Long-term efficacy and safety of bosutinib in patients with advanced leukemia following resistance/intolerance to imatinib and other tyrosine kinase inhibitors

A review of immunotargeted therapy for Philadelphia chromosome positive acute lymphoblastic leukaemia: making progress in chemotherapy-free regimens

Philadelphia chromosome-positive acute lymphoblastic leukemia (PH + ALL) is the most common cytogenetic abnormality of B-ALL in adults and is associated with poor prognosis. Previously, the only curative treatment option in PH + ALL was allogeneic hematopoietic stem cell transplantation (Allo-HSCT). Since 2000, targeted therapy combined with chemotherapy, represented by the tyrosine kinase inhibitor Imatinib, has become the first-line treatment for PH + ALL. Currently, the remission rate and survival rate of Imatinib are superior to those of simple chemotherapy, and it can also improve the efficacy of transplantation. More recently, some innovative immune-targeted therapy greatly improved the prognosis of PH + ALL, such as Blinatumomab and Inotuzumab Ozogamicin. For patients with ABL1 mutations and those who have relapsed or are refractory to other treatments, targeted oral small molecule drugs, monoclonal antibodies, Bispecific T cell Engagers (BiTE), and chimeric antigen receptor (CAR) T cells immunotherapy are emerging as potential treatment options. These new therapeutic interventions are changing the treatment landscape for PH + ALL. In summary, this review discusses the current advancements in targeted therapeutic agents shift in the treatment strategy of PH + ALL towards using more tolerable chemotherapy-free induction and consolidation regimens confers better disease outcomes and might obviate the need for HSCT.

Tyrosine kinase inhibitors in cancers: Treatment optimization - Part I

A multitude of TKI has been developed and approved targeting various oncogenetic alterations. While these have provided improvements in efficacy compared with conventional chemotherapies, resistance to targeted therapies occurs. Mutations in the kinase domain result in the inability of TKI to inactivate the protein kinase. Also, gene amplification, increased protein expression and downstream activation or bypassing of signalling pathways are commonly reported mechanisms of resistance. Improved understanding of mechanisms involved in TKI resistance has resulted in the development of new generations of targeted agents. In a race against time, the search for new, more potent and efficient drugs, and/or combinations of drugs, remains necessary as new resistance mechanisms to the latest generation of TKI emerge. This review examines the various generations of TKI approved to date and their common mechanisms of resistance, focusing on TKI targeting BCR-ABL, epidermal growth factor receptor, anaplastic lymphoma kinase and BRAF/MEK tyrosine kinases.

Management and outcome of patients with chronic myeloid leukemia in blast phase in the tyrosine kinase inhibitor era - analysis of the European LeukemiaNet Blast Phase Registry

Blast phase (BP) of chronic myeloid leukemia (CML) still represents an unmet clinical need with a dismal prognosis. Due to the rarity of the condition and the heterogeneity of the biology and clinical presentation, prospective trials and concise treatment recommendations are lacking. Here we present the analysis of the European LeukemiaNet Blast Phase Registry, an international collection of the clinical presentation, treatment and outcome of blast phases which had been diagnosed in CML patients after 2015. Data reveal the expected heterogeneity of the entity, lacking a clear treatment standard. Outcomes remain dismal, with a median overall survival of 23.8 months (median follow up 27.8 months). Allogeneic stem cell transplantation (alloSCT) increases the rate of deep molecular responses. De novo BP and BP evolving from a previous CML do show slightly different features, suggesting a different biology between the two entities. Data show that outside clinical trials and in a real-world setting treatment of blast phase is individualized according to disease- and patient-related characteristics, with the aim of blast clearance prior to allogeneic stem cell transplantation. AlloSCT should be offered to all patients eligible for this procedure.

Boosting synergism of chemo- and immuno-therapies via switching paclitaxel-induced apoptosis to mevalonate metabolism-triggered ferroptosis by bisphosphonate coordination lipid nanogranules

Conventional chemotherapy based on cytotoxic drugs is facing tough challenges recently following the advances of monoclonal antibodies and molecularly targeted drugs. It is critical to inspire new potential to remodel the value of this classical therapeutic strategy. Here, we fabricate bisphosphonate coordination lipid nanogranules (BC-LNPs) and load paclitaxel (PTX) to boost the chemo- and immuno-therapeutic synergism of cytotoxic drugs. Alendronate in BC-LNPs@PTX, a bisphosphonate to block mevalonate metabolism, works as both the structure and drug constituent in nanogranules, where alendronate coordinated with calcium ions to form the particle core. The synergy of alendronate enhances the efficacy of paclitaxel, suppresses tumor metastasis, and alters the cytotoxic mechanism. Differing from the paclitaxel-induced apoptosis, the involvement of alendronate inhibits the mevalonate metabolism, changes the mitochondrial morphology, disturbs the redox homeostasis, and causes the accumulation of mitochondrial ROS and lethal lipid peroxides (LPO). These factors finally trigger the ferroptosis of tumor cells, an immunogenic cell death mode, which remodels the suppressive tumor immune microenvironment and synergizes with immunotherapy. Therefore, by switching paclitaxel-induced apoptosis to mevalonate metabolism-triggered ferroptosis, BC-LNPs@PTX provides new insight into the development of cytotoxic drugs and highlights the potential of metabolism regulation in cancer therapy.

Cross-intolerance with bosutinib after prior tyrosine kinase inhibitors for Philadelphia chromosome-positive leukemia: long-term analysis of a phase I/II study

Not available.

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.

Bosutinib-induced massive pleural effusion: Cross-intolerance with all tyrosine kinase inhibitors

BACKGROUND

The discovery of tyrosine kinase inhibitors provided a breakthrough in the treatment of chronic myeloid leukemia. Nowadays, the management of tyrosine kinase inhibitor-related side effects is one of the important problems in chronic myeloid leukemia treatment. Grades 3-4 pulmonary toxicity; especially pleural effusion is mostly seen with dasatinib treatment but rarely seen with nilotinib and bosutinib. Development of cross-intolerance due to pleural effusion is not an expected situation. Pleural effusion related to tyrosine kinase inhibitors is mostly exudative in nature with abundant lymphocytes.

