Nivolumab for classical Hodgkin's lymphoma after failure of both autologous stem-cell transplantation and brentuximab vedotin: a multicentre, multicohort, single-arm phase 2 trial

Phase II Study of the Efficacy and Safety of Pembrolizumab for Relapsed/Refractory Classic Hodgkin Lymphoma

Purpose Hodgkin Reed-Sternberg cells harbor alterations in chromosome 9p24.1, leading to overexpression of programmed death-ligand 1 (PD-L1) and PD-L2. Pembrolizumab, a programmed death 1-blocking antibody, demonstrated a high overall response rate (ORR) in patients with relapsed or refractory classic Hodgkin lymphoma (rrHL) in phase I testing. Methods KEYNOTE-087 ( ClinicalTrials.gov identifier, NCT02453594) was a single-arm phase II study of pembrolizumab in three cohorts of patients with rrHL, defined on the basis of lymphoma progression after (1) autologous stem cell transplantation (ASCT) and subsequent brentuximab vedotin (BV); (2) salvage chemotherapy and BV, and thus, ineligible for ASCT because of chemoresistant disease; and (3) ASCT, but without BV after transplantation. Patients received pembrolizumab 200 mg once every 3 weeks. Response was assessed every 12 weeks. The primary end points were ORR by central review and safety. Results A total of 210 patients were enrolled and treated (69 in cohort 1, 81 in cohort 2, and 60 in cohort 3). At the time of analysis, patients received a median of 13 treatment cycles. Per central review, the ORR was 69.0% (95% CI, 62.3% to 75.2%), and the complete response rate was 22.4% (95% CI, 16.9% to 28.6%). By cohort, ORRs were 73.9% for cohort 1, 64.2% for cohort 2, and 70.0% for cohort 3. Thirty-one patients had a response ≥ 6 months. The safety profile was largely consistent with previous pembrolizumab studies. Conclusion Pembrolizumab was associated with high response rates and an acceptable safety profile in patients with rrHL, offering a new treatment paradigm for this disease.

Immunotherapy in hematologic malignancies: past, present, and future

The field of immunotherapy in cancer treatments has been accelerating over recent years and has entered the forefront as a leading area of ongoing research and promising therapies that have changed the treatment landscape for a variety of solid malignancies. Prior to its designation as the Science Breakthrough of the Year in 2013, cancer immunotherapy was active in the treatment of hematologic malignancies. This review provides a broad overview of the past, present, and potential future of immunotherapy in hematologic malignancies.

FDA Approval Summary: Nivolumab for the Treatment of Relapsed or Progressive Classical Hodgkin Lymphoma

On May 17, 2016, after an expedited priority review, the U.S. Food and Drug Administration granted accelerated approval to nivolumab for the treatment of patients with classical Hodgkin lymphoma (cHL) that has relapsed or progressed after autologous hematopoietic stem cell transplantation (HSCT) and post-transplantation brentuximab vedotin (BV). Nivolumab in cHL had been granted breakthrough therapy designation. Accelerated approval was based on two single-arm, multicenter trials in adults with cHL. In 95 patients with relapsed or progressive cHL after autologous HSCT and post-transplantation BV, nivolumab, dosed at 3 mg/kg intravenously every 2 weeks, produced a 65% (95% confidence interval: 55%-75%) objective response rate (58% partial remission, 7% complete remission). The estimated median duration of response was 8.7 months, with 4.6-month median follow-up for response duration. The median time to response was 2.1 (range: 0.7-5.7) months. Among 263 patients with cHL treated with nivolumab, 21% reported serious adverse reactions (ARs). The most common all-grade ARs (reported in ≥20%) were fatigue, upper respiratory tract infection, cough, pyrexia, diarrhea, elevated transaminases, and cytopenias. Infusion-related reaction and hypothyroidism or thyroiditis occurred in >10% of patients; other immune-mediated ARs, occurring in 1%-5%, included rash, pneumonitis, hepatitis, hyperthyroidism, and colitis. A new Warning and Precaution was issued for complications of allogeneic HSCT after nivolumab, including severe or hyperacute graft-versus-host disease, other immune-mediated ARs, and transplant-related mortality. Continued approval for the cHL indication may be contingent upon verification of clinical benefit in a randomized trial. The Oncologist 2017;22:585-591 IMPLICATIONS FOR PRACTICE: Based on response rate and duration in single-arm studies, nivolumab is a new treatment option for patients with classical Hodgkin lymphoma (cHL) that has relapsed or progressed despite autologous hematopoietic stem cell transplantation (HSCT) and brentuximab vedotin. This was the first U.S. Food and Drug Administration marketing application for a programmed cell death 1 inhibitor in hematologic malignancies. The use of immune checkpoint blockade in cHL represents a new treatment paradigm. The safety of allogeneic HSCT after nivolumab requires further evaluation, as does the safety of nivolumab after allogeneic HSCT.

