Bosutinib is active in chronic phase chronic myeloid leukemia after imatinib and dasatinib and/or nilotinib therapy failure

Practical considerations in the management of patients treated with bosutinib for chronic myeloid leukemia

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.

Critical review of clinical data and expert-based recommendations for the use of bosutinib in the treatment of chronic myeloid leukemia

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.

Imatinib therapy of chronic myeloid leukemia significantly reduces carnitine cell intake, resulting in adverse events

OBJECTIVE

A prominent, safe and efficient therapy for patients with chronic myeloid leukemia (CML) is inhibiting oncogenic protein BCR::ABL1 in a targeted manner with imatinib, a tyrosine kinase inhibitor. A substantial part of patients treated with imatinib report skeletomuscular adverse events affecting their quality of life. OCTN2 membrane transporter is involved in imatinib transportation into the cells. At the same time, the crucial physiological role of OCTN2 is cellular uptake of carnitine which is an essential co-factor for the mitochondrial β-oxidation pathway. This work investigates the impact of imatinib treatment on carnitine intake and energy metabolism of muscle cells.

METHODS

HTB-153 (human rhabdomyosarcoma) cell line and KCL-22 (CML cell line) were used to study the impact of imatinib treatment on intracellular levels of carnitine and vice versa. The energy metabolism changes in cells treated by imatinib were quantified and compared to changes in cells exposed to highly specific OCTN2 inhibitor vinorelbine. Mouse models were used to test whether in vitro observations are also achieved in vivo in thigh muscle tissue. The analytes of interest were quantified using a Prominence HPLC system coupled with a tandem mass spectrometer.

RESULTS

This work showed that through the carnitine-specific transporter OCTN2, imatinib and carnitine intake competed unequally and intracellular carnitine concentrations were significantly reduced. In contrast, carnitine preincubation did not influence imatinib cell intake or interfere with leukemia cell targeting. Blocking the intracellular supply of carnitine with imatinib significantly reduced the production of most Krebs cycle metabolites and ATP. However, subsequent carnitine supplementation rescued mitochondrial energy production. Due to specific inhibition of OCTN2 activity, the influx of carnitine was blocked and mitochondrial energy metabolism was impaired in muscle cells in vitro and in thigh muscle tissue in a mouse model.

CONCLUSIONS

This preclinical experimental study revealed detrimental effect of imatinib on carnitine-mediated energy metabolism of muscle cells providing a possible molecular background of the frequently occurred side effects during imatinib therapy such as fatigue, muscle pain and cramps.

Efficacy and safety of bosutinib in previously treated patients with chronic myeloid leukemia: final results from the BYOND trial

This final analysis from the phase 4 BYOND trial reports outcomes with bosutinib in patients with previously treated chronic myeloid leukemia (CML); 163 patients with CML resistant/intolerant to previous tyrosine kinase inhibitors received bosutinib (starting dose: 500 mg QD). At study completion (median follow-up, 47.8 months), 48.1% (n = 75/156) of patients with Philadelphia chromosome-positive chronic phase CML were still receiving treatment. Among evaluable patients, 71.8% (95% CI, 63.9-78.9) and 59.7% (95% CI, 51.4-67.7) attained or maintained major molecular response (MMR) and molecular response (MR)4, respectively, at any time on treatment. The majority of patients achieved a deeper molecular response relative to baseline while on bosutinib. Kaplan-Meier probabilities (95% CI) of maintaining MMR and MR4 at 36 months were 87.2% (78.0-92.7) and 80.7% (69.4-88.1), respectively. At 48 months, the Kaplan-Meier overall survival rate was 88.3% (95% CI, 81.8-92.6); there were 17 deaths, including 2 that were considered CML related. Long-term adverse events (AEs) were consistent with the known safety profile of bosutinib, and no new safety issues were identified. The management of AEs through dose reduction maintained efficacy while improving tolerability. These results support the use of bosutinib in patients with previously treated CML.ClinicalTrials.gov, NCT02228382.

Exploring treatment decision-making in chronic myeloid leukemia in chronic phase

The introduction of tyrosine kinase inhibitors (TKIs) has transformed the treatment of chronic myeloid leukemia (CML). Each approved TKI has its own risk-benefit profile, and patients have choices across lines of therapy. Identifying the initial and subsequent treatment that will lead to the best possible outcome for individual patients is challenging. In this review, we summarize data for each approved TKI across lines of therapy in patients with CML in chronic phase, highlighting elements of each agent's safety and efficacy profile that may impact patient selection, and provide insights into individualized treatment sequencing decision-making aimed at optimizing patient outcomes.

A Review of the Therapeutic Role of Bosutinib in Chronic Myeloid Leukemia

The development of the BCR::ABL1 tyrosine kinase inhibitors (TKIs) has transformed Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML) from a fatal disease to an often-indolent illness that, when managed effectively, can restore a life expectancy close to that of the normal population. Bosutinib is a second-generation TKI approved for adults with Ph-positive CML in chronic phase, accelerated phase, or blast phase that is resistant or intolerant to prior therapy, and for newly diagnosed Ph-positive chronic phase CML. This review details the efficacy of bosutinib for the treatment of CML in the first- and second-line settings, as well as in third- and later-line settings for high-risk patients resistant or intolerant to at least 2 TKIs. It also outlines bosutinib studies that provide evidence for dose-optimization strategies that can be used to improve efficacy and effectively manage adverse events. The studies that provide evidence for specific patient populations benefiting particularly from bosutinib dose-optimization strategies are also discussed. The well-established, long-term side-effect profile and the potential to make dose adjustments with bosutinib make it an appropriate treatment option for patients with CML. Bosutinib has demonstrated a positive impact on health-related quality of life and an important role in the long-term treatment of patients with CML.

Tyrosine kinase inhibitor resistance in de novo BCR::ABL1-positive BCP-ALL beyond kinase domain mutations

ABSTRACT

A better understanding of ABL1 kinase domain mutation-independent causes of tyrosine kinase inhibitor (TKI) resistance is needed for BCR::ABL1-positive B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Although TKIs have dramatically improved outcomes, a subset of patients still experiences relapsed or refractory disease. We aimed to identify potential biomarkers of intrinsic TKI resistance at diagnosis in samples from 32 pediatric and 19 adult patients with BCR::ABL1-positive BCP-ALL. Reduced ex vivo imatinib sensitivity was observed in cells derived from newly diagnosed patients who relapsed after combined TKI and chemotherapy treatment compared with cells derived from patients who remained in continuous complete remission. We observed that ex vivo imatinib resistance was inversely correlated with the amount of (phosphorylated) BCR::ABL1/ABL1 protein present in samples that were taken at diagnosis without prior TKI exposure. This suggests an intrinsic cause of TKI resistance that is independent of functional BCR::ABL1 signaling. Simultaneous deletions of IKZF1 and CDKN2A/B and/or PAX5 (IKZF1plus), as well as deletions of PAX5 alone, were related to ex vivo imatinib resistance. In addition, somatic lesions involving ZEB2, SETD2, SH2B3, and CRLF2 were associated with reduced ex vivo imatinib sensitivity. Our data suggest that the poor prognostic value of IKZF1(plus) deletions is linked to intrinsic mechanisms of TKI resistance other than ABL1 kinase domain mutations in newly diagnosed pediatric and adult BCR::ABL1-positive BCP-ALL.

