Immunotherapy in Hodgkin Lymphoma: Present Status and Future Strategies

Current Issues and Future Perspectives of Targeted Therapies in Primary Mediastinal Large B-Cell Lymphoma

Primary mediastinal large B-cell lymphoma (PMLBCL) is a rare, aggressive B-cell lymphoma, sharing common features with diffuse large B-cell lymphoma (DLBCL) and Hodgkin lymphoma (HL). PMLBCL is usually cured with single-hit immunochemotherapy in the first-line setting. Relapses tend to be aggressive and may be unresponsive to conventional chemotherapy. Autologous stem cell transplant (ASCT) remains a viable option for chemosensitive patients; nevertheless, targeted therapies appear to be highly promising. Checkpoint inhibitors (CPIs) have already transformed the course of relapse/refractory disease, while CD-19-directed Chimeric Antigen Receptor (CAR) T-cell therapy may produce remarkably favorable outcomes. The exact position of CAR T-cells and CPIs in the treatment algorithm, along with the role of radiotherapy and ASCT, remains to be precisely determined. In the current review, we aim to present the recent research on targeted agents in PMLBCL and define their sequencing within the treatment algorithm, mainly in the relapse/refractory setting.

Proceedings from the First Onco Summit: LATAM Chapter, 19-20 May 2023, Rio de Janeiro, Brazil

The Onco Summit 2023: The Latin American (LATAM) Chapter took place over two days, from 19-20 May 2023, in Brazil. The event aimed to share the latest updates across various oncology disciplines, address critical clinical challenges, and exchange best practices to ensure optimal patient treatment. More than 30 international and regional speakers and more than 300 oncology specialists participated in the Summit. The Summit discussions centered on common challenges and therapeutic advances in cancer care, with a specific focus on the unique obstacles faced in LATAM and examples of adaptable strategies to address these challenges. The Summit also facilitated the establishment of a network of oncologists, hematologists, and scientists in LATAM, enabling collaboration to improve cancer care, both in this region and globally, through drug development and clinical research. This report summarizes the key discussions from the Summit for the global and LATAM oncology community.

Toward a paradigm shift in prognostication and treatment of early-stage Hodgkin lymphoma

Twenty years after the conceptual revolution that occurred in the millennium turnaround upon the introduction of PET/CT in lymphoma staging, restaging, and prognostication, a number of new parameters for PET reading have been proposed: (1) the shift from a qualitative to a semi-quantitative reading for PET reporting, (2) an international consensus on these novel interpretation keys, (3) a standardized and agreed procedure to measure the total metabolic tumour volume (TMTV), and (4) the proposition of new indexes to portray the tumour spread: (D-Max and Total Lesion Surface -TLS). These proved to be very powerful prognosticators, able to revolutionize the traditional Ann Arbor four-stage lymphoma staging. During the 17° Lugano meeting on lymphoma, one main question was asked to experts attending a closed workshop dedicated to new metrics for lymphoma diagnosis, staging, restaging, and prognostication: "Should the traditional 4-stage anatomic staging system be simplified to a more clinically relevant 2-stage system (e.g., limited vs. extensive disease)?" Early-stage HL is an example of how these new metrics could fit with this proposal.

How Early Can Checkpoint Inhibitors Induce a Complete Metabolic Response in Chemorefractory Hodgkin Lymphoma?

ABSTRACT

A 24-year-old man with classical Hodgkin lymphoma was lost to follow-up after metabolic complete remission (mCR). He presented 4 years later with B-symptoms and impaired clinical condition. Relapsed classical Hodgkin lymphoma was diagnosed. PET/CT revealed stage IVB with liver and spleen involvement. Two liver function-adjusted salvage attempts were ineffective. Pembrolizumab was instituted with gradual clinical improvement. PET was missed before treatment for a life-threatening condition and was performed on day +10 showing a near mCR. A mCR was confirmed before cycle 2, on day +21, underlining-for the first time in the literature-the possibility to achieve very early mCR with pembrolizumab.