Nivolumab Therapy for Synchronous ALK-Positive Lung Cancer and Gastric Cancer

Nivolumab is an immune checkpoint inhibitor with demonstrated efficacy against several malignant tumors. Alterations in driver oncogenes such as EGFR and ALK are a poor prognostic factor in nivolumab therapy for non-small cell lung cancer (NSCLC), whereas a smoking history is a well-known, favorable prognostic factor. However, an efficacy of nivolumab therapy for multiple primary malignant tumors (MPMTs) has not been reported, and its efficacy for driver oncogene-positive NSCLC in smokers is unclear. Herein, we report the case of a patient with a history of heavy smoking who developed synchronous ALK-positive NSCLC and gastric cancer that responded to nivolumab therapy. A 76-year-old man who was a heavy smoker presented to our hospital with symptoms of hoarseness and dysphagia. He was ultimately diagnosed with ALK-positive advanced NSCLC. An ALK inhibitor (alectinib) was administered, and the lung cancer lesions showed improvement. The alectinib therapy was continued for 5 months. Thereafter, the lesions in the left lower lobe of the lung showed regrowth. During the same period, the patient experienced epigastric pain. Gastrointestinal endoscopy examination revealed gastric cancer. He was administered nivolumab to treat both the lung cancer and the gastric cancer. Two months later, both the lung lesions and the gastric lesions had diminished in size. Nivolumab therapy might be an effective therapy for synchronous MPMTs and NSCLC in heavy smokers, even if the lung cancer possesses driver oncogene mutations.

Immune checkpoint blockade for hematologic malignancies: a review

Immune checkpoint blockade has revolutionized the treatment of cancer, with impressive responses seen in a broad variety of tumor types. Blockade of immune checkpoints and immune signaling antibodies has shown promise in multiple types of hematologic malignancies (HMs), with dramatic single agent responses for pembrolizumab and nivolumab in Hodgkin lymphoma (HL). In this review, we outline the current state of immune checkpoint blockade drug development in HMs, and discuss mechanisms of activity and resistance, and highlight potential targets in the immune tumor microenvironment (TME). Blockade of T-cell checkpoint molecules PD-1/PD-L1 and CTLA-4 are the most clinically mature of the immune checkpoint strategies. Novel and upcoming strategies for immune checkpoint blockade drug development in HMs using innovative combinations to modulate immunologic targets shows significant promise as a way to expand the number of patients with blood cancers who could benefit from immunotherapy.