A safety review of tyrosine kinase inhibitors for chronic myeloid leukemia

INTRODUCTION

Since the introduction of first tyrosine kinase inhibitor (TKI) imatinib, the treatment of chronic myeloid leukemia (CML) has reached excellent survival expectancies. Long survival rates bring about issues regarding TKI safety.

AREAS COVERED

The aim of this review is to compare the side effects of current TKIs both in the first and later lines and outline a safety andprofile of CML treatment. Seminal studies on TKIs and other newer drugs and extended follow-up of these studies; real-life data of each drug were usedduring the course of this. PubMed was used as a search database and onlyarticles in English were included.

EXPERT OPINION

With longer follow-up CML patients, resistant slowgrade adverse events seem to be the major obstacle in the way of treatmentefficacy. If efficacy is the priority, vigorous treatment of side effect and administration of full dose TKI are reasonable. But when treatment goals are reached, dose modifications or alternative treatment regimens may be acceptedpossible. More studies are needed on dose modification protocols and potential benefits and safety of treatment-free remission.

Impact of age and comorbidities on the efficacy and tolerability of bosutinib in previously treated patients with chronic myeloid leukemia: results from the phase 4 BYOND study

In the phase 4 BYOND trial, patients with pretreated chronic myeloid leukemia (CML) received bosutinib (starting dose: 500 mg/day). Efficacy and safety after ≥3 years of follow-up in 156 patients with Philadelphia chromosome-positive chronic phase CML by age and Charlson Comorbidity Index scores (without the age component; mCCI) is reported. Cumulative major molecular response rates at any time on treatment were 73.6%, 64.5%, and 74.1% in patients <65, 65-74, and ≥75 years of age, and 77.9%, 63.0%, and 59.3% in patients with mCCI scores 2, 3, and ≥4, respectively. Patients <65, 65-74, and ≥75 years of age experienced grade 3/4 treatment-emergent adverse events (TEAEs) at rates of 74.7%, 78.8%, and 96.4% and permanent discontinuations due to AEs at rates of 22.1%, 39.4%, and 46.4%, respectively. In patients with mCCI 2, 3, and ≥4, respective rates of grade 3/4 TEAEs were 77.8%, 77.8%, and 86.7%, and permanent discontinuations due to AEs were 25.3%, 33.3%, and 43.3%. In conclusion, a substantial proportion of patients maintained/achieved cytogenetic and molecular responses across age groups and mCCI scores. Older patients (≥75 years) and those with high comorbidity burden (mCCI ≥4) may require more careful monitoring due to the increased risk of TEAEs. Clinicaltrials.gov: NCT02228382.

[Optimizing the use of bosutinib in patients with chronic-phase chronic myeloid leukemia: Recommendations of a panel of experts from the Fi-LMC (French CML working group)]

The treatment of chronic myeloid leukemia relies on orally available tyrosine kinase inhibitors targeting the BCR::ABL1 oncoprotein. Bosutinib is a second generation adenosine triphosphate-competitive inhibitor approved for use in frontline adult chronic phase-chronic myeloid leukemia and all phases-chronic myeloid leukemia in the second line setting or beyond. Its efficacy was demonstrated in several pivotal clinical trials at 400mg once daily in the first line context and at 500mg once daily beyond first line. Bosutinib-related adverse events frequently occur early after treatment initiation and include gastro-intestinal symptoms and cytolytic hepatitis. These drug-related adverse events must be properly managed in order to preserve safety, efficacy and treatment acceptability. The French chronic myeloid leukemia study group gathered a panel of experts in hematology, pharmacology and hepatology in order to elaborate practical recommendations on the management of bosutinib treatment. These recommendations aim at optimizing the short and long-term tolerance and benefit/risk balance of bosutinib, mainly focusing at gastro-intestinal and liver toxicities.

Therapy for patients with chronic phase-chronic myeloid leukemia previously treated with ⩾2 tyrosine kinase inhibitors: a systematic literature review

Background

ATP-competitive tyrosine kinase inhibitors (TKIs) are the current standard of care for patients with chronic phase-chronic myeloid leukemia (CP-CML) in the first-line and second-line (2 L) setting. Treatment after 2 L is not clearly established.

Objective

The objective of this study was to summarize the available evidence to compare the efficacy and safety of interventions in the treatment of CP-CML patients who had received ⩾2 prior TKIs.

Design

A systematic literature review was performed.

Data source and methods

A systematic literature review (SLR) of studies published until May 2021, reporting clinical outcomes in adult patients with CP-CML who had received ⩾ 2 prior TKIs was performed. Studies were identified through the database searches via Ovid platform (Embase, MEDLINE Epub Ahead of Print, In-Process and Other Non-Indexed Citations, and Cochrane Central Register of Controlled Trials), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), bibliographic search of relevant reviews, and proceedings from the previous 3 years of the key conferences in the field of oncology.

Results

Our search identified 38 relevant studies. Among the identified studies of the current third-line treatments, the major molecular response (MMR) rate for ponatinib was 19.0-66.7%, 23.3-25.5% for asciminib, 19.2% for omacetaxine, and 13.2% for bosutinib at 6 months. The complete cytogenetic response (CCyR) rate was 21.4-64.8% for ponatinib, 38.7-40.8% for asciminib, 18-24.2% for bosutinib, and 16.1% for omacetaxine at 6 months.

Conclusion

The findings from current SLR demonstrated the lack of data for patients with CML treated with ⩾2 TKIs. TKIs such as asciminib, ponatinib, and bosutinib are valid options for those patients. Further research is needed to identify the best treatment option for patients with CML receiving later lines of therapy.

Step-in dosing of bosutinib in pts with chronic phase chronic myeloid leukemia (CML) after second-generation tyrosine kinase inhibitor (TKI) therapy: results of the Bosutinib Dose Optimization (BODO) Study

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.

Population modeling of bosutinib exposure-response in patients with newly diagnosed chronic phase chronic myeloid leukemia

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.

A Multicenter Retrospective Chart Review Study of Treatment and Disease Patterns and Clinical Outcomes of Patients with Chronic-Phase Chronic Myeloid Leukemia in Third-Line Treatment or with T315I Mutation

This retrospective chart review study investigated the clinical burden of adult patients with chronic-phase chronic myeloid leukemia (CP-CML) treated at three centers in France (2006-2021) who failed on two or more tyrosine kinase inhibitors (TKIs; third-line [3L]+ cohort) or harbored the BCR::ABL1 T315I mutation (T315I cohort). In the 3L+ cohort (N = 157; median age at diagnosis, 56 years), TKIs received in 3L (median duration: 17 months) were dasatinib (32%), nilotinib (19%), imatinib (18%), ponatinib (17%), and bosutinib (14%). Of the 145 patients with documented responses in 3L, 42% experienced major molecular response (MMR) at 12 months. Median event-free survival [95% confidence interval] was 53.6 [44.0, 67.5] months, and median progression-free survival and overall survival (OS) were not reached. Achieving MMR in 3L was associated with a decreased mortality risk. In the T315I cohort (N = 17; 52 years), 41% of patients received five or more lines of therapy. Following identification of the T315I mutation, ponatinib was the most common TKI used (59%); the median [interquartile range] OS was 5 [3-10] years. The most common adverse events were infections (3L+ cohort) and thrombocytopenia (T315I cohort) (both 18%). Well-tolerated therapies that achieve durable responses are needed in 3L or earlier to improve CP-CML prognosis.

