Nivolumab for Relapsed/Refractory Classic Hodgkin Lymphoma After Failure of Autologous Hematopoietic Cell Transplantation: Extended Follow-Up of the Multicohort Single-Arm Phase II CheckMate 205 Trial

Toripalimab: the First Domestic Anti-Tumor PD-1 Antibody in China

Toripalimab (Tuoyi™) is a selective, recombinant, humanized monoclonal antibody against programmed death protein 1 (PD-1) developed by Shanghai Junshi Bioscience Co., Ltd. Toripalimab is able to bind to PD-1 and block the interaction with its ligands. The binding of toripalimab to PD-1 is mainly attributed to the heavy chain of the former and the FG loop of the latter. Toripalimab received a conditional approval in China for the treatment of melanoma (second-line) in December, 2018. It has also received approvals to treat nasopharyngeal carcinoma (first-line and third-line) and urothelial carcinoma (second-line) in 2021. Additionally, several orphan drug designations were granted to toripalimab by the US Food and Drug Administration. Toripalimab has exhibited primary anti-tumor effects in tumors such as melanoma, lung cancer, digestive tract tumors, hepatobiliary and pancreatic tumors, neuroendocrine neoplasms, nasopharyngeal carcinoma and urothelial carcinoma. It showed a satisfactory anti-tumor effect and long-term survival benefits in Chinese melanoma patients, while the combination of axitinib with toripalimab exhibited an impressive result in metastatic mucosal melanoma. As a checkpoint inhibitor, toripalimab was generally well-tolerated in the enrolled patients. Due to different study populations, comparisons could not be made directly between toripalimab and other drugs in most cases. Nevertheless, the introduction of toripalimab may offer a valuable choice for decision-making in the treatment of tumors in the future.

Vogt-Koyanagi-Harada syndrome-like uveitis after nivolumab administration as a treatment for ovarian cancer

PURPOSE

To report a case of Vogt-Koyanagi-Harada (VKH) syndrome-like posterior uveitis after nivolumab administration to treat an ovarian cancer with an electrophysiological finding. A 61-year-old woman with ovarian cancer (stage 3A) and salpingo-oophorectomy surgery history visited the clinic complaining of blurred vision in both eyes. She had been enrolled a clinical trial using nivolumab in patients with ovarian cancer. She received four cycles of nivolumab administration and experienced blurred vision one week before the initial visit. There was no remarkable finding in the anterior segment and the vitreous body. Multiple subretinal fluid accumulations and serous retinal detachment were identified on the posterior pole. Subretinal fluid with choroidal folding was noted in optical coherence tomography, and multiple leakage points were also observed in wide-field fundus fluorescein angiography. Therefore, intravenous high-dose steroid pulse therapy was applied under the diagnosis of VKH syndrome-like posterior uveitis induced by an immunotherapy agent. After steroid therapy, the subretinal fluid was absorbed completely, and the patient's visual acuity was recovered to the normal range. The amplitudes in the multifocal electroretinogram were also restored after the treatment.

CONCLUSION

Nivolumab is a human IgG4 monoclonal antibody and an immune checkpoint inhibitor. It is associated with the upregulation of T-cell activity by interfering with the interaction between the programmed death-1 (PD-1) receptor and the PD-ligand. Targeted therapy using immunotherapy agents has been widely used for malignant melanoma, lung cancer, renal cell carcinoma, and other cancers. However, immunotherapy agents such as nivolumab can induce autoimmune-related adverse events including uveitis. This report suggests that VKH syndrome-like posterior uveitis could be induced by nivolumab administration for an ovarian cancer treatment, which was resolved by steroid pulse therapy.

Targeted Therapy in Leukaemia, Lymphoma and Myeloma

Historically, most advances in cancer therapy have been pioneered by clinicians managing the blood diseases [...].

Lymphocyte HLA-DR/CD-38 co-expression correlates with Hodgkin lymphoma cell cytotoxicity in vitro independent of PD-1/PD1-L pathway

The interactions between Hodgkin and Reed Sternberg cells and tumor microenvironment, the changes that occur with therapy and, in particular, checkpoint inhibition are not fully understood. Understanding these is key to optimizing outcomes for patients with Hodgkin lymphoma (HL). We evaluated the immunophenotypic characteristics of cytotoxic, helper T and NK lymphocytes upon in vitro stimulation, cell-mediated cytotoxicity against HL cells, HDLM-2 and KM-H2, and the association with effector cell activation state, as well as changes in cytotoxicity following PD-1 or PDL-1 blockade. Higher HLA-DR/CD38 expression on effector cells was associated with increased cytotoxicity against HL cells. All effector cell types were cytotoxic of HL cells, though achieved maximum activation and cytotoxicity at variable timepoints. HLA-DR/CD38 co-expression correlated with cytotoxicity, but PD-1 expression did not. There was no significant change in cell-mediated cytotoxicity following PD-1/PDL-1 blockade. The mechanism of action of checkpoint inhibitors may not be limited to direct PD-1/PDL-1 blockade.

High efficacy of PD-1 inhibitor after initial failure of PD-L1 inhibitor in Relapsed/Refractory classical Hodgkin Lymphoma

PURPOSE

We sought to understand the clinical course and molecular phenotype of patients who showed disease progression after programmed cell death ligand 1 (PD-L1) inhibitor treatment but subsequently responded to PD-1 inhibitor treatment. We also explored the response to PD-1-axis targeted therapy of classical Hodgkin lymphoma (cHL) according to genetically driven PD-L1 and programmed cell death ligand 2 (PD-L2) expression.

METHODS

Five patients in a phase II clinical trial of CS1001 (PD-L1 inhibitor) for relapsed or refractory (R/R) cHL were retrospectively reviewed. Formalin-fixed, paraffin-embedded whole tissues from the five patients were evaluated for 9p24.1 genetic alterations based on FISH and the expression of PD-L1, PD-L2, PD-1, major histocompatibility complex (MHC) class I-II, and the tumor microenvironment factorsCD163 and FOXP3 in the microenvironmental niche, as revealed by multiplex immunofluorescence.

RESULTS

All five patients showed primary refractory disease during first-line treatment. Four patients received PD-1 inhibitor after dropping out of the clinical trial, and all demonstrated at least a partial response. The progression-free survival ranged from 7 to 28 months (median = 18 months), and 9p24.1 amplification was observed in all five patients at the PD-L1/PD-L2 locus. PD-L1 and PD-L2 were colocalized on Hodgkin Reed-Sternberg (HRS) cells in four of the five (80%) patients. There was differential expression of PD-L1 and PD-L2 in cells in the tumor microenvironment in cHL, especially in HRS cells, background cells and tumor-associated macrophages.

CONCLUSIONS

PD-L1 monotherapy may not be sufficient to block the PD-1 pathway; PD-L2 was expressed in HRS and background cells in cHL. The immunologic function of the PD-L2 pathway in anti-tumor activity may be underestimated in R/R cHL. Further study is needed to elucidate the anti-tumor mechanism of PD-1 inhibitor and PD-L1 inhibitor treatment.

EBV-associated diseases: Current therapeutics and emerging technologies

EBV is a prevalent virus, infecting >90% of the world's population. This is an oncogenic virus that causes ~200,000 cancer-related deaths annually. It is, in addition, a significant contributor to the burden of autoimmune diseases. Thus, EBV represents a significant public health burden. Upon infection, EBV remains dormant in host cells for long periods of time. However, the presence or episodic reactivation of the virus increases the risk of transforming healthy cells to malignant cells that routinely escape host immune surveillance or of producing pathogenic autoantibodies. Cancers caused by EBV display distinct molecular behaviors compared to those of the same tissue type that are not caused by EBV, presenting opportunities for targeted treatments. Despite some encouraging results from exploration of vaccines, antiviral agents and immune- and cell-based treatments, the efficacy and safety of most therapeutics remain unclear. Here, we provide an up-to-date review focusing on underlying immune and environmental mechanisms, current therapeutics and vaccines, animal models and emerging technologies to study EBV-associated diseases that may help provide insights for the development of novel effective treatments.