Relevance Analysis of TPM2 and Clinicopathological Characteristics in Breast Cancer

Background

The function of tropomyosin 2 (TPM2) in breast cancer is still far understudied. In this study, we aim to explore the roles of TPM2 in breast cancer progression.

Methods

This research included 155 breast cancer tissues. The expression of TPM2 was analyzed by immunohistochemical staining and grading. The mRNA expression of TPM2 in pan-cancer was analyzed with The Cancer Genome Atlas (TCGA) data plate form. The differential expression of TPM2 protein and the differential promoter methylation level of TPM2 between breast cancer tissues and normal breast tissues were analyzed by the UALCAN online database. The relationship between TPM2 and signaling pathways was interpreted by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) pathway enrichment analyses. The survival curve of TPM2 was analyzed across the Kaplan-Meier plotter online database. Furthermore, the relationship between TPM2 expression and infiltrating macrophages was validated through in vitro co-culture experiments.

Results

TPM2 expression was significantly down-regulated in breast cancer samples. In addition, TPM2 expression was correlated with lymph node metastasis and high-grade histopathological morphology. The receiver operating characteristic (ROC) curve indicated that TPM2 expression could well distinguish between normal breast tissue and breast cancer tissue. TPM2 may have potential value in breast cancer diagnosis. Bioinformatics analysis illustrated that TPM2 was mainly involved in extracellular matrix organization, collagen fibril organization, cell junction assembly, focal adhesion, cAMP signaling pathway, estrogen signaling pathway, Wnt signaling pathway, and adaptive immune system. TPM2 expression was correlated with immune infiltrating cells and immune checkpoint molecules. Our in vitro co-culture experiments showed that the M2 macrophages could upregulate the expression of TPM2.

Conclusion

TPM2 may play key roles in breast cancer occurrence and development, especially in cancer metastasis. TPM2 may be a potential biomarker for breast cancer diagnosis.

Prognostic Impact of Serum β2-Microglobulin Levels in Hodgkin Lymphoma Treated with ABVD or Equivalent Regimens: A Comprehensive Analysis of 915 Patients

The significance of serum beta-2 microglobulin (sβ2m) in Hodgkin lymphoma (HL) is controversial. We analyzed 915 patients with HL, who were treated with ABVD or equivalent regimens with or without radiotherapy. Sβ2m levels were measured by a radioimmunoassay (upper normal limit 2.4 mg/L). Sequential cutoffs (1.8-3.0 by 0.1 mg/L increments, 3.5 and 4.0 mg/L) were tested along with ROC analysis. The median sβ2m levels were 2.20 mg/L and were elevated (>2.4 mg/L) in 383/915 patients (41.9%). Higher sβ2m was associated with inferior freedom from progression (FFP) at all tested cutoffs. The best cutoff was 2.0 mg/L (10-year FFP 83% vs. 70%, p = 0.001), which performed better than the 2.4 mg/L cutoff ("normal versus high"). In multivariate analysis, sβ2m > 2.0 mg/L was an independent adverse prognostic factor in the whole patient population. In multivariate overall survival analysis, sβ2m levels were predictive at 2.0 mg/L cutoff in the whole patient population and in advanced stages. Similarly, sβ2m > 2.0 mg/L independently predicted inferior HL-specific survival in the whole patient population. Our data suggest that higher sβ2m is an independent predictor of outcome in HL but the optimal cutoff lies within the normal limits (i.e., at 2.0 mg/L) in this predominantly young patient population, performing much better than a "normal versus high" cutoff set at 2.4 mg/L.

The Role of mTOR in B Cell Lymphoid Malignancies: Biologic and Therapeutic Aspects

Non-Hodgkin lymphoma's (NHL) incidence is rising over time, and B cell lymphomas comprise the majority of lymphomas. The phosphoinositide 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homologue 1 (Akt)/mammalian target of the rapamycin (mTOR) signaling pathway plays a critical role in a variety of cellular processes, such as cell proliferation and survival. Its role in lymphomagenesis is confirmed in many different types of B cell lymphomas. This review is mainly focused on the PI3K/v-akt/mTOR pathway-related oncogenic mechanisms in B cell NHLs with an emphasis on common B cell lymphoma types [diffuse large B cell lymphoma (DLBCL) and mantle cell lymphoma (MCL)]. Furthermore, it summarizes the literature regarding the clinical applications of the mTOR inhibitors temsirolimus and everolimus in B cell NHLs, which have been tested in a range of clinical trials enrolling patients with B cell malignancies, either as monotherapy or in combination with other agents or regimens.

