Phase 1 study of CAR-37 T cells in patients with relapsed or refractory CD37+ lymphoid malignancies.

We report on the first-in-human clinical trial using chimeric antigen receptor (CAR) T-cells targeting CD37, an antigen highly expressed in B- and T-cell malignancies (clinicaltrials.gov NCT04136275). Five patients with relapsed or refractory CD37+ lymphoid malignancies were enrolled and infused with autologous CAR-37 T-cells. CAR-37 T-cells expanded in the peripheral blood of all patients and, at peak, comprised >94% of the total lymphocytes in 4/5 patients. Tumor responses were observed in 4/5 patients, with 3 complete responses, 1 mixed response, and 1 patient whose disease progressed rapidly and with relative loss of CD37 expression. Three patients experienced prolonged and severe pancytopenia, and in two of these patients, efforts to ablate CAR-37 T-cells (which were engineered to co-express truncated EGFR) with cetuximab, were unsuccessful. Hematopoiesis was restored in these two patients following allogeneic hematopoietic stem cell transplantation. No other severe, non-hematopoietic toxicities occurred. We investigated the mechanisms of profound pancytopenia and did not observe activation of CAR-37 T-cells in response to hematopoietic stem cells in vitro or hematotoxicity in humanized models. Patients with pancytopenia had sustained high levels of IL-18, with low levels of IL-18 binding protein in their peripheral blood. IL-18 levels were significantly higher in CAR-37-treated patients relative to both cytopenic and non-cytopenic cohorts of CAR-19-treated cohorts of patients. In conclusion, CAR-37 T-cells exhibited anti-tumor activity, with significant CAR expansion and cytokine production. CAR-37 T-cells may be an effective therapy in hematologic malignancies as a bridge to hematopoietic stem cell transplant.

Cellular Mass Response to Therapy Correlates With Clinical Response for a Range of Malignancies.

PURPOSE: Cancer patients with advanced-stage disease have poor prognosis, typically having limited options for efficacious treatment, and genomics-based therapy guidance continues to benefit only a fraction of patients. Next-generation ex vivo approaches, such as cell mass-based response testing (MRT), offer an alternative precision medicine approach for a broader population of patients with cancer, but validation of clinical feasibility and potential impact remain necessary. MATERIALS AND METHODS: We evaluated the clinical feasibility and accuracy of using live-cell MRT to predict patient drug sensitivity. Using a unified measurement workflow with a 48-hour result turnaround time, samples were subjected to MRT after treatment with a panel of drugs in vitro. After completion of therapeutic course, clinical response data were correlated with MRT-based predictions of outcome. Specimens were collected from 104 patients with solid (n = 69) and hematologic (n = 35) malignancies, using tissue formats including needle biopsies, malignant fluids, bone marrow aspirates, and blood samples. Of the 81 (78%) specimens qualified for MRT, 41 (51%) patients receiving physician-selected therapies had treatments matched to MRT. RESULTS: MRT demonstrated high concordance with clinical responses with an odds ratio (OR) of 14.80 (P = .0003 [95% CI, 2.83 to 102.9]). This performance held for both solid and hematologic malignances with ORs of 20.67 (P = .0128 [95% CI, 1.45 to 1,375.57]) and 8.20 (P = .045 [95% CI, 0.77 to 133.56]), respectively. Overall, these results had a predictive accuracy of 80% (P = .0026 [95% CI, 65 to 91]). CONCLUSION: MRT showed highly significant correlation with clinical response to therapy. Routine clinical use is technically feasible and broadly applicable to a wide range of samples and malignancy types, supporting the need for future validation studies.

Distinct cellular dynamics associated with response to CAR-T therapy for refractory B cell lymphoma.