Asciminib monotherapy in patients with CML-CP without BCR::ABL1 T315I mutations treated with at least two prior TKIs: 4-year phase 1 safety and efficacy results

Asciminib is approved for patients with Philadelphia chromosome-positive chronic-phase chronic myeloid leukemia (CML-CP) who received ≥2 prior tyrosine kinase inhibitors or have the T315I mutation. We report updated results of a phase 1, open-label, nonrandomized trial (NCT02081378) assessing the safety, tolerability, and antileukemic activity of asciminib monotherapy 10-200 mg once or twice daily in 115 patients with CML-CP without T315I (data cutoff: January 6, 2021). After ≈4-year median exposure, 69.6% of patients remained on asciminib. The most common grade ≥3 adverse events (AEs) included increased pancreatic enzymes (22.6%), thrombocytopenia (13.9%), hypertension (13.0%), and neutropenia (12.2%); all-grade AEs (mostly grade 1/2) included musculoskeletal pain (59.1%), upper respiratory tract infection (41.7%), and fatigue (40.9%). Clinical pancreatitis and arterial occlusive events (AOEs) occurred in 7.0% and 8.7%, respectively. Most AEs occurred during year 1; the subsequent likelihood of new events, including AOEs, was low. By data cutoff, among patients without the indicated response at baseline, 61.3% achieved BCR::ABL1 ≤ 1%, 61.6% achieved ≤0.1% (major molecular response [MMR]), and 33.7% achieved ≤0.01% on the International Scale. MMR was maintained in 48/53 patients who achieved it and 19/20 who were in MMR at screening, supporting the long-term safety and efficacy of asciminib in this population.

Allogeneic hematopoietic cell transplantation in patients with chronic phase chronic myeloid leukemia in the era of third generation tyrosine kinase inhibitors: A retrospective study by the chronic malignancies working party of the EBMT

Following the introduction of tyrosine kinase inhibitors (TKI), the number of patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) for chronic phase (CP) chronic myeloid leukemia (CML) has dramatically decreased. Imatinib was the first TKI introduced to the clinical arena, predominantly utilized in the first line setting. In cases of insufficient response, resistance, or intolerance, CML patients can subsequently be treated with either a second or third generation TKI. Between 2006 and 2016, we analyzed the impact of the use of 1, 2, or 3 TKI prior to allo-HCT for CP CML in 904 patients. A total of 323-, 371-, and 210 patients had 1, 2, or 3 TKI prior to transplant, respectively; imatinib (n = 778), dasatinib (n = 508), nilotinib (n = 353), bosutinib (n = 12), and ponatinib (n = 44). The majority had imatinib as first TKI (n = 747, 96%). Transplants were performed in CP1, n = 549, CP2, n = 306, and CP3, n = 49. With a median follow-up of 52 months, 5-year OS for the entire population was 64.4% (95% CI 60.9-67.9%), PFS 50% (95% CI 46.3-53.7%), RI 28.7% (95% CI 25.4-32.0%), and NRM 21.3% (95% CI 18.3-24.2%). No difference in OS, PFS, RI, or NRM was evident related to the number of TKI prior to allo-HCT or to the type of TKI (p = ns). Significant factors influencing OS and PFS were > CP1 versus CP1 and Karnofsky performance (KPS) score > 80 versus ≤80, highlighting CP1 patients undergoing allo-HCT have improved survival compared to >CP1 and the importance of careful allo-HCT candidate selection.

RETRACTED: hsa-miR-23a~27a~24-2 cluster members inhibit aggressiveness of breast cancer cells by commonly targeting NCOA1, NLK and RAP1B

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. The corresponding author notified the journal of three examples of image duplication within the published article (two in Figure 3D and one in Figure 4A), and requested a corrigendum. As per journal policy when considering corrigendum requests, the journal requested the authors to provide source data relating to these affected figures. The editorial team noticed 12 additional suspected image duplications within the supplied source data and the corresponding author was informed. Upon submission of revised source data, the editorial team noticed two new suspected image duplications. The editorial team have concerns about the provenance of the data and therefore the Editor-in-Chief decided to retract the article.

A retrospective observational research study to describe the real-world use of bosutinib in patients with chronic myeloid leukemia in the United Kingdom and the Netherlands

Objectives

To describe the real‐world effectiveness and safety of bosutinib in patients with chronic myeloid leukemia (CML).

Methods

This was a multi‐center, retrospective, non‐interventional chart review study conducted in 10 hospitals in the United Kingdom and the Netherlands.

Results

Eighty‐seven patients were included. Bosutinib was the third‐line tyrosine kinase inhibitor (TKI) in 33 (38%) and fourth‐line in 44 (51%) patients. Median treatment duration was 15.6 months. Among 84 patients in chronic phase (CP) at baseline, 26 (31%) switched to bosutinib due to resistance and 57 (68%) due to intolerance to prior TKIs. Cumulative complete cytogenetic and major molecular response rates in CP patients were 67% and 55%, respectively. After a median follow‐up of 21.5 months, nine (11%) patients in CP died; estimated overall survival rates at 1 and 2 years postbosutinib initiation were 95% and 91%, respectively. Overall, 33/87 (38%) patients discontinued bosutinib due to either lack of efficacy/disease progression (17%), adverse events (14%), death (2%), or other reasons (5%). Eighty‐two (94%) patients experienced ≥1 adverse event possibly related to bosutinib, most commonly diarrhea (52%).

Conclusions

Bosutinib used in routine clinical practice in heavily pretreated patients with CML is an effective treatment for patients in CP and is generally tolerable.

Development of a Sensitive and High-Throughput Assay for Simultaneous Quantification of 5 Tyrosine Kinase Inhibitors and 2 Active Metabolites in Human Plasma Using Ultra-high Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry

BACKGROUND

Breakpoint cluster region-Abelson (BCR-ABL) tyrosine kinase inhibitors (TKIs) demonstrate improved therapeutic efficacy in chronic myeloid leukemia (CML). However, drug-drug interactions, nonadherence, and host-related factors may influence plasma concentrations. Therefore, therapeutic drug monitoring may be necessary for patients presenting inadequate treatment responses or adverse events. Herein, the authors aimed to develop a more sensitive and high-throughput method than those previously reported to simultaneously quantify 5 TKIs (imatinib, nilotinib, dasatinib, bosutinib, and ponatinib) and 2 active metabolites (N-desmethyl imatinib and N-desmethyl ponatinib) using ultra-performance liquid chromatography coupled with tandem mass spectrometry.

METHODS

Plasma samples were prepared according to a solid-phase extraction protocol using an Oasis MCX µElution plate. The assay fulfilled the requirements of the US Food and Drug Administration for assay validation, with a lower limit of quantification of 0.2 ng/mL for dasatinib, 0.3 ng/mL for N-desmethyl ponatinib, 0.5 ng/mL for N-desmethyl imatinib, bosutinib, and ponatinib, and 2.5 ng/mL for imatinib and nilotinib.

RESULTS

Within-batch and batch-to-batch precision at the lower limit of quantification and quality control levels were within 14.3% and 10.9%, respectively. Within-batch and batch-to-batch accuracies ranged from 15.5% to 13.0% and 5.70% to 7.03%, respectively. A positive electrospray ionization mode was used with a run time of 6.0 minutes. The assay applicability was verified by the successful measurement of 78 clinical samples from patients undergoing CML therapy.