Immunotherapy for the treatment of Hodgkin lymphoma

INTRODUCTION

Most patients with Hodgkin lymphoma (HL) enjoy durable remissions following front-line treatment but 30% of patients are refractory or relapse after first line therapy. Salvage chemotherapy followed by autologous stem cell transplantation (ASCT) can cure an additional 50-55% of relapsing patients but new treatments are needed for patients with HL who are refractory or relapse after ASCT. Immunotherapy has emerged as a promising treatment for the management of these patients. The availability of the anti-CD30 antibody brentuximab vedotin and new targeted drugs such as immune checkpoint inhibitors, show promising clinical activity in patients with HL and are important milestones for the management of patients with HL particularly for those who have progressed after standard initial therapy and ASCT. Areas covered: Overview of the results from the most relevant clinical trials including monoclonal antibody-based therapy in HL. Phase 2 and phase 3 trials including brentuximab vedotin and immune checkpoints inhibitors in patients with Hodgkin lymphoma have been reviewed. In addition, the potential impact of these new therapies in the management of patients with newly diagnosed HL has also been addressed. Expert commentary: Anti-CD30 antibody brentuximab vedotin and immune checkpoint inhibitors have shown promising results in patients with relapsed and refractory HL. Administration of these therapies earlier in the course of the disease might reduce the proportion of relapsed or refractory patients and, subsequently, minimize the number of patients undergoing high-dose therapy and autologous stem cell transplantation. We have little doubt that this will have substantial effects on the outcome for future generations of HL patients.

PD-1 blockade with nivolumab in relapsed/refractory primary central nervous system and testicular lymphoma

Primary central nervous system (CNS) lymphoma (PCNSL) and primary testicular lymphoma (PTL) are rare extranodal large B-cell lymphomas with similar genetic signatures. There are no standard-of-care treatment options for patients with relapsed and refractory PCNSL and PTL, and the overall prognosis is poor. PCNSLs and PTLs exhibit frequent 9p24.1 copy-number alterations and infrequent translocations of 9p24.1 and associated increased expression of the programmed cell death protein 1 (PD-1) ligands, PD-L1 and PD-L2. The activity of PD-1 blockade in other lymphomas with 9p24.1 alterations prompted us to test the efficacy of the anti-PD1 antibody, nivolumab, in 4 patients with relapsed/refractory PCNSL and 1 patient with CNS relapse of PTL. All 5 patients had clinical and radiographic responses to PD-1 blockade, and 3 patients remain progression-free at 13⁺ to 17⁺ months. Our data suggest that nivolumab is active in relapsed/refractory PCNSL and PTL and support further investigation of PD-1 blockade in these diseases.

Targeting the programmed cell death 1 pathway in Hodgkin lymphoma: the place of nivolumab

Nivolumab is a humanized immunoglobulin gamma-4 kappa anti-programmed cell death 1 monoclonal antibody that is currently approved in the treatment of several solid tumors and recently gained accelerated approval in classical Hodgkin lymphoma (cHL) that has relapsed or progressed following autologous hematopoietic stem-cell transplantation and post-transplantation brentuximab vedotin. The purpose of this article is to review the immunophysiologic basis, clinical efficacy, and toxicity of nivolumab in the treatment of cHL. In addition, we will review ongoing clinical trials and potential future directions of checkpoint inhibition in the treatment of cHL.

Novel agents in classical Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is the most common hematological malignancy in young adults and can be cured in most cases. However, relapsed and refractory Hodgkin lymphoma, certain patient groups, such as elderly patients, and toxicity of first-line treatment still pose significant challenges. Consequently, new treatment options are needed. Recently, many new treatment concepts have been evaluated in clinical trials. Targeted drug-antibody conjugates and immune checkpoint inhibitors have decisively changed treatment approaches. This review aims to give a comprehensive overview of novel agents in Hodgkin lymphoma that have been recently or are currently being evaluated in clinical trials. In addition to dedicated sections on brentuximab vedotin (BV) and immune checkpoint inhibitors, other emerging substances and concepts are discussed. In doing so, this review compares trial results regarding safety and efficacy. A special focus lies on the effect novel agents will have on the different treatment settings faced by clinicians involved in the treatment of Hodgkin lymphoma.

