Expectations and outcomes of varying treatment strategies for CML presenting during pregnancy.

Diagnosing chronic myeloid leukaemia (CML) during pregnancy is rare. Tyrosine kinase inhibitors (TKIs) have traditionally been contraindicated owing to their teratogenicity. Management decisions should consider the risks to mother and foetus of uncontrolled disease and teratogenic medications. Further cases are required to build upon the paucity of current literature. We report 22 cases of CML diagnosed during pregnancy from 2002 to date. Twenty-one pregnancies resulted in healthy babies and one patient miscarried. Some patients remained untreated throughout pregnancy but the majority received one or both of interferon-α and leucapheresis. One patient was started on imatinib at Week 26, and one on hydroxycarbamide in the third trimester. We report haematological parameters during pregnancy to provide clinicians with realistic expectations of management. There were no fetal abnormalities related to treatment during pregnancy. Seventeen patients achieved at least major molecular response on first-line TKI. A diagnosis of CML during pregnancy can be managed without significant consequences for mother or child. Leucapheresis and interferon-α are generally safe throughout pregnancy. Despite having been avoided previously, there is growing evidence that certain TKIs may be used in particular circumstances during the later stages of pregnancy. Future work should aim to further elucidate this safety profile.

Dasatinib induces endothelial dysfunction leading to impaired recovery from ischaemia.

Chronic myeloid leukaemia (CML) management is complicated by treatment-emergent vascular adverse events seen with tyrosine kinase inhibitors (TKIs) such as nilotinib, dasatinib and ponatinib. Pleural effusion and pulmonary arterial hypertension (PAH) have been associated with dasatinib treatment. Endothelial dysfunction and impaired angiogenesis are hallmarks of PAH. In this study, we explored, at cellular and whole animal levels, the connection between dasatinib exposure and disruption of endothelial barrier integrity and function, leading to impaired angiogenesis. Understanding the mechanisms whereby dasatinib initiates PAH will provide opportunities for intervention and prevention of such adverse effects, and for future development of safer TKIs, thereby improving CML management.

Haematopoietic stem cell transplantation after reduced intensity conditioning in children and adolescents with chronic myeloid leukaemia: A prospective multicentre trial of the I-BFM Study Group.

This prospective multicentre trial evaluated the safety and the efficacy of a thiotepa/melphalan-based reduced intensity conditioning (RIC) haematopoietic stem cell transplantation (HSCT) in children and adolescents with chronic myeloid leukaemia (CML) in chronic phase (CP). Thirty-two patients were transplanted from matched siblings or matched unrelated donors. In 22 patients, HSCT was performed due to insufficient molecular response or loss of response to first- or second-generation tyrosine kinase inhibitor (TKI), with pretransplant BCR::ABL1 transcripts ranging between 0.001% and 33%. The protocol included a BCR::ABL1-guided intervention with TKI retreatment in the first year and donor lymphocyte infusions (DLI) in the second-year post-transplant. All patients engrafted. The 1-year transplant-related mortality was 3% (confidence interval [CI]: 0%-6%). After a median follow-up of 6.3 years, 5-year overall survival and event-free survival are 97% (CI: 93%-100%) and 91% (CI: 79%-100%) respectively. The current 5-year leukaemia-free survival with BCR::ABL1 <0.01% is 97% (CI: 88%-100%) and the current TKI- and DLI-free survival is 95% (CI: 85%-100%). The incidence of chronic graft-versus-host disease (GvHD) was 32%, being severe in four patients (13%). At last follow-up, 31 patients are GvHD-free and have stopped immunosuppression. RIC HSCT following pretreatment with TKI is feasible and effective in children and adolescents with CP-CML with an excellent disease-free and TKI-free survival.

The Mozart effect in chronic myeloid leukaemia.

Clinical research has not been able to establish whether the differences between first- and second-generation BCR-ABL 1 kinase inhibitors are clinically relevant with regard to outcome. In the study by Alcazer et al., a relevant difference seems to emerge-paradoxically in the absence of the drugs-as demonstrated by differences in the relapse kinetics after cessation of therapy. Commentary on: Alcazer et al. Kinetics of molecular recurrence after tyrosine kinase inhibitor cessation in chronic phase chronic myelogenous leukaemia patients. Br J Haematol 2024;204:1536-1539.