Tislelizumab: A Modified Anti-tumor Programmed Death Receptor 1 Antibody

Tislelizumab is an anti-programmed death receptor 1 (PD-1) monoclonal immunoglobulin G 4 antibody developed by BeiGene. The structure of tislelizumab has been modified to maximally inhibit the binding of PD-1 to programmed death ligand 1 (PD-L1) and minimize the binding of tislelizumab to Fcγ receptors. In clinical studies, tislelizumab has shown preliminary anti-tumor effects in various solid tumors, such as Hodgkin's lymphoma, urothelial carcinoma, lung cancer, gastric and esophageal cancer, liver cancer, nasopharyngeal carcinoma, colorectal cancer, and microsatellite instability-high/mismatch repair-deficient tumors. In addition, it also showed new promise in solid tumor treatment in combination with ociperlimab. Due to its satisfactory anti-tumor effects, tislelizumab has received approvals in China for the treatment of classical Hodgkin's lymphoma, urothelial carcinoma, squamous non-small cell lung cancer, non-squamous non-small cell lung cancer, and hepatocellular carcinoma, and it is now under investigation for a new indication in microsatellite instability-high/mismatch repair-deficient tumors. Moreover, it has been granted orphan designations in hepatocellular carcinoma, esophageal cancer, and gastric cancer, including cancer of the gastroesophageal junction, by the US Food and Drug Administration. Tislelizumab has an acceptable safety profile; the most common adverse effects include fatigue, anemia, and decreased neutrophil count, while the most fatal events have been related to respiratory infection or failure, and hepatic injury. Tislelizumab has an economic advantage compared with other well-studied PD-1/PD-L1 inhibitors; thus, the introduction of it could provide clinical oncologists with an effective weapon against tumors and may alleviate the burden of cancer patients.

Recent advances in primary resistance mechanisms against immune checkpoint inhibitors

PURPOSE OF REVIEW

The resistance of immune checkpoint inhibitors (ICIs) has become an obstacle to further improve the survival of patients with advanced cancer. This review provides an overview of recent advances in primary resistance mechanisms of ICIs.

RECENT FINDINGS

With the improvement of study approach, new characteristics and trends have emerged in the classification of tumor immune subtypes. The effects of germline genetic on tumor microenvironment and the efficacy of immunotherapy have been further studied. Exosomal programmed death-ligand 1 (PD-L1) is an increasing focus of research in primary resistance mechanisms of ICIs. In addition to antibiotics and steroids, the influence of other concomitant medications on the efficacy of ICIs has recently gained more attention.

SUMMARY

Exploring the resistance mechanisms of ICIs is one of the great challenges in the field of tumor immunotherapy. Continued work to understand the resistance mechanism of ICIs is ongoing.

Real-world outcomes of autologous and allogeneic hematopoietic stem cell transplantation for relapsed/refractory Hodgkin lymphoma in the era of novel therapies: a Canadian perspective

BACKGROUND

Despite high cure rates with frontline therapy for Hodgkin lymphoma (HL), about 30% of patients will relapse or have primary refractory disease (R/r). Autologous hematopoietic stem cell transplantation (AHSCT) is the standard of care for R/r disease and alloHSCT is a curative option for patients in second relapse. Novel agents are being incorporated for the treatment of R/r HL, such that the optimal timing of transplant is currently being challenged. Additionally, because access to these new agents varies amongst transplant centers, we sought to offer a Canadian perspective to the treatment of R/r HL and demonstrate the utility and effectiveness of both AHSCT and alloHSCT for the treatment of R/r HL.

METHODS

This single-center retrospective study examined outcomes in 89 consecutive patients with R/r HL treated with AHSCT between January 2007 and December 2019. A total of 17 patients underwent alloHSCT either as a tandem auto-allo approach or as salvage therapy.

RESULTS

With a median follow-up of 5.0 years, the estimated 5-year PFS and OS for patients undergoing AHSCT were 57.5% (95% CI 45.2-68.0) and 81.3% (95% CI 70.0-88.8), respectively. Corresponding figures for patients who underwent alloHSCT were 76.5% (95% CI 48.8-90.4) and 82.4% (95% CI 54.7-93.9). NRM at 100 days and 5 years was 0% and 9.4% post AHSCT and 0% and 5.9% post alloHSCT. Cumulative incidence (CI) of acute GVHD at day +100 was 35.3% (95% CI 17.7 - 62.3) and CI of chronic GVHD at 1 year was 23.5% (95% CI 6.9 - 45.8).

CONCLUSIONS

AHSCT and alloHSCT can both provide robust and prolonged disease control and new agents should be used as a bridge to improve the curative potential of these definitive cellular therapies.

How to choose first salvage therapy in Hodgkin lymphoma: traditional chemotherapy vs novel agents

Approximately 10% to 30% of patients with classical Hodgkin lymphoma (cHL) develop relapsed or refractory (R/R) disease. Of those patients, 50% to 60% show long-term progression-free survival after standard salvage chemotherapy followed by high-dose chemotherapy (HDCT) and autologous stem cell transplant (ASCT). In the past decade, novel therapies have been developed, such as the CD30-directed antibody-drug conjugate brentuximab vedotin and immune checkpoint inhibitors, which have greatly extended the treatment possibilities for patients with R/R cHL. Several phase 1/2 clinical trials have shown promising results of these new drugs as monotherapy or in combination with chemotherapy, but unfortunately, very few randomized phase 3 trials have been performed in this setting, making it difficult to give evidence-based recommendations for optimal treatment sequencing. Two important goals for the improvement in the treatment of R/R cHL can be identified: (1) increasing long-term progression-free and overall survival by optimizing risk-adapted treatment and (2) decreasing toxicity in patients with a low risk of relapse of disease by evaluating the need for HDCT/ASCT in these patients. In this review, we discuss treatment options for patients with R/R cHL in different settings: patients with a first relapse, primary refractory disease, and in patients who are ineligible or unfit for ASCT. Results of clinical trials investigating novel therapies or strategies published over the past 5 years are summarized.

Immune Regulatory Processes of the Tumor Microenvironment under Malignant Conditions

The tumor microenvironment (TME) is a critical regulator of tumor growth, progression, and metastasis. Since immune cells represent a large fraction of the TME, they play a key role in mediating pro- and anti-tumor immune responses. Immune escape, which suppresses anti-tumor immunity, enables tumor cells to maintain their proliferation and growth. Numerous mechanisms, which have been intensively studied in recent years, are involved in this process and based on these findings, novel immunotherapies have been successfully developed. Here, we review the composition of the TME and the mechanisms by which immune evasive processes are regulated. In detail, we describe membrane-bound and soluble factors, their regulation, and their impact on immune cell activation in the TME. Furthermore, we give an overview of the tumor/antigen presentation and how it is influenced under malignant conditions. Finally, we summarize novel TME-targeting agents, which are already in clinical trials for different tumor entities.

Tumor Microenvironment of Lymphomas and Plasma Cell Neoplasms: Broad Overview and Impact on Evaluation for Immune Based Therapies

Lymphomas and plasma cell neoplasms are a heterogenous group of malignancies derived from lymphocytes. They are a significant cause of patient morbidity and mortality. Advances in morphologic, immunophenotypic and molecular techniques have led to better understanding of the pathogenesis and diagnosis of these neoplasms. Advances in treatment, particularly immune-based therapies, increasingly allow for targeted therapies of these diseases. Mechanistic studies using animal models and clinical trials have revealed the importance of the tumor microenvironment on disease pathogenesis, progression, and response to therapy in these malignancies. Simultaneous progress in diagnostic techniques has made it feasible to generate high-resolution, high-throughput data from the tumor microenvironment with spatial context. As the armamentarium of targeted therapies and diagnostic techniques grows, there is potential to harness these advances to better stratify patients for targeted therapies, including immune-based therapies, in hematologic malignancies.