Long-term outcomes for patients with Hodgkin lymphoma at increased risk of progression or relapse

Although advancements in the treatment of Hodgkin lymphoma have enabled many patients to be cured of their disease, about half of patients who relapse or experience refractory disease ultimately fail treatment, even after autologous stem cell transplant. Risk stratification is crucial to enable escalation of therapy in patients at increased risk for progression while allowing for less intensive therapy in lower risk groups. Utilization of clinical factors to inform risk scores was common practice, but this historical approach has been supplemented by PET/CT risk adapted management. Long-term outcomes of high-risk patients have improved over the decades with advancements in therapy and emergence of novel agents including antibody-drug conjugates and immune checkpoint inhibitors, yet further research is urgently needed. Herein, we review long-term outcomes of patients with Hodgkin lymphoma at increased risk for progression or relapse and discuss limitations of current risk strategies.

The value of FDG PET/CT imaging in outcome prediction and response assessment of lymphoma patients treated with immunotherapy: a meta-analysis and systematic review

PURPOSE

Treatment strategies of lymphoid malignancies have been revolutionized by immunotherapy. Because of the inherent property of Hodgkin lymphoma and some subtypes of non-Hodgkin lymphoma as a highly FDG-avid tumor, functional ¹⁸F-FDG PET/CT imaging is already embedded in their routine care. Nevertheless, the question is whether it is still valuable in the context of these tumors being treated with immunotherapy. Herein, we will review the value of ¹⁸F-FDG PET/CT imaging lymphoid tumors treated with immunotherapy regimens.

METHODS

A comprehensive literature search of the PubMed database was conducted on the value of the ¹⁸F-FDG PET/CT for immunotherapy response monitoring of patients with malignant lymphoma. The articles were considered eligible if they met all of the following inclusion criteria: (a) clinical studies on patients with different types of malignant lymphoma, (b) treatment with anti-CD20 antibodies, immune checkpoint inhibitors or immune cell therapies, (c) and incorporated PET/CT with ¹⁸F-FDG as the PET tracer.

RESULTS

From the initial 1488 papers identified, 91 were ultimately included in our study. In anti-CD20 therapy, the highest pooled hazard ratios (HRs) of baseline, early, and late response monitoring parameters for progression-free survival (PFS) belong to metabolic tumor volume (MTV) (3.19 (95%CI: 2.36-4.30)), maximum standardized uptake value (SUVmax) (3.25 (95%CI: 2.08-5.08)), and Deauville score (DS) (3.73 (95%CI: 2.50-5.56)), respectively. These measurements for overall survival (OS) were MTV (4.39 (95%CI: 2.71-7.08)), DS (3.23 (95%CI: 1.87-5.58)), and DS (3.64 (95%CI: 1.40-9.43)), respectively. Early and late ¹⁸F-FDG PET/CT response assessment in immune checkpoint inhibitors (ICI) and immune cell therapy might be an effective tool for prediction of clinical outcome.

CONCLUSION

For anti-CD20 therapy of lymphoma, the MTV as a baseline ¹⁸F-FDG PET/CT-derived parameter has the highest HRs for PFS and OS. The DS as visual criteria in early and late response assessment has higher HRs for PFS and OS compared to the international harmonization project (IHP) visual criteria in anti-CD20 therapy. Early changes in ¹⁸F-FDG PET parameters may be predictive of response to ICIs and cell therapy in lymphoma patients.