CASE REPORT

Massive pleural effusion developed in a 59-year-old male patient with chronic myeloid leukemia, who was being treated with bosutinib. In the past, the patient had experienced massive pleural effusion also with dasatinib and nilotinib. The evaluation for differential diagnosis of pleural effusion did not reveal any additional malignancy.

MANAGEMENT AND OUTCOME

After discontinuation of bosutinib and initiation of prednisolone, pleural effusion was totally resolved. Prednisolone was gradually discontinued and third-generation tyrosine kinase inhibitor ponatinib was started. After 12 months of follow-up, massive pleural effusion occurred again, leading to discontinuation of ponatinib.

DISCUSSION

Cross-intolerance is an important problem in the tyrosine kinase inhibitor era. The significance of this case is the development of cross-intolerance to all second-generation tyrosine kinase inhibitors and furthermore to a third-generation tyrosine kinase inhibitor. Management strategies for pleural effusion and close follow-up are important.

Current Management of Chronic Myeloid Leukemia Myeloid Blast Phase

Despite the major advancements in the management of chronic phase (CP) chronic myeloid leukemia (CML), blast crisis (BC) remains a major therapeutic challenge. BC can be myeloid, lymphoid, or mixed lineage with myeloid BC being the most common type. BC in CML is mediated by aberrant tyrosine kinase activity of the BCR::ABL fusion protein. The introduction of BCR::ABL tyrosine kinase inhibitor (TKI) has been a gamechanger in the treatment of CML and there has been a significant reduction in the incidence of BC. The main treatment goal in BC is to achieve a second CP and consolidate that with an allogeneic stem cell transplantation (SCT) in eligible patients. The outcomes in BC remain dismal even in the current era. In this review, we provide an overview of the biology and current therapeutic approach in myeloid BC.

Treatment of blast phase chronic myeloid leukaemia: A rare and challenging entity

Despite the success of BCR-ABL-specific tyrosine kinase inhibitors (TKIs) such as imatinib in chronic phase (CP) chronic myeloid leukaemia (CML), patients with blast phase (BP)-CML continue to have a dismal outcome with median survival of less than one year from diagnosis. Thus BP-CML remains a critical unmet clinical need in the management of CML. Our understanding of the biology of BP-CML continues to grow; genomic instability leads to acquisition of mutations which drive leukaemic progenitor cells to develop self-renewal properties, resulting in differentiation block and a poor-prognosis acute leukaemia which may be myeloid, lymphoid or bi-phenotypic. Similar advances in therapy are urgently needed to improve patient outcomes; however, this is challenging given the rarity and heterogeneity of BP-CML, leading to difficulty in designing and recruiting to prospective clinical trials. This review will explore the treatment of BP-CML, evaluating the data for TKI therapy alone, combinations with intensive chemotherapy, the role of allogeneic haemopoietic stem cell transplantation, the use of novel agents and clinical trials, as well as discussing the most appropriate methods for diagnosing BP and assessing response to therapy, and factors predicting outcome.

The Role of Bosutinib in Chronic Myeloid Leukemia: An Indian Perspective

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.

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.

Bosutinib-induced lung injury: a report of two cases and literature review

The prognosis of patients with chronic myeloid leukemia (CML) has improved dramatically since the development of tyrosine kinase inhibitors (TKIs). Three second-generation TKIs, including bosutinib, are currently approved for treatment of CML, and show a faster and deeper clinical response than imatinib. Common adverse events (AEs) of bosutinib are diarrhea and hepatic toxicity; however, lung complications are rare. Here, we report two cases of bosutinib-induced severe lung injury, along with a literature review. The events of these cases occurred at early time points and severity was extremely high, requiring high-flow oxygen and steroid treatments. Compared to previously reported cases, the prevalence and severity of the damage may vary among different ethnicities. However, bosutinib-induced lung injury can cause life-threatening complications. In conclusion, patients treated with bosutinib should be monitored carefully to mitigate serious drug-induced lung injury.

Blast and accelerated phase CML: room for improvement

Tyrosine kinase inhibitors (TKIs) revolutionized the treatment of chronic myeloid leukemia (CML). With TKI therapy, the percentage of patients who progress to accelerated phase (AP) or blast phase (BP) CML has decreased from more than 20% to 1% to 1.5% per year. Although AP- and BP-CML occur in a minority of patients, outcomes in these patients are significantly worse compared with chronic phase CML, with decreased response rates and duration of response to TKI. Despite this, TKIs have improved outcomes in advanced phase CML, particularly in de novo AP patients, but are often inadequate for lasting remissions. The goal of initial therapy in advanced CML is a return to a chronic phase followed by consideration for bone marrow transplantation. The addition of induction chemotherapy with TKI is often necessary for achievement of a second chronic phase. Given the small population of patients with advanced CML, development of novel treatment strategies and investigational agents is challenging, although clinical trial participation is encouraged in AP and BP patients, whenever possible. We review the overall management approach to advanced CML, including TKI selection, combination therapy, consideration of transplant, and novel agents.

Chronic myeloid leukaemia

Tyrosine-kinase inhibitors have changed the natural history of chronic myeloid leukaemia in such a way that patients with adequate access to these agents, who are properly managed, and who respond well to this treatment can expect a near-normal life expectancy. Achieving this goal requires an adequate understanding of the patient's treatment goals, careful monitoring for the achievement of optimal response hallmarks, implementation of proper interventions according to the attainment of such endpoints, adequate recognition and management of adverse events, and acknowledgment of the relevance of comorbidities. Treatment with tyrosine-kinase inhibitors, once considered lifelong, has become terminable for at least some patients, and promising new agents are emerging for those whose disease does not respond to any of the multiple therapeutic options currently available. If these advances reach all patients with chronic myeloid leukaemia, cure might eventually become a reality in most instances.