Body mass index is not associated with survival outcomes and immune-related adverse events in patients with Hodgkin lymphoma treated with the immune checkpoint inhibitor nivolumab

Background

Overweight and obese patients with solid tumors receiving anti-programmed cell death-1 (PD-1)/PD-ligand-1(PD-L1) immune checkpoint inhibitors exhibit improved survival and higher risk of immune-related adverse events (irAEs) than those with a normal body mass index (BMI). In classic Hodgkin lymphoma (cHL), the impact of BMI on survival and immune-related toxicity is unknown. We evaluated for the first time associations of BMI with survival and irAEs in patients with relapsed/refractory (RR)-cHL undergoing PD-1 blockade.

Methods

Data from a multicenter study on 133 patients treated with the anti-PD1 antibody nivolumab (July 2015–December 2016) were retrieved from a prospective database. Progression-free (PFS), overall survival (OS), incidence and severity of irAEs according to BMI categories were estimated by Kaplan–Meier method, landmark-analyses and Cox regressions.

Results

Patients, mostly males (63%, n = 84) with a median age of 35 years (range, 15–82), advanced stage (75%), B symptoms (63%), bulky disease (24%), a median of 4 previous treatments (range, 1–9), received a median of 18 nivolumab doses (range, 1–57). No statistically significant differences across BMI subgroups emerged as to PFS, with 1-year rates of 67.1% for both normal weight (n = 66; 49.6%) and overweight (n = 31; 23.3%) patients. Underweight (n = 12; 9%) and obese (n = 24; 18%) patients had a 1-year PFS of 54.5% and 49%, respectively. In survival analyses, BMI either as a continuous (P = 0.5) or categorical (P for trend = 0.63) variable failed to associate with PFS. Response rates and time-to-response did not cluster in any BMI subset. No BMI-related differences in OS emerged across normal, overweight and obese patients but underweight patients had the worst survival. Occurrence of irAEs of whatever severity did not statistically associate with BMI.

Conclusions

In patients with RR-cHL receiving nivolumab, no statistically significant differences emerged in response rates, PFS and OS across BMI categories of normal weight, overweight and obese. Overweight/obese patients did not display an increased risk of irAEs. The exquisite sensitivity to anti-PD-1 antibodies, the unique cytokine milieu and effector pathways triggered by nivolumab in cHL, may represent biologic ‘equalizers’ counteracting the immunoregulatory effects of adiposity. Differently from solid tumors, BMI is not associated with treatment efficacy and immune-related toxicity and does not represent a predictive tool for PD-1-targeted immunotherapies in cHL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03134-4.

Efficacy and safety of nivolumab combined with brentuximab vedotin after nivolumab monotherapy failure in patients with relapsed and refractory classic Hodgkin lymphoma

Objectives

Therapy of patients with relapsed and refractory classic Hodgkin lymphoma (r/r cHL) after PD-1 inhibitors failure remains an unresolved issue. The aim of this study was to evaluate the efficacy and safety of the combination of nivolumab with brentuximab vedotin (Nivo + BV) after nivolumab monotherapy failure.

Methods

This study retrospectively analyzed 21 patients with r/r cHL who were treated with the combination of Nivo + BV after Nivo failure. The response was evaluated by PET–CT scan according to the LYRIC criteria. Adverse events (AEs) were assessed according to NCI CTCAE v.4.03.

Results

Median follow-up was 19 (9–47) months. The ORR was 57%. The median OS was not reached, 24 month OS was 80% (95% CI 50–93%). Median PFS was 12 months with 24 month PFS of 31% (95% CI 12–53%). Any grade AEs were observed in 12 patients (63%), 3–4 grade AEs in 2 patients (10%). Allogeneic hematopoietic stem cell transplantation (allo-HSCT) after Nivo + BV was performed in 8 (38%) patients. The median time between Nivo + BV and allo-HSCT was 8 (5–21) months.

Conclusions

Combination of Nivo + BV in r/r cHL after nivolumab monotherapy failure is potentially an effective and safe approach.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10147-021-02085-6.

Advances in CD30- and PD-1-targeted therapies for relapsed or refractory Hodgkin lymphoma

The current standard approach for relapsed or refractory (R/R) Hodgkin lymphoma (HL) is salvage chemotherapy, followed by autologous stem cell transplantation (ASCT). However, this therapeutic regimen is successful in only half of patients with relapsed or refractory classical HL. In addition, some patients with R/R HL are ineligible for ASCT. To improve survival time and quality of life and decrease the acute and long-term toxicities of therapy, many schemes for the treatment of R/R HL have emerged. Recently, the use of targeted therapy and immunotherapy represents an important advance in the treatment of R/R HL. The CD30 antibody drug conjugate brentuximab vedotin (BV) and programmed death-1 (PD-1) receptor checkpoint inhibitors nivolumab and pembrolizumab are effective and well-tolerated treatments for R/R HL patients, broadening treatment options for these patients. BV and anti-PD-1 antibodies can be used as monotherapy or combined with other chemotherapy regimens for rescue treatment, consolidation treatment and second-line treatment of R/R HL. In this article, we review current pathobiology knowledge of R/R HL and summarize recent advances in therapy schemes.

Improved post-ASCT survival of relapsed/refractory classical Hodgkin lymphoma patients in the era of novel agents

Utilization of novel agents such as brentuximab vedotin (BV) and check-point inhibitors (CI) has increased in patients with relapsed/refractory (r/r) classical Hodgkin Lymphoma (cHL). We conducted a retrospective study of 209 patients who had ASCT for r/r cHL at our institution and compared outcomes of those who had ASCT from 2010-2018 (cohort 2, n = 110) with those who had ASCT between 2000 and 2009 (cohort 1, n = 99). The median OS was 7.6 years for cohort 1 [HR 2.08; 95% CI 1.14-3.80; p = 0.017] and not reached for cohort 2; with 4-year improved OS difference of 15% (80% vs 65%) in cohort 2 vs cohort 1. The median PFS of cohort 1 was 30 months vs 39 months for cohort 2[HR 1.24; 95% CI 0.82-1.88; p = 0.3]. This study highlights improved OS of r/r cHL patients who have received ASCT in the novel agent era due to the exposure to agents such as BV and CIs.

Immunosuppressive Microenvironment and Efficacy of PD-1 Inhibitors in Relapsed/Refractory Classic Hodgkin Lymphoma: Checkpoint Molecules Landscape and Macrophage Populations

Simple Summary

Classic Hodgkin lymphoma contains rare malignant Hodgkin/Reed–Sternberg cells and abundant reactive populations in the tumor microenvironment. Many aspects of the interaction between tumor cells and immune cells remain unclear. Nevertheless, the microenvironment is believed to play a crucial role in tumor resistance and progression. Current knowledge about the role and dynamics of the tumor microenvironment in Hodgkin lymphoma during anti-PD-1 treatment is limited. The aim of this study was to identify possible predictive and prognostic morphological markers in the treatment of patients with relapsed or refractory classic Hodgkin lymphoma treated with nivolumab and to assess the variability of reactive cell populations after nivolumab therapy. The study was aimed to optimize therapeutic strategy in patients with relapsed or refractory classic Hodgkin lymphoma.

Abstract

To date, the impact of the tumor microenvironment on the prognosis of patients with classic Hodgkin lymphoma (cHL) during anti-PD-1 therapy has been studied insufficiently. This retrospective study included 61 primary samples of lymph nodes from patients who had relapsed/refractory (r/r) cHL and were treated with nivolumab. Repeated samples were obtained in 15 patients at relapse or disease progression after immunotherapy. Median follow-up was 55 (13–63) months. The best overall response rate and progression-free survival (PFS) were analyzed depending on the expression of CD68, CD163, PD-1, LAG-3, TIM-3, CTLA-4, TIGIT, CD163/c-maf in the tumor microenvironment in primary and sequential biopsies. The combination of CD163/c-maf antibodies was used for the identification of M2 macrophages (M2). A low number of macrophages in primary samples was associated with inferior PFS during nivolumab treatment (for CD163-positive cells p = 0.0086; for CD68-positive cells p = 0.037), while a low number of M2 with higher PFS (p = 0.014). Complete response was associated with a lower level of M2 (p = 0.011). In sequential samples (before and after nivolumab therapy) an increase in PD-1 (p = 0.011) and LAG-3 (p = 0.0045) and a depletion of CD68 (p = 0.057) and CD163 (p = 0.0049)-positive cells were observed. The study expands understanding of the cHL microenvironment structure and dynamics during nivolumab therapy in patients with r/r cHL.