The third-generation anti-CD30 CAR T-cells specifically homing to the tumor and mediating powerful antitumor activity

CAR T-cell therapy is well tolerated and effective in patients with Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL). However, even second- generation anti-CD30 CAR T-cells with CD28 (28z) costimulatory domains failed to achieve the desired rate of complete responses. In the present study, we developed second-generation (CD28z) and third-generation (CD28BBz) CAR T-cells targeting CD30 and investigated their efficacy in vitro and in vivo. Both of CD28z and CD28BBz anti-CD30 CAR T cells were similar regarding amplification, T cell subsets distribution, T cell activity, effector/memory and exhaustion. However, we found that the 28BBz anti-CD30 CAR T-cells persist long-term, specifically homing to the tumor and mediating powerful antitumor activity in tumor xenograft models. Subsequently, we also demonstrated that the third generation anti-CD30 CAR T-cells have miner side effects or potential risks of tumorigenesis. Thus, anti-CD30 CAR T-cells represent a safe and effective treatment for Hodgkin lymphoma.

Dissecting Tumor-Immune Microenvironment in Breast Cancer at a Spatial and Multiplex Resolution

The tumor immune microenvironment (TIME) is an important player in breast cancer pathophysiology. Surrogates for antitumor immune response have been explored as predictive biomarkers to immunotherapy, though with several limitations. Immunohistochemistry for programmed death ligand 1 suffers from analytical problems, immune signatures are devoid of spatial information and histopathological evaluation of tumor infiltrating lymphocytes exhibits interobserver variability. Towards improved understanding of the complex interactions in TIME, several emerging multiplex in situ methods are being developed and gaining much attention for protein detection. They enable the simultaneous evaluation of multiple targets in situ, detection of cell densities/subpopulations as well as estimations of functional states of immune infiltrate. Furthermore, they can characterize spatial organization of TIME—by cell-to-cell interaction analyses and the evaluation of distribution within different regions of interest and tissue compartments—while digital imaging and image analysis software allow for reproducibility of the various assays. In this review, we aim to provide an overview of the different multiplex in situ methods used in cancer research with special focus on breast cancer TIME at the neoadjuvant, adjuvant and metastatic setting. Spatial heterogeneity of TIME and importance of longitudinal evaluation of TIME changes under the pressure of therapy and metastatic progression are also addressed.

Monoclonal Antibodies in the Treatment of Diffuse Large B-Cell Lymphoma: Moving beyond Rituximab

Although rituximab has revolutionized the treatment of diffuse large B-cell lymphoma (DLBCL), a significant proportion of patients experience refractory disease or relapse early after the end of treatment. The lack of effective treatment options in the relapsed/refractory (R/R) setting had made the prognosis of these patients dismal. The initial enthusiasm for novel anti-CD20 antibodies had been short-lived as they failed to prove their superiority to rituximab. Therefore, research has focused on developing novel agents with a unique mechanism of action. Among them, two antibody-drug conjugates, namely polatuzumab vedotin (PolaV) and loncastuximab tesirine, along with tafasitamab, an anti-CD19 bioengineered antibody, have been approved for the treatment of R/R DLBCL. Whereas PolaV has been FDA and EMA approved, EMA has not approved loncastuximab tesirine and tafasitamab yet. Results from randomized trials, as well as real-life data for PolaV have been promising. Novel agents as bispecific antibodies bridging CD3 on T-cells to CD20 have shown very promising results in clinical trials and are expected to gain approval for treatment of R/R DLBCL soon. As the therapeutic armamentarium against DLBCL is expanding, an improvement in survival of patients with R/R and higher cure rates might soon become evident.

Efficacy of Brentuximab Vedotin and Nivolumab in Refractory or Relapsed Hodgkin Lymphoma: A Systematic Review

The central dilemma in treating patients with refractory or relapsed classical Hodgkin lymphoma (RRHL) is the developed resistance to chemotherapy. In recent years, significant advances have been made with the introduction of targeted immunotherapy such as brentuximab vedotin (BV) and nivolumab (NV). As monotherapy, BV and NV have demonstrated high response rates but with an opportunity for disease progression. In other studies, BV or NV is given in combination with chemotherapy as a bridge to hematopoietic stem cell transplantation for curative therapy. This review will investigate the effect of BV and NV as single agents, in combination with each other, or given concurrently with chemotherapy on the response and survival rate of patients with RRHL.