Mismatched related donor allogeneic haematopoietic cell transplantation compared to other donor types for Ph+ chronic myeloid leukaemia: A retrospective analysis from the Chronic Malignancies Working Party of the EBMT.

Allogeneic haematopoietic cell transplantation (allo-HCT) remains an option for tyrosine kinase inhibitor-resistant chronic myeloid leukaemia (CML) in first chronic phase (CP1) and high-risk patients with advanced disease phases. In this European Society for Blood and Marrow Transplantation (EBMT) registry-based study of 1686 CML patients undergoing first allo-HCT between 2012 and 2019, outcomes were evaluated according to donor type, particularly focusing on mismatched related donors (MMRDs). Median age at allo-HCT was 46 years (IQR 36-55). Disease status was CP1 in 43%, second CP (CP2) or later in 27%, accelerated phase in 12% and blast crisis in 18%. Donor type was matched related (MRD) in 39.2%, MMRD in 8.1%, matched unrelated (MUD) in 40.2%, and mismatched unrelated (MMUD) in 12.6%. In 4 years, overall survival (OS) for MRD, MMRD, MUD and MMUD was 61%, 56%, 63% and 59% (p = 0.21); relapse-free survival (RFS) was 48%, 42%, 52% and 46% (p = 0.03); cumulative incidence of relapse (CIR) was 33%, 37%, 27% and 30% (p = 0.07); non-relapse mortality (NRM) was 19%, 21%, 21% and 24% (p = 0.21); and graft-versus-host disease (GvHD)-free/relapse-free survival (GRFS) was 16%, 18%, 22% and 15% (p = 0.05) respectively. On multivariate analysis, MMRD use associated with longer engraftment times and higher risk of graft failure compared to MRD or MUD. There was no statistical evidence that MMRD use associated with different OS, RFS and incidence of GvHD compared to other donor types.

How to improve treatment-free remission eligibility in chronic myeloid leukaemia?

The achievement of treatment-free remission (TFR) has become a significant clinical end-point in the management of patients with chronic myeloid leukaemia (CML), providing an opportunity to discontinue therapy with tyrosine kinase inhibitors (TKIs) while maintaining deep molecular response (DMR). Early studies, such as the French STIM trial, have demonstrated that a portion of patients can maintain DMR after treatment cessation, with rates ranging from 40% to 50%, and most relapses occurring within the first 6 months. Key prognostic factors for successful TFR, including treatment duration, duration of DMR, risk scores, and transcript type, have been identified. Optimal patient selection for TFR remains a challenge, but recent research provides insights into potential strategies to increase TFR eligibility. Evidence suggests that early intervention switching to achieve optimal response, treatment combinations, proactive switch in the case of absence of DMR, dose-optimization and induction-maintenance approach can improve molecular responses and, consequently, enhance TFR eligibility. In this review, we report and discuss all the potential therapeutic strategies that may enhance eligibility for a first attempt at TFR, with a particular emphasis on potential future approaches.

Higher prevalence of harbouring BCR::ABL1 in first-degree relatives of chronic myeloid leukaemia (CML) patients compared to normal population.

BACKGROUND: The role of familial influence in chronic myeloid leukaemia (CML) occurrence is less defined. Previously, we conducted a study to determine the prevalence of harbouring BCR::ABL1 in our local adult normal population (designated as StudyN). We present our current study, which investigated the prevalence of harbouring BCR::ABL1 in the normal first-degree relatives of local CML patients (designated as StudyR). We compared and discussed the prevalence of StudyR and StudyN to assess the familial influence in CML occurrence. METHODS: StudyR was a cross-sectional study using convenience sampling, recruiting first-degree relatives of local CML patients aged ≥ 18 years old without a history of haematological tumour. Real-time quantitative polymerase chain reaction standardised at the International Scale (BCR::ABL1-qPCRIS) was performed according to standard laboratory practice and the manufacturer's protocol. RESULTS: A total of 96 first-degree relatives from 41 families, with a mean age of 39 and a male-to-female ratio of 0.88, were enrolled and analysed. The median number of relatives per family was 2 (range 1 to 5). Among them, 18 (19%) were parents, 39 (41%) were siblings, and 39 (41%) were offspring of the CML patients. StudyR revealed that the prevalence of harbouring BCR::ABL1 in the first-degree relatives was 4% (4/96), which was higher than the prevalence in the local normal population from StudyN, 0.5% (1/190). All four positive relatives were Chinese, with three of them being female (p > 0.05). Their mean age was 39, compared to 45 in StudyN. The BCR::ABL1-qPCRIS levels ranged between 0.0017%IS and 0.0071%IS, similar to StudyN (0.0023%IS to 0.0032%IS) and another study (0.006%IS to 0.016%IS). CONCLUSION: Our study showed that the prevalence of harbouring BCR::ABL1 in the first-degree relatives of known CML patients was higher than the prevalence observed in the normal population. This suggests that familial influence in CML occurrence might exist but could be surpassed by other more dominant influences, such as genetic dilutional effects and protective genetic factors. The gender and ethnic association were inconsistent with CML epidemiology, suggestive of a higher familial influence in female and Chinese. Further investigation into this topic is warranted, ideally through larger studies with longer follow-up periods.