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.

Inotuzumab ozogamicin with bosutinib for relapsed or refractory Philadelphia chromosome positive acute lymphoblastic leukemia or lymphoid blast phase of chronic myeloid leukemia

Relapsed/refractory (R/R) Philadelphia chromosome positive acute lymphoblastic leukemia (Ph + ALL) and lymphoid blast phase of chronic myeloid leukemia (LBP-CML) have poor outcomes. We designed a phase 1/2 study combining inotuzumab ozogamicin with bosutinib for this patient population. Patients with T315I mutation were excluded. Bosutinib was administered daily at three dose levels (300 mg/d, 400 mg/d, 500 mg/d) in a 3 + 3 design. Inotuzumab ozogamicin was dosed weekly during cycle one, and once every 4 weeks subsequently for a total of six cycles. The primary objective was to determine the safety and the maximum tolerated dose (MTD) of bosutinib in combination with inotuzumab ozogamicin. Eighteen patients were enrolled (Ph-positive ALL, n = 16; LBP-CML, n = 2). The median age was 62 years (range, 19-74) and the median number of prior therapies was one (range, 1-5). Dose limiting toxicities included grade 3 skin rash and bosutinib 400 mg daily was determined as the MTD. The most frequent grade 3/4 treatment-emergent adverse events were thrombocytopenia (60%) and neutropenia (38%). A complete response (CR) / CR with incomplete count recovery (CRi) was achieved in 15/18 (83%) patients; 11/18 (61%) patients achieved negative measurable residual disease by flow cytometry. Complete molecular response was noted in 10/18 (56%) patients. The 30-day mortality was 0%. After a median follow-up of 44 months, the median duration of response and overall survival were 7.7 months and 13.5 months, respectively. Six patients had a subsequent allogeneic stem cell transplant. No patient developed veno-occlusive disease. Inotuzumab ozogamicin with bosutinib was well tolerated in R/R Ph-positive ALL and LBP-CML.

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.

Bosutinib-associated interstitial lung disease and pleural effusion: A case report and literature review

Bosutinib is a tyrosine kinase inhibitor approved for the management of chronic myeloid leukemia (CML). Interstitial lung disease and pleural effusion are pulmonary side effects of TKIs rarely associated with bosutinib treatment.

Recommendations for the management of cardiovascular risk in patients with chronic myeloid leukemia on tyrosine kinase inhibitors: risk assessment, stratification, treatment and monitoring

This manuscript summarizes the results of the consensus meeting composed of hematologists and cardiologists to establish recommendations for the prevention and follow-up of cardiovascular (CV) risk in patients with chronic myeloid leukemia (CML) treated with BCR-ABL tyrosine kinase inhibitors (TKIs) from the point of view of clinical practice and from the perspective of hematology consultation. In the first medical appointment, the CV risk factors should be identified to perform the baseline risk stratification, based on the Brazilian Guideline of Dyslipidemia and Atherosclerosis Prevention Update (risk levels: very high, high, intermediate and low). Once stratified, the treatment of the CV risk factors should be administered. If the patient presents risk factors, such as hypertension, diabetes, renal disease, smoking and hypercholesterolemia, the evaluation and initial treatment may be done by the hematologist, being an option the request for evaluation by a specialist. If the patient has a history of previous CV disease, we recommend referral to a specialist. As the CV risk score is dynamic and the control of risk factors can reduce the patient risk, this expert consensus recommends that the re-evaluation of the CV risk after the baseline should be performed at 3 months, 6 months and 12 months. After this period, it should be done annually and, for specific patients, at the clinician's discretion. The evaluation of the baseline CV risk and the safe administration of a TKI allow the patient to benefit from the maximum treatment, avoiding unwanted effects.

Treatment and outcome of Philadelphia chromosome-positive acute lymphoblastic leukemia in adults after relapse

INTRODUCTION

Despite the significant progress that has been made over the last years in the front-line treatment of Philadelphia (Ph) chromosome-positive acute lymphoblastic leukemia (ALL), relapses are frequent and their treatment remains a challenge, especially among patients with resistant BCR-ABL1 mutations.

AREAS COVERED

This manuscript reviews available data for the treatment of adult patients with relapsed/refractory Ph-positive ALL, with a focus on the role of tyrosine kinase inhibitors (TKIs), monoclonal antibodies, and immunotherapy.

EXPERT OPINION

Although a majority of patients with first relapsed Ph-positive ALL respond to subsequent salvage chemotherapy plus TKI combination, their outcomes remain poor. The main predictor of survival is the achievement of major molecular response anytime during the morphological response. More treatment strategies to improve survival are under investigation. Monoclonal antibodies and bispecific antibody constructs hold considerable promise in improving the outcomes of patients with relapsed ALL including Ph-positive ALL.

Philadelphia Chromosome-Positive Leukemia in the Lymphoid Lineage-Similarities and Differences with the Myeloid Lineage and Specific Vulnerabilities

Philadelphia chromosome (Ph) results from a translocation between the breakpoint cluster region (BCR) gene on chromosome 9 and ABL proto-oncogene 1 (ABL1) gene on chromosome 22. The fusion gene, BCR-ABL1, is a constitutively active tyrosine kinase which promotes development of leukemia. Depending on the breakpoint site within the BCR gene, different isoforms of BCR-ABL1 exist, with p210 and p190 being the most prevalent. P210 isoform is the hallmark of chronic myeloid leukemia (CML), while p190 isoform is expressed in majority of Ph-positive B cell acute lymphoblastic leukemia (Ph+ B-ALL) cases. The crucial component of treatment protocols of CML and Ph+ B-ALL patients are tyrosine kinase inhibitors (TKIs), drugs which target both BCR-ABL1 isoforms. While TKIs therapy is successful in great majority of CML patients, Ph+ B-ALL often relapses as a drug-resistant disease. Recently, the high-throughput genomic and proteomic analyses revealed significant differences between CML and Ph+ B-ALL. In this review we summarize recent discoveries related to differential signaling pathways mediated by different BCR-ABL1 isoforms, lineage-specific genetic lesions, and metabolic reprogramming. In particular, we emphasize the features distinguishing Ph+ B-ALL from CML and focus on potential therapeutic approaches exploiting those characteristics, which could improve the treatment of Ph+ B-ALL.

