Neutrophil Extracellular Traps Are Increased in Chronic Myeloid Leukemia and Are Differentially Affected by Tyrosine Kinase Inhibitors.

Cardiovascular complications are increasingly reported with the use of certain tyrosine kinase inhibitors (TKIs) to treat chronic myeloid leukemia (CML). We studied neutrophil extracellular trap (NET) formation in CML and evaluated the effect of TKIs on NET formation. Neutrophils isolated from treatment-naïve patients with CML showed a significant increase in NET formation compared to matched controls at baseline and after stimulation with ionomycin (IO) and phorbol 12-myristate 13-acetate (PMA). Expression of citrullinated histone H3 (H3cit), peptidyl arginine deiminase 4 (PAD4) and reactive oxygen species (ROS) was significantly higher in CML samples compared to controls. Pre-treatment of neutrophils with TKIs was associated with a differential effect on NET formation, and ponatinib significantly augmented NET-associated elastase and ROS levels as compared to controls and other TKIs. BCR-ABL1 retroviral transduced HoxB8-immortalized mouse hematopoietic progenitors, which differentiate into neutrophils in-vitro, demonstrated increased H3cit & myeloperoxidase (MPO) expression consistent with excess NET formation. This was inhibited by Cl-amidine, a PAD4 inhibitor, but not by the NADPH inhibitor diphenyleneiodonium (DPI). Ponatinib pre-exposure significantly increased H3cit expression in HoxB8-BCR-ABL1 cells after stimulation with IO. In summary, CML is associated with increased NET formation, which is augmented by ponatinib, suggesting a possible role for NETs in promoting vascular toxicity in CML.

Identifying Tyrosine Kinase Inhibitor Nonadherence in Chronic Myeloid Leukemia: Subanalysis of TAKE-IT Pilot Study.

BACKGROUND: There are inconsistencies in reports on correlates for nonadherence (NA) to tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML). The diagnostic accuracy of subjective adherence measures using electronic monitoring (EM) as the reference standard is yet to be determined. This study aimed to evaluate correlates of TKI NA using EM and test the diagnostic accuracy of subjective adherence measures. PATIENTS AND METHODS: CML patients receiving a TKI for any duration were enrolled at 4 hematology institutes, and adherence was measured for 4 months. EM adherence was the reference adherence measure, expressed as the percentage of days with the drug taken as prescribed. Subjective adherence was measured using the Basel Assessment of Adherence to Immunosuppressive Medications Scale (BAASIS) self-report and clinician-reported visual analog scale (VAS) at 2 time points. Baseline theory-derived correlates of NA were identified using single and multiple regression analysis. The diagnostic accuracy of BAASIS and clinician-reported VAS was tested against an exploratory EM NA cutoff of < 95%. RESULTS: The median EM adherence (n = 55) was 97.5% (range, 48-100%), while the 25th percentile was 92.1%. Lack of membership in a CML patient support group, living alone, and third-line treatment were associated with EM NA on multiple regression analysis. The BAASIS self-report (n = 94) had a sensitivity of 67% and a specificity of 71% for diagnosing NA, while clinician-reported VAS (n = 89) had a sensitivity of 78% and specificity of 42%. CONCLUSION: A quarter of patients had potentially clinically meaningful NA. These NA correlates and the BAASIS provide a basis for identifying nonadherent patients who can be targeted by interventions.

Effect of Adherence-enhancing Interventions on Adherence to Tyrosine Kinase Inhibitor Treatment in Chronic Myeloid Leukemia (TAKE-IT): A Quasi-experimental Pre-Post Intervention Multicenter Pilot Study.

BACKGROUND: Nonadherence to tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML) has been associated with inferior outcomes. Scarce evidence exists on the effectiveness of adherence-enhancing interventions. The present pilot study evaluated the feasibility and effectiveness of an intervention to improve TKI adherence in adult CML patients. PATIENTS AND METHODS: Using a quasi-experimental pre-post intervention design, we included a convenience sample of 58 CML patients (median age, 60.5 years; interquartile range, 19) receiving TKI treatment in 4 hematology institutes in Israel (median previous treatment duration, 34 months; interquartile range, 60). Of the 58 patients, 36 (62%) were receiving first-line treatment. TKI adherence was assessed using electronic monitoring for 7 months (4 months for the baseline assessment and for 3 months after the intervention) and defined as the percentage of days with dosing taken as prescribed. The multilevel intervention combined training of health care workers and multiple behavioral change techniques (eg, motivational interviewing, feedback on electronic monitoring printouts, behavioral change techniques tailored to reasons for nonadherence). The baseline and postintervention adherence were compared using generalized estimating equation models. RESULTS: The median baseline electronically monitored adherence (n = 55) was 97.5% (range, 48%-100%). The odds of taking the drug daily as prescribed were 58% greater after intervention (odds ratio, 1.58; 95% confidence interval [CI], 1.16-2.15). Adherence improved by only 1.5% overall (95% CI, 0.1%-2.8%) but by 8.5% (i.e. from 71.2% average adherence before intervention, to 79.6% after; P = .04) in a subgroup of 10 nonadherent patients (baseline adherence < 90%). CONCLUSION: TKI adherence improved with our pilot intervention, mainly in patients with suboptimal baseline adherence.

Immune thrombocytopenia: recent progress in pathophysiology and treatment.

Immune thrombocytopenia (ITP) is a rare autoimmune disorder with an incidence of 3 to 5 per 100 000 individuals. In children, the disease is self-limited and is most commonly virus related (acute ITP) whereas in adults, the disease is typically chronic. The age distribution of adult ITP displays 2 peaks; the first in younger adults aged 18 to 40 with a female predominance and the second in people aged older than 60 with men and women affected equally. Our approach to ITP has evolved over the past several years: there has been a change in nomenclature and ITP now denotes "immune thrombocytopenia" (the "I" no longer denoting "idiopathic") and "purpura" no longer features in the name of the disease; new insights into the pathogenesis of ITP have revealed the importance of impaired megakaryocytopoiesis in the condition; underlying mechanisms of secondary ITP have been elucidated and finally novel thrombopoietic agents have been shown to be effective in the treatment of ITP in randomized clinical trials. In this article, we review important recent advances in the pathogenesis and treatment of ITP.