The FABD domain is critical for the oncogenicity of BCR/ABL in chronic myeloid leukaemia.

BACKGROUND: Abnormally expressed BCR/ABL protein serves as the basis for the development of chronic myeloid leukaemia (CML). The F-actin binding domain (FABD), which is a crucial region of the BCR/ABL fusion protein, is also located at the carboxyl end of the c-ABL protein and regulates the kinase activity of c-ABL. However, the precise function of this domain in BCR/ABL remains uncertain. METHODS: The FABD-deficient adenovirus vectors Ad-BCR/ABL△FABD, wild-type Ad-BCR/ABL and the control vector Adtrack were constructed, and 32D cells were infected with these adenoviruses separately. The effects of FABD deletion on the proliferation and apoptosis of 32D cells were evaluated by a CCK-8 assay, colony formation assay, flow cytometry and DAPI staining. The levels of phosphorylated BCR/ABL, p73, and their downstream signalling molecules were detected by western blot. The intracellular localization and interaction of BCR/ABL with the cytoskeleton-related protein F-actin were identified by immunofluorescence and co-IP. The effect of FABD deletion on BCR/ABL carcinogenesis in vivo was explored in CML-like mouse models. The degree of leukaemic cell infiltration was observed by Wright‒Giemsa staining and haematoxylin and eosin (HE) staining. RESULTS: We report that the loss of FABD weakened the proliferation-promoting ability of BCR/ABL, accompanied by the downregulation of BCR/ABL downstream signals. Moreover, the deletion of FABD resulted in a change in the localization of BCR/ABL from the cytoplasm to the nucleus, accompanied by an increase in cell apoptosis due to the upregulation of p73 and its downstream proapoptotic factors. Furthermore, we discovered that the absence of FABD alleviated leukaemic cell infiltration induced by BCR/ABL in mice. CONCLUSIONS: These findings reveal that the deletion of FABD diminished the carcinogenic potential of BCR/ABL both in vitro and in vivo. This study provides further insight into the function of the FABD domain in BCR/ABL.

The BCR::ABL1 tyrosine kinase inhibitors ponatinib and nilotinib differentially affect endothelial angiogenesis and signalling.

BCR::ABL1 inhibitors, the treatment of choice for the majority of patients with chronic myeloid leukaemia (CML), can cause vascular side effects that vary between agents. The exact underlying mechanisms are still poorly understood, but the vascular endothelium has been proposed as a site of origin. The present study investigates the effects of three BCR::ABL1 inhibitors, ponatinib, nilotinib and imatinib, on angiogenesis and signalling in human endothelial cells in response to vascular endothelial growth factor (VEGF). The experiments were performed in endothelial cells isolated from human umbilical veins. After exposure to imatinib, ponatinib and nilotinib, the angiogenic capacity of endothelial cells was assessed in spheroid assays. VEGF-induced signalling pathways were examined in Western blotting experiments using different specific antibodies. RNAi technology was used to downregulate proteins of interest. Intracellular cGMP levels were measured by ELISA. Imatinib had no effect on endothelial function. Ponatinib inhibited VEGF-induced sprouting, while nilotinib increased spontaneous and VEGF-stimulated angiogenesis. These effects did not involve wild-type ABL1 or ABL2, as siRNA-mediated knockdown of these kinases did not affect angiogenesis and VEGF signalling. Consistent with their effects on sprouting, ponatinib and nilotinib affected angiogenic pathways in opposite directions. While ponatinib inhibited VEGF-induced signalling and cGMP formation, nilotinib activated angiogenic signalling, in particular phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2). The latter occurred in an epidermal growth factor receptor (EGFR)-dependent manner possibly via suppressing Fyn-related kinase (FRK), a negative regulator of EGFR signalling. Both, pharmacological inhibition of Erk1/2 or EGFR suppressed nilotinib-induced angiogenic sprouting. These results support the notion that the vascular endothelium is a site of action of BCR::ABL1 inhibitors from which side effects may arise, and that the different vascular toxicity profiles of BCR::ABL1 inhibitors may be due to their different actions at the molecular level. In addition, the as yet unknown pro-angiogenic effect of nilotinib should be considered in the treatment of patients with comorbidities associated with pathological angiogenesis, such as ocular disease, arthritis or obesity.