Secondary Resistant Mutations to Small Molecule Inhibitors in Cancer Cells

Secondary resistant mutations in cancer cells arise in response to certain small molecule inhibitors. These mutations inevitably cause recurrence and often progression to a more aggressive form. Resistant mutations may manifest in various forms. For example, some mutations decrease or abrogate the affinity of the drug for the protein. Others restore the function of the enzyme even in the presence of the inhibitor. In some cases, resistance is acquired through activation of a parallel pathway which bypasses the function of the drug targeted pathway. The Catalogue of Somatic Mutations in Cancer (COSMIC) produced a compendium of resistant mutations to small molecule inhibitors reported in the literature. Here, we build on these data and provide a comprehensive review of resistant mutations in cancers. We also discuss mechanistic parallels of resistance.

Management of Chronic Myeloid Leukemia in Advanced Phase

Management of chronic myeloid leukemia (CML) in advanced phases remains a challenge also in the era of tyrosine kinase inhibitors (TKIs) treatment. Cytogenetic clonal evolution and development of resistant mutations represent crucial events that limit the benefit of subsequent therapies in these patients. CML is diagnosed in accelerated (AP) or blast phase (BP) in <5% of patients, and the availability of effective treatments for chronic phase (CP) has dramatically reduced progressions on therapy. Due to smaller number of patients, few randomized studies are available in this setting and evidences are limited. Nevertheless, three main scenarios may be drawn: (a) patients diagnosed in AP are at higher risk of failure as compared to CP patients, but if they achieve optimal responses with frontline TKI treatment their outcome may be similarly favorable; (b) patients diagnosed in BP may be treated with TKI alone or with TKI together with conventional chemotherapy regimens, and subsequent transplant decisions should rely on kinetics of response and individual transplant risk; (c) patients in CP progressing under TKI treatment represent the most challenging population and they should be treated with alternative TKI according to the mutational profile, optional chemotherapy in BP patients, and transplant should be considered in suitable cases after return to second CP. Due to lack of validated and reliable markers to predict blast crisis and the still unsatisfactory results of treatments in this setting, prevention of progression by careful selection of frontline treatment in CP and early treatment intensification in non-optimal responders remains the main goal. Personalized evaluation of response kinetics could help in identifying patients at risk for progression.

Ponatinib in the Treatment of Chronic Myeloid Leukemia and Philadelphia Chromosome-Positive Acute Leukemia: Recommendations of a German Expert Consensus Panel with Focus on Cardiovascular Management

Treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute leukemia (Ph+ ALL) has been revolutionized with the advent of tyrosine kinase inhibitors (TKIs). Most patients with CML achieve long-term survival similar to individuals without CML due to treatment with TKIs not only in frontline but also in further lines of therapy. The third-generation TKI ponatinib has demonstrated efficacy in patients with refractory CML and Ph+ ALL. Ponatinib is currently the most potent TKI in this setting demonstrating activity against T315I mutant clones. However, ponatinib's safety data revealed a dose-dependent, increased risk of serious cardiovascular (CV) events. Guidance is needed to evaluate the benefit-risk profile of TKIs, such as ponatinib, and safety measures to prevent treatment-associated CV events. An expert panel of German hematologists and cardiologists summarize current evidence regarding ponatinib's efficacy and CV safety profile. We propose CV management strategies for patients who are candidates for ponatinib.

Research Progress of Axl Inhibitors

Axl, a Receptor Tyrosine Kinase (RTK) belonging to the TAM (Axl, Mer, Tyro3) family, participates in many signal transduction cascades after mostly being stimulated by Growth arrestspecific 6(Gas6). Axl is widely expressed in many organs, such as macrophages, endothelial cells, heart, liver and skeletal muscle. Over-expression and activation of Axl are associated with promoting chemotherapy resistance, cell proliferation, invasion and metastasis in many human cancers, such as breast, lung, and pancreatic cancers. Therefore, the research and development of Axl inhibitors is of great significance to strengthen the means of cancer treatment, especially to solve the problem of drug resistance. Axl inhibitors have attracted more and more researchers' attention in recent years. This review discusses the research progress of Axl inhibitors in recent years.

Blinatumomab administered concurrently with oral tyrosine kinase inhibitor therapy is a well-tolerated consolidation strategy and eradicates measurable residual disease in adults with Philadelphia chromosome positive acute lymphoblastic leukemia

Incorporation of ABL-targeted oral tyrosine kinase inhibitors (TKIs) into frontline therapeutic regimens has improved outcomes for adults with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL). However, patients with persistent minimal residual disease (MRD) exhibit increased risk of relapse. Combining consolidative chemotherapy with TKIs may increase rates of infectious complications, organ toxicity, hospitalization, and non-relapse mortality. Blinatumomab has demonstrated single-agent activity in patients with relapsed B-ALL or persistent MRD, including Ph + B-ALL. We have used blinatumomab concomitantly with commercially available TKIs as consolidative therapy to spare toxicities of conventional chemotherapy. We evaluated 11 adults with previously treated Ph + B-ALL who received blinatumomab concurrent with TKI (ponatinib, n = 5; dasatinib, n = 4; nilotinib, n = 1; imatinib, n = 1) to eradicate MRD or sustain MRD-negativity. Eight of 9 patients with MRD achieved BCR-ABL1 negativity (complete molecular response, CMR) after a median of one cycle; 2/2 patients without measurable disease durably maintained CMR. Cytokine release syndrome (all grade 1-2) was observed in 3/11 patients; one patient experienced transient grade 1 neurologic toxicity. Transient grade 2 transaminitis was observed in 6/11 patients, including 4/5 recipients of blinatumomab + ponatinib. This small series suggests blinatumomab + TKI is a safe and effective consolidation strategy for patients with Ph + ALL to achieve or maintain CMR.

