Prolonged cytopenias after immune effector cell therapy and lymphodepletion in patients with leukemia, lymphoma and solid tumors.

BACKGROUND AIMS: The success of chimeric antigen receptor (CAR) T-cell therapy in treating B-cell malignancies has led to the evaluation of CAR T-cells targeting a variety of other malignancies. Although the efficacy of CAR T-cells is enhanced when administered post-lymphodepleting chemotherapy, this can trigger bone marrow suppression and sustained cytopenia after CD19.CAR T-cell therapy. Additionally, systemic inflammation associated with CAR T-cell activity may contribute to myelosuppression. Cytopenias, such as neutropenia and thrombocytopenia, elevate the risk of severe infections and bleeding, respectively. However, data on the incidence of prolonged cytopenias after immune effector therapy in the solid tumor context remain limited. OBJECTIVE: We compared the incidence of prolonged cytopenias after immune effector therapy including genetically modified T-cells, virus-specific T-cells (VSTs) and NKT-cells, as well non-gene-modified VSTs for leukemia, lymphoma, and solid tumors (ST) to identify associated risk factors. METHODS: A retrospective analysis was conducted of 112 pediatric and adult patients with relapsed and/or refractory cancers who received lymphodepleting chemotherapy followed by immune effector therapy. Patients treated with 13 distinct immune effector cell therapies through 11 single-center clinical trials and 2 commercial products over a 6-year period were categorized into 3 types of malignancies: leukemia, lymphoma and ST. We obtained baseline patient characteristics and adverse events data for each participant, and tracked neutrophil and platelet counts following lymphodepletion. RESULTS: Of 112 patients, 104 (92.9%) experienced cytopenias and 88 (79%) experienced severe cytopenias. Patients with leukemia experienced significantly longer durations of severe neutropenia (median duration of 14 days) compared with patients with lymphoma (7 days) or ST (11 days) (P = 0.002). Patients with leukemia also had a higher incidence of severe thrombocytopenia (74.1%), compared with lymphoma (46%, P = 0.03) and ST (14.3%, P < 0.0001). Prolonged cytopenias were significantly associated with disease type (63% of patients with leukemia, 44% of patients with lymphoma, and 22.9% of patients with ST, P = 0.006), prior hematopoietic stem cell transplant (HSCT) (66.7% with prior HSCT versus 38.3% without prior HSCT, P = 0.039), and development of immune effector cell-associated neurotoxicity syndrome (ICANS) (75% with ICANS versus 38% without ICANS, P = 0.027). There was no significant association between prolonged cytopenias and cytokine release syndrome. CONCLUSIONS: Immune effector recipients often experience significant cytopenias due to marrow suppression following lymphodepletion regardless of disease, but prolonged severe cytopenias are significantly less common after treatment of patients with lymphoma and solid tumors.

Pediatric liposarcoma: A case series and literature review.

Liposarcoma is arare soft tissue sarcoma in children. While prognosis, clinical behavior, and response to therapy among the various histologic subtypes are well described in adults, data in children are limited. Here, we describe our experience treating 14 children with liposarcoma at a large, academic pediatric center and review the available pediatric literature. This comprehensive report adds treatment, survival, and genomic data to pediatric liposarcoma literature.

Incidence and predictors of treatment-related conjugated hyperbilirubinemia during early treatment phases for children with acute lymphoblastic leukemia.

Conjugated hyperbilirubinemia (CHB) and liver transaminase elevation are known complications of acute lymphoblastic leukemia (ALL) therapy, but host risk factors are poorly understood. Among 373 children diagnosed with ALL between 2011 and 2016, clinically significant CHB and transaminase elevation were observed in 15 (4.0%) and 12 (3.2%) children, respectively, during induction and consolidation. Body mass index ≥95th percentile (odds ratio 9.20, 95% confidence interval 2.56-32.96) was the only host factor independently associated with CHB, and no host factors were associated with transaminase elevation. Obese patients warrant closer monitoring of hepatic function to facilitate early intervention prior to the development of severe, adverse hepatic events.

Malignant melanoma incidence among children and adolescents in Texas and SEER 13, 1995-2013.