Clinical outcomes of chronic myeloid leukaemia patients taking asciminib through a Managed Access Programme (MAP) in Australia.

Asciminib is a novel allosteric STAMP (specifically targets the ABL myristoyl pocket) inhibitor of the BCR::ABL1 oncogene. Real-world clinical outcomes of patients with tyrosine kinase inhibitor (TKI)-resistant/intolerant chronic myeloid leukaemia (CML) in Australia on the Managed Access Programme for asciminib showed higher molecular responses for those with intolerance versus resistance ± intolerance to their last TKI. There remains a clinical need to improve outcomes in patients with CML who have resistance to multiple TKIs, especially in the ponatinib-pretreated cohort.

Bilateral vision loss at high altitude: A diagnostic dilemma.

A young male patient of 22 years inducted at 11,000 feet altitude presented with a sudden onset bilateral diminution of vision associated with easy fatiguability and generalised weakness. Fundus examination revealed preretinal haemorrhages and Roth spots both eyes, owing to which differential diagnosis of high altitude retinopathy (HAR) and haematological disorders was considered. On systemic examination, he had pallor with massive splenomegaly. Haematological investigation revealed high total leucocyte count (TLC) 2.96 lac (normal 4000-11,000/uL) with peripheral blood smear showing increase in basophils, neutrophil precursors, myelocyte bulge, anaemia with no blasts suggestive of chronic myeloid leukaemia-chronic phase. Hence, a diagnosis of chronic myeloid leukaemia (chronic phase) with no features of tumour lysis syndrome was made. Patient was started on Tab hydroxyurea 50 mg twice a daily and managed by haemato-oncologist and required no further active ophthalmological intervention.

Molecular Evaluation of the Impact of Polymorphic Variants in Apoptotic (Bcl-2/Bax) and Proinflammatory Cytokine (TNF-α/IL-8) Genes on the Susceptibility and Progression of Myeloproliferative Neoplasms: A Case-Control Biomarker Study.

