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.

Practical guidelines for monitoring and management of coagulopathy following tisagenlecleucel CAR T-cell therapy.

Cytokine release syndrome (CRS) is a systemic inflammatory response associated with chimeric antigen receptor T-cell (CAR-T) therapies. In severe cases, CRS can be associated with coagulopathy and hypofibrinogenemia. We present our global multicenter experience with CRS-associated coagulopathy after tisagenlecleucel therapy in 137 patients with relapsed or refractory B-cell acute lymphoblastic leukemia from the ELIANA and ENSIGN trials. These trials included clinical guidelines for fibrinogen replacement during CRS-associated coagulopathy. Hypofibrinogenemia requiring replacement was observed only in patients with severe CRS. A higher percentage of patients who required replacement were <10 years old, compared with those who did not require replacement. Twenty-three patients received replacement for hypofibrinogenemia (<1.5 g/L); 9 of them developed marked hypofibrinogenemia (<1 g/L). Very low fibrinogen levels (<1 g/L) were documented in patients before maximal CRS (n = 1), during maximal CRS (n = 7), and at CRS improvement (n = 1). Although hypofibrinogenemia was the most clinically significant coagulopathy, some patients also developed prolonged prothrombin time and activated partial thromboplastin time and increased international normalized ratio, further increasing the risk of bleeding. Hypofibrinogenemia was effectively managed using fibrinogen concentrate or cryoprecipitate replacement; severe (grade 4) bleeding events were rare (n = 2). CRS-associated coagulopathy with hypofibrinogenemia is manageable according to empiric guidelines of fibrinogen replacement for CAR-T trials. Fibrinogen concentrate should be used when cryoprecipitate is not reliably available. Monitoring fibrinogen levels in patients with moderate or severe CRS is essential for avoiding potentially fatal bleeding events. These trials were registered at www.clinicaltrials.gov as #NCT02435849 and #NCT02228096.

Vitamin D effect on umbilical cord blood characteristics: a comparison between African Americans and Caucasians.

BACKGROUND: Umbilical cord blood (UCB) units collected from African Americans (AAs) have lower total nucleated cell (TNC) and CD34+ cell counts and are more likely to disqualify for banking compared to other ethnic groups. Furthermore, AAs have higher prevalence of 25-hydroxyvitamin D (25(OH)D) deficiency. Given the importance of 25(OH)D in hematopoiesis, we examined the racial differences in UCB unit 25(OH)D content and its correlation with UCB cellular characteristics. STUDY DESIGN AND METHODS: A total of 119 UCB units that did not meet the TNC count banking criteria were analyzed. Fifty-one UCB units were collected from AA mothers and 68 from Caucasian mothers. We analyzed UCB volume, hematocrit (Hct), TNCs, mononuclear cells (MNCs), CD34+ cells, plasma 25(OH)D concentration, and progenitor clonogenic capacity measured by colony-forming cell (CFC) assay. RESULTS: Compared to Caucasians, AAs had significantly lower UCB 25(OH)D levels (p<0.0001), TNCs (p=0.002), MNCs (p=0.026), and CD34+ cells (p=0.026). Severe deficiency (25(OH)D<10 ng/mL) was only detected in AAs. No difference in median CFC count/10,000 MNCs was detected between AAs and Caucasians. Independent of race, a significant association was detected between 25(OH)D level and TNCs (r=0.193 p=0.035) and Hct (r=0.196 p=0.033). CONCLUSION: These results indicate the importance of 25(OH)D level as a racially independent predictor of UCB cellular characteristics and support further investigation of bioactive vitamin D and other predictors of hematopoiesis on cord blood quality.

Rare form of autosomal dominant thalassemia--hemoglobin Hakkari.

Autosomal dominant Beta Thalassemias are rare and are due to point or frame shift mutations resulting in production of abnormal unstable beta chains of hemoglobin which precipitate leading to hemolysis and anemia. We describe a case of Hemoglobin Hakkari, a rare variant of dominant Thalassemia arising due to a de novo mutation in the exon 2 of the beta globin gene.

Late effects in hematopoietic cell transplant recipients with acquired severe aplastic anemia: a report from the late effects working committee of the center for international blood and marrow transplant research.

With improvements in hematopoietic cell transplant (HCT) outcomes for severe aplastic anemia (SAA), there is a growing population of SAA survivors after HCT. However, there is a paucity of information regarding late effects that occur after HCT in SAA survivors. This study describes the malignant and nonmalignant late effects in survivors with SAA after HCT. A descriptive analysis was conducted of 1718 patients post-HCT for acquired SAA between 1995 and 2006 reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). The prevalence and cumulative incidence estimates of late effects are reported for 1-year HCT survivors with SAA. Of the HCT recipients, 1176 (68.5%) and 542 (31.5%) patients underwent a matched sibling donor (MSD) or unrelated donor (URD) HCT, respectively. The median age at the time of HCT was 20 years. The median interval from diagnosis to transplantation was 3 months for MSD HCT and 14 months for URD HCT. The median follow-up was 70 months and 67 months for MSD and URD HCT survivors, respectively. Overall survival at 1 year, 2 years, and 5 years for the entire cohort was 76% (95% confidence interval [CI]: 74-78), 73% (95% CI: 71-75), and 70% (95% CI: 68-72). Among 1-year survivors of MSD HCT, 6% had 1 late effect and 1% had multiple late effects. For 1-year survivors of URD HCT, 13% had 1 late effect and 2% had multiple late effects. Among survivors of MSD HCT, the cumulative incidence estimates of developing late effects were all <3% and did not increase over time. In contrast, for recipients of URD HCT, the cumulative incidence of developing several late effects exceeded 3% by 5 years: gonadal dysfunction 10.5% (95% CI: 7.3-14.3), growth disturbance 7.2% (95% CI: 4.4-10.7), avascular necrosis 6.3% (95% CI: 3.6-9.7), hypothyroidism 5.5% (95% CI: 2.8-9.0), and cataracts 5.1% (95% CI: 2.9-8.0). Our results indicated that all patients undergoing HCT for SAA remain at risk for late effects, must be counseled about, and should be monitored for late effects for the remainder of their lives.

An in vivo model of double-unit cord blood transplantation that correlates with clinical engraftment.

Double-unit cord blood transplantation (DCBT) appears to enhance engraftment despite sustained hematopoiesis usually being derived from a single unit. To investigate DCBT biology, in vitro and murine models were established using cells from 39 patient grafts. Mononuclear cells (MNCs) and CD34(+) cells from each unit alone and in DCB combination were assessed for colony-forming cell and cobblestone area-forming cell potential, and multilineage engraftment in NOD/SCID/IL2R-γ(null) mice. In DCB assays, the contribution of each unit was measured by quantitative short tandem repeat region analysis. There was no correlation between colony-forming cell (n = 10) or cobblestone area-forming cell (n = 9) numbers and clinical engraftment, and both units contributed to DCB cocultures. In MNC transplantations in NOD/SCID/IL2R-γ(null) mice, each unit engrafted alone, but MNC DCBT demonstrated single-unit dominance that correlated with clinical engraftment in 18 of 21 cases (86%, P < .001). In contrast, unit dominance and clinical correlation were lost with CD34(+) DCBT (n = 11). However, add-back of CD34(-) to CD34(+) cells (n = 20) restored single-unit dominance with the dominant unit correlating not with clinical engraftment but also with the origin of the CD34(-) cells in all experiments. Thus, unit dominance is an in vivo phenomenon probably associated with a graft-versus-graft immune interaction mediated by CD34(-) cells.