BACKGROUND: Epidemiological knowledge and predictors of melanoma among children and adolescents in multiethnic populations are limited. PROCEDURE: Using data from the Texas Cancer Registry (TCR) and the Surveillance, Epidemiology, and End Results (SEER) 13 database, we identified incident melanoma cases diagnosed at 0-20 years old during 1995-2013 in Texas and the United States, respectively. Using negative binomial regression, associations between demographic factors and melanoma incidence rates (IR) were evaluated by calculating incidence rate ratios (IRR) and 95% confidence intervals (CI). Annual percent change in IRs was assessed with joinpoint regression. RESULTS: Overall, the melanoma IR was 4.16 (TCR, n = 634) and 4.84 (SEER, n = 1260) per million. Females, adolescents, non-Hispanic (NH) whites, and Hispanics had higher IRs compared with other groups (P < 0.05). In adjusted analyses, Hispanics had a higher incidence of melanoma than NH non-whites (Texas IRR = 2.17; 95% CI, 1.30-3.61; SEER IRR = 2.88; 95% CI, 1.97-4.21). In Texas, NH whites with melanoma were more likely to live in low poverty areas, whereas the opposite trend was observed in Hispanics. Melanoma IRs increased throughout 1995-2004 followed by an average annual decrease of 7.6% (95% CI, -12.6%, -2.2%) in Texas and 6.0% (95% CI, -8.5%, -3.4%) in SEER during 2005-2013 (P < 0.05). However, these decreasing trends were not observed among Hispanics or those <10 years old. CONCLUSION: Although the overall melanoma IR in children and adolescents appears to be decreasing, this trend is not evident among Hispanics and young children, implicating the need for further research investigating the etiologies and risk factors in these groups.

Targeting the tumour profile using broad spectrum chimaeric antigen receptor T-cells.

A variety of distinct and redundant mechanisms support tumour propagation and survival. Tumour parenchyma consists of a variety of geographically diverse cells with varying genetic expression among subclonal populations. Additionally, the solid tumour microenvironment consists of a dense network of stromal, vascular and immune cells altered by a number of mechanisms not only to tolerate but often to enhance cancer growth. The limited spectrum of chimaeric antigen receptor (CAR) T-cell specificity in the face of this dynamic landscape is one of the greatest challenges facing CAR T-cell therapy for solid tumours. Thus targeting multiple cancer-specific markers simultaneously could result in improved efficacy by broadening the therapeutic reach to include multiple subclonal populations of the tumour parenchyma as well as elements of the tumour microenvironment. Over the last 10 years, we and others have developed multiplex platforms that target the tumour profile rather than single tumour-restricted antigens. These platforms introduce a new dimension that may be key to the successful development of T-cell therapies for solid tumours and to the mitigation of relapses due to antigen escape.

Autologous HER2-specific CAR T cells after lymphodepletion for advanced sarcoma: a phase 1 trial.

In this prospective, interventional phase 1 study for individuals with advanced sarcoma, we infused autologous HER2-specific chimeric antigen receptor T cells (HER2 CAR T cells) after lymphodepletion with fludarabine (Flu) ± cyclophosphamide (Cy): 1 × 108 T cells per m2 after Flu (cohort A) or Flu/Cy (cohort B) and 1 × 108 CAR+ T cells per m2 after Flu/Cy (cohort C). The primary outcome was assessment of safety of one dose of HER2 CAR T cells after lymphodepletion. Determination of antitumor responses was the secondary outcome. Thirteen individuals were treated in 14 enrollments, and seven received multiple infusions. HER2 CAR T cells expanded after 19 of 21 infusions. Nine of 12 individuals in cohorts A and B developed grade 1-2 cytokine release syndrome. Two individuals in cohort C experienced dose-limiting toxicity with grade 3-4 cytokine release syndrome. Antitumor activity was observed with clinical benefit in 50% of individuals treated. The tumor samples analyzed showed spatial heterogeneity of immune cells and clustering by sarcoma type and by treatment response. Our results affirm HER2 as a CAR T cell target and demonstrate the safety of this therapeutic approach in sarcoma. ClinicalTrials.gov registration: NCT00902044 .