The regulation of apoptosis (the programmed cell death) is dependent on the crucial involvement of BCL2 and BAX. The Bax-248G>A and Bcl-2-938 C>A polymorphic variations in the promoter sequences of the Bax and Bcl-2 gene have been recently associated with low Bax expression, progression to advanced stages, treatment resistance, and shortened overall survival rate in some hematological malignancies, including chronic myeloid leukemia (CML) and other myeloproliferative neoplasms. Chronic inflammation has been linked to various stages of carcinogenesis wherein pro-inflammatory cytokines play diverse roles in influencing cancer microenvironment leading to cell invasion and cancer progression. Cytokines such as TNF-α and IL-8 have been implicated in cancer growth in both solid and hematological malignancies with studies showing their elevated levels in patients. Genomic approaches have in recent years provided significant knowledge with the regard to the association of certain SNPs (single nucleotide polymerphisms) either in a gene or its promoter that can influence its expression, with the risk and susceptibility to human diseases including cancer. This study has investigated the consequences of promoter SNPs in apoptosis genes Bax-248G>A (rs4645878)/Bcl-2-938C>A (rs2279115) and pro-inflammatory cytokines TNF-α rs1800629 G>A/IL-8 rs4073 T>A on the risk and susceptibility towards hematological cancers. The study design has 235 individuals both male and female enrolled as subjects that had 113 cases of MPDs (myeloproliferative disorders) and 122 healthy individuals as controls. The genotyping studies were conducted through ARMS PCR (amplification-refractory mutation system PCR). The Bcl-2-938 C>A polymorphism showed up in 22% of patients in the study, while it was observed in only 10% of normal controls. This difference in genotype and allele frequency between the two groups was significant (p = 0.025). Similarly, the Bax-248G>A polymorphism was detected in 6.48% of the patients and 4.54% of the normal controls, with a significant difference in genotype and allele frequency between the groups (p = 0.048). The results suggest that the Bcl-2-938 C>A variant is linked to an elevated risk of MPDs in the codominant, dominant, and recessive inheritance models. Moreover, the study indicated allele A as risk allele which can significantly increase the risk of MPDs unlike the C allele. In case of Bax gene covariants, these were associated with an increased risk of MPDs in the codominant inheritance model and dominant inheritance model. It was found that the allele A significantly enhanced the risk of MPDs unlike the G allele. The frequencies of IL-8 rs4073 T>A in patients was found to be TT (16.39%), AT (36.88%) and AA (46.72%), compared to controls who were more likely to have frequencies of TT (39.34%), AT (37.70%) and AA (22.95%) as such, respectively. There was a notable overrepresentation of the AA genotype and GG homozygotes among patients compared to controls in TNF-α polymorphic variants, with 6.55% of patients having the AA genotype and 84% of patients being GG homozygotes, compared to 1.63% and 69%, respectively in controls. The data from the current study provide partial but important evidence that polymorphisms in apoptotic genes Bcl-2-938C>A and Bax-248G>A and pro-inflammatory cytokines IL-8 rs4073 T>A and TNF-α G>A may help predict the clinical outcomes of patients and determine the significance of such polymorphic variations in the risk of myeloproliferative diseases and their role as prognostic markers in disease management using a case-control study approach.

Dasatinib plus Peg-Interferon alpha 2b combination in newly diagnosed chronic phase chronic myeloid leukaemia: Results of a multicenter phase 2 study (DASA-PegIFN study).

Superior rates of deep molecular response (DMR) have been reported with the combination of tyrosine kinase inhibitors and pegylated-interferon-alpha (Peg-IFN) in patients with newly diagnosed chronic phase-chronic myeloid leukaemia (CP-CML). In this setting, this study investigated the efficacy and safety of dasatinib combined to Peg-IFN-α2b (Dasa-PegIFN, NCT01872442). A total of 79 patients (age ≤65 years) started dasatinib; 61 were eligible for Peg-IFNα-2b add-on therapy at month 3 for a maximum 21-months duration. Dasatinib was continued thereafter. The primary endpoint was the cumulative rate of molecular response 4.5 log (MR4.5 ) by 12 months. The results are reported for the 5-year duration of the study. Grade 3 neutropenia was frequent with the combination but did not induce severe infection (one of grade 3). Other adverse events were generally low grade (4% of grade 3-4) and expected. Seventy-nine per cent and 61% of patients continued the Peg-IFN until months 12 and 24, respectively. Overall, at these time points, MR4.5 rates were 25% and 38%, respectively. Thereafter, 32% and 46% of patients achieved a sustained (≥2 years) MR4.5 or MR4 , respectively. This work established the feasibility and high rates of achievement of early and sustained DMR (a prerequisite for treatment-free-remission) with dasatinib and Peg-IFNα-2b combination as initial therapy.

Treatment-free remission after dasatinib in patients with chronic myeloid leukaemia in chronic phase with deep molecular response: Final 5-year analysis of DASFREE.

Patients with chronic myeloid leukaemia in chronic phase (CML-CP) who have a sustained deep molecular response (DMR) are eligible to discontinue treatment and attempt treatment-free remission (TFR). In the DASFREE study (ClinicalTrials.gov; NCT01850004), the 2-year TFR rate after dasatinib discontinuation was 46%; here we present the 5-year update. Patients with a stable DMR after ≥2 years of dasatinib therapy discontinued treatment and were followed for 5 years. At a minimum follow-up of 60 months, in 84 patients discontinuing dasatinib, the 5-year TFR rate was 44% (n = 37). No relapses occurred after month 39 and all evaluable patients who relapsed and restarted dasatinib (n = 46) regained a major molecular response in a median of 1.9 months. The most common adverse event during the off-treatment period was arthralgia (18%, 15/84); a total of 15 withdrawal events were reported in nine patients (11%). At the 5-year final follow-up, almost half of the patients who discontinued dasatinib after a sustained DMR maintained TFR. All evaluable patients who experienced a relapse quickly regained a DMR after restarting dasatinib, demonstrating that dasatinib discontinuation is a viable and potentially long-term option in patients with CML-CP. The safety profile is consistent with the previous report.

