Ansell, Stephen M.

Disease overview: Hodgkin lymphoma (HL) is an uncommon B‐cell lymphoid malignancy affecting 9,050 new patients annually and representing approximately 11.2% of all lymphomas in the United States. Diagnosis: HL is composed of two distinct disease entities; the more commonly diagnosed classical HL and the rare nodular lymphocyte predominant HL. Nodular sclerosis, mixed cellularity, lymphocyte depletion, and lymphocyte‐rich HL are subgroups under the designation of classical HL. Risk stratification: An accurate assessment of the stage of disease in patients with HL is critical for the selection of the appropriate therapy. Prognostic models that identify patients at low or high risk for recurrence, as well as the response to therapy as determined by positron emission tomography (PET) scan, are used to optimize therapy. Risk‐Adapted Therapy: Initial therapy for HL patients is based on the histology of the disease, the anatomical stage and the presence of poor prognostic features. Patients with early stage disease are typically treated with combined modality strategies utilizing abbreviated courses of combination chemotherapy followed by involved‐field radiation therapy, while those with advanced stage disease receive a longer course of chemotherapy often without radiation therapy. Management of relapsed/refractory disease: High‐dose chemotherapy (HDCT) followed by an autologous stem cell transplant (ASCT) is the standard of care for most patients who relapse following initial therapy. For patients who fail HDCT with ASCT, brentuximab vedotin, PD‐1 blockade, nonmyeloablative allogeneic transplant or participation in a clinical trial should be considered. Am. J. Hematol. 91:435–442, 2016. © 2016 Wiley Periodicals, Inc.

Tumor-specific cytotoxic T cells have the capacity to target and eradicate malignant B cells in patients with Hodgkin and non-Hodgkin lymphoma; however, multiple mechanisms, including regulatory T cells, immunosuppressive ligands, and immune exhaustion, suppress an effective antitumor immune response. One mechanism that is used by malignant cells to inhibit the immune response is overexpression of programmed death ligand 1 or 2 (PD-L1 or PD-L2) on the cancer cell surface. These ligands interact with the programmed death-1 (PD-1) receptor expressed on intratumoral T cells and provide an inhibitory signal, thereby suppressing the antitumor immune response. Monoclonal antibodies that block PD-1 signaling prevent T-cell inhibition and promote a T-cell–mediated antilymphoma response. Blocking antibodies that are directed against PD-1 or PD-L1 are currently being tested in patients with lymphoma and have shown remarkable efficacy, particularly in patients with relapsed Hodgkin lymphoma. On the basis of the promising activity of this approach, PD-1 inhibitors are being used as single-agent therapy in patients with relapsed Hodgkin lymphoma, and these inhibitors are also being tested in combination with standard chemotherapy or targeted agents in ongoing clinical trials.

Key Points The risk of transformation of NLPHL to DLBCL is 0.74 per 100 patient-years of follow-up. Risk factors for transformation include prior exposure to chemotherapy and splenic involvement at time of diagnosis.

Malignant cells may subvert and escape endogenous host immune surveillance by up‐regulation of immune inhibitory signals known as immune checkpoints. These checkpoints are important therapeutic targets, and antibodies that block checkpoint signaling have shown remarkable efficacy in some solid tumors as well as in some refractory hematologic malignancies. In hematologic cancers, the mechanism of these checkpoints is complex, as the tumor and immune system are one and the same. In this review, we evaluate the biology of checkpoint inhibition, review the current data on its efficacy in lymphoid tumors, and explore uncertainties in the field, including those involving the precise mechanisms of action, the appropriate timing of therapy, and the differences in response rate between lymphoid tumor types.

Summary Peripheral T‐cell lymphomas ( PTCL ) have suboptimal outcomes using conventional CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy. The anti‐folate pralatrexate, the first drug approved for patients with relapsed/refractory PTCL , provided a rationale to incorporate it into the front‐line setting. This phase 2 study evaluated a novel front‐line combination whereby cyclophosphamide, etoposide, vincristine and prednisone ( CEOP ) alternated with pralatrexate ( CEOP ‐P) in PTCL . Patients achieving a complete or partial remission ( CR / PR ) were eligible for consolidative stem cell transplantation ( SCT ) after 4 cycles. Thirty‐three stage II ‐ IV PTCL patients were treated: 21 PTCL ‐not otherwise specified (64%), 8 angioimmunoblastic T cell lymphoma (24%) and 4 anaplastic large cell lymphoma (12%). The majority (61%) had stage IV disease and 46% were International Prognostic Index high/intermediate or high risk. Grade 3–4 toxicities included anaemia (27%), thrombocytopenia (12%), febrile neutropenia (18%), mucositis (18%), sepsis (15%), increased creatinine (12%) and liver transaminases (12%). Seventeen patients (52%) achieved a CR . The 2‐year progression‐free survival and overall survial, were 39% (95% confidence interval 21–57) and 60% (95% confidence interval 39–76), respectively. Fifteen patients (45%) (12 CR ) received SCT and all remained in CR at a median follow‐up of 21·5 months. CEOP ‐P did not improve outcomes compared to historical data using CHOP . Defining optimal front line therapy in PTCL continues to be a challenge and an unmet need.

Hodgkin lymphoma is a rare lymphoid malignancy affecting ∼9,200 new patients in the United States annually. Progress in the management of this disease over the past 50 years has been remarkable and the prognosis of this malignancy has changed from a uniformly fatal process to one in which the vast majority of patients are expected to be cured. This remarkable progress has been due to the use of combination approaches incorporating chemotherapy and radiation therapy, and now more recently antibody‐drug conjugates and immune checkpoint inhibitors. The goal for the future is to develop treatment combinations that successfully treat all patients and markedly decrease the long‐term side effects. Am. J. Hematol. 91:109–112, 2016. © 2015 Wiley Periodicals, Inc.