CAR T-cells that target acute B-lineage leukemia irrespective of CD19 expression.

Chimeric antigen receptor (CAR) T-cells targeting CD19 demonstrate remarkable efficacy in treating B-lineage acute lymphoblastic leukemia (BL-ALL), yet up to 39% of treated patients relapse with CD19(-) disease. We report that CD19(-) escape is associated with downregulation, but preservation, of targetable expression of CD20 and CD22. Accordingly, we reasoned that broadening the spectrum of CD19CAR T-cells to include both CD20 and CD22 would enable them to target CD19(-) escape BL-ALL while preserving their upfront efficacy. We created a CD19/20/22-targeting CAR T-cell by coexpressing individual CAR molecules on a single T-cell using one tricistronic transgene. CD19/20/22CAR T-cells killed CD19(-) blasts from patients who relapsed after CD19CAR T-cell therapy and CRISPR/Cas9 CD19 knockout primary BL-ALL both in vitro and in an animal model, while CD19CAR T-cells were ineffective. At the subcellular level, CD19/20/22CAR T-cells formed dense immune synapses with target cells that mediated effective cytolytic complex formation, were efficient serial killers in single-cell tracking studies, and were as efficacious as CD19CAR T-cells against primary CD19(+) disease. In conclusion, independent of CD19 expression, CD19/20/22CAR T-cells could be used as salvage or front-line CAR therapy for patients with recalcitrant disease.

Tumor response and endogenous immune reactivity after administration of HER2 CAR T cells in a child with metastatic rhabdomyosarcoma.

Refractory metastatic rhabdomyosarcoma is largely incurable. Here we analyze the response of a child with refractory bone marrow metastatic rhabdomyosarcoma to autologous HER2 CAR T cells. Three cycles of HER2 CAR T cells given after lymphodepleting chemotherapy induces remission which is consolidated with four more CAR T-cell infusions without lymphodepletion. Longitudinal immune-monitoring reveals remodeling of the T-cell receptor repertoire with immunodominant clones and serum autoantibodies reactive to oncogenic signaling pathway proteins. The disease relapses in the bone marrow at six months off-therapy. A second remission is achieved after one cycle of lymphodepletion and HER2 CAR T cells. Response consolidation with additional CAR T-cell infusions includes pembrolizumab to improve their efficacy. The patient described here is a participant in an ongoing phase I trial (NCT00902044; active, not recruiting), and is 20 months off T-cell infusions with no detectable disease at the time of this report.

Tandem CAR T cells targeting HER2 and IL13Rα2 mitigate tumor antigen escape.

In preclinical models of glioblastoma, antigen escape variants can lead to tumor recurrence after treatment with CAR T cells that are redirected to single tumor antigens. Given the heterogeneous expression of antigens on glioblastomas, we hypothesized that a bispecific CAR molecule would mitigate antigen escape and improve the antitumor activity of T cells. Here, we created a CAR that joins a HER2-binding scFv and an IL13Rα2-binding IL-13 mutein to make a tandem CAR exodomain (TanCAR) and a CD28.ζ endodomain. We determined that patient TanCAR T cells showed distinct binding to HER2 or IL13Rα2 and had the capability to lyse autologous glioblastoma. TanCAR T cells exhibited activation dynamics that were comparable to those of single CAR T cells upon encounter of HER2 or IL13Rα2. We observed that TanCARs engaged HER2 and IL13Rα2 simultaneously by inducing HER2-IL13Rα2 heterodimers, which promoted superadditive T cell activation when both antigens were encountered concurrently. TanCAR T cell activity was more sustained but not more exhaustible than that of T cells that coexpressed a HER2 CAR and an IL13Rα2 CAR, T cells with a unispecific CAR, or a pooled product. In a murine glioblastoma model, TanCAR T cells mitigated antigen escape, displayed enhanced antitumor efficacy, and improved animal survival. Thus, TanCAR T cells show therapeutic potential to improve glioblastoma control by coengaging HER2 and IL13Rα2 in an augmented, bivalent immune synapse that enhances T cell functionality and reduces antigen escape.