CONCLUSIONS

The method allows assessment of trough concentrations of TKIs and active metabolites in patients with CML, and hence can be used to assess blood samples in routine clinical settings.

An evaluation of asciminib for patients with chronic myeloid leukemia previously treated with ≥2 Tyrosine Kinase Inhibitors

INTRODUCTION

: To date, five tyrosine kinase inhibitors (TKIs) are available for treating chronic myeloid leukemia (CML) patients in clinical practice. Despite this, a significant proportion of patients will ultimately develop failure to approved TKIs due to intolerance or resistance. Consequently, new treatment approaches are still required in this unmet clinical need. Asciminib, a first-in-class BCR::ABL1 inhibitor Specifically Targeting the ABL Myristoyl Pocket (STAMP), has the potential to overcome resistance/intolerance to prior TKI treatment.

AREAS COVERED

This review will cover the mechanism of action, pharmacokinetic profile and clinical data of asciminib based on available information from laboratory studies, clinical trials and real world evidence.

EXPERT OPINION

Recent approval of asciminib will require positioning of this drug in the treatment algorithm of CML patients failing initial TKI therapy. Available data support the lack of cross-intolerance of asciminib with other TKIs and its favorable cardiovascular toxicity profile. In addition, asciminib has demonstrated considerable efficacy in CML patients who have failed at least two TKIs, although preliminary data suggest that this efficacy may be lower in those previously exposed to ponatinib. The introduction of asciminib in clinical practice may represent an important step forward in the management of CML.

Ponatinib for the treatment of adult patients with resistant or intolerant Chronic-Phase Chronic Myeloid Leukemia

INTRODUCTION

Patients with chronic myeloid leukemia in chronic phase (CP-CML) who are resistant or intolerant to second-generation tyrosine kinase inhibitors (TKIs) may benefit from treatment with a third-generation TKI, like ponatinib.

AREAS COVERED

In this review, the authors discuss the role of ponatinib, an oral pan-inhibitor of BCR-ABL1, with potent activity in heavily pretreated patients, including T315I mutation. In the long-term follow-up of the PACE trial, 60% of patients with prior TKIs exposure achieved a major cytogenetic response with ponatinib and 40% a major molecular response; 5-year overall survival was 73%. Cardiovascular adverse events represent the major toxicity associated with ponatinib. Adopting a dose-reduction approach appeared to be safe: starting with 45 or 30 mg and decreasing to 15 mg once BCR-ABL1/ABL1≤1% is achieved. In patients who are not candidates for ponatinib therapy, asciminib or other novel TKIs like HQP1351, represent alternative options.

EXPERT OPINION

In patients with CP-CML resistant or intolerant to second-generation TKIs, we favor using a third-generation TKI such as ponatinib. Although we initiate a donor search as soon as a patient fails a second-generation TKI, we still prefer treating patients with ponatinib and will only consider transplantation in the event of no response or disease progression.

Treatment of Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia in Adults

Simple Summary

Outcome of patients with Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) dramatically improved during the past 20 years with the advent of tyrosine kinase inhibitors and monoclonal antibodies. Their great efficacy in young and fit patients led to question our reliance on chemotherapy and allogeneic hematopoietic stem cell transplantation. Moreover, these well-tolerated treatments can be safely administrated even in the elderly that represent the majority of Ph+ ALL patient. This review will focus on the recent changes of paradigm in the management of Ph+ ALL patients and the development of novel therapeutic strategies.

Abstract

Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) is the most common subtype of B-ALL in adults and its incidence increases with age. It is characterized by the presence of BCR-ABL oncoprotein that plays a central role in the leukemogenesis of Ph+ ALL. Ph+ ALL patients traditionally had dismal prognosis and long-term survivors were only observed among patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first complete remission (CR1). However, feasibility of allo-HSCT is limited in this elderly population. Fortunately, development of increasingly powerful tyrosine kinase inhibitors (TKIs) from the beginning of the 2000′s dramatically improved the prognosis of Ph+ ALL patients with complete response rates above 90%, deep molecular responses and prolonged survival, altogether with good tolerance. TKIs became the keystone of Ph+ ALL management and their great efficacy led to develop reduced-intensity chemotherapy backbones. Subsequent introduction of blinatumomab allowed going further with development of chemo free strategies. This review will focus on these amazing recent advances as well as novel therapeutic strategies in adult Ph+ ALL.

Safety profile of bosutinib in Japanese versus non-Japanese patients with chronic myeloid leukemia: a pooled analysis

Bosutinib has been investigated in multiple clinical trials globally, including Japan, for treatment of chronic myeloid leukemia (CML). A pooled analysis of seven Pfizer-sponsored clinical trials evaluated the safety of bosutinib in Japanese (n = 138) vs non-Japanese (n = 1210) patients with CML. First-line bosutinib was administered in 54.3% vs 41.4% of patients, and second-line or later bosutinib in the remainder. Median treatment duration was 1.4 vs 2.3 years, and median relative dose intensity 78.1% vs 90.0%. Any-grade treatment-emergent adverse events (TEAEs) occurred in 100.0% vs 98.9% (grade ≥ 3: 81.9% vs 75.2%). In both groups, the most common TEAEs relevant to bosutinib were gastrointestinal (92.8% vs 84.7%), liver function (72.5% vs 34.8%), rash (63.8% vs 37.4%), and myelosuppression (55.1% vs 50.7%). TEAEs led to dose reduction in 65.2% vs 50.6%, dose interruption in 78.3% vs 68.8%, and permanent treatment discontinuation in 30.4% vs 25.4% of patients. The safety profile of bosutinib in Japanese patients was generally consistent with that in non-Japanese patients, despite a higher incidence of gastrointestinal, liver function, and rash events. TEAEs were largely manageable with dose modifications and supportive care in both groups. These data may help optimize TEAE management and outcomes in Japanese patients receiving bosutinib for CML. Trial registration ClinicalTrials.gov: NCT02130557, NCT03128411, NCT00574873, NCT00261846, NCT01903733, NCT00811070, NCT02228382.

Loss of Integrin-Linked Kinase Sensitizes Breast Cancer to SRC Inhibitors

SRC is a nonreceptor tyrosine kinase with key roles in breast cancer development and progression. Despite this, SRC tyrosine kinase inhibitors have so far failed to live up to their promise in clinical trials, with poor overall response rates. We aimed to identify possible synergistic gene-drug interactions to discover new rational combination therapies for SRC inhibitors. An unbiased genome-wide CRISPR-Cas9 knockout screen in a model of triple-negative breast cancer revealed that loss of integrin-linked kinase (ILK) and its binding partners α-Parvin and PINCH-1 sensitizes cells to bosutinib, a clinically approved SRC/ABL kinase inhibitor. Sensitivity to bosutinib did not correlate with ABL dependency; instead, bosutinib likely induces these effects by acting as a SRC tyrosine kinase inhibitor. Furthermore, in vitro and in vivo models showed that loss of ILK enhanced sensitivity to eCF506, a novel and highly selective inhibitor of SRC with a unique mode of action. Whole-genome RNA sequencing following bosutinib treatment in ILK knockout cells identified broad changes in the expression of genes regulating cell adhesion and cell-extracellular matrix. Increased sensitivity to SRC inhibition in ILK knockout cells was associated with defective adhesion, resulting in reduced cell number as well as increased G1 arrest and apoptosis. These findings support the potential of ILK loss as an exploitable therapeutic vulnerability in breast cancer, enhancing the effectiveness of clinical SRC inhibitors.