Tumor Flare Reaction in a Classic Hodgkin Lymphoma Patient Treated With Brentuximab Vedotin and Tislelizumab: A Case Report

Background

Tumor flare reaction (TFR) is a clinical syndrome, which is mainly associated with painful and swollen lymph nodes or splenomegaly, slight fever, bone pain, and skin rash during treatment with immune-related drugs, causing difficulty in distinguishing TFR from disease progression. Brentuximab vedotin (BV) and programmed death 1 (PD-1) inhibitor are two ideal drugs used for the treatment of classic Hodgkin lymphoma, but few studies have reported their adverse effects in association with TFR. The efficacy and safety of monotherapy or combination therapy with these drugs needs to be further evaluated. It is essential to determine whether treated patients can develop TFR, thus enabling more accurate diagnosis and treatment.

Case presentation

A 26-year-old female patient, diagnosed with classic Hodgkin lymphoma, had received 2 + 3 cycles of ABVD chemotherapy (a combination of adriamycin, bleomycin, vinblastine, and dacarbazine) and 4 cycles of PD-1 inhibitor (tislelizumab) therapy but exhibited poor efficacy. Subsequently, she was given combination therapy of BV (100 mg) + tislelizumab (200 mg). However, a slight fever, painful and swollen axillary lymph nodes, multiple skin rashes with pruritus, joint pain, and fatigue with poor appetite appeared during the treatment. Ultrasound (US) scans revealed that multiple lymph nodes were significantly enlarged. After treatment with low-dose dexamethasone and cetirizine, the symptoms were alleviated. A biopsy of the left axillary lymph node revealed that lymphoid tissue exhibited proliferative changes, without tumor cell infiltration. These findings were consistent with the clinical and pathological manifestations of TFR.

Conclusion

Combination therapy with BV and PD-1 inhibitor was effective in the treatment of relapsed or refractory classic Hodgkin lymphoma. The results suggest that the combination therapy may cause TFR, and biopsy and also continuous imaging observation are important to determine the disease stage. This approach allows clinicians to decide whether to continue the current treatment plan, and alerts them to the occurrence of excessive activation of the immune system.

Risk of thyroid disorders in adult and childhood Hodgkin lymphoma survivors 40 years after treatment

Thyroid abnormalities are well reported following childhood treatment for Hodgkin Lymphoma (HL). Limited information exists for adult patients and after modern treatments. We analyzed risks of thyroid disorders in 237 female participants treated at the Royal Marsden Hospital 1970-2015. Multivariable analyses of risk according to treatment and time-related factors, survival analyses, and Cox regression modeling were undertaken. Overall, 33.8% of patients reported thyroid disorders (hypothyroidism 30.0% and thyroid nodules 6.8%). Cumulative prevalence was 42.9% by 40 years follow-up. Risks were greatest after supradiaphragmatic radiotherapy (RR = 5.0, p < 0.001), and increasing dose (RR = 1.03/Gy, p < 0.001). There was no association with a chemotherapy agent. Risks of thyroid disease were as raised following adult as childhood treatment. There was no trend in risk by decade of supradiaphragmatic radiotherapy treatment. Risks of thyroid disease after supradiaphragmatic radiotherapy are as great after adult as childhood treatment and persist after more recent treatment periods.

[A decade of checkpoint inhibitors: current standard of care and future trends]

Therapy with checkpoint inhibitors still revolutionizes the therapeutical landscape in oncology. Since the first approval of a checkpoint inhibitor for the therapy of malignant melanoma 2011, many other approvals in the field of hematology and oncology followed. Besides monotherapy, a rapidly increasing number of trials is investigating checkpoint inhibitors in different combination therapies for advanced disease. Cumulating evidence suggests checkpoint blockade also as promising option for (neo)-adjuvant treatment. Here we review the different treatment strategies of mono- and combination-therapies. Additionally, important biomarkers for the treatment with checkpoint inhibitors are discussed.

