The role of pembrolizumab in relapsed/refractory primary mediastinal large B-cell lymphoma

Primary mediastinal large B-cell lymphoma (PMBCL) is a subtype of diffuse large B-cell lymphoma (DLBCL). PMBCL comprises approximately 10% of DLBCLs, thus making it a rare variant of DLBCL. Cure rates for PMBCL with upfront regimens like DA-REPOCH exceed 90%. However, if there is a poor response to this first-line therapy, relapsed/refractory PMBCL (rrPMBCL) has limited treatment options. The historic trend is to treat rrPMBCL with salvage regimens commonly used for DLBCL followed by high-dose therapy and autologous stem cell transplant (HDT-ASCT); however, response rates to salvage therapy remain low and few patients are able to proceed to transplant. An interesting feature of PMBCL is that even though it is classified as a subtype of DLBCL, PMBCL actually shares many clinical, pathologic, and genetic features with classical Hodgkin lymphoma (cHL). For example, both frequently express program death ligand 1 and 2 (PD-L1/2), which is not seen in other mature B-cell lymphomas. The expression of PD-L1/2 in PMBCL makes PDL1 inhibitors, such as pembrolizumab, an attractive therapeutic target. Pembrolizumab is an effective and well-tolerated therapy now approved for a number of cancer types from advanced melanoma to relapsed/refractory cHL. There are now multi-institutional trials underway assessing the role of pembrolizumab in the treatment of rrPMBCL.

Related papers:

title: Autologous bone marrow transplantation as compared with salvage chemotherapy in relapses of chemotherapy-sensitive non-Hodgkin's lymphoma.
abstract: High-dose chemotherapy followed by autologous bone marrow transplantation is a therapeutic option for patients with chemotherapy-sensitive non-Hodgkin's lymphoma who have relapses. In this report we describe a prospective randomized study of such treatment.



A total of 215 patients with relapses of non-Hodgkin's lymphoma were treated between July 1987 and June 1994. All patients received two courses of conventional chemotherapy. The 109 patients who had a response to chemotherapy were randomly assigned to receive four courses of chemotherapy plus radiotherapy (54 patients) or radiotherapy plus intensive chemotherapy and autologous bone marrow transplantation (55 patients).



The overall rate of response to conventional chemotherapy was 58 percent; among patients with relapses after chemotherapy, the response rate was 64 percent, and among those with relapses during chemotherapy, the response rate was 21 percent. There were three deaths from toxic effects among the patients in the transplantation group, and none among those in the group receiving chemotherapy without transplantation. The two groups did not differ in terms of prognostic factors. The median follow-up time was 63 months. The response rate was 84 percent after bone marrow transplantation and 44 percent after chemotherapy without transplantation. At five years, the rate of event-free survival was 46 percent in the transplantation group and 12 percent in the group receiving chemotherapy without transplantation (P = 0.001), and the rate of overall survival was 53 and 32 percent, respectively (P = 0.038).



As compared with conventional chemotherapy, treatment with high-dose chemotherapy and autologous bone marrow transplantation increases event-free and overall survival in patients with chemotherapy-sensitive non-Hodgkin's lymphoma in relapse.

title: Primary mediastinal lymphoma in adults.
abstract: The incidence of primary mediastinal lymphoma in adults was investigated in 184 patients with non-Hodgkin's lymphoma. This entity was defined as disease within the mediastinum in patients who presented with symptoms due to an enlarging mediastinal mass. Of 184 patients, 17 presented with primary mediastinal lymphoma. All had a diffuse histologic pattern. The most common pathologic type was poorly differentiated lymphocytic lymphoma, diffuse (PDL-D), (11 cases). In nine of these 11 cases the patients had tumors of convoluted lymphocytes. The presentation was rapid in onset, with heart failure, pericarditis, dyspnea and superior vena caval syndrome predominating. Eleven of the 17 were clinical stage I or II, but eight of these had widespread disease on pathologic staging or rapid dissemination soon after diagnosis. In conclusion (1) primary mediastinal lymphoma is always diffuse in histology. (2) The most frequent pathologic type is PDL-D, with convoluted morphology. (3) Compression of vital intra-thoracic structures is common. (4) Although seemingly localized at presentation, this entity usually implies disseminated disease.