The double-edged sword: Harnessing PD-1 blockade in tumor and autoimmunity

Immune checkpoint blockade has demonstrated success in treating cancer but can lead to immune-related adverse events (irAEs), illustrating the centrality of these pathways in tolerance. Here, we describe programmed cell death protein 1 (PD-1) control of T cell responses, focusing on its unique restraint of regulatory T cell function. We examine successes and limitations of checkpoint blockade immunotherapy and review clinical and mechanistic features of irAEs. Last, we discuss strategies to modulate PD-1 blockade to enhance antitumor immunity while limiting autoimmunity.

Immune checkpoint blockade in the treatment of malignant tumor: current statue and future strategies

After being stagnant for decades, there has finally been a paradigm shift in the treatment of cancer with the emergence and application of immune checkpoint inhibitors (ICIs). The most extensively utilized ICIs are targeting the pathways involving programmed death-1 (PD-1) and cytotoxic T-lymphocyte associated protein 4 (CTLA-4). PD-1, as an crucial immune inhibitory molecule, by and large reasons the immune checkpoint response of T cells, making tumor cells get away from immune surveillance. Programmed cell death ligand-1 (PD-L1) is exceptionally expressed in most cancers cells and approves non-stop activation of the PD-1 pathway in the tumor microenvironment. PD-1/PD-L1 inhibitors can block the combination of PD-1 and PD-L1, inhibit hostile to regulatory signals, and restore the activity of T cells, thereby bettering immune response. The current researchers assume that the efficacy of these drugs is related to PD-L1 expression in tumor tissue, tumor mutation burden (TMB), and other emerging biomarkers. Although malignant tumors can benefit from the immunotherapy of PD-1/PD-L1 inhibitors, formulating a customized medication model and discovering biomarkers that can predict efficacy are the new trend in the new era of malignant tumor immunotherapy. This review summarizes the mechanism of action of PD-1/PD-L1 inhibitors, their clinical outcomes on various malignant tumors, their efficacy biomarkers, as well as predictive markers of irAEs.

Immune checkpoint inhibition for the treatment of cancers: An update and critical review of ongoing clinical trials

Advances in Cancer immunotherapy in the past few years include the development of medications that modulate immune checkpoint proteins. Cytotoxic T-lymphocyte antigen 4 (CTLA4), programmed cell death protein 1 (PD1), and programmed cell death ligand 1 (PD-L1) are three co-inhibitory receptors that are expressed in the tumor microenvironment. Immune checkpoint inhibitors (ICI) that target these biomarkers unleash the properties of effector T cells that are licensed to kill cancer cells. Immune checkpoint blockade has dramatically changed the treatment landscape of many cancers. In this Review, we describe the current data regarding clinical trials of ICIs in six important cancers, including hepatocellular carcinoma (HCC), renal cell cancer (RCC), hodgkin lymphoma (HL), non-hodgkin lymphoma (NHL), non-small cell lung cancer (NSCLC), and head and neck cancer carcinoma (HNSCC).

CD8+ T Lymphocytes Immune Depletion and LAG-3 Overexpression in Hodgkin Lymphoma Tumor Microenvironment Exposed to Anti-PD-1 Immunotherapy

Background: Resistance to anti-PD-1 remains a considerable clinical challenge for the treatment of patients with classical Hodgkin lymphoma (cHL), and mechanisms of anti-PD-1 resistance remain unknown. This pilot study aims to investigate the tumor microenvironment in patients with cHL relapsing after anti-PD-1. Methods: This study investigated tumor samples of eight patients with cHL, including four patients exposed to anti-PD-1 with a paired longitudinal histological analysis before and after anti-PD-1, and four patients not exposed to anti-PD-1 who served as control for the cellular biological investigations. Fresh cells tumor microenvironment analysis included phenotypic characterization of their T cell surfaces immune checkpoint markers PD-1, PD-L1, ICOS, TIM-3, LAG-3, 41-BB and BTLA. Tumor tissues immunohistochemistry staining included CD30, CD4, CD8, CD68, CD163, PD-L1, PD-1, LAG-3 and TIM-3. Findings: Paired longitudinal tumor tissues analysis in the tumor microenvironment found a CD8+ lymphocytes tumor depletion and an increase of LAG-3 staining after anti-PD-1 exposure. The fresh cells analysis of the tumor microenvironment in patients exposed to anti-PD-1 found CD8+ lymphocyte depletion, with an elevated CD4+/CD8+ lymphocytes ratio (median ratio 9.77 in exposed anti-PD-1 versus 2.39 in not-exposed anti-PD-1 patients; p = 0.0943). On the cell surfaces of CD4+ lymphocytes, the median positive expression of LAG-3 was significantly higher in the samples exposed to anti-PD-1 compared to the controls (15.05 [IQR:17.91-10.65] versus 3.84 [IQR 1.87-6.57]; p = 0.0376). Interpretation: This pilot study proposes hypotheses for understanding the resistance to immunotherapies in patients with Hodgkin lymphoma. Hodgkin lymphoma exposed to anti-PD-1 correlated in tumor microenvironment with an immune depletion of CD8+ T lymphocytes and overexpression of LAG-3 on CD4+ helper T lymphocytes.

Classical Hodgkin lymphoma

Classical Hodgkin lymphoma is one of the more frequent lymphomas and is generally considered a highly curable disease with standard first-line chemotherapy and radiotherapy in some cases. Despite these outstanding results, major problems remain unresolved. First, there are still patients who will not be cured with front-line regimens and, second, many patients who are cured of classical Hodgkin lymphoma continue to die prematurely due to the late toxic effects of their therapy. Because the median age of patients with classical Hodgkin lymphoma is in the mid-30s, the disease's impact on the number of years lost from productive life is remarkable. In recent years, the gold standard of chemotherapy (often combined with radiotherapy) has changed, with the approval of immunotherapy mostly in relapse settings.

Camrelizumab for relapsed or refractory classical Hodgkin lymphoma: Extended follow-up of the multicenter, single-arm, Phase 2 study

Camrelizumab (a humanized high-affinity IgG4 mAb against programmed death-l) showed potent antitumor activity, well tolerance and controllable safety in patients with relapsed or refractory classical Hodgkin lymphoma (r/r cHL), based on the primary analysis of a Phase 2 study. Here, we present the extended follow-up outcomes. Seventy-five patients who had failed to achieve a remission or experienced progression after autologous stem cell transplantation or had received at least two lines of systemic chemotherapies were enrolled to receive camrelizumab 200 mg every 2 weeks. With a median follow-up of 36.2 months (range, 7.2-38.1), objective response rate per independent central review was 76.0% (95% confidence interval [CI], 64.7-85.1). Among the 57 responders, 31 (54.4%) had ongoing responses. Median duration of response was 31.7 months (95% CI, 16.7-not reached). Median progression-free survival was 22.5 months (95% CI, 14.7-not reached). Thirty-six-month overall survival rate was 82.7% (95% CI, 72.0-89.5). Reactive capillary endothelial proliferation (RCEP) occurred in 97.3% of patients (73/75), but all RCEP were Grade 1 or 2 in severity and 67.1% of these patients (49/73) achieved complete resolution. Occurrence of new RCEP lesions was rare (8/42 [19.0%] at 12 months; 2/32 [6.3%] at 24 months). No treatment-related deaths occurred, and no new toxicities were reported. With extended follow-up, camrelizumab monotherapy continues to provide a robust and durable response, long survival and manageable safety in r/r cHL patients.

