Cellular therapy for hematologic malignancies is a rapidly evolving field, with new iterations of novel constructs being developed at a rapid pace. Since the initial reports of chimeric antigen ...receptor T cell (CAR T cell)success in CD19+ B cell malignancies, multiple clinical trials of CAR T cell therapy directed to CD19 have led to the approval of this therapy by the FDA and the European Medicines Agency for specific indications. Despite strikingly similar efficacy, investigators at multiple centers participating in these studies have observed the nuances of each CAR T cell product, including variability in manufacturing, availability, and toxicity profiles. Here we review state-of-the-art clinical data on CD19-directed CAR T cell therapies in B cell hematologic malignancies, advances made in understanding and modeling associated toxicities, and several exciting advances and creative solutions for overcoming challenges with this therapeutic modality.
Axicabtagene ciloleucel (axi-cel) was approved by the Food and Drug Administration for relapsed aggressive B-cell non-Hodgkin lymphoma in part on the basis of durable remission rates of approximately ...40% in a clinical trial population. Whether this efficacy, and the rates of toxicity, would be consistent in a postcommercial setting, with relaxed eligibility criteria and bridging therapy, is unknown. This study describes the efficacy and safety correlates and outcomes in this setting.
One hundred twenty-two patients from 7 medical centers in the United States were treated with axi-cel and were included in a modified intent-to-treat (mITT) analysis. Seventy-six patients (62%) were ineligible for the ZUMA-1 trial. Response and toxicity rates, duration of response (DOR), survival, and covariates are described on the basis of the mITT population. Correlative studies on blood and tumor samples were performed to investigate potential biomarkers of response and resistance.
Median follow-up was 10.4 months. In the mITT population, the best overall and complete response (CR) rates were 70% and 50%, respectively. Median DOR and progression-free survival (PFS) were 11.0 and 4.5 months in all patients and were not reached (NR) in CR patients. Median overall survival (OS) was NR; 1-year OS was 67% (95% CI, 59% to 77%). Although response rates were similar in the ZUMA-1-eligible and ZUMA-1-ineligible groups (70%
68%), there was a statistically significant improvement in CR rate (63%
42%,
= .016), DOR (median, NR
5.0 months;
= .014), PFS (median, NR
3.3 months;
= .020), and OS (1-year OS, 89%
54%;
< .001) in patients who were ZUMA-1 eligible. Rates of grade ≥ 3 cytokine release syndrome and neurotoxicty were 16% and 35%, respectively.
Axi-cel yields similar rates of overall response and toxicity in commercial and trial settings, although CR rates and DOR were more favorable in patients eligible for ZUMA-1.
With the notable exception of B-cell malignancies, the efficacy of chimeric antigen receptor (CAR) T cells has been limited, and CAR T cells have not been shown to expand and persist in patients with ...nonlymphoid tumors. Here we demonstrate that redirection of primary human T cells with a CAR containing the inducible costimulator (ICOS) intracellular domain generates tumor-specific IL-17-producing effector cells that show enhanced persistence. Compared with CARs containing the CD3ζ chain alone, or in tandem with the CD28 or the 4-1BB intracellular domains, ICOS signaling increased IL-17A, IL-17F, and IL-22 following antigen recognition. In addition, T cells redirected with an ICOS-based CAR maintained a core molecular signature characteristic of TH17 cells and expressed higher levels of RORC, CD161, IL1R-1, and NCS1. Of note, ICOS signaling also induced the expression of IFN-γ and T-bet, consistent with a TH17/TH1 bipolarization. When transferred into mice with established tumors, TH17 cells that were redirected with ICOS-based CARs mediated efficient antitumor responses and showed enhanced persistence compared with CD28- or 4-1BB-based CAR T cells. Thus, redirection of TH17 cells with a CAR encoding the ICOS intracellular domain is a promising approach to augment the function and persistence of CAR T cells in hematologic malignancies.