The epidemiology of haematological cancers in Sarawak, Malaysia (1996 to 2015).

BACKGROUND: Published epidemiological studies of haematological cancers are few. Hereby we present a 20-year epidemiological data of haematological cancers in Sarawak from a population-based cancer registry. METHODS: Haematological cancer cases with ICD-10 coded C81-C96 and ICD-O coded /3 diagnosed from 1996 to 2015 were retrieved from Sarawak Cancer Registry. Adult was defined as those 15 years and above. Incidence rate (IR) was calculated based on yearly Sarawak citizen population stratified to age, gender, and ethnic groups. Age-standardised IR (ASR) was calculated using Segi World Standard Population. RESULTS: A total of 3,947 cases were retrieved and analysed. ASR was 10 and male predominance (IR ratio 1.32, 95%CI 1.24,1.41). Haematological cancers generally had a U-shaped distribution with lowest IR at age 10-14 years and exponential increment from age 40 years onwards, except acute lymphoblastic leukaemia (ALL) with highest IR in paediatric 2.8 versus adult 0.5. There was a significant difference in ethnic and specific categories of haematological cancers, of which, in general, Bidayuh (IR ratio 1.13, 95%CI 1.00, 1.27) and Melanau (IR ratio 0.54, 95%CI 0.45, 0.65) had the highest and lowest ethnic-specific IR, respectively, in comparison to Malay. The ASR (non-Hodgkin lymphoma, acute myeloid leukaemia, ALL, chronic myeloid leukaemia, and plasma cell neoplasm) showed a decreasing trend over the 20 years, -2.09 in general, while Hodgkin lymphoma showed an increasing trend of + 2.80. There was crude rate difference between the 11 administrative divisions of Sarawak. CONCLUSIONS: This study provided the IR and ASR of haematological cancers in Sarawak for comparison to other regions of the world. Ethnic diversity in Sarawak resulted in significant differences in IR and ASR.

Patient-guided dose reduction of tyrosine kinase inhibitors in chronic myeloid leukaemia (RODEO study): study protocol for a prospective, multicentre, single-arm trial.

BACKGROUND: Dose reduction of tyrosine kinase inhibitors (TKI) in patients with chronic myeloid leukaemia (CML) with an optimal response to TKIs may support cost-effective medication use by maintaining therapeutic effectiveness while reducing adverse events and medication costs. As the choice for dose reduction depends on patients' individual needs and preferences, a patient-centred approach is warranted. Therefore, a study to evaluate the effectiveness of patient-guided dose reduction in patients with CML who are in a major or deep molecular response is designed. METHODS: This study is a prospective, multicentre, single-arm study. 147 patients with CML (aged ≥ 18 years) in chronic phase, who are treated with imatinib, bosutinib, dasatinib, nilotinib or ponatinib, and have reached at least major molecular response (defined as having BCR-ABL levels < 0.1% for an uninterrupted period of 6 months) are eligible. Patients will use an online patient decision aid and a shared decision making consultation will be held, after which patients who choose to will receive a personalised, lower TKI dose. Primary outcome is the proportion of patients with intervention failure at 12 months after dose reduction, defined as patients who have restarted their initial dose due to (expected) loss of major molecular response. For this, BCR-ABL1 levels will be analysed from blood samples drawn at baseline, 6 weeks after dose reduction and 3-monthly thereafter. Secondary outcomes include the proportion of patients with intervention failure at 6 and 18 months after dose reduction. Other outcomes include differences before and after dose reduction regarding the number and severity of patient-reported side effects; quality of life; beliefs about medicines; and medication adherence. Patients' level of decisional conflict and regret after choosing dose reduction will be assessed, as will the decisional process experienced by patients and healthcare providers. DISCUSSION: Outcomes of this trial using a personalised approach will provide clinical and patient-reported data to guide future dose reduction of TKIs in CML. If the strategy appears to be effective, it may be implemented as another valid option to offer next to standard of care to prevent potential unnecessary exposure to higher TKI doses in this selected group of patients. TRIAL REGISTRATION: EudraCT number 2021-006581-20.