PD-1 inhibitors increase the incidence and risk of pneumonitis in cancer patients in a dose-independent manner: a meta-analysis

Therapies that targeted PD-1 have shown remarkable rates of durable clinical responses in patients with various tumor types. However, the extent and knowledge of pulmonary toxicities associated with PD-1 blockade, mainly manifested as pneumonitis, remains obscure. In this study, a total of 6360 subjects from 16 phase II/III clinical trials were pooled for meta-analysis to evaluate the overall incidence and risk of PD-1 inhibitors-related pneumonitis in cancer patients. The incidence of pneumonitis during anti-PD-1 immunotherapy was 2.92% (95%CI: 2.18–3.90%) for all-grade and 1.53% (95%CI: 1.15–2.04%) for high-grade pneumonitis. Compared with routine chemotherapy, PD-1 inhibitors were associated with a significant increased risk of pneumonitis. Moreover, among the types of tumor treated with PD-1 inhibitors, the melanoma patients have the lowest incidence of pneumonitis, while the non-small cell lung cancer (NSCLC) and renal cell carcinoma (RCC) patients have the highest. Furthermore, no significant differences were detected in the incidences of all- and high-grade pneumonitis between high-dose and low-dose groups of PD-1 inhibitors. In conclusion, PD-1 inhibitors were probably associated with an increased risk of pneumonitis in a dose-independent manner, compared with routine chemotherapeutic agents. The frequency and severity of treatment-mediated pneumonitis was quite different in patients with various tumor types.

Immunotherapy: incorporation in the evolving paradigm of renal cancer management and future prospects

Significant progress has been made in the management of renal cell carcinoma (RCC) during the last few decades. In early stage, localized disease, surgical resection remains the modality of choice, with no therapeutic interventions as options for post-operative therapy other than simple observation and clinical surveillance. However, treatment options in the advanced or metastatic setting are increasing at a dizzying pace, initially with cytokine therapy, then with the increased availability of targeted therapy including novel small-molecule inhibitors of receptor tyrosine kinases and monoclonal antibodies targeting novel proteins, establishing them as the current standard of care. Even more recently, immunotherapy has seen tremendous development in the form of immune checkpoint inhibition and vaccines. Overall, these interventions have gradually changed the landscape of cancer management in general, and metastatic renal cell carcinoma (mRCC) in particular. This is exemplified by the recent United States Food and Drug Administration (USFDA) approval of nivolumab for patients with mRCC after failure of TKI therapy. In this review, we present a brief overview of the current management of mRCC, primarily the clear cell subtype (ccRCC), and discuss the major clinical trials and data on the immunotherapy in advanced or mRCC.

Novel treatment concepts in Hodgkin lymphoma

Treatment of classical Hodgkin's lymphoma (HL) has been a success story, with cure of localized disease with radiotherapy in the 1930s, cure of advanced stages with combination chemotherapy with/without radiotherapy in the mid-1960s and continuous improvements since then. Nonetheless, at present approximately 2% of patients with classical HL are primarily refractory to conventional therapy with only 50% becoming long-term survivors. Another 13% of patients relapse, with only 60% being alive 10 years postrecurrence (as exemplified in this review in a Swedish cohort of 18- to 65-year-old patients diagnosed during the period 1992-2009). Recently, novel targeted drugs were approved for refractory/relapsed HL and here we review results of trials that form the basis for these approvals as well as new trials. In summary, brentuximab vedotin can be used in refractory patients (i) as a complement to high-dose chemotherapy with autologous stem cell transplantation (SCT) improving the chances of being able to proceed to an allogenic SCT and cure, (ii) as consolidation after autologous SCT and (iii) as palliative life-prolonging treatment. However, we have yet to determine whether this drug provides the greatest benefit in first- or second-line treatment, as consolidation or in refractory disease or relapse. Trials of immune checkpoint inhibitors, such as those targeting programmed death 1 (nivolumab and pembrolizumab), and thus not primarily the tumour cells, have shown overall response rates of >65%. Long-term results and data from Phase III trials are still lacking, but nivolumab recently gained approval in refractory patients already treated with brentuximab vedotin and autologous SCT. Other novel treatments of interest include T cells with a chimeric antigen receptor and combination therapies with histone deacetylase inhibitors.