SIGNIFICANCE

A CRISPR-Cas9 screen reveals that loss of integrin-linked kinase synergizes with SRC inhibition, providing a new opportunity for enhancing the clinical effectiveness of SRC inhibitors in breast cancer.

A phase 3, open-label, randomized study of asciminib, a STAMP inhibitor, vs bosutinib in CML after 2 or more prior TKIs

Patients with chronic myeloid leukemia in chronic phase (CML-CP) resistant/intolerant to ≥2 tyrosine kinase inhibitors (TKIs) are at high risk of experiencing poor outcomes because of disease biology and inadequate efficacy and/or safety of current therapies. Asciminib, a first-in-class BCR-ABL1 inhibitor Specifically Targeting the ABL Myristoyl Pocket (STAMP), has the potential to overcome resistance/intolerance to approved TKIs. In this phase 3, open-label study, patients with CML-CP previously treated with ≥2 TKIs were randomized (2:1) to receive asciminib 40 mg twice daily vs bosutinib 500 mg once daily. Randomization was stratified by major cytogenetic response (MCyR) status at baseline. The primary objective was to compare the major molecular response (MMR) rate at week 24 for asciminib vs bosutinib. A total of 233 patients were randomized to asciminib (n = 157) or bosutinib (n = 76). Median follow-up was 14.9 months. The MMR rate at week 24 was 25.5% with asciminib and 13.2% with bosutinib. The difference in MMR rate between treatment arms, after adjusting for MCyR at baseline, was 12.2% (95% confidence interval, 2.19-22.30; 2-sided P = .029). Fewer grade ≥3 adverse events (50.6% vs 60.5%) and adverse events leading to treatment discontinuation (5.8% vs 21.1%) occurred with asciminib than with bosutinib. The study showed a superior efficacy of asciminib compared with that of bosutinib, together with a favorable safety profile. These results support the use of asciminib as a new therapy in patients with CML-CP who are resistant/intolerant to ≥2 prior TKIs. This trial was registered at www.clinicaltrials.gov as #NCT03106779.

Pharmacology and pharmacovigilance of protein kinase inhibitors

Protein kinase inhibitors experienced their advent in the 2000s. Their market introduction made it possible to constitute a class of targeted therapies administered orally. This name was chosen to mark a break with conventional chemotherapy drugs, but it is important to stress that these are multi-target drugs with complex affinity profiles. Adverse effects can be explained by direct interactions with their targets of interest, chosen for their indications (on-target) but also interactions with other targets (off-target). The adverse effect profiles of these drugs are therefore varied and it is possible to identify common profiles related to inhibitions of common targets. Identification of these targets has improved the global understanding of the pathophysiological mechanisms underlying the onset of adverse drug reactions as well as of the related diseases, and makes it possible to predict the adverse effect profile of new protein kinase inhibitors based on their affinities. In this review, we describe the main adverse drug reactions associated with protein kinase inhibitors, their frequency and their plausible mechanisms of action.

Acute Lymphoblastic Leukemia, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Acute Lymphoblastic Leukemia (ALL) focus on the classification of ALL subtypes based on immunophenotype and cytogenetic/molecular markers; risk assessment and stratification for risk-adapted therapy; treatment strategies for Philadelphia chromosome (Ph)-positive and Ph-negative ALL for both adolescent and young adult and adult patients; and supportive care considerations. Given the complexity of ALL treatment regimens and the required supportive care measures, the NCCN ALL Panel recommends that patients be treated at a specialized cancer center with expertise in the management of ALL This portion of the Guidelines focuses on the management of Ph-positive and Ph-negative ALL in adolescents and young adults, and management in relapsed settings.

Efficacy and safety following bosutinib dose reduction in patients with Philadelphia chromosome‒positive leukemias

The recommended starting dose of bosutinib is 500 mg/day for chronic-phase (CP) or accelerated-/blast-phase Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) resistant/intolerant to prior therapy. However, some patients may require dose reductions to manage the occurrences of adverse events (AEs). Bosutinib efficacy and safety were evaluated following dose reductions in a phase I/II study of Ph+ patients with CP CML resistant/intolerant to imatinib or imatinib plus dasatinib and/or nilotinib, and those with accelerated-/blast-phase CML or acute lymphoblastic leukemia after at least imatinib treatment. In all, 570 patients with ≥4 years' follow-up were included in this analysis. Among 144 patients who dose-reduced to bosutinib 400 mg/day (without reduction to 300 mg/day), 22 (15 %) had complete cytogenetic response (CCyR) before and after reduction, 40 (28 %) initially achieved CCyR after reduction, and 4 (3 %) only had CCyR before reduction. Among 95 patients who dose-reduced to bosutinib 300 mg/day, 23 (24 %) had CCyR before and after reduction, 13 (14 %) initially achieved CCyR after reduction, and 3 (3 %) only had CCyR before reduction. Results were similar to matched controls who remained on 500 mg/day, indicating dose reductions had not substantially affected efficacy. The incidence of treatment-emergent AEs was lower after dose reductions, particularly for gastrointestinal events. The incidence of hematologic toxicities generally was similar before and after dose reduction. The management of AEs with bosutinib through dose reduction can lead to improved/maintained efficacy and better tolerability; still, approximately half of patients on treatment at year 4 maintained a dose of ≥500 mg/day. ClinicalTrials.gov: NCT00261846.

dbMCS: A Database for Exploring the Mutation Markers of Anti-Cancer Drug Sensitivity

The identification of mutation markers and the selection of appropriate treatment for patients with specific genome mutations are important steps in the development of targeted therapies and the realization of precision medicine for human cancers. To investigate the baseline characteristics of drug sensitivity markers and develop computational methods of mutation effect prediction, we presented a manually curated online- based database of mutation Markers for anti-Cancer drug Sensitivity (dbMCS). Currently, dbMCS contains 1271 mutations and 4427 mutation-disease-drug associations (3151 and 1276 for sensitivity and resistance, respectively) with their PubMed indexed articles. By comparing the mutations in dbMCS with the putative neutral polymorphisms, we investigated the characteristics of drug sensitivity markers. We found that the mutation markers tend to significantly impact on high-conservative regions both in DNA sequences and protein domains. And some of them presented pleiotropic effects depending on the tumor context, appearing concurrently in the sensitivity and resistance categories. In addition, we preliminarily explored the machine learning-based methods for identifying mutation markers of anti-cancer drug sensitivity and produced optimistic results, which suggests that a reliable dataset may provide new insights and essential clues for future cancer pharmacogenomics studies. dbMCS is available at http://bioinfo.aielab.cc/dbMCS/.

Comparison of incidence/occurrence of cardiovascular events between ponatinib vs bosutinib among patients with at least one prior line of tyrosine kinase inhibitors in chronic myeloid leukemia in a community setting in the United States

INTRODUCTION

In this real-world study, the incidence of cardiovascular events (CV) including major adverse cardiac events (MACE), arterial occlusive events (AOE), and venous occlusive events (VOE) was evaluated in chronic myeloid leukemia (CML) patients treated with ponatinib or bosutinib in a US commercial database population.