•ICOS-based CARs program bipolar TH17/TH1 cells with augmented effector function and in vivo persistence.•The expression of selected CAR endodomains can program T cells for their subsequent differentiation fates and effector functions.
Tisagenlecleucel is a CD19 chimeric antigen receptor (CAR) T-cell therapy approved for treatment of pediatric and young adult patients with relapsed/refractory acute lymphoblastic leukemia (ALL) and ...adults with non-Hodgkin lymphoma (NHL). The initial experience with tisagenlecleucel in a real-world setting from a cellular therapy registry is presented here. As of January 2020, 511 patients were enrolled from 73 centers, and 410 patients had follow-up data reported (ALL, n = 255; NHL, n = 155), with a median follow-up of 13.4 and 11.9 months for ALL and NHL, respectively. Among patients with ALL, the initial complete remission (CR) rate was 85.5%. Twelve-month duration of response (DOR), event-free survival, and overall survival (OS) rates were 60.9%, 52.4%, and 77.2%, respectively. Among adults with NHL, the best overall response rate was 61.8%, including an initial CR rate of 39.5%. Six-month DOR, progression-free survival, and OS rates were 55.3%, 38.7%, and 70.7%, respectively. Grade ≥3 cytokine release syndrome and neurotoxicity were reported in 11.6% and 7.5% of all patients, respectively. Similar outcomes were observed in patients with in-specification and out-of-specification products as a result of viability <80% (range, 61% to 79%). This first report of tisagenlecleucel in the real-world setting demonstrates outcomes with similar efficacy and improved safety compared with those seen in the pivotal trials.
•Represents the largest set of safety and efficacy data for tisagenlecleucel.•Outcomes in the real-world setting are similar to results in the pivotal trials.
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Chimeric antigen receptor (CAR) T cells targeting CD19 have emerged as a leading engineered T-cell therapy for relapsed/refractory B-cell non-Hodgkin lymphoma. The phase 1/2 clinical trials that led ...to US Food and Drug Administration approval excluded patients with central nervous system (CNS) involvement, due to strict eligibility criteria. Here, we report on our institutional experience with 8 secondary CNS lymphoma patients treated with commercial tisagenlecleucel. No patient experienced greater than grade 1 neurotoxicity, and no patient required tocilizumab or steroids for CAR T-cell–mediated toxicities. Biomarker analysis suggested CAR T-cell expansion, despite the absence of systemic disease, and early response assessments demonstrated activity of IV infused CAR T cells within the CNS space.
•Tisagenlecleucel for secondary CNS lymphoma has an acceptable safety profile.•Preliminary results using tisagenlecleucel demonstrate activity in a heavily pretreated population.
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Chimeric antigen receptor (CAR)-T-cell therapy for solid tumors is limited due to heterogeneous target antigen expression and outgrowth of tumors lacking the antigen targeted by CAR-T cells directed ...against single antigens. Here, we developed a bicistronic construct to drive expression of a CAR specific for EGFRvIII, a glioblastoma-specific tumor antigen, and a bispecific T-cell engager (BiTE) against EGFR, an antigen frequently overexpressed in glioblastoma but also expressed in normal tissues. CART.BiTE cells secreted EGFR-specific BiTEs that redirect CAR-T cells and recruit untransduced bystander T cells against wild-type EGFR. EGFRvIII-specific CAR-T cells were unable to completely treat tumors with heterogenous EGFRvIII expression, leading to outgrowth of EGFRvIII-negative, EGFR-positive glioblastoma. However, CART.BiTE cells eliminated heterogenous tumors in mouse models of glioblastoma. BiTE-EGFR was locally effective but was not detected systemically after intracranial delivery of CART.BiTE cells. Unlike EGFR-specific CAR-T cells, CART.BiTE cells did not result in toxicity against human skin grafts in vivo.
