Cancer immunotherapy has revolutionized the field of oncology in recent years. Harnessing the immune system to treat cancer has led to a large growth in the number of novel immunotherapeutic strategies, including immune checkpoint inhibition, chimeric antigen receptor T-cell therapy and cancer vaccination. In this review, we will discuss the current landscape of immuno-oncology research, with a focus on elements that influence immunotherapeutic outcomes. We will also highlight recent advances in basic aspects of tumor immunology, in particular, the role of the immunosuppressive cells within the tumor microenvironment in regulating antitumor immunity. Lastly, we will discuss how the understanding of basic tumor immunology can lead to the development of new immunotherapeutic strategies.

Chimeric antigen receptor T-cell (CAR-T) therapies are effective in many hematologic malignancies; however, adverse events including cytokine release syndrome (CRS) and immune effector cell–associated neurotoxicity syndrome (ICANS) can affect a significant number of patients. Those who develop refractory CRS or ICANS have few treatment options. Siltuximab, a monoclonal antibody binding circulating interleukin-6, has been proposed to have clinical activity in both CRS and ICANS. We conducted a multicenter retrospective analysis of siltuximab treatment for CRS and ICANS after CAR-T therapy in a real-world cohort from 6 academic centers. Fifty-four patients were evaluated. Sixteen patients had CRS previously treated with tocilizumab and 17 patients had ICANS previously treated with steroids. Of the patients with CRS at the time of siltuximab, 75% had improvement in CRS grade. Of the patients with ICANS at the time of siltuximab, 60% had improvement in ICANS grade. To our knowledge, this is the largest cohort of patients treated with siltuximab for CRS and/or ICANS after CAR-T therapies. Siltuximab appeared to be effective for both CRS and ICANS, including previously treated toxicities. These data support the use of siltuximab in CRS and ICANS as well as provide rationale for future prospective studies.

Marginal zone lymphomas (MZLs) consist of a diverse family of malignancies, which are derived from B-cells. The disease subtypes are recognized extranodal, nodal, and splenic MZLs. The disease characteristics, clinical course, and treatment vary considerably based on the site of involvement. In 2017, the US Food and Drug Administration approved ibrutinib, a first in class Bruton’s tyrosine kinase inhibitor that revolutionized the care of chronic lymphocytic leukemia patients; for, the treatment of relapsed/refractory MZL based on pivotal open-label Phase II trial demonstrated an overall response rate of 48%, with a complete response rate of 3%, median progression-free survival of 14.2 months, and median overall survival not yet reached at a median follow-up of 19.4 months. In this review, we aim to summarize the current conundrums in the management of MZL and the evolving role of ibrutinib in the treatment of MZL.

Despite the increasing utilization of bridging radiotherapy (Br-RT), its impact on chimeric antigen receptor T-cell therapy (CAR-T) efficacy and toxicity remains poorly characterized. We retrospectively reviewed patients with relapsed/refractory B-cell lymphomas (BCLs) who received Br-RT followed by CAR-T from 2018 to 2020 across 10 institutions. Br-RT toxicities were graded per Common Terminology Criteria for Adverse Events version 5.0, and cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) per American Society for Transplantation and Cellular Therapy Consensus Guidelines. One hundred seventy-two patients (168 large BCL) received Br-RT before axicabtagene ciloleucel (73%), tisagenlecleucel (24%), or brexucabtagene autoleucel (2%). At leukapheresis, most patients (74%) had advanced-stage disease and 39% had bulky disease measuring ≥10cm. Comprehensive Br-RT was administered to 39% and bridging systemic therapy to 35%. Among all patients, grade ≥3 Br-RT toxicity occurred in 2% (1 grade 5 toxicity), grade ≥3 CRS in 9%, and grade ≥3 ICANS in 24%. Median follow-up was 31.3 months. Two-year progression-free survival (PFS) and overall survival (OS) were 38% and 53%, respectively. On multivariable analysis, comprehensive Br-RT was associated with superior PFS (hazard ratio [HR], 0.38; P < .001) and OS (HR, 0.48; P = .011). Patients with lactate dehydrogenase (LDH) normalization after Br-RT (high pre-Br-RT LDH, normal post-Br-RT LDH) had superior PFS and OS compared with those with high post-Br-RT LDH and similar PFS and OS compared with those with normal baseline LDH. In this particularly high-risk cohort, Br-RT before CAR-T demonstrates an acceptable toxicity profile with favorable clinical outcomes compared with historical controls. Comprehensive Br-RT and LDH normalization after Br-RT may be associated with superior PFS and OS.

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized treatment for relapsed/refractory B-cell non-Hodgkin lymphoma (NHL). Robust biomarkers and a complete understanding of CAR T-cell function in the postinfusion phase remain limited. Here, we used a 37-color spectral flow cytometry panel to perform high dimensional single-cell analysis of postinfusion samples in 26 patients treated with CD28 costimulatory domain containing commercial CAR T cells for NHL and focused on computationally gated CD8+ CAR T cells. We found that the presence of postinfusion Programmed cell death protein 1 (PD-1)+ CD8+ CAR T cells at the day 14 time point highly correlated with the ability to achieve complete response (CR) by 6 months. Further analysis identified multiple subtypes of CD8+ PD-1+ CAR T cells, including PD-1+ T cell factor 1 (TCF1)+ stem-like CAR T cells and PD-1+ T-cell immunoglobulin and mucin-domain containing-3 (TIM3)+ effector-like CAR T cells that correlated with improved clinical outcomes such as response and progression-free survival. Additionally, we identified a subset of PD-1+ CD8+ CAR+ T cells with effector-like function that was increased in patients who achieved a CR and was associated with grade 3 or higher immune effector cell–associated neurotoxicity syndrome. Here, we identified robust biomarkers of response to CD28 CAR T cells and highlight the importance of PD-1 positivity in CD8+ CAR T cells after infusion in achieving CR.