Harnessing the immune system through programmed death-1 blockade in the management of Hodgkin lymphoma

Immunotherapy is a rapidly evolving therapeutic option in the treatment of lymphoma. Neoplastic cells evade immune recognition through the programmed death (PD)-1/PD-ligand immune checkpoint pathway. Several novel agents have been developed to restore the immune system's ability to recognize and destroy cancer cells. Nivolumab and pembrolizumab are two anti-PD-1 antibodies that have demonstrated success in the treatment of refractory Hodgkin lymphoma. Harnessing the immune system's ability to target neoplastic cells, ideally without the use of cytotoxic chemotherapeutic agents, is one way in which these novel agents are changing the therapeutic landscape in the treatment of lymphomas. Here, we review the emerging data regarding checkpoint inhibitors in the management of Hodgkin lymphoma, the unique adverse effects encountered with the use of these agents, and a practical approach to the management of these adverse effects. Additionally, we discuss upcoming trials that will further assess the promising future developments of checkpoint inhibition in the treatment of not only Hodgkin lymphoma but also other B cell lymphomas and myeloma. These agents offer immense promise of a future where many lymphomas can be treated without the toxic effects of chemotherapeutic agents.

Emerging role of checkpoint blockade therapy in lymphoma

Following the successful application of immune checkpoint blockade therapy (CBT) in refractory solid tumors, it has recently gained momentum as a promising modality in the treatment of relapsed lymphoma. This significant therapeutic advance stems from decades of research that elucidated the role of immune regulation pathways and the mechanisms by which tumors can engage these critical pathways to escape immune detection. To date, two main pathways, the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death 1 (PD-1), have emerged as key targets of CBT demonstrating unprecedented activity particularly in heavily pretreated relapsed/refractory Hodgkin lymphoma and some forms of non-Hodgkin disease. Herein we provide a brief discussion of checkpoint blockade in the context of lymphoma biology with a specific focus on novel checkpoint inhibitors and their therapeutic activity. We discuss current clinical trials and the landscape of CBT to underscore both the remarkable progress and foreseeable limitations of this novel treatment strategy. In particular, we build upon state-of-the-art knowledge and clinical insights gained from the early trials to review potential approaches to how CBT may be integrated with other treatment modalities, including chemoimmunotherapy to improve patient outcomes in the future. Finally, as the role of CBT evolves to potentially become a cornerstone of therapy in refractory/relapsed lymphoma, we briefly emphasize the importance of predictive biomarkers in an effort to select appropriate patients who are most likely to derive benefit from CBT.

Successful treatment with low-dose nivolumab in refractory Hodgkin lymphoma after allogeneic stem cell transplantation

Previous studies have reported that an antibody that blocks programmed cell death 1 (PD-1) has therapeutic activity in patients with refractory/relapsed Hodgkin lymphoma (HL). However, the safety and efficacy of these agents in the post-allogeneic stem cell transplantation (allo-SCT) setting are not well known. Here, we describe a patient who was diagnosed as classical HL and treated with five regimens of chemotherapies with autologous SCT. Complete remission (CR) was not achieved following this initial treatment, so we performed allo-SCT from an HLA-matched sibling donor. Since his disease progressed at day 403 after allo-SCT, we decided to use nivolumab in the treatment of his refractory disease. To prevent the worsening of his chronic graft-versus-host disease (GVHD), we reduced the initial dose and frequency of nivolumab compared with the previous report. After four courses of 0.5 mg/kg of nivolumab every three weeks, FDG-PET imaging showed partial response (PR) to the treatment, a remarkable result. However, since the escalated dose of 2 mg/kg resulted in worsening of dyspnea and skin sclerosis, we initiated systemic administration of prednisolone and reduced nivolumab to 1 mg/kg. At the time of this report, his HL is in stable PR with three weekly administration of nivolumab and steroid controlled mild chronic GVHD.