Immune effector cell (IEC) therapies offer durable and sustained remissions in significant numbers of patients with hematological cancers. While these unique immunotherapies have improved outcomes ...for pediatric and adult patients in a number of disease states, as ‘living drugs,’ their toxicity profiles, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), differ markedly from conventional cancer therapeutics. At the time of article preparation, the US Food and Drug Administration (FDA) has approved tisagenlecleucel, axicabtagene ciloleucel, and brexucabtagene autoleucel, all of which are IEC therapies based on genetically modified T cells engineered to express chimeric antigen receptors (CARs), and additional products are expected to reach marketing authorization soon and to enter clinical development in due course. As IEC therapies, especially CAR T cell therapies, enter more widespread clinical use, there is a need for clear, cohesive recommendations on toxicity management, motivating the Society for Immunotherapy of Cancer (SITC) to convene an expert panel to develop a clinical practice guideline. The panel discussed the recognition and management of common toxicities in the context of IEC treatment, including baseline laboratory parameters for monitoring, timing to onset, and pharmacological interventions, ultimately forming evidence- and consensus-based recommendations to assist medical professionals in decision-making and to improve outcomes for patients.
Chimeric antigen receptors redirect T cells (CAR-T) to target cancer cells. There are limited data characterizing cardiac toxicity and cardiovascular (CV) events among adults treated with CAR-T.
The ...purpose of this study was to evaluate the possible cardiac toxicities of CAR-T.
The registry included 137 patients who received CAR-T. Covariates included the occurrence and grade of cytokine release syndrome (CRS) and the administration of tocilizumab for CRS. Cardiac toxicity was defined as a decrease in the left ventricular ejection fraction or an increase in serum troponin. Cardiovascular events were a composite of arrhythmias, decompensated heart failure, and CV death.
The median age was 62 years (interquartile range IQR: 54 to 70 years), 67% were male, 88% had lymphoma, and 8% had myeloma. Approximately 50% were treated with commercial CAR-T (Yescarta or Kymriah), and the remainder received noncommercial products. CRS, occurring a median of 5 days (IQR: 2 to 7 days) after CAR-T, occurred in 59%, and 39% were grade ≥2. Tocilizumab was administered to 56 patients (41%) with CRS, at a median of 27 h (IQR: 16 to 48 h) after onset. An elevated troponin occurred in 29 of 53 tested patients (54%), and a decreased left ventricular ejection fraction in 8 of 29 (28%); each occurred only in patients with grade ≥2 CRS. There were 17 CV events (12%, 6 CV deaths, 6 decompensated heart failure, and 5 arrhythmias; median time to event of 21 days), all occurred with grade ≥2 CRS (31% patients with grade ≥2 CRS), and 95% of events occurred after an elevated troponin. The duration between CRS onset and tocilizumab administration was associated with CV events, where the risk increased 1.7-fold with each 12-h delay to tocilizumab.
Among adults, cardiac injury and CV events are common post–CAR-T. There was a graded relationship among CRS, elevated troponin, and CV events, and a shorter time from CRS onset to tocilizumab was associated with a lower rate of CV events.
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Despite remarkable success in the treatment of hematological malignancies, CAR T-cell therapies for solid tumors have floundered, in large part due to local immune suppression and the effects of ...prolonged stimulation leading to T-cell dysfunction and exhaustion. One mechanism by which gliomas and other cancers can hamper CAR T cells is through surface expression of inhibitory ligands such as programmed cell death ligand 1 (PD-L1). Using the CRIPSR-Cas9 system, we created universal CAR T cells resistant to PD-1 inhibition through multiplexed gene disruption of endogenous T-cell receptor (TRAC), beta-2 microglobulin (B2M) and PD-1 (PDCD1). Triple gene-edited CAR T cells demonstrated enhanced activity in preclinical glioma models. Prolonged survival in mice bearing intracranial tumors was achieved after intracerebral, but not intravenous administration. CRISPR-Cas9 gene-editing not only provides a potential source of allogeneic, universal donor cells, but also enables simultaneous disruption of checkpoint signaling that otherwise impedes maximal antitumor functionality.
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