Acute Lymphoblastic Leukemia: Clinical Studies: Improving Outcomes with Cellular Therapy

895  Updated Analysis of the Efficacy and Safety of Tisagenlecleucel in Pediatric and Young Adult Patients with Relapsed/Refractory (r/r) Acute Lymphoblastic Leukemia

Stephan A. Grupp, et al.

The Abstract concludes: With longer follow-up, the ELIANA study continues to confirm the efficacy of a single infusion of tisagenlecleucel in pediatric and young adults with ALL without additional therapy. AEs were effectively and reproducibly managed globally by appropriately trained personnel at study sites. The achievement of high overall response rates and deep remissions, in combination with the median duration of response and overall survival not being reached, further corroborate previously reported results.


896  Preliminary Data on Safety, Cellular Kinetics and Anti-Leukemic Activity of UCART19, an Allogeneic Anti-CD19 CAR T-Cell Product, in a Pool of Adult and Pediatric Patients with High-Risk CD19+ Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia

Reuben Benjamin,, et al.

The Abstract concludes: Pooled data of 20 pts show an acceptable and manageable safety profile of UCART19. Severe CRS was reported in 15%. Only 2 G1 cutaneous acute GvHD were observed and no severe neurotoxicity was reported. In this heavily pre-treated population, 88% pts of evaluable pts (14/16) achieved CR or CRi of which 86% (12/14) achieved MRD-. All pts who achieved MRD- had evidence of UCART19 expansion. Updated data, including data for the highest dose level in CALM study, will be presented (NCT 02746952, NCT02808442).


897  Updated Phase 1 Results of Zuma-3: Kte-C19, an Anti-CD19 Chimeric Antigen Receptor T Cell Therapy, in Adult Patients with Relapsed/Refractory Acute Lymphoblastic Leukemia

William G. Wierda, et al.

The Abstract concludes: High rates of remission were achieved by adult patients with R/R ALL, with approximately three-quarters of patients achieving CR or CRi with undetectable MRD after a single dose of KTE-C19 in ZUMA-3. The safety profile was generally manageable, and most cases of high-grade CRS and neurologic events resolved. These results demonstrate that KTE-C19 offers clinical benefit for patients with otherwise limited treatment options.


898  Phase 1 Study of CD19/CD22 Bispecific Chimeric Antigen Receptor (CAR) Therapy in Children and Young Adults with B Cell Acute Lymphoblastic Leukemia (ALL)

Liora M Schultz, et al.

The Abstract concludes: In this phase I study, we demonstrate safety and tolerability of this bispecific CD19/CD22 CAR at a dose of 1x106CAR T cells/kg in pediatric patients with relapsed/refractory B cell ALL. The CD19/22-bispecific CAR mediated antileukemic activity in 100% of patients studied thus far. Long-term follow up and further accrual will be required to inform the effect of bispecific CAR targeting on surface antigen remodeling.


899  Evaluation of In Vivo CAR Transgene Levels in Relapsed/Refractory Pediatric and Young Adult ALL and Adult DLBCL Tisagenlecleucel-Treated Patients

Rakesh Awasthi,et al.

The Abstract concludes: In both ALL and DLBCL, CAR transgene is initially detected at high levels with high variability in both responders and non-responders. While the majority of responding pts tend to have persistent transgene levels, some pts maintain favorable clinical responses despite a lack of quantifiable transgene. These results indicate that qPCR testing for CAR transgene in blood of tisagenlecleucel treated pts should not be used for making treatment decisions for individual pts. In addition, the qPCR measurements in peripheral blood do not reflect on the trafficking of CAR positive cells to sites outside peripheral blood.

The assessment by flow cytometry remains an important assay to distinguish high expression in responding vs non-responding pts in ALL and CLL, and further evaluation of target tissue is needed in DLBCL to understand the utility of CAR expression as a means to distinguish responder and non-responders. Also, further data are needed to improve our understanding of how CAR transgene levels relate to disease burden and duration of response and whether this information is clinically useful.


900  Is There an Increased Risk of ALL in Patients with First Cancers Treated with Radiotherapy and/or Chemotherapy?

Remco J Molenaar, et al.

The Abstract concludes: Among patients treated for a first cancer, receipt of RT and/or CT was associated with higher relative risks and hazards for developing ALL than those not receiving cytotoxic modalities. Patients with hematologic first cancers (myeloid lineage or plasma cell dyscrasias) had the highest hazards of developing ALL as second cancer. When considering the risk kinetics and subgroup analyses in patients with solid first cancers, RT only or RT + CT, but not CT only, associate with increased risks for ALL. To our knowledge this is the largest evaluation of the risk of ALL in cancer patients treated with various modalities. Differentially elevated risks of ALL observed in cancer cohorts based on the treatment modality that was received for a prior cancer suggests a possible biological mechanism that needs to be explored further.