MATERIALS AND METHODS

CML patients aged ≥18 years with use of 1 or 2 prior tyrosine kinase inhibitors prescribed bosutinib or ponatinib were selected from the IBM® MarketScan® Research database. Cox proportional hazard model analyses were conducted to examine any difference in CV event risk.

RESULTS

Ponatinib and bosutinib was associated with similar incidence and risk of CV events, including MACEs (HR: 1.02; 95% CI: 0.35, 3.01), AOEs (HR: 0.90; 95% CI: 0.43, 1.85) and VOEs (HR: 0.92; 95% CI: 0.44, 1.94).

CONCLUSION

Treatment with ponatinib or bosutinib was not associated with significant differences in the incidence of CV events in CML patients.

The role of E255K/V-inclusive mutations in a Philadelphia-positive acute lymphoblastic leukemia with mutation evolution during sequential TKIs therapies: A case report

RATIONALE

Until recently, the survival rate in patients with Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) was approximately 30%. Tyrosine kinase inhibitors (TKIs), which are a new class of drugs that target BCR-ABL fusion protein, have shown to be effective in treating Ph+ ALL in adults. However, the resistance mechanisms that promote the disease recurrence have altered the initial success of these revolutionary agents.

PATIENT CONCERNS

A 71-year-old Chinese female patient who suffered from severe shoulder and back pain for 1 week.

DIAGNOSIS

The patient was diagnosed with Ph+ ALL (B-cell) because of the following items. Complete blood count showed extremely abnormal white blood cell count (26.26×109/l), hemoglobin concentration (65 g/l) and platelet count (14×109/l). And because that Bone marrow aspirate showed 72.5% lymphoblasts and 59.30% lymphoblasts were confirmed by flow cytometry (FCM). At mean time, Real-time fluorescent quantitative PCR analysis confirmed that the P190 BCR/ABL fusion gene expression was 5.9%. Karyotype analysis indicated the following: 45, XX, -7, t (922) (q34; q11) [cp3].

INTERVENTIONS

The patient was treated with chemotherapy and different TKIs including imatinib, dasatinib, ponatinib, and bosutinib.

OUTCOMES

The patient achieved complete remissions with different TKIs after diagnose but relapsed afterward and died of infection.

LESSONS

Multidrug-resistant mutations within the BCR-ABL1 kinase domain are an emerging clinical problem for patients receiving sequential TKIs therapy. Acquisition of E255K/V-inclusive mutations is usually associated with ponatinib resistance, thus it is necessary to screen out new real pan-inhibitor compounds for all BCR/ABL mutations and figure out the potential efficacy of asciminib-based drug combinations in the future.

Recent Progress in the Development of Quinoline Derivatives for the Exploitation of Anti-Cancer Agents

BACKGROUND

Along with the progress in medicine and therapies, the exploitation of anti-cancer agents focused more on the vital signaling pathways and key biological macromolecules. With rational design and advanced synthesis, quinoline derivatives have been utilized frequently in medicinal chemistry, especially in developing anti-cancer drugs or candidates.

METHODS

Using DOI searching, articles published before 2020 all over the world have been reviewed as comprehensively as possible.

RESULTS

In this review, we selected the representative quinoline derivate drugs in market or clinical trials, classified them into five major categories with detailed targets according to their main mechanisms, discussed the relationship within the same mechanism, and generated a summative discussion with prospective expectations. For each mechanism, the introduction of the target was presented, with the typical examples of quinoline derivate drugs.

CONCLUSION

This review has highlighted the quinoline drugs or candidates, suited them into corresponding targets in their pathways, summarized and discussed. We hope that this review may help the researchers who are interested in discovering quinoline derivate anti-cancer agents obtain considerable understanding of this specific topic. Through the flourishing period and the vigorous strategies in clinical trials, quinoline drugs would be potential but facing new challenges in the future.

Clonal Upregulation of Effector Cytotoxic T Lymphocytes in a Patient with Multiple Tyrosine Kinase Inhibitor-Refractory Chronic Myeloid Leukemia with Long-Term Survival

We present the case of a patient with multiple tyrosine kinase inhibitor (TKI)-refractory chronic phase chronic myeloid leukemia (CP-CML) with a T315I mutation of abl1. Dasatinib, a second-generation TKI, was administered as the initial treatment but achieved neither a cytogenetic nor molecular response. A mutational analysis of abl1 revealed that the patient had a T315I mutation. The patient was then administered ponatinib, a third-generation TKI, which is thought to be effective against T315I; however, the complete blood counts became within normal limits, and neither a cytogenetic nor molecular response was achieved. However, the patient has maintained a healthy chronic phase (with no blast crises) for more than 5½ years since the diagnosis of CP-CML. T-cell receptor (TCR) repertoire analyses using peripheral blood revealed a remarkable clonal expansion of effector cytotoxic T lymphocytes (CTLs) that contained TCR V beta 13.6. We observed the clonal expansion of naïve CTLs with TCR V beta 13.6; however, no clonality was observed in the memory CTLs. The naïve and effector CTLs persisted at very high percentages since the seventh month after starting dasatinib. The CTLs could not have led to the molecular response; therefore, there might be plenty of CML stem cells remaining in the bone marrow. Therefore, although the CTLs might have prevented the disease from developing blast crises over more than 5 years, the CTLs might not have been able to become memory CTLs.

Long-term cardiac, vascular, hypertension, and effusion safety of bosutinib in patients with Philadelphia chromosome-positive leukemia resistant or intolerant to prior therapy

INTRODUCTION

Long-term follow-up (≥4 years) demonstrated a low incidence of cardiac and vascular treatment-emergent adverse events (TEAEs) with bosutinib treatment. We evaluated cardiac, vascular, hypertension, and effusion TEAEs after ≥ 7 years of follow-up in patients with Philadelphia chromosome-positive (Ph+) leukemia.

METHODS

This retrospective analysis of a phase I/II study and its ongoing extension study included data from patients with chronic phase chronic myeloid leukemia (CML) treated with bosutinib after resistance/intolerance to imatinib (CP2L) or to imatinib plus dasatinib and/or nilotinib (CP3L), and those with accelerated/blast phase CML or acute lymphoblastic leukemia after treatment with, at a minimum, imatinib (ADV).

RESULTS

In all, 570 patients were treated with bosutinib; median treatment duration was 11.1 months (range: 0.03-133.1). The incidence of cardiac, vascular, hypertension, and effusion-related TEAEs was 10.9%, 8.8%, 9.1%, and 13.3%, respectively. Few patients had maximum grade 3-4 TEAEs (cardiac, 3.9%; vascular, 4.0%; hypertension, 3.0%; effusion, 4.6%). Grade 5 TEAEs occurred in the cardiac (0.7%) and vascular (1.8%) clusters only. In years 5-7, fewer than 5% of patients each year had newly occurring cardiac, vascular, hypertension, or effusion TEAEs. The exposure-adjusted TEAE rates (patients with TEAEs/total patient-year) pooled across CP2L, CP3L, and ADV cohorts were as follows: cardiac, 0.044; vascular, 0.035; hypertension, 0.038; and effusion, 0.056, of which, correspondingly, 0.9%, 1.2%, 0%, and 2.1% required treatment discontinuation.

CONCLUSIONS

The incidence of cardiac, hypertension, vascular, and effusion events was low in patients with Ph+ CML resistant or intolerant to prior therapy who were treated with bosutinib.