The Continuum of Thyroid Disorders Related to Immune Checkpoint Inhibitors: Still Many Pending Queries

BACKGROUND

Until more data are available to shed light on the thyroid disorders related to immune checkpoint inhibitors (ICPi) implemented for the treatment of hematological malignancies, the decision-making is guided by pertinent data derived mostly from solid tumors.

METHODS

The present review provides a comprehensive and updated overview of the thyroid disorders related to ICPi, namely to inhibitors of cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death (PD) 1 (PD-1), and the ligand of the latter (PD-L1).

RESULTS

With the increasing recognition of ir thyroid disorders, many outstanding issues have emerged. Ir thyroid disorders are reminiscent of, but not identical to, thyroid autoimmunity. Interclass and intraclass ICPi differences regarding thyroid immunotoxicity await interpretation. The available data concerning the predictive value of thyroid autoantibodies for the development of ir thyroid disorders are inconclusive. Mounting data indicate an association of ir thyroid disorders with ICPi efficacy, but a causative link is still lacking. The path forward is a tailored approach, entailing: (i) the validation of tumor-specific, patient-specific, and ICPi-specific predictive factors; (ii) appropriate patient selection; (iii) the uncoupling of antitumor immunity from immunotoxicity; (iv) a multidisciplinary initiative; and (v) global registry strategies.

CONCLUSIONS

Untangling and harnessing the interrelationship of immuno-oncology with endocrinology underlying the ir thyroid disorders will yield the optimal patient care.

Immunotherapy of cancer tumors with inhibition of PD-1 membrane protein and its ligands interaction

The identification of the PD-1 receptor by Tasuku Honjo and CTLA-4 by James Ellison marked the beginning of the study of new regulatory pathways activating the immune response. The term “immune checkpoints” was introduced to denote the system of inhibitory mechanisms that include these proteins. The review presents the literature data on the molecular characteristics of the membrane protein PD-1 (programmed cell death 1 receptor) and its role in the regulation of immunity. We consider the PD-1 pathways used of by tumor cells to escape the immune response. The discovery of immune checkpoints made it possible to develop a new type of targeting therapy for cancer. The review presents the results of clinical trials of drugs that block the interaction between the PD-1 and its ligands in various types of cancer. These drugs include nivolumab, pembrolizumab, and avelumab. Studies of these drugs efficacy in patients with various types of cancer localization were conducted within the CheckMate, KEYNOTE and JAVELIN Solid Tumor programs, with some research being in progress. We analyze the results of studying the clinical efficacy of the drugs in patients with melanoma, lung cancer, renal cell cancer, colorectal cancer, classical Hodgkin’s lymphoma, Merkel carcinoma and stomach cancer. Both positive and inconclusive results in the treatment of patients are noted. These data made it possible to identify promising directions for the use of the drugs in certain localizations of the malignant process, as well as to determine the dose and time of their use to obtain an objective positive response to treatment.

Quality-of-life analysis of pembrolizumab vs brentuximab vedotin for relapsed/refractory classical Hodgkin lymphoma

Pembrolizumab improved health-related quality of life over brentuximab vedotin in patients with relapsed/refractory cHL

Pembrolizumab should be considered the preferred treatment option for relapsed/refractory cHL post-ASCT or in patients ineligible for ASCT

KEYNOTE-204 (NCT02684292) demonstrated a progression-free survival advantage for pembrolizumab over brentuximab vedotin (BV) in patients who had relapsed or refractory classical Hodgkin lymphoma (R/R cHL) following, or who were ineligible for, autologous stem cell transplantation (ASCT). Health-related quality of life (HRQoL), measured by patient-reported outcomes (PROs) from KEYNOTE-204, are reported from patients who received ≥1 dose of study treatment and completed ≥1 PRO assessment. The EORTC QoL Questionnaire Core 30 (QLQ-C30) and EuroQoL EQ-5D were administered at baseline, every 6 weeks until week 24, and every 12 weeks thereafter. Prespecified end points included least squares mean (LSM) changes from baseline to week 24 and time to true deterioration (TTD; ≥10-point decline from baseline). Comparisons were evaluated using 2-sided P values uncontrolled for multiplicity. High compliance at baseline (>90%) and through week 24 (>80%) was demonstrated across treatment groups (PRO analysis set: pembrolizumab, n = 146; BV, n = 150). The EORTC QLQ-C30 global health status (GHS)/quality of life (QoL) score improved from baseline to week 24 on pembrolizumab and worsened on BV and demonstrated significant LSM differences at 24 weeks (GHS/QoL: 8.60 [95% confidence interval, 3.89-13.31]; P = .0004). Significant improvements were observed in each QLQ-C30 domain except emotional and cognitive functioning. Compared with BV, pembrolizumab prolonged TTD for GHS/QoL (hazard ratio, 0.40 [95% CI, 0.22-0.74]; P = .003) and each QLQ-C30 domain except cognitive functioning. In conclusion, pembrolizumab demonstrated overall improvements in PROs of HRQoL measures over BV in the KEYNOTE-204 study. These data and previously reported efficacy results support pembrolizumab as the preferred treatment option for patients with R/R cHL who are ineligible for or experience relapse after ASCT.

Emerging Landscape of Immunotherapy for Primary Central Nervous System Lymphoma

Simple Summary

Primary central nervous system lymphoma (PCNSL) is characterized by its location in the central nervous system comprising the brain, the eye, the cerebrospinal fluid and the spinal cord and a poor prognosis with the current chemotherapies. Immunotherapies represent a new paradigm in the care of patients with B-cell lymphoma, but, till recently, immunotherapies studies excluded patients with PCNSL because of the lack of knowledge on the immune network in the brain. Recent studies shed a new light on the origin and characteristics of the CNS immune cells. We review the current experimental preclinical and clinical developments of immunotherapies in CNS lymphoma as well as the effects of targeted therapies on the brain microenvironment. We provide perspectives for improving the efficacy of immunotherapies in the specific setting of PCNSL for a better prognosis of this disease.

Abstract

Primary central nervous system lymphoma (PCNSL) is, mainly, a diffuse large B-cell lymphoma (DLBCL) with a non-germinal center B-cell (non-GCB) origin. It is associated with a poor prognosis and an unmet medical need. Immunotherapy has emerged as one of the most promising areas of research and is now part of the standard treatment for many solid and hematologic tumors. This new class of therapy generated great enthusiasm for the treatment of relapsed/refractory PCNSL. Here, we discuss the challenges of immunotherapy for PCNSL represented by the lymphoma cell itself and the specific immune brain microenvironment. We review the current clinical development from the anti-CD20 monoclonal antibody to CAR-T cells, as well as immune checkpoint inhibitors and targeted therapies with off-tumor effects on the brain microenvironment. Perspectives for improving the efficacy of immunotherapies and optimizing their therapeutic role in PCNSL are suggested.

Stem-Cell Transplantation in Adult Patients with Relapsed/Refractory Hodgkin Lymphoma

Although the majority of patients with Hodgkin lymphoma (HL) are cured with initial therapy, in 85–90% of early stage and 70–80% of advanced-stage disease cases, relapse remains a major problem. Autologous stem-cell transplantation (auto-HCT) after salvage chemotherapy is currently considered to be the standard of care for patients who relapse after first-line chemotherapy or for whom first-line treatment fails. The curative capacity of auto-HCT has been improving with the introduction of new drug-based salvage strategies and consolidation strategies after auto-HCT. Allogeneic stem-cell transplantation (allo-HCT) represents a reasonable treatment option for young patients who relapse or progress after auto-HCT and have chemosensitive disease at the time of transplantation. Allo-HCT is a valid treatment strategy for patients with relapse/refractory HL (r/r HL) because the results have improved over time, mainly with the safe combination of allo-HCT and new drugs. Bearing in mind that outcomes after haploidentical stem-cell transplantation (haplo-HCT) are comparable with those for matched sibling donors and matched unrelated donors, haplo-HCT is now the preferred alternative donor source for patients with r/r HL without a donor or when there is urgency to find a donor if a matched related donor is not present. The development of new drugs such as anti-CD 30 monoclonal antibodies and checkpoint inhibitors (CPI) for relapsed or refractory HL has demonstrated high response rates and durable remissions, and challenged the role and timing of HCT. The treatment of patients with HL who develop disease recurrence or progression after allo-HCT remains a real challenge and an unmet need.