Management of adverse events associated with bosutinib treatment of chronic-phase chronic myeloid leukemia: expert panel review

Bosutinib, a BCR-ABL1 tyrosine kinase inhibitor (TKI), has been available for several years as a treatment for chronic-, accelerated-, and blast-phase chronic myeloid leukemia (CML), for patients with resistance or intolerance to prior therapy. In 2017, the BFORE trial demonstrated efficacy of bosutinib as first-line treatment in adult patients with newly diagnosed chronic-phase chronic myeloid leukemia (CP-CML). The most common adverse events (AEs) of any grade in bosutinib-treated patients in BFORE were diarrhea, nausea, thrombocytopenia, increased alanine aminotransferase, and increased aspartate aminotransferase, consistent with the most commonly reported AEs in earlier studies. To balance the efficacy and tolerability of treatment to optimize patient adherence with medications, treating physicians commonly use various strategies such as initiating treatment at a lower dose, dose reduction, or dose interruption, depending on the type and severity of the AEs and the clinical setting. In light of the recent data from first-line treatment, an expert panel of hematologists reviewed management strategies for the use of bosutinib in treatment of CP-CML and made the recommendations reported here. Although the panel focused on first-line treatment, the principles can be for the most part extended to bosutinib use in later lines of treatment. Recommendations include advice regarding prophylaxis and management for diarrhea. The panel also considered optimum timing for referral to a specialist for specific AEs. Across the commonly occurring AEs, the panel highlighted the importance of education and communication with patients about anticipated AEs.

Ponatinib for Treating Chronic Myeloid Leukaemia: An Evidence Review Group Perspective of a NICE Single Technology Appraisal

As part of its single technology appraisal process, the National Institute for Health and Care Excellence (NICE) invited the company that manufactures ponatinib (Inclusig^®; Incyte Corporation) to submit evidence for the clinical and cost effectiveness for previously treated chronic myeloid leukaemia (CML) and Philadelphia-chromosome-positive acute lymphoblastic leukaemia (Ph+ ALL). This paper focusses on the three phases of CML: the chronic phase (CP), the accelerated phase (AP) and the blast crisis phase (BP). The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). This article presents the critical review of the company's submission by the ERG and the outcome of the NICE guidance. Clinical evidence for ponatinib was derived from a phase II, industry-sponsored, single-arm, open-label, multicentre, non-comparative study. Despite the limited evidence and potential for biases, this study demonstrated that ponatinib was likely to be an effective treatment (in terms of major cytogenetic response and major haematological response) with an acceptable safety profile for patients with CML. Given the absence of any head-to-head studies comparing ponatinib with other relevant comparators, the company undertook a matching-adjusted indirect comparison (MAIC) of ponatinib with bosutinib. The approach was only used for patients with CP-CML because comprehensive data were not available for the AP- or BP-CML groups to allow the matching technique to be used. Despite the uncertainty about the MAIC approach, ponatinib was considered likely to offer advantages over bosutinib in the third-line setting, particularly for complete cytogenetic response. The company developed two health economic models to assess the cost effectiveness of ponatinib for the treatment of patients in CP-CML or in advanced CML (AP- or BP-CML, which were modelled separately). The company did not adequately explore the uncertainty in the survivor functions. As a result, the ERG believed the uncertainty in the decision problem was underestimated. Exploratory analyses undertaken by the ERG produced the following results for ponatinib. In CP-CML, from £18,246 to £27,667 per quality-adjusted life-year (QALY) gained compared with best supportive care (BSC), from £19,680 to £37,381 per QALY gained compared with bosutinib and from £18,279 per QALY gained to dominated compared with allogeneic stem cell transplant (allo-SCT). In AP-CML, the cost per QALY gained for ponatinib ranged from £7123 to £17,625 compared with BSC, and from dominating to £61,896 per QALY gained compared with allo-SCT. In BP-CML, the cost effectiveness of ponatinib ranged from £5033 per QALY gained to dominated compared with allo-SCT, although it was likely to be at the more favourable end of this range, and dominant in all scenarios compared with BSC. The NICE appraisal committee concluded that ponatinib is a cost-effective use of NHS resources in the considered population, subject to the company providing the agreed discount in the Patient Access Scheme.

Bosutinib in chronic myeloid leukemia: patient selection and perspectives

During recent years, the therapeutic landscape in chronic myeloid leukemia (CML) has changed significantly. Since the clinical introduction of tyrosine kinase inhibitors (TKIs) approximately 15 years ago, patients' concerns have shifted from reduced life expectancy toward long-term toxicities of TKI, depth of remission, and the probability of successful treatment discontinuation. Patients with newly diagnosed CML in chronic phase (at least with a Sokal score not exceeding intermediate) may now expect an almost normal life expectancy. However, even if almost 30% of all newly diagnosed chronic-phase patients might eventually be facing the prospect of a life without CML-specific treatment, based on current knowledge, most, if not all, patients would have to undergo an expected minimum of 5-8 years of TKI treatment and the majority would face a life-long exposure to the side-effects of TKIs. At present, 5 different TKIs are licensed for the treatment of CML, that is, imatinib, which is a first-generation TKI (including its generic derivatives); nilotinib, dasatinib, and bosutinib, which are second-generation TKIs; as well as ponatinib, which is a so-called third-generation TKI and is supposed to be used for patients harboring the T315I-mutation. One of the important, yet unanswered questions is the choice of the best possible TKI upfront for each individual patient. Bosutinib is currently licensed for patients with CML after failure or intolerance of at least 2 other TKIs. It can also be prescribed according to label if after failure of the first TKI therapy, another option does not seem feasible. This review focuses on the existing data on clinical efficacy, tolerability, and side effects of bosutinib treatment in CML patients with the aim to identify patient characteristics and treatment scenarios most suitable for treatment with bosutinib.