Chronic Myeloid Leukemia: Modern therapies, current challenges and future directions

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm caused by a reciprocal translocation [t(9;22)(q34;q11.2)] that leads to the fusion of ABL1 gene sequences (9q34) downstream of BCR gene sequences (22q11) and is cytogenetically visible as Philadelphia chromosome (Ph). The resulting BCR/ABL1 chimeric protein is a constitutively active tyrosine kinase that activates multiple signaling pathways, which collectively lead to malignant transformation. During the early (chronic) phase of CML (CP-CML), the myeloid cell compartment is expanded, but differentiation is maintained. Without effective therapy, CP-CML invariably progresses to blast phase (BP-CML), an acute leukemia of myeloid or lymphoid phenotype. The development of BCR-AB1 tyrosine kinase inhibitors (TKIs) revolutionized the treatment of CML and ignited the start of a new era in oncology. With three generations of BCR/ABL1 TKIs approved today, the majority of CML patients enjoy long term remissions and near normal life expectancy. However, only a minority of patients maintain remission after TKI discontinuation, a status termed treatment free remission (TFR). Unfortunately, 5-10% of patients fail TKIs due to resistance and are at risk of progression to BP-CML, which is curable only with hematopoietic stem cell transplantation. Overcoming TKI resistance, improving the prognosis of BP-CML and improving the rates of TFR are areas of active research in CML.

Bosutinib in the real-life treatment of chronic myeloid leukemia patients aged >65 years resistant/intolerant to previous tyrosine-kinase inhibitors

To evaluate the role of bosutinib in elderly patients aged >65 years with chronic myeloid leukemia (CML), a real-life cohort of 101 chronic-phase CML patients followed up in 23 Italian centers and treated with bosutinib in second or a subsequent line was retrospectively evaluated. Starting dose of bosutinib was 500 mg/day in 25 patients (24.8%), 400 mg/day in 7 patients (6.9%), 300 mg/day in 33 patients (32.7%), 200 mg/day in 34 patients (33.6%), and 100 mg/day in 2 patients (2.0%). Grade 3/4 hematological toxicity occurred in 7/101 patients (6.9%) and grade 3/4 extra-hematological toxicity in 19/101 patients (18.8%). Permanent bosutinib discontinuation due to toxicity was needed in 12 patients (11.9%). Among the 96 patients evaluable for response, 74 (77.0%) achieved a complete cytogenetic response (CCyR), while 64 of these 74 patients in CCyR (66.6% of all 96 evaluable patients) also achieved a molecular response (MR) (major MR [MR 3.0] in 21 [21.8%], deep MR [MR 4.0/4.5] in 43 [44.8%]). The 3-year event-free survival and overall survival of the whole patients' cohort from bosutinib start were 60.9% (CI 95% 49.3-72.5) and 86.4% (CI 95% 77.2-95.6), respectively. Our real-life data show that bosutinib is effective, with a favorable safety profile, also in elderly patients with important comorbidities and resistance and/or intolerance to previous tyrosine-kinase inhibitor treatments. As a consequence, it could play a significant role in current clinical practice for frail patients.

Higher red blood cell distribution width at diagnose is a simple negative prognostic factor in chronic phase-chronic myeloid leukemia patients treated with tyrosine kinase inhibitors: A retrospective study

The aim of this study was to evaluate the ability of the red blood cell distribution width (RDW) to predict prognosis and treatment response in chronic myeloid leukemia (CML)-chronic phase (CP) patients treated with tyrosine kinase inhibitor (TKIs).We retrospectively enrolled 93 newly diagnosed CML-CP patients treated with TKIs from 2009 to 2018 at the First Hospital of Lanzhou University. Patients were divided into 2 groups using an RDW of 18.65% determined by receiver operating characteristic curve analysis. We analyzed the correlation of treatment responses and the RDW compared to common scoring systems, as well as the correlation of the RDW with disease outcome, including overall survival (OS) and progression-free survival (PFS), and demographic and laboratory factors affecting outcome. Univariate analysis and Cox regression analysis were used.The median age of patients was 40 years, and 51 patients (54.8%) were men. A high RDW could predict treatment response at 3 months (P = .03) and 6 months (P = .02). The RDW was significantly lower in patients who achieved molecular response by 3 months (P < .001) and complete cytogenetic response by 6 months (P = .001) than in those who did not respond. Patients with a high RDW (>18.65%, n = 35) had significantly worse 5-year OS (77.1% vs 96.6%; P = .008) and PFS (80.0% vs 98.3%; P = .002) than those with a low RDW (≤18.65%, n = 58). Multivariate analysis demonstrated that a high RDW was an adverse predictor of OS (P = .005, HR (hazard ratio) = 9.741) and PFS (P = .009, HR = 16.735).The RDW is a readily available prognostic marker of outcome in patients with CML-CP and can predict treatment response to TKIs. Further larger and prospective studies are required.

Bosutinib reduces endothelial permeability and organ failure in a rat polytrauma transfusion model

BACKGROUND

Trauma-induced shock is associated with endothelial dysfunction. We examined whether the tyrosine kinase inhibitor bosutinib as an adjunct therapy to a balanced blood component resuscitation strategy reduces trauma-induced endothelial permeability, thereby improving shock reversal and limiting transfusion requirements and organ failure in a rat polytrauma transfusion model.

METHODS

Male Sprague-Dawley rats (n=13 per group) were traumatised and exsanguinated until a MAP of 40 mm Hg was reached, then randomised to two groups: red blood cells, plasma and platelets in a 1:1:1 ratio with either bosutinib or vehicle. Controls were randomised to sham (median laparotomy, no trauma) with bosutinib or vehicle. Organs were harvested for histology and wet/dry (W/D) weight ratio.

RESULTS

Traumatic injury resulted in shock, with higher lactate levels compared with controls. In trauma-induced shock, the resuscitation volume needed to obtain a MAP of 60 mm Hg was lower in bosutinib-treated animals (2.8 [2.7-3.2] ml kg^-1) compared with vehicle (6.1 [5.1-7.2] ml kg^-1, P<0.001). Lactate levels in the bosutinib group were 2.9 [1.7-4.8] mM compared with 6.2 [3.1-14.1] mM in the vehicle group (P=0.06). Bosutinib compared with vehicle reduced lung vascular leakage (W/D ratio of 5.1 [4.6-5.3] vs 5.7 [5.4-6.0] (P=0.046) and lung injury scores (P=0.027).

CONCLUSIONS

Bosutinib as an adjunct therapy to a balanced transfusion strategy reduced resuscitation volume, improved shock reversal, and reduced vascular leak and organ injury in a rat polytrauma model.

Computational and Biological Investigations on Abl1 Tyrosine Kinase: A Review

Abl1 tyrosine kinase is a validated target for the treatment of chronic myeloid leukemia. It is a form of cancer that is difficult to treat and much research is being done to identify new molecular entities and to tackle drug resistance issues. In recent years, drug resistance of Abl1 tyrosine kinase has become a major healthcare concern. Second and third-generation TKI reported better responses against the resistant forms; still they had no impact on long-term survival prolongation. New compounds derived from natural products and organic small molecule inhibitors can lay the foundation for better clinical therapies in the future. Computational methods, experimental and biological studies can help us understand the mechanism of drug resistance and identify novel molecule inhibitors. ADMET parameters analysis of reported drugs and novel small molecule inhibitors can also provide valuable insights. In this review, available therapies, point mutations, structure-activity relationship and ADMET parameters of reported series of Abl1 tyrosine kinase inhibitors and drugs are summarised. We summarise in detail recent computational and molecular biology studies that focus on designing drug molecules, investigation of natural product compounds and organic new chemical entities. Current ongoing research suggests that selective targeting of Abl1 tyrosine kinase at the molecular level to combat drug resistance in chronic myeloid leukemia is promising.