Overcoming BCR::ABL1 dependent and independent survival mechanisms in chronic myeloid leukaemia using a multi-kinase targeting approach.

BACKGROUND: Despite improved patient outcome using tyrosine kinase inhibitors (TKIs), chronic myeloid leukaemia (CML) patients require life-long treatment due to leukaemic stem cell (LSC) persistence. LSCs reside in the bone marrow (BM) niche, which they modify to their advantage. The BM provides oncogene-independent signals to aid LSC cell survival and quiescence. The bone-morphogenetic pathway (BMP) is one pathway identified to be highly deregulated in CML, with high levels of BMP ligands detected in the BM, accompanied by CML stem and progenitor cells overexpressing BMP type 1 receptors- activin-like kinases (ALKs), especially in TKI resistant patients. Saracatinib (SC), a SRC/ABL1 dual inhibitor, inhibits the growth of CML cells resistant to the TKI imatinib (IM). Recent studies indicate that SC is also a potent ALK inhibitor and BMP antagonist. Here we investigate the efficacy of SC in overcoming CML BCR::ABL1 dependent and independent signals mediated by the BM niche both in 2D and 3D culture. METHODS: CML cells (K562 cell line and CML CD34+ primary cells) were treated with single or combination treatments of: IM, SC and the BMP receptors inhibitor dorsomorphin (DOR), with or without BMP4 stimulation in 2D (suspension) and 3D co-culture on HS5 stroma cell line and mesenchymal stem cells in AggreWell and microfluidic devices. Flow cytometry was performed to investigate apoptosis, cell cycle progression and proliferation, alongside colony assays following treatment. Proteins changes were validated by immunoblotting and transcriptional changes by Fluidigm multiplex qPCR. RESULTS: By targeting the BMP pathway, using specific inhibitors against ALKs in combination with SRC and ABL TKIs, we show an increase in apoptosis, altered cell cycle regulation, fewer cell divisions, and reduced numbers of CD34+ cells. Impairment of long-term proliferation and differentiation potential after combinatorial treatment also occurred. CONCLUSION: BMP signalling pathway is important for CML cell survival. Targeting SRC, ABL and ALK kinases is more effective than ABL inhibition alone, the combination efficacy importantly being demonstrated in both 2D and 3D cell cultures highlighting the need for combinatorial therapies in contrast to standard of care single agents. Our study provides justification to target multiple kinases in CML to combat LSC persistence.

Blood is made in the spongy inner most section of the bone, called the bone marrow. The bone marrow is where normal blood stem cells live that are responsible for producing the different blood cell types; white blood cells (fight infections), red blood cells (carrying oxygen around the body), platelets (blood clotting) and other cells which support this process. Chronic myeloid leukaemia (CML) is a type of blood cancer that starts in the bone marrow. CML occurs when a normal blood stem cell becomes damaged, forming a leukaemia stem cell (LSC), leading to blood cancer. LSCs multiply and generate many faulty cancerous white blood cells that do not work properly. Patients are treated with a drug called imatinib, which reduces the number of cancerous cells circulating in the body. In many cases, this treatment is not enough to cure the disease because the bone marrow protects the LSCs from the drug meaning patients must remain on long term treatment. This work has discovered one of the ways in which the bone marrow protects LSCs from treatments and has used this knowledge to test new drugs that stop this protection. Our findings show that by combining two drugs, one that overcomes this protection and one that directly targets the cancerous cells, we can destroy more of the LSCs. These findings are a step closer towards a cure for CML and could improve treatment for patients in the future. Video Abstract.

Cardiovascular risk in chronic myeloid leukaemia: A multidisciplinary consensus on screening and management.