Ponatinib efficacy and safety in Philadelphia chromosome-positive leukemia: final 5-year results of the phase 2 PACE trial

Ponatinib has potent activity against native and mutant BCR-ABL1, including BCR-ABL1^T315I The pivotal phase 2 Ponatinib Ph⁺ ALL and CML Evaluation (PACE) trial evaluated efficacy and safety of ponatinib at a starting dose of 45 mg once daily in 449 patients with chronic myeloid leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL) resistant/intolerant to dasatinib or nilotinib, or with BCR-ABL1^T315I This analysis focuses on chronic-phase CML (CP-CML) patients (n = 270) with 56.8-month median follow-up. Among 267 evaluable patients, 60%, 40%, and 24% achieved major cytogenetic response (MCyR), major molecular response (MMR), and 4.5-log molecular response, respectively. The probability of maintaining MCyR for 5 years was 82% among responders. Dose reductions were implemented in October 2013 to decrease the risk of arterial occlusive events (AOEs); ≥90% of CP-CML patients who had achieved MCyR or MMR maintained response 40 months after elective dose reductions. Estimated 5-year overall survival was 73%. In CP-CML patients, the most common treatment-emergent adverse events were rash (47%), abdominal pain (46%), thrombocytopenia (46%), headache (43%), dry skin (42%), and constipation (41%). The cumulative incidence of AOEs in CP-CML patients increased over time to 31%, while the exposure-adjusted incidence of new AOEs (15.8 and 4.9 per 100 patient-years in years 1 and 5, respectively) did not increase over time. These final PACE results demonstrate ponatinib provides durable and clinically meaningful responses, irrespective of dose reductions, in this population of heavily pretreated CP-CML patients. This trial was registered at www.clinicaltrials.gov as #NCT01207440.

Practical management of toxicities associated with bosutinib in patients with Philadelphia chromosome-positive chronic myeloid leukemia

Bosutinib (SKI-606) is an oral, dual Src/Abl tyrosine kinase inhibitor (TKI) approved for treatment of patients with Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) that is resistant or intolerant to prior TKI therapy or for whom other TKIs are not appropriate choices. The objective of this review is to provide a longitudinal summary of toxicities that may arise during treatment with second-line or later bosutinib in patients with Ph+ chronic phase CML and to provide strategies for managing these toxicities. As bosutinib is not currently indicated for newly diagnosed CML, toxicities associated with first-line treatment are not reviewed. Recognition and optimal management of these toxicities can facilitate patient compliance and affect treatment outcomes.

[Effect of MDR1 and CYP3A5 gene polymorphisms on outcomes of patients receiving imatinib treatment for chronic myeloid leukemia]

OBJECTIVE

To study the effect of MDR1 and CYP3A5 gene polymorphisms on the outcomes of imatinib treatment in patients with chronic myeloid leukemia (CML).

METHODS

A total of 100 patients with CML treated with imatinib were enrolled in this study, including 50 patients with cytogenetic relapse (study group) and 50 without cytogenetic relapse (control group) during the follow-up for 45 months. For all the patients, single nucleotide polymorphisms (SNPs) of C1236T, C3435T, and G2677T/A loci in the MDR1 gene and A6986G locus in CYP3A5 gene were genotyped and the trough levels of imatinib was measured using LC-MS/MS. The relationship between SNPs of the loci and the risk of cytogenetic relapse were analyzed.

RESULTS

The risk of cytogenetic recurrence was significantly higher in patients with CC genotypes of MDR1-C1236T and MDR1-C3435T than in those with CT + TT genotypes (P < 0.05). The median survival time of the patients with TT genotypes of MDR1-C3435T and MDR1-C1236T was significantly higher than that of patients with CC genotypes and CT genotypes (P < 0.05). The incidences of hematologic toxicity and neutropenia were significantly higher in patients with cytogenetic relapse than in those without cytogenetic relapse (P < 0.05). MDR1-C3435T genotype and imatinib concentration were independent predictors of cytogenetic relapse of CML.

CONCLUSIONS

The risk of cytogenetic relapse of CML was significantly affected by SNPs of C1236T and C3435T loci of MDR1 gene and blood imatinib concentration. MDR1-C3435T genotype can be used as a potential biomarker for predicting cytogenetic relapse in CML patients.

Bosutinib Versus Imatinib for Newly Diagnosed Chronic Myeloid Leukemia: Results From the Randomized BFORE Trial

Purpose Bosutinib is a potent dual SRC/ABL kinase inhibitor approved for adults with Philadelphia chromosome-positive chronic myeloid leukemia (CML) resistant and /or intolerant to prior therapy. We assessed the efficacy and safety of bosutinib versus imatinib for first-line treatment of chronic-phase CML. Methods In this ongoing, multinational, phase III study, 536 patients with newly diagnosed chronic-phase CML were randomly assigned 1:1 to receive 400 mg of bosutinib once daily (n = 268) or imatinib (n = 268). Per protocol, efficacy was assessed in patients who were Philadelphia chromosome-positive with typical (e13a2/e14a2) transcripts (bosutinib, n = 246; imatinib, n = 241). Patients with Philadelphia chromosome-negative-/ BCR-ABL1-positive status and those with unknown Philadelphia chromosome status and/or atypical BCR-ABL1 transcript type were excluded from this population. Results The major molecular response (MMR) rate at 12 months (primary end point) was significantly higher with bosutinib versus imatinib (47.2% v 36.9%, respectively; P = .02), as was complete cytogenetic response (CCyR) rate by 12 months (77.2% v 66.4%, respectively; P = .0075). Cumulative incidence was favorable with bosutinib (MMR: hazard ratio, 1.34; P = .0173; CCyR: hazard ratio, 1.38; P < .001), with earlier response times. Four patients (1.6%) receiving bosutinib and six patients (2.5%) receiving imatinib experienced disease progression to accelerated/blast phase. Among treated patients, 22.0% of patients receiving bosutinib and 26.8% of patients receiving imatinib discontinued treatment, most commonly for drug-related toxicity (12.7% and 8.7%, respectively). Grade ≥ 3 diarrhea (7.8% v 0.8%) and increased ALT (19.0% v 1.5%) and AST (9.7% v 1.9%) levels were more common with bosutinib. Cardiac and vascular toxicities were uncommon. Conclusion Patients who received bosutinib had significantly higher rates of MMR and CCyR and achieved responses faster than those who received imatinib. Consistent with the known safety profile, GI events and transaminase elevations were more common with bosutinib. Results indicate bosutinib may be an effective first-line treatment for chronic-phase CML.