Reverted exhaustion phenotype of circulating lymphocytes as immune correlate of anti-PD1 first-line treatment in Hodgkin lymphoma

While classical Hodgkin lymphoma (HL) is highly susceptible to anti-programmed death protein 1 (PD1) antibodies, the exact modes of action remain controversial. To elucidate the circulating lymphocyte phenotype and systemic effects during anti-PD1 1st-line HL treatment we applied multicolor flow cytometry, FluoroSpot and NanoString to sequential samples of 81 HL patients from the NIVAHL trial (NCT03004833) compared to healthy controls. HL patients showed a decreased CD4 T-cell fraction, a higher percentage of effector-memory T cells and higher expression of activation markers at baseline. Strikingly, and in contrast to solid cancers, expression for 10 out of 16 analyzed co-inhibitory molecules on T cells (e.g., PD1, LAG3, Tim3) was higher in HL. Overall, we observed a sustained decrease of the exhausted T-cell phenotype during anti-PD1 treatment. FluoroSpot of 42.3% of patients revealed T-cell responses against ≥1 of five analyzed tumor-associated antigens. Importantly, these responses were more frequently observed in samples from patients with early excellent response to anti-PD1 therapy. In summary, an initially exhausted lymphocyte phenotype rapidly reverted during anti-PD1 1st-line treatment. The frequently observed IFN-y responses against shared tumor-associated antigens indicate T-cell-mediated cytotoxicity and could represent an important resource for immune monitoring and cellular therapy of HL.

Cardiac Toxicity Associated with Cancer Immunotherapy and Biological Drugs

Cancer immunotherapy significantly contributed to an improvement in the prognosis of cancer patients. Immunotherapy, including human epidermal growth factor receptor 2 (HER2)-targeted therapies, immune checkpoint inhibitors (ICI), and chimeric antigen receptor-modified T (CAR-T), share the characteristic to exploit the capabilities of the immune system to kill cancerous cells. Trastuzumab is a monoclonal antibody against HER2 that prevents HER2-mediated signaling; it is administered mainly in HER2-positive cancers, such as breast, colorectal, biliary tract, and non-small-cell lung cancers. Immune checkpoint inhibitors (ICI) inhibit the binding of CTLA-4 or PD-1 to PDL-1, allowing T cells to kill cancerous cells. ICI can be used in melanomas, non-small-cell lung cancer, urothelial, and head and neck cancer. There are two main types of T-cell transfer therapy: tumor-infiltrating lymphocytes (or TIL) therapy and chimeric antigen receptor-modified T (CAR-T) cell therapy, mainly applied for B-cell lymphoma and leukemia and mantle-cell lymphoma. HER2-targeted therapies, mainly trastuzumab, are associated with left ventricular dysfunction, usually reversible and rarely life-threatening. PD/PDL-1 inhibitors can cause myocarditis, rare but potentially fulminant and associated with a high fatality rate. CAR-T therapy is associated with several cardiac toxic effects, mainly in the context of a systemic adverse effect, the cytokines release syndrome.

Harnessing Treg Homeostasis to Optimize Posttransplant Immunity: Current Concepts and Future Perspectives

CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) are functionally distinct subsets of mature T cells with broad suppressive activity and have been shown to play an important role in the establishment of immune tolerance after allogeneic hematopoietic stem cell transplantation (HSCT). Tregs exhibit an activated phenotype from the stage of emigration from the thymus and maintain continuous proliferation in the periphery. The distinctive feature in homeostasis enables Tregs to respond sensitively to small environmental changes and exert necessary and sufficient immune suppression; however, on the other hand, it also predisposes Tregs to be susceptible to apoptosis in the inflammatory condition post-transplant. Our studies have attempted to define the intrinsic and extrinsic factors affecting Treg homeostasis from the acute to chronic phases after allogeneic HSCT. We have found that altered cytokine environment in the prolonged post-HSCT lymphopenia or peri-transplant use of immune checkpoint inhibitors could hamper Treg reconstitution, leading to refractory graft-versus-host disease. Using murine models and clinical trials, we have also demonstrated that proper intervention with low-dose interleukin-2 or post-transplant cyclophosphamide could restore Treg homeostasis and further amplify the suppressive function after HSCT. The purpose of this review is to reconsider the distinctive characteristics of post-transplant Treg homeostasis and discuss how to harness Treg homeostasis to optimize posttransplant immunity for developing a safe and efficient therapeutic strategy.

Avelumab in relapsed/refractory classical Hodgkin lymphoma: phase 1b results from the JAVELIN Hodgkins trial

The 9p24.1 chromosomal alteration in classical Hodgkin lymphoma (cHL) is associated with increased expression of programmed death ligand 1 (PD-L1)/PD-L2 and an immunosuppressive tumor microenvironment. Blockade of PD-L1/PD-1 interactions with avelumab (anti-PD-L1) is hypothesized to restore antitumor immunity. JAVELIN Hodgkins was a phase 1b, multiple-dose, open-label, randomized, parallel-arm trial of avelumab in patients with relapsed/refractory (R/R) cHL. Primary end points included avelumab target occupancy by dose/schedule in peripheral blood immune cells and pharmacokinetic parameters. Secondary end points included safety and antitumor activity. Four dose levels and 2 dosing schedules were investigated: 70, 350, and 500 mg administered every 2 weeks; 500 mg every 3 weeks; and 10 mg/kg every 2 weeks. Thirty-one patients with R/R cHL were randomized; 9 (29.0%) and 20 (64.5%) had received 3 or ≥4 prior anticancer treatments, respectively. Target occupancy of >90% was observed across all treatment arms, throughout the dosing interval. Avelumab pharmacokinetic data were similar to those previously reported. The most common treatment-related adverse events of any grade were infusion-related reaction (30.0%), nausea (20.0%), increased alanine aminotransferase and rash (16.7% each), and fatigue (13.3%). The objective response rate (ORR) in all randomized patients was 41.9%, with a complete response rate of 19.4%; ORR in those with prior allogeneic hematopoietic stem cell transplant (allo-HSCT) was 55.6%. Due to decreased use of allo-HSCT in patients with R/R cHL, the expansion phase enrolling post-allo-HSCT patients was terminated. Avelumab was tolerable and demonstrated antitumor activity in heavily pretreated patients with cHL, suggesting that PD-L1 blockade may be sufficient for therapeutic benefit in cHL. This trial was registered at www.clinicaltrials.gov as #NCT02603419.

9p24.1 alterations and programmed cell death 1 ligand 1 expression in early stage unfavourable classical Hodgkin lymphoma: an analysis from the German Hodgkin Study Group NIVAHL trial

High programmed cell death 1 ligand 1 (PD-L1) protein expression and copy number alterations (CNAs) of the corresponding genomic locus 9p24.1 in Hodgkin- and Reed-Sternberg cells (HRSC) have been shown to be associated with favourable response to anti-PD-1 checkpoint inhibition in relapsed/refractory (r/r) classical Hodgkin lymphoma (cHL). In the present study, we investigated baseline 9p24.1 status as well as PD-L1 and major histocompatibility complex (MHC) class I and II protein expression in 82 biopsies from patients with early stage unfavourable cHL treated with anti-PD-1-based first-line treatment in the German Hodgkin Study Group (GHSG) NIVAHL trial (ClinicalTrials.gov Identifier: NCT03004833). All evaluated specimens showed 9p24.1 CNA in HRSC to some extent, but with high intratumoral heterogeneity and an overall smaller range of alterations than reported in advanced-stage or r/r cHL. All but two cases (97%) showed PD-L1 expression by the tumour cells in variable amounts. While MHC-I was rarely expressed in >50% of HRSC, MHC-II expression in >50% of HRSC was found more frequently. No obvious impact of 9p24.1 CNA or PD-L1 and MHC-I/II expression on early response to the highly effective anti-PD-1-based NIVAHL first-line treatment was observed. Further studies evaluating an expanded panel of potential biomarkers are needed to optimally stratify anti-PD-1 first-line cHL treatment.