Fatal graft-versus-host disease after allogeneic stem cell transplantation in a patient recently exposed to nivolumab

Allogeneic hematopoietic stem cell transplantation and checkpoint blockade therapy are immune-based salvage therapies for Hodgkin's lymphoma; however, the use of programmed death 1 blocking agents in the allogeneic stem cell transplantation setting could augment the incidence of steroid refractory graft-versus-host disease. Few studies suggest that that nivolumab is safe in patients previously treated with an allogeneic stem cell transplantation. Likewise, there are very limited data on the use of nivolumab before allogeneic stem cell transplantation. Here, we report a case of fatal graft-versus-host disease in a patient who underwent allogeneic stem cell transplantation 26 days after the last administration of nivolumab. Careful monitoring and close clinical assessment of atypical presentation for graft-versus-host disease in these patients, interval of time from nivolumab administration to allogeneic stem cell transplantation, drug dosage adjustments or more effective allo prophilaxys should been evaluated in prospective clinical trial.

Challenges and opportunities for checkpoint blockade in T-cell lymphoproliferative disorders

The T-cell lymphoproliferative disorders are a heterogeneous group of non-Hodgkin’s lymphomas (NHL) for which current therapeutic strategies are inadequate, as most patients afflicted with these NHL will succumb to disease progression within 2 years of diagnosis. Appreciation of the genetic and immunologic landscape of these aggressive NHL, including PD-L1 (B7-H1, CD274) expression by malignant T cells and within the tumor microenvironment, provides a strong rationale for therapeutic targeting this immune checkpoint. While further studies are needed, the available data suggests that responses with PD-1 checkpoint blockade alone will unlikely approach those achieved in other lymphoproliferative disorders. Herein, we review the unique challenges posed by the T-cell lymphoproliferative disorders and discuss potential strategies to optimize checkpoint blockade in these T-cell derived malignancies.

Renal complications of immune checkpoint blockade

Immune checkpoint inhibitors have been approved for a variety of cancer species. Renal complications in use of these agents are not very common compared with other immune-related adverse events (irAE). However, it is crucial for physicians to recognize and manage renal manifestations of irAE. In this review, we will summarize the up-to-date knowledge of the clinical presentation, pathologic features, and management of renal irAE. In addition, we will discuss the safety of immune checkpoint inhibitors in patients with chronic kidney disease as well as in kidney transplant recipients.

Nivolumab in the Treatment of Hodgkin Lymphoma

Despite an extensive immune infiltrate that is recruited to the tumor by malignant Reed-Sternberg cells in Hodgkin lymphoma, the antitumor immune response is ineffective and unable to eradicate the malignant cells. The ineffective immune response is in part due to PD-1 signaling that renders intratumoral immune cells anergic. Reed-Sternberg cells have been shown to upregulate expression of the PD-1 ligands, PD-L1 and PD-L2, due to either genetic alterations at chromosome 9p24.1 or Epstein-Barr virus infection, and these ligands suppress the function of PD-1⁺ intratumoral T cells. Blockade of PD-1 signaling has proven to be a highly successful therapeutic approach, and the use of the anti-PD-1 mAb nivolumab recently received accelerated approval by the FDA for patients with classical Hodgkin lymphoma that has relapsed or progressed after autologous stem cell transplant and posttransplantation brentuximab vedotin. Initial clinical trials using nivolumab in this patient population resulted in high response rates that were durable. Adverse events associated with nivolumab included immune-mediated adverse reactions and infusion reactions, but these were well tolerated, allowing for continued nivolumab administration. Clinical trials are now in progress to test the use of nivolumab in combination with standard chemotherapy or with novel agents with a goal of improving the outcome of patients with Hodgkin lymphoma. Clin Cancer Res; 23(7); 1623-6. ©2016 AACR.

