioinformatics to repurpose drugs for the treatment of EC. Further investigation will be undertaken to explore the mechanisms involved in the application of BCR-ABL1 and AR for treating of EC.

Abstract Background The BELA and BFORE trials compared bosutinib starting doses of 500 mg once daily (QD) and 400 mg QD, respectively, with imatinib in adults with newly diagnosed chronic phase chronic myeloid leukemia (CP‐CML). The B1871048 trial evaluated bosutinib 400 mg QD in Japanese patients with newly diagnosed CP‐CML. Aim This analysis assessed the impact of a lower bosutinib starting dose on key efficacy and safety outcomes. Materials & Methods A pharmacokinetic model was used to estimate metrics of bosutinib exposure, and logistic regression was used to investigate relationships with efficacy (cumulative major molecular response [MMR] and cumulative complete cytogenetic response [CCyR]) and safety outcomes (eight prespecified adverse events). Results Totals of 573 and 574 patients were included in the efficacy and safety endpoint analyses, respectively. Cumulative MMR and CCyR were similar across studies. Log(Ctrough) and log(Cavg) were significant predictors of MMR and CCyR, and the probability of achieving MMR or CCyR increased 1.3‐fold or 2.7‐fold for every 1 unit increase in log(Ctrough) or log(Cavg), respectively. An exposure–response relationship was identified between time‐to‐event and risk of diarrhea, nausea, and vomiting. Significant relationships were also observed between time‐to‐event and log(Cavg), Ctrough, and Cavg with diarrhea, nausea, and vomiting, respectively. Discussion A bosutinib exposure‐response relationship with safety and efficacy was observed. Conclusion Compared with 500 mg QD, a bosutinib starting dose of 400 mg QD improved tolerability in some patients with newly diagnosed CP‐CML without compromising efficacy. ClinicalTrials.gov identifiers: NCT00574873; NCT02130557; NCT03128411.

Effective inactivation of the HER2-HER3 tumor driver has remained elusive because of the challenging attributes of the pseudokinase HER3. We report a structure-function study of constitutive HER2-HER3 signaling to identify opportunities for targeting. The allosteric activation of the HER2 kinase domain (KD) by the HER3 KD is required for tumorigenic signaling and can potentially be targeted by allosteric inhibitors. ATP binding within the catalytically inactive HER3 KD provides structural rigidity that is important for signaling, but this is mimicked, not opposed, by small molecule ATP analogs, reported here in a bosutinib-bound crystal structure. Mutational disruption of ATP binding and molecular dynamics simulation of the apo KD of HER3 identify a conformational coupling of the ATP pocket with a hydrophobic AP-2 pocket, analogous to EGFR, that is critical for tumorigenic signaling and feasible for targeting. The value of these potential target sites is confirmed in tumor growth assays using gene replacement techniques.

Objective: to summarize scientific information about the basic principles of modern drug therapy for patients with chronic myeloid leukemia (CML) considering their individual characteristics.Material and methods. The basis of the study included modern scientific articles and clinical guidelines on CML diagnosis and treatment (2021), State Register of Medicines (SRM) of the Russian Federation, instructions for the use of medicines. The following methods were used: structural analysis, analytical method, content analysis, retrospective analysis, systematic approach, situational-logical and graphical methods of analysis.Results. The analysis made it possible to summarize scientific information about the basic principles of drug therapy for patients suffering from CML. It was revealed that the problem of CML therapy today is relevant, since every year there is an increase in the incidence of this nosology. Currently, the most significant is the prescription of tyrosine kinase inhibitors (TKIs), since they have pronounced effects and are well tolerated by patients. Therapy for CML in TKIs prescription consists of several lines. Imatinib is the first line therapy because it has better safety profile. There are combinations with imatinib; for example, it is used together with interferon alfa, which allows, in some cases, to increase the response to treatment. The following drugs are used in the second line: nilotinib, dasatinib, bosutinib, ponatinib. If TKI therapy is ineffective, it is possible to prescribe standard chemotherapy, interferon therapy, or bone marrow transplantation in the absence of contraindications. Studies are underway on the possibility of using and including in clinical guidelines such drugs as arsenic trioxide, decitabine, omacetaxime, inhibitors of farnesyl transferases, granulocyte-macrophage factors, antitumor vaccines. The analysis of SRM identified 27 trade names for TKIs, the share of domestic drugs was 60%. There were no Russian analogues for bosutinib and ponatinib in SRM, which are recommended for use in case of ineffective TKI therapy of previous lines.Conclusion. The study of drug provision for CML patients is an urgent task for pharmaceutical practice and for the healthcare system as a whole. Currently, the acute issues are the individual approach to the treatment of each CML patient considering concomitant diseases, and the search for new, more effective drugs that can increase the life expectancy and quality of life of patients suffering from this disease.