Highly proliferative and functional PD-1+ and TIM-3+ T cells are transiently increased in multiple myeloma following autologous hematopoietic stem cell transplantation

The aim of our prospective study was to assess recovery dynamics and functional characteristics of PD-1⁺ and TIM-3⁺ T cells in multiple myeloma (MM) patients following high-dose chemotherapy (HDCT) with autologous hematopoietic stem cell transplantation (AHSCT). Peripheral blood, autograft and bone marrow samples were obtained from 46 MM patients before conditioning, at the engraftment, following six and 12 months post-transplant. Frequencies of CD4⁺ and CD8⁺ T cells expressing PD-1 and TIM-3 and intracellular expression of Ki-67 and Granzyme B were evaluated. Counts of PD-1⁺ and TIM-3⁺ T cells at the engraftment were significantly higher comparing with the levels before HDCT and 6-12 months following AHSCT. The post-transplant increase in the studied subsets was due to a temporary enhancement in proliferation activity. The cytotoxic potential of PD-1- and TIM-3-expressing CD8⁺ T cells was higher at the engraftment comparing with the pre-transplant and remained at the same level for at least 12 months. The increase in CD4⁺PD-1⁺ and CD8⁺TIM-3⁺ T cells at the engraftment was associated with higher absolute counts of their reinfused counterparts. Circulating PD-1⁺ CD8⁺ and TIM-3⁺ CD4⁺ T cells were increased in patients after post-transplant relapse comparing with the ones in remission. Homeostatic proliferation plays a key role in the upregulation of inhibitory checkpoint receptors on functional T cells under lymphopenic conditions. In this regard, it is difficult to predict both the efficacy and adverse reactions of therapy with checkpoint inhibitors on the course of MM after HDCT with AHSCT. Précis. Homeostatic proliferation plays apparently a key role in the upregulation of PD-1 and TIM-3 on functional T cells after AHSCT and appears to be a normal physiological process, contrary to relapse-associated increase in PD-1⁺ and TIM-3⁺ T cells.

Immune PET Imaging

Fluorodeoxyglucose (FDG) PET/CT is sensitive to metabolic, immune-related, and structural changes that can occur in tumors in cancer immunotherapy. Unique mechanisms of immune checkpoint inhibitors (ICIs) occasionally make response evaluation challenging, because tumors and inflammatory changes are both FDG avid. These response patterns and sequelae of ICI immunotherapy, such as immune-related adverse events, are discussed. Immune-specific PET imaging probes at preclinical stage or in early clinical trials, which may help guide clinical management of cancer patients treated with immunotherapy and likely have applications outside of oncology for other diseases in which the immune system plays a role, are reviewed.

Allogeneic transplantation after PD-1 blockade for classic Hodgkin lymphoma

Anti-PD-1 monoclonal antibodies yield high response rates in patients with relapsed/refractory classic Hodgkin lymphoma (cHL), but most patients will eventually progress. Allogeneic hematopoietic cell transplantation (alloHCT) after PD-1 blockade may be associated with increased toxicity, raising challenging questions about the role, timing, and optimal method of transplantation in this setting. To address these questions, we assembled a retrospective cohort of 209 cHL patients who underwent alloHCT after PD-1 blockade. With a median follow-up among survivors of 24 months, the 2-year cumulative incidences (CIs) of non-relapse mortality and relapse were 14 and 18%, respectively; the 2-year graft-versus-host disease (GVHD) and relapse-free survival (GRFS), progression-free survival (PFS), and overall survival were 47%, 69%, and 82%, respectively. The 180-day CI of grade 3-4 acute GVHD was 15%, while the 2-year CI of chronic GVHD was 34%. In multivariable analyses, a longer interval from PD-1 to alloHCT was associated with less frequent severe acute GVHD, while additional treatment between PD-1 and alloHCT was associated with a higher risk of relapse. Notably, post-transplant cyclophosphamide (PTCy)-based GVHD prophylaxis was associated with significant improvements in PFS and GRFS. While awaiting prospective clinical trials, PTCy-based GVHD prophylaxis may be considered the optimal transplantation strategy for this patient population.

The EZH2 inhibitor tazemetostat upregulates the expression of CCL17/TARC in B-cell lymphoma and enhances T-cell recruitment

An inhibitor of the histone methyltransferase enhancer of zeste homologue 2 (EZH2), tazemetostat, has been developed for the treatment of B‐cell lymphoma, but its mechanisms of action are not fully elucidated. We screened for genes targeted by tazemetostat in eleven B‐cell lymphoma cell lines and found that tazemetostat significantly increased the expression of chemokine (C‐C motif) ligand 17 (CCL17)/thymus‐ and activation‐regulated chemokine (TARC) in all, which codes for a chemokine that is a hallmark of Hodgkin/Reed‐Sternberg (H/RS) cells in Hodgkin lymphoma. Notably, gene set enrichment analysis demonstrated a positive correlation between the genes upregulated by tazemetostat in five follicular lymphoma (FL) cell lines and those reported to be overexpressed in H/RS cells. The CCL17 promoter region was enriched in repressive histone modification H3K27me3, and tazemetostat induced H3K27 demethylation and activated gene transcription. CCL17 protein secretion was also induced by EZH2 inhibition, which was further enhanced by concurrent CpG stimulation. In vitro transwell migration assay demonstrated that CCL17 produced by tazemetostat‐treated B cells enhanced the recruitment of T cells, which had the potential to exert antilymphoma response. Analysis of publicly available human lymphoma databases showed that CCL17 gene expression was inversely correlated with the EZH2 activation signature and significantly paralleled the CD4⁺ and CD8⁺ T‐cell–rich signature in FL and germinal center B‐cell–like diffuse large B‐cell lymphoma. Our findings indicate that tazemetostat can potentially activate antilymphoma response by upregulating CCL17 expression in B‐cell lymphoma cells and promote T‐cell recruitment, which provides a rationale for its combination with immunotherapy.

Efficacy and safety of GLS-010 (zimberelimab) in patients with relapsed or refractory classical Hodgkin lymphoma: A multicenter, single-arm, phase II study

BACKGROUND

GLS-010 (zimberelimab) is a novel, fully human, anti-programmed death-1 monoclonal antibody that shows promising efficacy and safety in advanced solid tumors. This trial aimed to evaluate the efficacy and safety of GLS-010 (zimberelimab) in Chinese patients with relapsed or refractory classical Hodgkin lymphoma (r/r-cHL).

METHODS

This phase II, single-arm, open-label, multicenter clinical trial was conducted at 24 centers in China and enrolled patients with r/r-cHL after two or more lines of therapy. The patients were administered intravenous GLS-010 (zimberelimab) (240 mg, once every 2 weeks) until progression, death, unacceptable toxicity, or consent withdrawal. The primary end-point was the objective response rate assessed by an independent radiology review committee (IRC). This study was registered (NCT03655483).

RESULTS

Eighty-five patients were enrolled between August 2018 and August 2019. The median follow-up was 15.8 months. Seventy-seven patients (90.6%; 95% confidence interval [CI] 82.3-95.9) had an IRC-assessed objective response. The complete response rate was 32.9% (n = 28). The 12-month progression-free survival and overall survival rates were 78% (95% CI 67.5-85.6) and 99% (95% CI 91.9-99.8), respectively. Treatment-related adverse events (TRAEs) were observed in 92.9% of participants. Grade III or IV TRAEs occurred in 24 (28.2%) of the 85 participants. The most common grade III or IV TRAEs were abnormal hepatic function (5.9%), hyperuricemia (4.7%), decreased neutrophil count (3.5%), and increased weight (3.5%). Only one grade V AE, gastrointestinal infection, occurred.