Chimeric antigen receptor (CAR)-T cell therapy has revolutionized the treatment of hematologic malignancies. Approximately half of patients with refractory large B cell lymphomas achieve durable responses from CD19-targeting CAR-T treatment; however, failure mechanisms are identified in only a fraction of cases. To gain new insights into the basis of clinical response, we performed single-cell transcriptome sequencing of 105 pretreatment and post-treatment peripheral blood mononuclear cell samples, and infusion products collected from 32 individuals with large B cell lymphoma treated with either of two CD19 CAR-T products: axicabtagene ciloleucel (axi-cel) or tisagenlecleucel (tisa-cel). Expansion of proliferative memory-like CD8 clones was a hallmark of tisa-cel response, whereas axi-cel responders displayed more heterogeneous populations. Elevations in CAR-T regulatory cells among nonresponders to axi-cel were detected, and these populations were capable of suppressing conventional CAR-T cell expansion and driving late relapses in an in vivo model. Our analyses reveal the temporal dynamics of effective responses to CAR-T therapy, the distinct molecular phenotypes of CAR-T cells with differing designs, and the capacity for even small increases in CAR-T regulatory cells to drive relapse.

Rapid Quantum Magnetic IL-6 Point-of-Care Assay in Patients Hospitalized with COVID-19.

Interleukin-6 (IL-6) has been linked to several life-threatening disease processes. Developing a point-of-care testing platform for the immediate and accurate detection of IL-6 concentrations could present a valuable tool for improving clinical management in patients with IL-6-mediated diseases. Drawing on an available biobank of samples from 35 patients hospitalized with COVID-19, a novel quantum-magnetic sensing platform is used to determine plasma IL-6 concentrations. A strong correlation was observed between IL-6 levels measured by QDTI10x and the Luminex assay (r = 0.70, p-value < 0.001) and between QDTI80x and Luminex (r = 0.82, p-value < 0.001). To validate the non-inferiority of QDTI to Luminex in terms of the accuracy of IL-6 measurement, two clinical parameters­the need for intensive care unit admission and the need for mechanical intubation­were chosen. IL-6 concentrations measured by the two assays were compared with respect to these clinical outcomes. Results demonstrated a comparative predictive performance between the two assays with a significant correlation coefficient. Conclusion: In short, the QDTI assay holds promise for implementation as a potential tool for rapid clinical decision in patients with IL-6-mediated diseases. It could also reduce healthcare costs and enable the development of future various biomolecule point-of-care tests for different clinical scenarios.

Differential T-Cell Immunity to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in mRNA-1273- and BNT162b2-Vaccinated Individuals.

COVID-19 breakthrough cases among vaccinated individuals demonstrate the value of measuring long-term immunity to SARS-CoV-2 and its variants. We demonstrate that anti-spike T-cell responses and IgG antibody levels are maintained but decrease over time and are lower in BNT162b2- versus mRNA-1273-vaccinated individuals. T-cell responses to the variants are relatively unaffected.

Safety and efficacy of tisagenlecleucel in primary CNS lymphoma: a phase 1/2 clinical trial.

CD19-directed chimerical antigen receptor T-cell (CAR-T) products have gained US Food and Drug Administration approval for systemic large B-cell lymphoma. Because of concerns about potential immune cell-associated neurotoxicity syndrome (ICANS), patients with primary central nervous system (CNS) lymphoma (PCNSL) were excluded from all pivotal CAR-T studies. We conducted a phase 1/2 clinical trial of tisagenlecleucel in a highly refractory patients with PCNSL and significant unmet medical need. Here, we present results of 12 relapsed patients with PCNSL who were treated with tisagenlecleucel and followed for a median time of 12.2 months (range, 3.64-23.5). Grade 1 cytokine release syndrome was observed in 7/12 patients (58.3%), low-grade ICANS in 5/12 (41.6%) patients, and only 1 patient experienced grade 3 ICANS. Seven of 12 patients (58.3%) demonstrated response, including a complete response in 6/12 patients (50%). There were no treatment-related deaths. Three patients had ongoing complete remission at data cutoff. Tisagenlecleucel expanded in the peripheral blood and trafficked to the CNS. Exploratory analysis identified T-cell, CAR T, and macrophage gene signatures in cerebrospinal fluid following infusion when compared with baseline. Overall, tisagenlecleucel was well tolerated and resulted in a sustained remission in 3/7 (42.9%) of initial responders. These data suggest that tisagenlecleucel is safe and effective in this highly refractory patient population. This trial was registered at www.clinicaltrials.gov as #NCT02445248.

Humoral and cellular immunogenicity of SARS-CoV-2 vaccines in chronic lymphocytic leukemia: a prospective cohort study.