INTRODUCTION: Tyrosine kinase inhibitors (TKIs) have become the mainstay of treatment for chronic myeloid leukaemia (CML), but cardiovascular (CV) risk and exacerbation of underlying risk factors associated with TKIs have become widely debated. Real-world evidence reveals little application of CV risk factor screening or continued monitoring within UK CML management. This consensus paper presents practical recommendations to assist healthcare professionals in conducting CV screening/comorbidity management for patients receiving TKIs. METHODS: We conducted a multidisciplinary panel meeting and two iterative surveys involving 10 CML specialists: five haematologists, two cardio-oncologists, one vascular surgeon, one haemato-oncology pharmacist and one specialist nurse practitioner. RESULTS: The panel recommended that patients commencing second-/third-generation TKIs undergo formal CV risk assessment at baseline, with additional investigations and involvement of cardiologists/vascular surgeons for those with high CV risk. During treatment, patients should undergo CV monitoring, with the nature and frequency of testing dependent on TKI and baseline CV risk. For patients who develop CV adverse events, decision-making around TKI interruption, cessation or change should be multidisciplinary and balance CV and haematological risk. CONCLUSION: The panel anticipates these recommendations will support healthcare professionals in implementing CV risk screening and monitoring, broadly and consistently, and thereby help optimise TKI treatment for CML.

Feasibility of treatment-free remission with generic imatinib: Results of generic imatinib-free trial-in-chronic myeloid leukaemia-chronic phase study.

Background & objectives: Both innovator and generic imatinib are approved for the treatment of Chronic Myeloid Leukaemia-Chronic phase (CML-CP). Currently, there are no studies on the feasibility of treatment-free remission (TFR) with generic imatinib. This study attempted to determine the feasibility and efficacy of TFR in patients on generic Imatinib. Methods: In this single-centre prospective Generic Imatinib-Free Trial-in-CML-CP study, twenty six patients on generic imatinib for ≥3 yr and in sustained deep molecular response (BCR ABLIS ≤0.01% for more than two years) were included. After treatment discontinuation, patients were monitored with complete blood count and BCR ABLIS by real-time quantitative PCR monthly for one year and three monthly thereafter. Generic imatinib was restarted at single documented loss of major molecular response (BCR ABLIS>0.1%). Results: At a median follow up of 33 months (interquartile range 18.7-35), 42.3 per cent patients (n=11) continued to be in TFR. Estimated TFR at one year was 44 per cent. All patients restarted on generic imatinib regained major molecular response. On multivariate analysis, attainment of molecularly undetectable leukaemia (>MR5) prior to TFR was predictive of TFR [P=0.022, HR 0.284 (0.096-0.837)]. Interpretation & conclusions: The study adds to the growing literature that generic imatinib is effective and can be safely discontinued in CML-CP patients who are in deep molecular remission.

Association of CYP3A5*3, CYP3A4*18 & CYP2B6*6 polymorphisms with imatinib treatment outcome in Azerbaijani chronic myeloid leukaemia patients.

Background & objectives: Imatinib mesylate (IM) is a reliable first line treatment for chronic myeloid leukaemia (CML). Nevertheless, despite promising results, a considerable proportion of patients develop resistance to the drug. Cytochrome P450 (CYP) enzymes play a crucial role in IM metabolism. Thus, point mutations in CYP genes may modify IM enzyme activity resulting in insufficient treatment response. This investigation was aimed to identify the functional impact of CYP3A5*3, CYP3A4*18 and CYP2B6*6 polymorphisms on the IM response in patients with CML in Azerbaijan. Methods: Genotyping of CYP3A5*3, CYP3A4*18 and CYP2B6*6 was performed in 153 patients (102 IM non-responders and 51 IM responders) with CML by the PCR-restriction fragment length polymorphism (RFLP) assays. The odds ratios (ORs) with 95 per cent confidence intervals (CIs) were applied to assess the association between allelic variants and IM therapy outcome. The results were validated by sequencing. Results: The frequency of the CYP3A4*18 allele was considerably lower in the responder's group (97.1 vs. 100%; P=0.036). For CYP3A5*3, the allelic frequency was slightly higher among the IM responders (100 vs. 99.02%) with no significant difference. Although patients heterozygous (TC) for CYP2B6*6 demonstrated a higher risk of acquiring resistance (OR 1.04; 95% CI: 0.492-2.218), differences were not significant (P=0.909). In addition, the homozygous genotype (TT) demonstrated a lower risk of unresponsiveness (OR 0.72; 95% CI: 0.283-1.836), but associations were not significant (P=0.491). Interpretation & conclusions: Our results demonstrated that CYP3A4*18 was significantly associated with IM treatment response in patients with CML in Azerbaijan, whereas rather common CYP3A5*3 was identified to have no such association.