Chronic Myeloid Leukemia, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

Chronic myeloid leukemia (CML) is defined by the presence of Philadelphia chromosome (Ph) which results from a reciprocal translocation between chromosomes 9 and 22 [t(9;22] that gives rise to a BCR-ABL1 fusion gene. CML occurs in 3 different phases (chronic, accelerated, and blast phase) and is usually diagnosed in the chronic phase. Tyrosine kinase inhibitor therapy is a highly effective first-line treatment option for all patients with newly diagnosed chronic phase CML. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnosis and management of patients with chronic phase CML.

Repurposing of Kinase Inhibitors for Treatment of COVID-19

The outbreak of COVID-19, the pandemic disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spurred an intense search for treatments by the scientific community. In the absence of a vaccine, the goal is to target the viral life cycle and alleviate the lung-damaging symptoms of infection, which can be life-threatening. There are numerous protein kinases associated with these processes that can be inhibited by FDA-approved drugs, the repurposing of which presents an alluring option as they have been thoroughly vetted for safety and are more readily available for treatment of patients and testing in clinical trials. Here, we characterize more than 30 approved kinase inhibitors in terms of their antiviral potential, due to their measured potency against key kinases required for viral entry, metabolism, or reproduction. We also highlight inhibitors with potential to reverse pulmonary insufficiency because of their anti-inflammatory activity, cytokine suppression, or antifibrotic activity. Certain agents are projected to be dual-purpose drugs in terms of antiviral activity and alleviation of disease symptoms, however drug combination is also an option for inhibitors with optimal pharmacokinetic properties that allow safe and efficacious co-administration with other drugs, such as antiviral agents, IL-6 blocking agents, or other kinase inhibitors.

Bosutinib for pretreated patients with chronic phase chronic myeloid leukemia: primary results of the phase 4 BYOND study

Bosutinib is approved for newly diagnosed Philadelphia chromosome-positive (Ph+) chronic phase (CP) chronic myeloid leukemia (CML) and for Ph+ CP, accelerated (AP), or blast (BP) phase CML after prior treatment with tyrosine kinase inhibitors (TKIs). In the ongoing phase 4 BYOND study (NCT02228382), 163 CML patients resistant/intolerant to prior TKIs (n = 156 Ph+ CP CML, n = 4 Ph+ AP CML, n = 3 Ph-negative/BCR-ABL1+ CML) received bosutinib 500 mg once daily (starting dose). As of ≥1 year after last enrolled patient (median treatment duration 23.7 months), 56.4% of Ph+ CP CML patients remained on bosutinib. Primary endpoint of cumulative confirmed major cytogenetic response (MCyR) rate by 1 year was 75.8% in Ph+ CP CML patients after one or two prior TKIs and 62.2% after three prior TKIs. Cumulative complete cytogenetic response (CCyR) and major molecular response (MMR) rates by 1 year were 80.6% and 70.5%, respectively, in Ph+ CP CML patients overall. No patient progressed to AP/BP on treatment. Across all patients, the most common treatment-emergent adverse events were diarrhea (87.7%), nausea (39.9%), and vomiting (32.5%). The majority of patients had confirmed MCyR by 1 year and MMR by 1 year, further supporting bosutinib use for Ph+ CP CML patients resistant/intolerant to prior TKIs.

Current Treatment Options for Chronic Myeloid Leukemia Patients Failing Second-Generation Tyrosine Kinase Inhibitors

Despite the excellent overall survival (OS) of patients with chronic myeloid leukemia (CML), a significant proportion will not achieve optimal response to imatinib or second-generation tyrosine kinase inhibitors (2GTKI). For patients with inadequate response to 2GTKIs, alternative 2GTKIs or ponatinib are widely available treatment options in daily clinical practice. Treatment decisions should be guided by correct identification of the cause of treatment failure and accurate distinction between resistant from intolerant or nonadherence patients. This review aims to provide practical advice on how to select the best treatment option in each clinical scenario.

Long-Term Patterns of Oral Anticancer Agent Adoption, Duration, and Switching in Patients With CML

BACKGROUND

Oral tyrosine kinase inhibitors (TKIs) have been the standard of care for chronic myeloid leukemia (CML) since 2001. However, few studies have evaluated changes in the treatment landscape of CML over time. This study assessed the long-term treatment patterns of oral anticancer therapies among patients with CML.

METHODS

This retrospective cohort study included patients newly diagnosed with CML between January 1, 2000, and December 31, 2016, from 10 integrated healthcare systems. The proportion of patients treated with 5 FDA-approved oral TKI agents-bosutinib, dasatinib, imatinib, nilotinib, and ponatinib-in the 12 months after diagnosis were measured, overall and by year, between 2000 and 2017. We assessed the use of each oral agent through the fourth-line setting. Multivariable logistic regression estimated the odds of receiving any oral agent, adjusting for sociodemographic and clinical characteristics.

RESULTS

Among 853 patients with CML, 81% received an oral agent between 2000 and 2017. Use of non-oral therapies decreased from 100% in 2000 to 5% in 2005, coinciding with imatinib uptake from 65% in 2001 to 98% in 2005. Approximately 28% of patients switched to a second-line agent, 9% switched to a third-line agent, and 2% switched to a fourth-line agent. Adjusted analysis showed that age at diagnosis, year of diagnosis, and comorbidity burden were statistically significantly associated with odds of receiving an oral agent.

CONCLUSIONS

A dramatic shift was seen in CML treatments away from traditional, nonoral chemotherapy toward use of novel oral TKIs between 2000 and 2017. As the costs of oral anticancer agents reach new highs, studies assessing the long-term health and financial outcomes among patients with CML are warranted.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Bosutinib prevents vascular leakage by reducing focal adhesion turnover and reinforcing junctional integrity

Endothelial barrier dysfunction leads to edema and vascular leak, causing high morbidity and mortality. Previously, Abl kinase inhibition has been shown to protect against vascular leak. Using the distinct inhibitory profiles of clinically available Abl kinase inhibitors, we aimed to provide a mechanistic basis for novel treatment strategies against vascular leakage syndromes. We found that the inhibitor bosutinib most potently protected against inflammation-induced endothelial barrier disruption. In vivo, bosutinib prevented lipopolysaccharide (LPS)-induced alveolar protein extravasation in an acute lung injury mice model. Mechanistically, mitogen-activated protein 4 kinase 4 (MAP4K4) was identified as important novel mediator of endothelial permeability, which signaled via ezrin, radixin and moesin proteins to increase turnover of integrin-based focal adhesions. The combined inhibition of MAP4K4 and Abl-related gene (Arg, also known as ABL2) by bosutinib preserved adherens junction integrity and reduced turnover of focal adhesions, which synergistically act to stabilize the endothelial barrier during inflammation. We conclude that MAP4K4 is an important regulator of endothelial barrier integrity, increasing focal adhesion turnover and disruption of cell-cell junctions during inflammation. Because it inhibits both Arg and MAP4K4, use of the clinically available drug bosutinib might form a viable strategy against vascular leakage syndromes.