Pooled safety analysis of tisagenlecleucel in children and young adults with B cell acute lymphoblastic leukemia.

BACKGROUND: Tisagenlecleucel, an anti-CD19 chimeric antigen receptor T cell therapy, has demonstrated efficacy in children and young adults with relapsed/refractory B cell acute lymphoblastic leukemia (B-ALL) in two multicenter phase 2 trials (ClinicalTrials.gov, NCT02435849 (ELIANA) and NCT02228096 (ENSIGN)), leading to commercialization of tisagenlecleucel for the treatment of patients up to age 25 years with B-ALL that is refractory or in second or greater relapse. METHODS: A pooled analysis of 137 patients from these trials (ELIANA: n=79; ENSIGN: n=58) was performed to provide a comprehensive safety profile for tisagenlecleucel. RESULTS: Grade 3/4 tisagenlecleucel-related adverse events (AEs) were reported in 77% of patients. Specific AEs of interest that occurred ≤8 weeks postinfusion included cytokine-release syndrome (CRS; 79% (grade 4: 22%)), infections (42%; grade 3/4: 19%), prolonged (not resolved by day 28) cytopenias (40%; grade 3/4: 34%), neurologic events (36%; grade 3: 10%; no grade 4 events), and tumor lysis syndrome (4%; all grade 3). Treatment for CRS included tocilizumab (40%) and corticosteroids (23%). The frequency of neurologic events increased with CRS severity (p<0.001). Median time to resolution of grade 3/4 cytopenias to grade ≤2 was 2.0 (95% CI 1.87 to 2.23) months for neutropenia, 2.4 (95% CI 1.97 to 3.68) months for lymphopenia, 2.0 (95% CI 1.87 to 2.27) months for leukopenia, 1.9 (95% CI 1.74 to 2.10) months for thrombocytopenia, and 1.0 (95% CI 0.95 to 1.87) month for anemia. All patients who achieved complete remission (CR)/CR with incomplete hematologic recovery experienced B cell aplasia; however, as nearly all responders also received immunoglobulin replacement, few grade 3/4 infections occurred >1 year postinfusion. CONCLUSIONS: This pooled analysis provides a detailed safety profile for tisagenlecleucel during the course of clinical trials, and AE management guidance, with a longer follow-up duration compared with previous reports.

Tisagenlecleucel in Children and Young Adults with B-Cell Lymphoblastic Leukemia.

BACKGROUND: In a single-center phase 1-2a study, the anti-CD19 chimeric antigen receptor (CAR) T-cell therapy tisagenlecleucel produced high rates of complete remission and was associated with serious but mainly reversible toxic effects in children and young adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). METHODS: We conducted a phase 2, single-cohort, 25-center, global study of tisagenlecleucel in pediatric and young adult patients with CD19+ relapsed or refractory B-cell ALL. The primary end point was the overall remission rate (the rate of complete remission or complete remission with incomplete hematologic recovery) within 3 months. RESULTS: For this planned analysis, 75 patients received an infusion of tisagenlecleucel and could be evaluated for efficacy. The overall remission rate within 3 months was 81%, with all patients who had a response to treatment found to be negative for minimal residual disease, as assessed by means of flow cytometry. The rates of event-free survival and overall survival were 73% (95% confidence interval [CI], 60 to 82) and 90% (95% CI, 81 to 95), respectively, at 6 months and 50% (95% CI, 35 to 64) and 76% (95% CI, 63 to 86) at 12 months. The median duration of remission was not reached. Persistence of tisagenlecleucel in the blood was observed for as long as 20 months. Grade 3 or 4 adverse events that were suspected to be related to tisagenlecleucel occurred in 73% of patients. The cytokine release syndrome occurred in 77% of patients, 48% of whom received tocilizumab. Neurologic events occurred in 40% of patients and were managed with supportive care, and no cerebral edema was reported. CONCLUSIONS: In this global study of CAR T-cell therapy, a single infusion of tisagenlecleucel provided durable remission with long-term persistence in pediatric and young adult patients with relapsed or refractory B-cell ALL, with transient high-grade toxic effects. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT02435849 .).

A pediatric case of T-cell prolymphocytic leukemia.

T-cell Prolymphocytic Leukemia (T-PLL) is a rare entity, and to date has never been reported in children. Here, we describe the first pediatric case of T-PLL in a 16-year old male and review his clinical course through treatment. He underwent therapy with alemtuzumab and pentostatin, which was successful in inducing initial remission. He then underwent an allogeneic matched sibling stem cell transplant following a myeloablative conditioning regimen and remains disease-free 1.5 years after diagnosis.

Pseudohypopyon: Extramedullary relapse of acute myelogenous leukemia with poor prognosis.

An 11-month-old female presented to the emergency department with a 2-week history of fever, increasing fussiness, emesis, and decreased urine output. She was diagnosed with acute myelogenous leukemia. Systemic chemotherapy with intensified intrathecal cytarabine was started, and the patient achieved a clinical remission after the first course of induction. Towards the end of her second course of induction she developed pseudohypopyon in each eye on consecutive days, heralding a central nervous system relapse.

BCL-2 dependence and ABT-737 sensitivity in acute lymphoblastic leukemia.

Cancer cells acquire disruptions in normal signal transduction pathways and homeostatic mechanisms that would trigger apoptosis in normal cells. These abnormalities include genomic instability, oncogene activation, and growth factor independent proliferation. Therefore, cancer cells likely require a block in apoptosis in order to survive. Overexpression of the antiapoptotic protein BCL-2 provides a block in apoptosis that is frequently observed in cancer cells. We have developed methods for the detection and analysis of BCL-2 dependence and here apply them to acute lymphoblastic leukemia (ALL). BH3 profiling, a mitochondrial assay that classifies blocks in the intrinsic apoptotic pathway, indicated a dependence on BCL-2 of both ALL cell lines and primary samples. This dependence predicted that BCL-2 would be complexed with select pro-death BH3 family proteins, a prediction confirmed by the isolation of BCL-2 complexes with BIM. Furthermore, the BH3 profiling and protein analysis predicted that ALL cell lines and primary cells would be sensitive to ABT-737 as a single agent. Finally, BH3 profiling and protein studies accurately predicted a relative degree of sensitivity to BCL-2 antagonism in cell lines. The ALL cells studied exhibit BCL-2 dependence, supporting clinical trials of BCL-2 antagonists in ALL as single agents or combination therapies.

Gene expression-based chemical genomics identifies rapamycin as a modulator of MCL1 and glucocorticoid resistance.

Drug resistance remains a major obstacle to successful cancer treatment. A database of drug-associated gene expression profiles was screened for molecules whose profile overlapped with a gene expression signature of glucocorticoid (GC) sensitivity/resistance in acute lymphoblastic leukemia (ALL) cells. The screen indicated that the mTOR inhibitor rapamycin profile matched the signature of GC sensitivity. We tested the hypothesis that rapamycin would induce GC sensitivity in lymphoid malignancy cells and found that it sensitized to GC-induced apoptosis via modulation of antiapoptotic MCL1. These data indicate that MCL1 is an important regulator of GC-induced apoptosis and that the combination of rapamycin and glucocorticoids has potential utility in lymphoid malignancies. Furthermore, this approach represents a strategy for identification of promising combination therapies for cancer.