title: Diffuse histiocytic lymphoma with sclerosis: A clinicopathologic entity frequently causing superior venacaval obstruction
abstract: Of 107 patients with diffuse histiocytic lymphoma (DHL) seen at the University of Chicago, 14 (13%) were classified as having moderate to marked sclerosis. Three of the 14 (21%) had predominantly retroperitoneal masses. Fifty percent of our group, however, had bulky disease seen predominantly or exclusively in the mediastinum, and all of these individuals had superior venacaval (SVC) obstruction. Of the seven patients with SVC syndrome, three were in Pathologic Stage IIA, three were in Clinical Stage II, and only one was in Clinical Stage IIIA. No other patients with DHL displayed SVC obstruction or predominantly mediastinal disease. Five of seven patients with SVC syndrome had large cleaved cell histology. In spite of an apparently favorable histopathologic subtype and a tendency to localized involvement, patients with DHL and sclerosis who have bulky or disseminated disease appear to be resistant to mega‐voltage radiotherapy alone and relatively resistant to combination chemotherapy.

title: Primary Non‐Hodgkin's lymphoma of the mediastinum
abstract: Non‐Hodgkin's lymphoma localized to the mediastinum and adjacent structures occurred in 12 of 215 (6%) non‐Hodgkin's lymphoma patients seen at the Massachusetts General Hospital between 1975 and 1979. Lymphangiography, radionuclide scanning and whole body computerized tomography were used to exclude patients with extrathoracic disease at presentation. Eleven of the 12 patients presented with extensive contiguous extranodal disease (Stage IIE) with involvement of either the pericardium, sternum, chest wall, pulmonary parenchyma or, in four cases, with superior venacaval obstruction. Diffuse large cell lymphoma (eight cases) and diffuse poorly differentiated lymphocytic lymphoma (four cases) were the prevalent histlogic subtypes; no instances of lymphoblastic lymphoma without extrathoracic spread were encountered. None of four lymphomas studied could be characterized as either B‐ or T‐cell tumors utilizing conventional surface marker techniques. Ten of the 12 patients achieved complete remissions, either after treatment with combination chemotherapy alone (three patients) or after both chemotherapy and mediastinal irradiation (seven patients). Two of these ten have subsequently relapsed, but median survival has not been reached after a mean period of observation of 28 months. Primary nonlymphoblastic non‐Hodgkin's lymphoma of the mediastinum is more common than previously realized, displays aggressive contiguous spread within the chest and responds well to combination chemotherapy with or without adjuvant mediastinal irradiation.

title: Primary mediastinal non-Hodgkin's lymphomas: a morphologic and immunologic study of 19 cases.
abstract: Nineteen, primary, non-lymphoblastic, non-Hodgkin's lymphomas were investigated by conventional morphologic studies as well as immunologic studies using the application of a battery of monoclonal antibodies to frozen tissue sections. Seventeen of the lymphomas were diffuse large cell; one was large cell immunoblastic and one was a follicular and diffuse lymphoma of intermediate differentiation. Thirty-seven percent of the lymphomas showed prominent sclerosis, sometimes associated with the superior vena cava syndrome. Six of the cases showed evidence of immunoglobulin production with light chain restriction. Twelve additional cases were shown to be of B-cell lineage by B1/T015 expression but did not show evidence of immunoglobulin production. One case was a T-cell lymphoma of helper phenotype. Ia expression was found in 14 of 18 cases studied.

title: Mediastinal lymphoma of clear cell type is a tumor corresponding to terminal steps of B cell differentiation.
abstract: This article reports eight primary mediastinal tumors occurring in young adults (19 to 43 years, mean 29.4 years), predominantly female (six of eight) adults. Most patients responded badly to aggressive therapy. Progression is presently noted in one patient; five patients died 10, 11, 13, 18, and 22 months after diagnosis. No patient developed leukemia. The tumors were highly proliferative, had a diffuse growth pattern, and comprised clear cells of variable size. They could not be classified histologically, but could, however, be immunohistologically characterized as B cell lymphomas. In all cases, the immunophenotype was LC+, cALLa-, CD19+, CD20+, CD21-, Ig (surface/cytoplasm)-, and PC-1+. In addition, the neoplastic cells exhibited variable defects in the expression of HLA-A,B,C and HLA-DR and inconstant expression of other B cell-restricted/associated antigens. This combination of immunophenotypical and clinical features suggests that the mediastinal clear cell lymphoma (MCCL) is a previously undescribed type of B cell lymphoma corresponding to the terminal steps of B cell differentiation.