Paraneoplastic Intrahepatic Cholestasis in Supradiaphragmatic Classical Hodgkin Lymphoma Successfully Treated With Brentuximab Vedotin: A Case Report and Review of the Literature

BACKGROUND

Hepatic dysfunction in patients with classical Hodgkin lymphoma (cHL) is of multifactorial aetiology. Prompt evaluation with laboratory tests and imaging methods is sufficient for diagnosis in most cases. Intrahepatic cholestasis and vanishing bile duct syndrome (VBDS) may complicate cHL as rare paraneoplastic phenomena. Liver biopsy provides crucial evidence of cholestasis, and ductopenia, if present, confirms the diagnosis of VBDS.

CASE REPORT

We report on a cHL patient that presented with jaundice and bulky mediastinal disease and unfold the therapeutic dilemmas we confronted. Marked hyperbilirubinemia was successfully reversed with brentuximab vedotin (BV) at a dose of 1.2 mg/kg and the patient was subsequently treated with doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) at full doses, achieving complete metabolic response. A literature review of intrahepatic cholestasis in cHL is also presented based on currently available data with focus on treatment options and clinicopathologic associations.

CONCLUSION

VBDS and intrahepatic cholestasis are rare and potentially fatal complications of cHL. Their prompt recognition and appropriate treatment can dramatically affect cHL patients' outcome. BV, used at a reduced dose as a bridging therapy, should be considered as a high-priority treatment plan in these challenging cases.

A phase 1b study of AFM13 in combination with pembrolizumab in patients with relapsed or refractory Hodgkin lymphoma

In relapsed/refractory Hodgkin lymphoma (R/R HL), immunotherapies such as the anti-programmed death-1 inhibitor pembrolizumab have demonstrated efficacy as monotherapy and are playing an increasingly prominent role in treatment. The CD30/CD16A-bispecific antibody AFM13 is an innate immune cell engager, a first-in-class, tetravalent antibody, designed to create a bridge between CD30 on HL cells and the CD16A receptor on natural killer cells and macrophages, to induce tumor cell killing. Early studies of AFM13 have demonstrated signs of efficacy as monotherapy for patients with R/R HL and the combination of AFM13 with pembrolizumab represents a rational new treatment modality. Here, we describe a phase 1b, dose-escalation study to assess the safety and preliminary efficacy of AFM13 in combination with pembrolizumab in patients with R/R HL. The primary objective was estimating the maximum tolerated dose; the secondary objectives were to assess safety, tolerability, antitumor efficacy, pharmacokinetics, and pharmacodynamics. In this heavily pretreated patient population, treatment with the combination of AFM13 and pembrolizumab was generally well tolerated, with similar safety profiles compared to the known profiles of each agent alone. The combination of AFM13 with pembrolizumab demonstrated an objective response rate of 88% at the highest treatment dose, with an 83% overall response rate for the overall population. Pharmacokinetic assessment of AFM13 in the combination setting revealed a half-life of up to 20.6 hours. This proof-of-concept study holds promise as a novel immunotherapy combination worthy of further investigation. This phase 1b study was registered at www.clinicaltrials.gov as NCT02665650.

Immune checkpoint inhibitors in patients with pretreated HodgkinÊs lymphoma: a Korean single-center, retrospective study

Background

Immune checkpoint inhibitors have demonstrated efficacy in the treatment of classical Hodgkin’s lymphoma (cHL). We analyzed the efficacy and safety of pembrolizumab or nivolumab in patients with pretreated cHL.

Methods

Clinical data from the cancer chemotherapy registry of Samsung Medical Center were retrospectively analyzed to study patients with cHL treated with pembrolizumab or nivolumab between Oct 2015 and Dec 2018.