Bosutinib: A Potent Second-Generation Tyrosine Kinase Inhibitor

Bosutinib is one of the five tyrosine kinase inhibitors which are currently approved for the treatment of chronic myeloid leukemia. By its dual inhibition of Src and ABL kinase and also targeting further kinases, it creates a unique target portfolio which also explains its unique side effect profile. The approval of bosutinib in 2013 made the drug available for patients previously treated with one or more tyrosine kinase inhibitor(s) and for whom imatinib, nilotinib, and dasatinib are not considered appropriate treatment options. As initially the first-line clinical trial comparing bosutinib with imatinib in CML patients in chronic phase did not reach its primary endpoint and therefore the product was not licensed for first-line therapy, a second first-line trial, the so-called BFORE study, was performed and just recently the promising results have been published predicting a quick expansion of the existing label. In comparison with the other approved TKIs, bosutinib harbors a distinct side effect profile with only very few cardiovascular and thromboembolic events and minimal long-term safety issues with most adverse events happening during the first months of treatment. On the other hand, gastrointestinal side effects are very common (e.g., diarrhea rates in more than 80% of the patients) with bosutinib surprising some of the investigators during the early clinical trials evaluating bosutinib. Until then, several approaches have been used to face this problem resulting in extensive supportive efforts (such as early loperamid treatment) as well as new trials testing alternative dosing strategies with early dose adjustment schedules. This article reports preclinical and clinical data available for bosutinib both in hematologic diseases such as CML or ALL and solid tumours as well as other diseases and envisions future perspectives including additional patient groups in which bosutinib might be of clinical benefit.

Ponatinib in chronic myeloid leukemia (CML): Consensus on patient treatment and management from a European expert panel

Five tyrosine kinase inhibitors (TKIs) are currently approved in the European Union for treatment of chronic myeloid leukemia (CML) and all have considerable overlap in their indications. While disease-specific factors such as CML phase, mutational status, and line of treatment are key to TKI selection, other important features must be considered, such as patient-specific comorbidities and TKI safety profiles. Ponatinib, the TKI most recently approved, has demonstrated efficacy in patients with refractory CML, but is associated with an increased risk of arterial hypertension, sometimes severe, and serious arterial occlusive and venous thromboembolic events. A panel of European experts convened to discuss their clinical experience in managing patients with CML. Based on the panel discussions, scenarios in which a CML patient may be an appropriate candidate for ponatinib therapy are described, including presence of the T315I mutation, resistance to other TKIs without the T315I mutation, and intolerance to other TKIs.

Anoikis and EMT: Lethal "Liaisons" during Cancer Progression

Anoikis is a unique mode of apoptotic cell death that occurs consequentially to insufficient cell-matrix interactions. Resistance to anoikis is a critical contributor to tumor invasion and metastasis. The phenomenon is regulated by integrins, which upon engagement with components of the extracellular matrix (ECM) form adhesion complexes and the actin cytoskeleton drives the formation of cell protrusions used to adhere to ECM, directing cell migration. The epithelial-mesenchymal transition (EMT) confers stem cell properties and leads to acquisition of a migratory and invasive phenotype by causing adherens junction breakdown and circumventing anoikis in the tumor microenvironment. The investigation of drug discovery platforms for apoptosis-driven therapeutics identified several novel agents with antitumor action via reversing resistance to anoikis, inhibiting survival pathways and impacting the EMT landscape in human cancer. In this review, we discuss current evidence on the contribution of the anoikis phenomenon functionally linked to EMT to cancer metastasis and the therapeutic value of antitumor drugs that selectively reverse anoikis resistance and/or EMT to impair tumor progression toward the development/optimization of apoptosis-driven therapeutic targeting of metastatic disease.

Insights into the management of chronic myeloid leukemia in resource-poor settings: a Mexican perspective

INTRODUCTION

The arrival of targeted therapy for chronic myeloid leukemia (CML) was revolutionary. However, due to the high cost of tyrosine kinase inhibitors, access to this highly effective therapy with strict monitoring strategies is limited in low to middle-income countries. In this context, following standard recommendations proposed by experts in developed countries is difficult. Areas covered: This review aims to provide an insight into the management of patients with CML living in a resource-limited setting. It addresses several issues: diagnosis, initial treatment, disease monitoring, and additional treatment alternatives including allogeneic hematopoietic stem cell transplantation. Expert commentary: Imatinib is probably the most cost-effective TKI for initial treatment in developing and underdeveloped countries. Generic imatinib preparations should be evaluated before considering their widespread use. Adherence to treatment should be emphasized. Adequate monitoring can be performed through several methods successfully and is important for predicting outcomes, particularly early in the first year, and if treatment suspension is being considered. Access to further therapeutic alternatives should define our actions after failure or intolerance to imatinib, preferring additional TKIs if possible. Allogeneic transplantation in chronic phase is a viable option in this context.