title: A revised European-American classification of lymphoid neoplasms: a proposal from the International Lymphoma Study Group.
abstract: T HE HISTOLOGIC categorization of lymphoma has been a source of frustration for many years for both clinicians and pathologists. In the last 10 years, much new information has become available about the lymphomas, resulting in recognition of new entities and refinement of previously recognized disease categories, raising the question of whether it is time for a new lymphoma classification. In this paper we report the result of an international review of lymphomas, which we hope may clarify some of the confusion surrounding this topic. This review was conducted at a meeting of 19 hematopathologists with particular interest and experience in lymphomas (the International Lymphoma Study Group) in Berlin, Germany, in April 1993. At previous meetings in Europe and the United States, we had come to believe that, despite the variety of classification schemes used, many hematopathologists appeared to agree on a rather large number of distinct lymphoma entities that they recognize and diagnose in daily practice. We believed that we could provide a useful service to both pathologists and clinicians struggling with the classification of lymphomas by attempting to arrive at a consensus regarding the categories of lymphoid neoplasia that can be reliably recognized at present. What emerged from this meeting was, first, that each of us had independently evolved ways of viewing these diseases that were essentially identical. Surprisingly, there was little divergence between European and US participants. Second, it was evident that, while many of these lymphoma entities are recognized in the Kiel Classification,”6 the Lukes-Collins Classification,’ and the Working Formulation,* they often go by different names in different publications and may have variable criteria for diagno~is.~ Furthermore, we found that many of us had doubts about both the practical feasibility and the scientific validity of distinguishing certain subtypes in these systems. We also found that while some lymphoma categories are easy to recognize, others are disturbingly prone to subjective variability. This feature of lymphoma diagnosis has not been emphasized in previous schemes for classification, which imply that all categories are equally easy for the pathologist to recognize. Ideally lymphomas, like most other tumors, should be classified according to their presumed normal counterpart, to the extent possible. This should provide the best information about disease biology, natural history, and response to treatment. However, despite extensive study, the definition of lymphoid compartments in humans and movement of cells between these compartments still contains many uncertainties. Furthermore, there are difficulties in defining the full extent of the neoplastic clone in individual cases of lymphoma, and some well-defined lymphoma types lack obvious normal counterparts. Consequently, although differentiation schemes provide useful conceptual frameworks for

title: Primary mediastinal large B-cell lymphoma. A clinicopathologic study of 141 cases compared with 916 nonmediastinal large B-cell lymphomas, a GELA ("Groupe d'Etude des Lymphomes de l'Adulte") study.
abstract: Among non-Hodgkin's lymphomas, primary mediastinal large B-cell lymphoma (PMLCL) has been considered a separate entity that has specific clinical and histological aspects and a poor prognosis. In this study, we reexamined the clinicopathologic features and the response to current treatment of 141 PMLCL and compare them with 916 nonmediastinal large B-cell lymphomas (NMLCL) recorded in the same period and treated with similar combined chemotherapy. The clinical features of PMLCL at diagnosis were largely homogeneous and distinct from NMLCL, with a predilection for young women (59% with a mean age of 37 years versus 42% with a mean age of 54 years), bulky tumor (77% versus 7%, p < 10(4)), high serum lactic dehydrogenase (LDH) level 76% versus 51%, p < 10(4)), and frequent intrathoracic extension to adjacent organs such as pleura, pericardium, and lung. By contrast, extrathoracic or hematologic dissemination was uncommon (2% of bone marrow involvement versus 17%). All patients had diffuse large B-cell nonimmunoblastic, nonanaplastic lymphomas. Histological analysis of the 141 PMLCL evaluated two common patterns: the presence of large cells with clear cytoplasm (found in 38% of cases) and the presence of fibrosis (marked in 25% of cases). The presence of clear cells or intense fibrosis did not constitute prognostic indicators. Immunologic and molecular analysis assessed the profile of bcl-2 expression and the presence of Epstein-Barr virus (EBV)  30% expressed a high level of bcl-2 protein; EBER RNAs were detected by in situ hybridization in only two of the 41 cases tested. Monotypic light chain restriction could be demonstrated in seven of the 41 PMLCL tested on fixed-section. Treated with polychemotherapy regimens without radiotherapy, 79% of PMLCL patients achieved a complete remission compared with 68% in the NMLCL patient group (p = 0.01). Overall, 3-year survival rates were estimated at 66 and 61%, respectively (p = 0.05), and disease-free survival rates were not significantly different (61 versus 64%). Stratified analysis on the International Prognostic Index (based on age, tumor stage, serum LDH level, and performance status) showed no difference in the overall and disease-free survivals between the two lymphoma groups. In conclusion, PMLCL can be combined with other diffuse large B-cell lymphomas on morphologic grounds; it is not associated with EBV. It responds favorably to treatment and should be managed like other high-grade lymphomas of equivalent histology. However, the uncommon clinical presentation makes it a distinct entity.

title: New approach to classifying non-Hodgkin's lymphomas: clinical features of the major histologic subtypes. Non-Hodgkin's Lymphoma Classification Project.
abstract: Increasing knowledge about the biology of the non-Hodgkin's lymphomas has led to new approaches in classification. Rather than grouping lymphomas simply based on cell size, cell shape, and growth pattern, it is now possible to identify distinctive clinicopathologic entities. In many cases, the existence of specific immunologic and/or genetic features has confirmed the existence of these distinctive types of lymphoma. Since patients will be given these diagnoses by pathologists, it is important that clinicians be knowledgeable with regard to their clinical characteristics. The findings for the 13 most common lymphoma types that will be encountered in clinical practice are presented here.

