Disease detection methodologies in relapsed B-cell acute lymphoblastic leukemia: Opportunities for improvement.

BACKGROUND: Accurate disease detection is integral to risk stratification in B-cell acute lymphoblastic leukemia (ALL). The gold standard used to evaluate response in the United States includes morphologic evaluation and minimal residual disease (MRD) testing of aspirated bone marrow (BM) by flow cytometry (FC). This MRD assessment is usually made on a single aspirate sample that is subject to variability in collection techniques and sampling error. Additionally, central nervous system (CNS) assessments for ALL include evaluations of cytopathology and cell counts, which can miss subclinical involvement. PROCEDURE: We retrospectively compared BM biopsy, aspirate, and FC samples obtained from children and young adults with relapsed/refractory ALL to identify the frequency and degree of disease discrepancies in this population. We also compared CNS FC and cytopathology techniques. RESULTS: Sixty of 410 (14.6%) BM samples had discrepant results, 41 (10%) of which were clinically relevant as they resulted in a change in the assignment of marrow status. Discrepant BM results were found in 28 of 89 (31.5%) patients evaluated. Additionally, cerebrospinal fluid (CSF) FC identified disease in 9.7% of cases where cytopathology was negative. CONCLUSIONS: These results support further investigation of the role of concurrent BM biopsy, with aspirate and FC evaluations, and the addition of FC to CSF evaluations, to fully assess disease status and response, particularly in patients with relapsed/refractory ALL. Prospective studies incorporating more comprehensive analysis to evaluate the impact on clinical outcomes are warranted.

Impact of cytokine release syndrome on cardiac function following CD19 CAR-T cell therapy in children and young adults with hematological malignancies.

BACKGROUND: Chimeric antigen receptor (CAR) T-cell-associated cytokine release syndrome (CRS) may present with tachycardia, hemodynamic instability and reduced cardiac function. Pediatric CAR studies examining cardiac toxicity are limited. METHODS: We report on cardiac toxicity observed in children and young adults with hematologic malignancies enrolled in a CD19-28ζ CAR T-cell phase I trial (NCT01593696). All patients had a formal baseline echocardiogram. Real-time studies included echocardiograms on intensive care unit (ICU) transfer, and serial troponin and pro-B-type natriuretic peptide (pro-BNP) in the select patients. RESULTS: From July 2012 to March 2016, 52 patients, with a median age of 13.4 years (range 4.2-30.3) were treated. CRS developed in 37/52 (71%), which was grade 3-4 CRS in nine patients (17%). The median prior anthracycline exposure was 205 mg/m2 (range 70-620 mg/m2) in doxorubicin equivalents. The median baseline left ventricle ejection fraction (LVEF) and baseline LV global longitudinal strain (GLS) were 60% (range 50%-70%) and 16.8% (range 14.1%-23.5%, n=37) respectively. The majority, 78% (29/37), of patients had a reduced GLS <19% at baseline, and 6% (3/52) of patients had baseline LVEF <53%. ICU transfers occurred in 21 patients, with nine requiring vasoactive hemodynamic support and three necessitating >1 vasopressor. Six (12%) patients developed cardiac dysfunction (defined by >10% absolute decrease in LVEF or new-onset grade 2 or higher LV dysfunction, per CTCAE v4), among whom 4 had grade 3-4 CRS. Troponin elevations were seen in 4 of 13 patients, all of whom had low LVEF. Pro-BNP was elevated from baseline in 6/7 patients at the onset of CRS, with higher levels correlating with more severe CRS. Cardiac dysfunction fully resolved in all but two patients by day 28 post-CAR. CONCLUSION: Cardiac toxicity related to CD19-28ζ CAR T-cell-associated CRS was generally reversible by day 28 postinfusion. Implementation of more frequent monitoring with formal echocardiograms incorporating systemic analysis of changes in GLS, and cardiac biomarkers (troponin and proBNP) may help to earlier identify those patients at highest risk of severe cardiac systolic dysfunction, facilitating earlier interventions for CRS to potentially mitigate acute cardiac toxicity.