The approved dose of bosutinib in chronic phase CML is 400 mg QD in first-line and 500 mg QD in later-line treatment. However, given that gastrointestinal (GI) toxicity typically occurs early after treatment initiation, physicians often tend to start therapy with lower doses although this has never been tested systematically in prospective trials in the Western world. The Bosutinib Dose Optimization (BODO) Study, a multicenter phase II study, investigated the tolerability and efficacy of a step-in dosing concept of bosutinib (starting at 300 mg QD) in chronic phase CML patients in 2nd or 3rd line who were intolerant and/or refractory to previous TKI treatment. Of 57 patients included until premature closure of the study due to slow recruitment, 34 (60%) reached the targeted dose level of 500 mg QD following the 2-weekly step-in dosing regimen. While the dosing-in concept failed to reduce GI toxicity (grade II–IV, primary study endpoint) to < 40% (overall rate of 60%; 95% CI: 45–74%), bosutinib treatment (mean dosage: 403 mg/day) showed remarkable efficacy with a cumulative major molecular remission (MMR) rate of 79% (95% CI: 66 to 88%) at month 24. Of thirty patients refractory to previous therapy and not in MMR at baseline, 19 (64%) achieved an MMR during treatment. GI toxicity did not significantly impact on patient-reported outcomes (PRO) and led to treatment discontinuation in only one patient. Overall, the results of our trial support the efficacy and safety of bosutinib after failure of second-generation TKI pre-treatment. Trial registration: NCT02577926. [ABSTRACT FROM AUTHOR]

Bosutinib, widely used as a primary treatment for chronic myeloid leukemia (CML), is known to frequently cause cutaneous drug eruptions. Fixed Drug Eruption (FDE) is common, typically presenting as recurrent lesions that heal with residual hyperpigmentation. Diagnosing FDE, especially Non-Pigmenting Fixed Drug Eruption (NPFDE), is often challenging. A correlation exists between the dosage of certain medications, such as levetiracetam, and the emergence of drug eruptions. This report details a unique case of dose-dependent NPFDE caused by bosutinib. In managing cutaneous drug eruptions, particularly when the causative drug is crucial for treatment, a strategy of tapering the dosage should be considered. [ABSTRACT FROM AUTHOR]

Background: The BELA and BFORE trials compared bosutinib starting doses of 500 mg once daily (QD) and 400 mg QD, respectively, with imatinib in adults with newly diagnosed chronic phase chronic myeloid leukemia (CP‐CML). The B1871048 trial evaluated bosutinib 400 mg QD in Japanese patients with newly diagnosed CP‐CML. Aim: This analysis assessed the impact of a lower bosutinib starting dose on key efficacy and safety outcomes. Materials & Methods: A pharmacokinetic model was used to estimate metrics of bosutinib exposure, and logistic regression was used to investigate relationships with efficacy (cumulative major molecular response [MMR] and cumulative complete cytogenetic response [CCyR]) and safety outcomes (eight prespecified adverse events). Results: Totals of 573 and 574 patients were included in the efficacy and safety endpoint analyses, respectively. Cumulative MMR and CCyR were similar across studies. Log(Ctrough) and log(Cavg) were significant predictors of MMR and CCyR, and the probability of achieving MMR or CCyR increased 1.3‐fold or 2.7‐fold for every 1 unit increase in log(Ctrough) or log(Cavg), respectively. An exposure–response relationship was identified between time‐to‐event and risk of diarrhea, nausea, and vomiting. Significant relationships were also observed between time‐to‐event and log(Cavg), Ctrough, and Cavg with diarrhea, nausea, and vomiting, respectively. Discussion: A bosutinib exposure‐response relationship with safety and efficacy was observed. Conclusion: Compared with 500 mg QD, a bosutinib starting dose of 400 mg QD improved tolerability in some patients with newly diagnosed CP‐CML without compromising efficacy. ClinicalTrials.gov identifiers: NCT00574873; NCT02130557; NCT03128411. [ABSTRACT FROM AUTHOR]