Safety and efficacy of nivolumab in the treatment of cancers: A meta-analysis of 27 prospective clinical trials

Immune checkpoint inhibition therapy has benefited people and shown powerful anti-tumor activity during the past several years. Nivolumab, a fully human IgG4 monoclonal antibody against PD-1, is a widely studied immune checkpoint inhibitor for the treatment of cancers. To assess the safety and efficacy of nivolumab, 27 clinical trials on nivolumab were analyzed. Results showed that the summary risks of all grade adverse effects (AEs) and grade ≥3 AEs were 0.65 and 0.12. The rate of nivolumab-related death was 0.25%. The most common any grade AEs were fatigue (25.1%), rush (13.0%), pruritus (12.5%), diarrhea (12.1%), nausea (11.8%) and asthenia (10.4%). The most common grade ≥3 AEs were hypophosphatemia (only 2.3%) and lymphopenia (only 2.1%). The pooled objective response rate (ORR), 6-month progression-free survival (PFS) rate and 1-year overall survival (OS) rate were 0.26, 0.40 and 0.52, respectively. The odds ratio of ORR between PD-L1 positive and negative was 2.34 (95% CI 1.77-3.10, p < 0.0001). The odds ratios of ORR, 6-month PFS rate and 1-year OS rate between nivolumab and chemotherapeutics were 2.77 (95% CI 1.69-4.56, p < 0.0001), 1.97 (95% CI 1.02-3.81, p = 0.04) and 1.87 (95% CI 1.46-2.40, p <0.0001), respectively. In conclusion, nivolumab has durable outcomes with tolerable AEs and drug-related deaths in cancer patients. Nivolumab monotherapy has better treatment response compared with chemotherapy, whereas chemotherapeutics have significantly higher risk of adverse effects than nivolumab.

Classical Hodgkin Lymphoma with Reduced β2M/MHC Class I Expression Is Associated with Inferior Outcome Independent of 9p24.1 Status

In classical Hodgkin lymphoma (cHL), malignant Hodgkin Reed-Sternberg (HRS) cells evade antitumor immunity by multiple mechanisms, including perturbed antigen presentation and enhanced PD-1 signaling. HRS cell expression of the PD-1 ligands is attributable, in part, to copy number alterations of 9p24.1/CD274(PD-L1)/PDCD1LG2(PD-L2) Amplification of PD-L1/PD-L2 is associated with advanced clinical stage and inferior progression-free survival (PFS) following first-line (induction) therapy. The relationships between altered expression of β₂-microglobulin (β₂M), MHC class I, and MHC class II by HRS cells, PD-L1/PD-L2 amplification, and clinical outcome in cHL are poorly defined. We assessed these variables in diagnostic biopsy specimens from 108 patients with cHL who received uniform treatment and had long-term follow-up and found decreased/absent expression of β₂M/MHC class I in 79% (85/108) and decreased/absent expression of MHC class II in 67% (72/108) of cases. Patients with decreased/absent β₂M/MHC class I had shorter PFS, independent of PD-L1/PD-L2 amplification and advanced stage. Decreased or absent MHC class II was unrelated to outcome. These results suggest that MHC class I-mediated antigen presentation by HRS cells is an important component of the biological response to standard chemo/radiotherapy. The paucity of β₂M/MHC class I expression on HRS cells also prompts speculation regarding alternative mechanisms of action of PD-1 blockade in cHL. Cancer Immunol Res; 4(11); 910-6. ©2016 AACR.

PD-1 blockade in Hodgkin's lymphoma: learning new tricks from an old teacher

INTRODUCTION

Classical Hodgkin's Lymphoma (cHL) is characterized by genetic reliance on the PD-1 pathway. Rapid accumulation of data describing the role and efficacy of PD-1 and its blockade warrants a focused review.

AREAS COVERED

In this article, we will review the unique biologic features that predispose cHL to PD-1 inhibition, current data regarding the safety and efficacy of PD-1 inhibitors in the treatment of cHL, biomarkers of immune response, ongoing clinical trials with PD-1 inhibitors, as well as areas of uncertainty. Expert commentary: The biologic and genetic underpinnings of cHL make it unique among all malignancies in its exquisite sensitivity to PD-1 inhibition. High response rates to single agent PD-1 inhibitors in early phase clinical trials serve as further proof of concept. These data strongly support continued clinical investigation of the evolving role of PD-1 inhibition in classical Hodgkin's lymphoma, including the optimal sequence, setting, and combination to best exploit the immunologic properties of this disease.