Effects of Bosutinib Treatment on Renal Function in Patients With Philadelphia Chromosome-Positive Leukemias

BACKGROUND

The purpose of the study was to assess renal function in patients with Philadelphia chromosome-positive leukemias receiving bosutinib or imatinib.

PATIENTS AND METHODS

Patients received first-line bosutinib (n = 248) or imatinib (n = 251; phase III trial), or second-line or later bosutinib (phase I/II trial; n = 570). Adverse events (AEs) and changes from baseline in estimated glomerular filtration rate (eGFR) and serum creatinine were assessed.

RESULTS

Time from the last patient's first dose to data cutoff was ≥ 48 months. Renal AEs were reported in 73/570 patients (13%) receiving second-line or later bosutinib, and in 22/248 (9%) and 16/251 (6%) receiving first-line bosutinib and imatinib, respectively. eGFR in patients receiving bosutinib declined over time with more patients developing Grade ≥ 3b eGFR (< 45 mL/min/1.73 m² according to the Modification of Diet in Renal Disease method) with second-line or later bosutinib (139/570, 24%) compared with first-line bosutinib (26/248, 10%) and imatinib (25/251, 10%); time to Grade ≥ 3b eGFR was shortest with second-line or later bosutinib. Similar proportions of patients receiving second-line or later bosutinib (74/139, 53%), first-line bosutinib (15/26, 58%), and first-line imatinib (15/25, 60%) improved to ≥ 45 mL/min/1.73 m² eGFR as of the last follow-up. In a regression analysis, first-line treatment with bosutinib versus imatinib was not a significant predictor of Grade ≥ 3b eGFR.

CONCLUSION

Long-term bosutinib treatment is associated with an apparently reversible decline in renal function with frequency and characteristics similar to renal decline observed with long-term imatinib treatment. Patients with risk factors for Grade ≥ 3b eGFR should be monitored closely.

Bosutinib induced pleural effusions: Case report and review of tyrosine kinase inhibitors induced pulmonary toxicity

Tyrosine kinase inhibitors are known to cause pulmonary complications. We report a case of bosutinib related bilateral pleural effusions in a patient with chronic myeloid leukemia. Characteristics of the pleural fluid are presented. We also discuss other tyrosine kinase inhibitors induced pulmonary toxicities, including pulmonary hypertension and interstitial lung disease.

Long-term treatment with bosutinib in a phase 1/2 study in Japanese chronic myeloid leukemia patients resistant/intolerant to prior tyrosine kinase inhibitor treatment

This long-term follow-up of a completed phase 1/2 study assessed the safety and efficacy of bosutinib in Japanese Philadelphia chromosome-positive, chronic phase (CP) or advanced phase (ADV) chronic myeloid leukemia patients who were resistant/refractory or intolerant to prior tyrosine kinase inhibitor treatment. This analysis included 63 patients with a median bosutinib follow-up of 132 weeks (range 3‒372). In the CP second-line (2L) cohort, the cumulative major cytogenetic response (MCyR) and major molecular response (MMR) rates throughout the study were 73 and 53%, respectively. In the CP third-line (3L) cohort, the cumulative MCyR and MMR rates throughout the study were 70 and 40%, respectively. Of the eight ADV patients, MCyR was attained or maintained by 50% of patients, and complete hematologic response was attained or maintained by 25% of patients. Progression-free survival rate and overall survival rate at 96 weeks were, respectively, 91 and 98% in CP2L, 88 and 100% in CP3L, and 33 and 50% in ADV patients. The most common adverse events (>50%) reported were diarrhea (95%), nasopharyngitis (57%), and rash (57%). Bosutinib demonstrated durable efficacy and a manageable tolerability profile over long-term use in Japanese patients.ClinicalTrials.gov: NCT00811070.

Current approach to the treatment of chronic myeloid leukaemia

Of all the cancers, chronic myeloid leukaemia (CML) has witnessed the most rapid evolution of the therapeutic milieu in recent decades. The introduction of tyrosine kinase inhibitors (TKIs) as a therapeutic option has profoundly changed patient experience and outcome. The availability of multiple new highly effective therapies has increasingly underscored the importance of a good understanding of the underlying pathophysiological basis in CML, as well as patient-specific factors in choosing the right treatment for every individual. The treatment of CML has migrated in many jurisdictions from the office of a highly specialized malignant hematologist to the general hematologist or even a general practitioner. The goal of this review is to offer an overview of the modern approach to the treatment of CML, with an emphasis on chronic phase (CP) CML, including both TKI-based therapies such as imatinib, dasatinib, nilotinib, bosutinib and ponatinib, and non-TKI medications, such as omacetaxine. We discuss evidence behind each drug, most common and material adverse reactions and outline how this information can be used in selecting the right drug for the right patient. We also discuss evidence as it relates to other therapies, including stem cell transplant (SCT), and patients in accelerated (AP) and blastic phase (BP).

The development of agents targeting the BCR-ABL tyrosine kinase as Philadelphia chromosome-positive acute lymphoblastic leukemia treatment

INTRODUCTION

In Philadelphia chromosome-positive (Ph⁺) acute lymphoblastic leukemia (ALL), the BCR-ABL translocation is the main transforming event; consequently, it is targeted by ABL-tyrosine kinase inhibitors (TKIs), the first of which to be identified was imatinib mesylate. There are now four newer TKIs, three so-called second-generation inhibitors and one third generation inhibitor, all of which are more potent than imatinib in in vitro assays. Areas covered: This paper reviews the current knowledge on the function of BCR-ABL. Furthermore, this paper highlights the impact of this knowledge on the development of a targeted therapy approach in Ph⁺ ALL and the obstacles for the successful treatment with these drugs. Expert opinion: Identifying key components involved in disease pathogenesis may lead to new approaches that might overcome resistance mediated to the BCR-ABL TKIs. In a near future, the authors believe that monoclonal antibodies and immunotherapy should also be combined with TKIs and up-front chemotherapy for the successful treatment of ALL.