Comparison of bypassing agents in patients on emicizumab using global hemostasis assays.

INTRODUCTION: Emicizumab is a humanized bispecific monoclonal antibody licensed for patients with severe haemophilia A with and without inhibitors. Management of breakthrough bleeding in patients with inhibitors on emicizumab involves episodic treatment with bypassing agents (BPA), activated prothrombin complex concentrate (aPCC) or recombinant activated factor VII (rFVIIa). Thrombotic events and thrombotic microangiopathy were reported when patients on emicizumab received concomitant aPCC at relatively high doses yet such events were not reported with rFVIIa. We studied the effect of spiking various concentrations of BPA on plasma taken from patients on emicizumab. MATERIAL AND METHODS: Eleven patients with severe haemophilia A with inhibitors who are on emicizumab were recruited to participate. Blood samples drawn from patients were spiked in vitro with varying concentrations of aPCC and rFVIIa. All samples were tested utilizing global haemostasis assays, thromboelastography and thrombin generation assay. RESULTS: Thrombin generation increased with higher concentrations of spiked BPA with a normalized endogenous thrombin potential at a concentration of 0.05 IU/ml and 4 mcg/ml for aPCC and rFVIIa, respectively. Concentrations of aPCC in the range of licensed dosing led to excessive thrombin generation. Thromboelastography was not sufficiently sensitive. CONCLUSION: Due to the known thrombotic complications when emicizumab is used in conjunction with aPCC, there has been a large-scale abandonment of the use of aPCC in patients on emicizumab. However, it is possible that aPCC can be used safely with emicizumab albeit with lower doses than are typically prescribed. It would be important to test this hypothesis in a clinical study.

Clinical Significance of Isolated Myeloperoxidase Expression in Pediatric B-Lymphoblastic Leukemia.

Objectives: Diagnosis of B-cell acute lymphoblastic leukemia (B-ALL) requires immunophenotypic evidence of B-lineage and absence of specific myeloid or T-lineage markers. Rare cases of otherwise typical B-ALL express myeloperoxidase (MPO) detectable by flow cytometry with an absence of other myeloid markers, but the clinical significance of this finding is not well studied. Methods: A retrospective cohort analysis of flow cytometry and clinical data was performed to investigate the clinical outcome of this specific group of patients. Results: Twenty-nine cases of otherwise typical B-ALL that expressed MPO by flow cytometry (B-ALL-isoMPO) without expression of other myeloid markers were identified. The B-ALL-isoMPO group had a significantly increased incidence of relapse (univariate log rank P = .0083; multivariate hazard ratio, 2.50; 95% confidence interval, 1.07-5.85; P = .034) and significantly worse event-free survival by univariate analysis (log rank P = .0066) compared with a reference group of patients with B-ALL from the same time period (n = 264). Conclusions: To our knowledge, this is the first report to document the clinical outcomes in a group of pediatric patients with B-ALL that expresses MPO in the absence of other myeloid markers. This group had an increased rate of relapse and a worse event-free survival than the patients with B-ALL who did not express MPO.

Survival and quality of life for children with end-stage heart failure who are not candidates for cardiac transplant.

BACKGROUND: Some pediatric patients referred for heart transplant (HTx) are sub-optimal candidates. Their outcomes without HTx are presumed to be dismal, but have not been well described. Knowledge about their outcomes is critical when weighing the risks between a high-risk transplant and "terminal" palliation. METHODS: We retrospectively reviewed all HTx referrals from January 2005 to July 2013. We excluded those who were listed for HTx, or who were denied HTx due to being "too well," seeking only those who were in need of but not suitable for HTx. End-points included mortality and length of survival. RESULTS: Of 212 referrals, 39 (19%) (age 0 to 19 years, median 3.5 years) were denied HTx for reasons other than being too well. Twenty-eight (72%) had palliated congenital heart disease. Overall mortality during the follow-up period was 38% (n = 15) with a median follow-up time of 195 days (8 to 2,832 days). Ten patients received subsequent cardiac surgery with 1 death (10%) and median follow-up of 2.6 years. Mortality risk was not influenced by age, weight, growth failure, congenital heart disease or single-ventricle physiology. Mechanical ventilation (hazard ratio 6.31, p = 0.001) and inotrope dependence (hazard ratio 4.79, p = 0.006) were associated with the highest risk of mortality. Quality of life was measured with the PedsQL cardiac module and completed by 11 of 16 eligible patients with an overall average score of 70.2 ± 23.9. CONCLUSIONS: An advanced heart failure program can achieve satisfactory results for pediatric patients who are not suitable candidates for HTx. For some children, high-risk palliative surgery can result in better outcome than high-risk HTx. Mortality was related to the degree of heart failure at presentation rather than underlying heart disease.

B lymphocyte stimulator expression in pediatric systemic lupus erythematosus and juvenile idiopathic arthritis patients.

OBJECTIVE: To assess the expression of B lymphocyte stimulator (BLyS) in patients with pediatric systemic lupus erythematosus (SLE) or juvenile idiopathic arthritis (JIA). METHODS: Blood samples collected from patients with pediatric SLE (n = 56) and patients with JIA (n = 54) at the beginning and end of a 6-month interval were analyzed for plasma BLyS protein levels by enzyme-linked immunosorbent assay and for blood leukocyte full-length BLyS and DeltaBLyS messenger RNA (mRNA) levels by quantitative real-time polymerase chain reaction (normalized to 18S expression). Healthy siblings (n = 34) of these patients served as controls. RESULTS: In pediatric SLE, plasma BLyS protein and blood leukocyte BLyS mRNA levels were each significantly elevated, and plasma BLyS protein levels, but not blood leukocyte BLyS mRNA levels, were correlated with disease activity. In contrast, plasma BLyS protein levels were normal in JIA despite blood leukocyte BLyS mRNA levels being elevated to degrees similar to those in pediatric SLE. Among JIA patients, neither BLyS parameter was correlated with disease activity. In both pediatric SLE and JIA, the BLyS expression profiles remained stable at 6 months. CONCLUSION: Our findings indicate that, as previously noted in adult SLE, plasma BLyS protein and blood leukocyte BLyS mRNA levels are elevated in pediatric SLE. The correlation of plasma BLyS protein levels with disease activity points to BLyS as a candidate therapeutic target in pediatric SLE. Contrary to previous observations in adults with rheumatoid arthritis, plasma BLyS protein levels are normal in JIA despite elevated blood leukocyte BLyS mRNA levels. The absence of correlation between either of the BLyS parameters and disease activity in JIA calls for circumspection prior to assigning BLyS as a candidate therapeutic target in this disorder.