Results

Of the 20 patients, seven (35%) were enrolled in the study after a relapse following autologous hematopoietic stem cell transplantation (ASCT) and 12 (60%) after a relapse following receipt of brentuximab vedotin (BV). Sixteen (80%) patients received pembrolizumab, and four (20%) patients received nivolumab. The complete remission rate was 45% (9/20), and 30% (6/20) of patients achieved partial remission, for an overall response rate (RR) of 75% [15/20; 95% confidence interval (CI), 34.7‒93.3]. With a median follow-up duration of 14 months, the median PFS was 18 months (95% CI, 2.4‒33.5 mo), and the median OS was 36 months [95% CI, 36-not applicable (NA) mo]. Pembrolizumab and nivolumab were generally well tolerated.

Conclusion

In this study, pembrolizumab and nivolumab both demonstrated clinical efficacy and tolerability in patients with cHL who failed previous chemotherapy or ASCT.

Optimizing outcomes in relapsed/refractory Hodgkin lymphoma: a review of current and forthcoming therapeutic strategies

The outcome of patients with relapsed/refractory classical Hodgkin lymphoma (rr-cHL) has improved considerably in recent years owing to the approval of highly active novel agents such as brentuximab vedotin and Programmed Death-1 (PD-1) inhibitors. Although no randomized trials have been conducted to provide formal proof, it is almost undisputable that the survival of these patients has been prolonged. As autologous stem-cell transplantation (SCT) remains the standard of care for second-line therapy of most patients with rr-cHL, optimization of second-line regimens with the use of brentuximab vedotin, or, in the future, checkpoint inhibitors, is promising to increase both the eligibility rate for transplant and the final outcome. The need for subsequent therapy, and especially allogeneic SCT, can be reduced with brentuximab vedotin consolidation for 1 year, while pembrolizumab is also being tested in this setting. Several other drug categories appear to be active in rr-cHL, but their development has been delayed by the appearance of brentuximab vedotin, nivolumab and pembrolizumab, which have dominated the field of rr-cHL treatment in the last 5 years. Combinations of active drugs in chemo-free approaches may further increase efficacy and hopefully reduce toxicity in rr-cHL, but are still under development.

Classical Hodgkin's Lymphoma in the Era of Immune Checkpoint Inhibition

The ligation of programmed cell death 1 (PD-1) with programmed cell death ligand PD-L activates the immune checkpoint leading to T-cell dysfunction, exhaustion, and tolerance, especially in Hodgkin lymphoma (HL) where the PD-L/ Janus kinase (Jak) signaling was frequently found altered. Anti-PD-1 or anti-PD-L1 monoclonal antibodies can reverse this immune checkpoint, releasing the brake on T-cell responses. The characterization of the mechanisms regulating both the expression of PD-1 and PD-L and their function(s) in HL is ongoing. We provide in this review the recent findings focused on this aim with special attention on the major research topics, such as adverse events and resistance to PD-1–PD-L1 inhibitor treatment, together with a part about angiogenesis, extracellular vesicles, and microbiome in HL pathogenesis.

Signaling alterations caused by drugs and autophagy

Autophagy is an evolutionary conserved process that recycles cellular materials in times of nutrient restriction to maintain viability. In cancer therapeutics, the role of autophagy in response to multi-kinase inhibitors, alone or when combined with histone deacetylase (HDAC) inhibitors acts, generally, to facilitate the killing of tumor cells. Furthermore, the formation of autophagosomes and subsequent degradation of their contents can reduce the expression of HDAC proteins themselves as well as of other signaling regulatory molecules such as protein chaperones and mutated RAS proteins. Reduced levels of HDAC6 causes the acetylation and inactivation of heat shock protein 90, and, together with reduced expression of the chaperones HSP70 and GRP78, generates a strong endoplasmic reticulum (ER) stress response. Prolonged intense ER stress signaling causes tumor cell death. Reduced expression of HDACs 1, 2 and 3 causes the levels of programed death ligand 1 (PD-L1) to decline and the expression of Class I MHCA to increase which correlates with elevated immunogenicity of the tumor cells in vivo. This review will specifically focus on the downstream implications that result from autophagic-degradation of HDACs, RAS and protein chaperones.