Chronic lymphocytic leukemia (CLL), the most common leukemia worldwide, is associated with increased COVID-19 mortality. Previous studies suggest only a portion of vaccinated CLL patients develop severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike antibodies. Whether the elicited antibodies are functional and/or accompanied by functional T-cell responses is unknown. This prospective cohort study included patients with CLL who received SARS-CoV-2 and PCV13 vaccines (not concurrently). The primary cohort included adults with CLL off therapy. Coprimary outcomes were serologic response to SARS-CoV-2 (receptor binding domain [RBD] immunoassay) and PCV13 vaccines (23-serotype IgG assay). Characterization of SARS-CoV-2 antibodies and their functional activity and assessment of functional T-cell responses was performed. Sixty percent (18/30) of patients demonstrated serologic responses to SARS-CoV-2 vaccination, appearing more frequent among treatment-naïve patients (72%). Among treatment-naïve patients, an absolute lymphocyte count ≤24 000/µL was associated with serologic response (94% vs 14%; P < .001). On interferon-γ release assays, 80% (16/20) of patients had functional spike-specific T-cell responses, including 78% (7/9) with a negative RBD immunoassay, a group enriched for prior B-cell-depleting therapies. A bead-based multiplex immunoassay identified antibodies against wild-type and variant SARS-CoV-2 (α, ß, γ, and δ) in all tested patients and confirmed Fc-receptor binding and effector functions of these antibodies. Of 11 patients with negative RBD immunoassay after vaccination, 6 (55%) responded to an additional mRNA-based vaccine dose. The PCV13 serologic response rate was 29% (8/28). Our data demonstrate that SARS-CoV-2 vaccination induces functional T-cell and antibody responses in patients with CLL and provides the framework for investigating the molecular mechanisms and clinical benefit of these responses. This trial was registered at www.clinicaltrials.gov as #NCT05007860.

Profiling SARS-CoV-2 HLA-I peptidome reveals T cell epitopes from out-of-frame ORFs.

T cell-mediated immunity plays an important role in controlling SARS-CoV-2 infection, but the repertoire of naturally processed and presented viral epitopes on class I human leukocyte antigen (HLA-I) remains uncharacterized. Here, we report the first HLA-I immunopeptidome of SARS-CoV-2 in two cell lines at different times post infection using mass spectrometry. We found HLA-I peptides derived not only from canonical open reading frames (ORFs) but also from internal out-of-frame ORFs in spike and nucleocapsid not captured by current vaccines. Some peptides from out-of-frame ORFs elicited T cell responses in a humanized mouse model and individuals with COVID-19 that exceeded responses to canonical peptides, including some of the strongest epitopes reported to date. Whole-proteome analysis of infected cells revealed that early expressed viral proteins contribute more to HLA-I presentation and immunogenicity. These biological insights, as well as the discovery of out-of-frame ORF epitopes, will facilitate selection of peptides for immune monitoring and vaccine development.

SARS -CoV-2 T-cell immunity to variants of concern following vaccination.

Recently, two mRNA vaccines to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have become available, but there is also an emergence of SARS-CoV-2 variants with increased transmissibility and virulence1-6. A major concern is whether the available vaccines will be equally effective against these variants. The vaccines are designed to induce an immune response against the SARS-CoV-2 spike protein7,8, which is required for viral entry to host cells9. Immunity to SARS-CoV-2 is often evaluated by antibody production, while less is known about the T-cell response. Here we developed, characterized, and implemented two standardized, functional assays to measure T-cell immunity to SARS-CoV-2 in uninfected, convalescent, and vaccinated individuals. We found that vaccinated individuals had robust T-cell responses to the wild type spike and nucleocapsid proteins, even more so than convalescent patients. We also found detectable but diminished T-cell responses to spike variants (B.1.1.7, B.1.351, and B.1.1.248) among vaccinated but otherwise healthy donors. Since decreases in antibody neutralization have also been observed with some variants10-12, investigation into the T-cell response to these variants as an alternative means of viral control is imperative. Standardized measurements of T-cell responses to SARS-CoV-2 are feasible and can be easily adjusted to determine changes in response to variants.