CONCLUSIONS

GLS-010 (zimberelimab) appears to be effective and safe for the treatment of Chinese patients with r/r-cHL. Long-term follow-up is required to confirm these clinical benefits.

Synchronizing the use of allogeneic hematopoietic cell transplantation in checkpoint blockade therapy for Hodgkin lymphoma

INTRODUCTION

The use of checkpoint blockade therapy (CBT) has shown impressive results for the treatment of relapsed/refractory Hodgkin lymphoma (cHL). The impact of CBT depends on the reversal of an exhausted T-cell immune phenotype and a consequential increase in the immunological, anti-tumor effect derived from a patient's adaptive immunity. As most patients with classical Hodgkin lymphoma will relapse during or after this treatment, clinicians often provide consolidation with allogeneic hematopoietic cell transplantation (alloHCT) in fit patients. However, the mechanisms responsible for CBT efficacy can also be those that increase the risk of immunological complications after alloHCT.

AREAS COVERED

We carried out in-depth research on the current medical literature to report and discuss the mechanism of action of CBT within a cHL setting; clinical results of CBT in cHL setting pre-alloHCT and post-alloHCT; interactions between CBT and alloHCT; and further clinical considerations.

EXPERT OPINION

Checkpoint blockade therapy is an effective strategy for relapsed/refractory cHL. Its use is associated with higher immunological toxicities when administered before or after alloHCT. Whenever alloHCT is planned, clinicians should follow international recommendations such as using post-transplant cyclophosphamide GVHD prophylaxis.

Addition of chemotherapy to nivolumab after PD-1 inhibitor failure as bridge to allogeneic stem cell transplantation in classical Hodgkin's lymphoma: report on three cases and literature review

The poor prognosis of refractory or relapsed (R/R) classical Hodgkin's lymphoma (cHL) after autologous stem cell transplantation has improved greatly due to the introduction of brentuximab vedotin and PD-1 inhibitors. However, the duration of response achieved with these novel agents is too short. The information about the management of patients after anti-PD-1 therapy failure is very limited in cHL, although chemotherapy alone or combined with PD-1 inhibitors has shown encouraging results. We report three cases of heavily pretreated cHL, refractory to nivolumab monotherapy, successfully rescued with the addition of chemotherapy to nivolumab, as a bridge to allogeneic stem cell transplantation (allo-SCT). All three patients presented poor clinical features such as three to four previous lines including brentuximab vedotin and autologous stem cell transplantation, refractoriness to the last line of therapy previous to nivolumab, and rapid disease progression. Notwithstanding these characteristics and nivolumab failure, they achieved a complete response after the addition of chemotherapy, were consolidated with allo-SCT, and still remain in complete response. There are few studies concerning the combination of PD-1 inhibitors and chemotherapy after nivolumab failure, including one retrospective study and one phase II trial with nivolumab plus bendamustine. Therefore, only few patients are consolidated with allo-SCT. However, there are several ongoing trials investigating new combinations of chemotherapy and PD-1 inhibitors in R/R cHL, as well as in first line. All these data suggest that anti-PD-1 therapy may reprogram the immune system, activating and inhibiting effector and immunosuppressive cells, respectively, leading to overtake of chemorefractoriness. Allo-SCT can increase the immune-related events of patients treated with anti-PD-1 previously, consistent on acute graft-versus-host disease, sinusoidal obstruction syndrome, and noninfectious febrile syndrome. In conclusion, the combination of PD-1 inhibitor and chemotherapy may be a feasible therapy after anti-PD-1 treatment failure as a bridge to allo-SCT.

New approaches to managing relapsed/refractory Hodgkin lymphoma: the role of checkpoint inhibitors and beyond

Introduction: While most patients with Hodgkin lymphoma (HL) are successfully cured with frontline therapy, unfortunately far too many patients have primary refractory disease or relapse after initial treatment, and outcomes for these patients remain suboptimal.Areas Covered: Treatment for relapsed/refractory (R/R) HL remains an ongoing challenge; however, the approval of brentuximab vedotin (BV) and the checkpoint inhibitors pembrolizumab and nivolumab have given us promising therapies with high response rates and improved progression free survival. We performed a literature search using PubMed on all HL studies investigating immunotherapy within the past 10 years.Expert Opinion: Both BV and checkpoint inhibitors have good single agent activity but appear more effective when given together and combine well with chemotherapy. Other novel agents under study include bispecific chimeric antibody constructs and chimeric antigen receptor T-cells (CAR-T). Here we review the data supporting novel therapies and immunotherapies for R/R HL.

Bendamustine in combination with ifosfamide, etoposide, and vinorelbine (VIBE) is an effective salvage regimen for heavily pre-treated patients with relapsed or refractory Hodgkin lymphoma: a single-center experience

Background

This study evaluated the outcomes of patients with refractory/relapsed Hodgkin lymphoma (RRHL) treated with a bendamustine-based regimen in combination with ifosfamide, etoposide, and vinorelbine (VIBE).

Methods

Consecutive RRHL patients who were treated with the VIBE regimen were identified and studied for clinicopathologic characteristics, response to VIBE regimen, event-free survival (EFS), and feasibility of an autologous stem-cell transplant (autoSCT).

Results

In total, 24 patients received the VIBE regimen, and a median of 3 cycles were administered. In this cohort, 80% of the patients had received ≥2 prior lines of therapy. The overall and complete response rates with VIBE were 79% and 42%, respectively. After a median follow-up (following VIBE regimen) of 14 months (range, 3‒76), the 3-year EFS and OS were 46% and 74%, respectively. Of the eligible patients, 92% underwent successful AutoSCT. The mean CD34+ cell count in the autograft was 5.5×10⁶/kg (SD 2.07). Neutropenia was the commonest hematologic toxicity and it was observed in 42% of the patients. However, only 9% of the patients developed grade III/IV febrile neutropenia. Chemotherapy-induced nausea and vomiting were the second most common grade III/IV toxicities in our cohort of patients.

Conclusion

In this retrospective analysis, the combination regimen, VIBE, has shown good efficacy in heavily pre-treated patients with RRHL without compromising stem cell collection. These encouraging results provide a rationale for further development of this regimen.

Development and Implementation of Proton Therapy for Hodgkin Lymphoma: Challenges and Perspectives

Simple Summary

Hodgkin lymphoma (HL) is a highly curable disease; proton therapy for mediastinal HL irradiation might theoretically reduce late toxicities compared with classical radiotherapy techniques. However, optimal patient selection for this technique is subject to debate. While implementation at a larger scale of proton therapy for HL may face organizational, political, and societal challenges, new highly effective systematic drugs are being widely evaluated for this disease.

Abstract

Consolidative radiation therapy for early-stage Hodgkin lymphoma (HL) improves progression-free survival. Unfortunately, first-generation techniques, relying on large irradiation fields, were associated with an increased risk of secondary cancers, and of cardiac and lung toxicity. Fortunately, the use of smaller target volumes combined with technological advances in treatment techniques currently allows efficient organs-at-risk sparing without altering tumoral control. Recently, proton therapy has been evaluated for mediastinal HL treatment due to its potential to significantly reduce the dose to organs-at-risk, such as cardiac substructures. This is expected to limit late radiation-induced toxicity and possibly, second-neoplasm risk, compared with last-generation intensity-modulated radiation therapy. However, the democratization of this new technique faces multiple issues. Determination of which patient may benefit the most from proton therapy is subject to intense debate. The development of new effective systemic chemotherapy and organizational, societal, and political considerations might represent impediments to the larger-scale implementation of HL proton therapy. Based on the current literature, this critical review aims to discuss current challenges and controversies that may impede the larger-scale implementation of mediastinal HL proton therapy.