title: Large cell lymphoma of the mediastinum: a B‐cell tumour of probable thymic origin
abstract: Fifteen cases of non‐Hodgkin's lymphoma of the anterior mediastinum are reported. In the first group of four, fresh tissue was available and immunohistochemical studies demonstrated their B‐cell origin, with monotypic immunoglobulin production in two. Only fixed tissue was available in the second group of 11 patients. All stained with antibody to leucocyte common antigen (PD7/26) and three showed monotypic immunoglobulin production. If the two groups are combined seven of the 15 tumours were clearly of B‐cell origin. Classification on morphological grounds was difficult, with most tumours showing mixtures of centroblasts and large centrocytes, and the original diagnoses had included Hodgkin's disease (three), thymoma (one) and undifferentiated carcinoma (two). None of the patients had evidence of extra‐thoracic disease at presentation and when this developed the organs involved were liver (one), kidney (two) and thyroid (one). Direct extension within the chest led to infiltration of chest wall, sternum, lung, superior vena cava and other structures. The site of origin, lack of nodal involvement and, in one case, presence of residual thymus around the tumour indicate an origin in thymic B‐cells.

title: Primary mediastinal B-cell lymphoma with sclerosis: an aggressive tumor with distinctive clinical and pathologic features.
abstract: To evaluate the clinical features of presentation, the morphologic and immunohistochemical pattern, the modality of spread, and the response to current treatments of patients with primary mediastinal B-cell lymphoma, a recently documented subtype of non-Hodgkin's lymphoma (NHL).



Thirty consecutive patients (14 males, 16 females; median age, 26 years) with primary mediastinal B-cell lymphoma with sclerosis were studied.



The clinical aspects were largely homogeneous: 93% presented with chest symptoms of a rapidly enlarging mass of the anterior mediastinum; the tumor was bulky in 73%, and superior vena cava syndrome (SVCS) was present in 57%. Also, patients without SVCS symptoms showed subclinical venacaval compression at computed tomographic (CT) scan, for a total incidence of caval obstruction of 80%. Intrathoracic extension to adjacent organs was seen in 47% of patients. Despite its invasive behavior, only four patients showed extrathoracic spread at diagnosis. In 23 cases, the tumor presented with morphologic features that resembled follicular center-cell lymphomas. In seven, the neoplastic population was composed mainly of centrocyte-like cells with abundant clear cytoplasm not referable to any known B-cell lymphoma subtype. All cases showed huge sclerosis. Of 29 patients assessable for response, 16 (55%) achieved a complete response (CR): five of 14 (36%) treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), and 11 of 15 (73%) treated with methotrexate plus leucovarin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B) or etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (VACOP-B) (P = .047). We could identify no clinical, biologic, or histopathologic features significantly correlated with response. After chemotherapy, 14 of 16 remitters received consolidation radiotherapy to the mediastinum. At 3 years, the actuarial survival rate is 38% for all cases and 72% for remitters. None of the 13 patients who did not achieve CR responded to salvage treatments.



This study shows that primary mediastinal B-cell lymphoma with sclerosis is a distinctive subtype of NHL with unique clinicopathologic aspects and aggressive behavior. Prompt recognition and aggressive treatment may provide long survival in a good proportion of cases. However, a subset of patients is extremely refractory to first- and second-line treatment. Conventional prognostic factors seem inadequate to identify these very-poor-risk cases.

title: CNS involvement in primary mediastinal large B-cell lymphoma.
abstract: The risk of CNS involvement by non-Hodgkin's Lymphoma (NHL) has been associated with bone marrow and/or testicular involvement; however, it was recently reported that the number of extranodal sites is a more reliable predictor of CNS disease. Because primary mediastinal thymic large B-cell lymphoma (PMLCL) has a high propensity for involving extranodal sites, we investigated the frequency and pattern of CNS involvement in PMLCL.



The medical records of 219 patients with aggressive NHL, consecutively entered onto protocols at the National Cancer Institute between 1987 and 1998, were retrospectively reviewed.



Twenty-three patients (11%) had clinical and pathologic features of PMLCL. These patients were young (median age, 29 years), female (61%), and presented with massive mediastinal adenopathy (70%). Extranodal disease occurred at presentation in 70% and at relapse in 93% of patients and involved contiguous intrathoracic structures and/or distant sites, including the lungs, kidneys, liver, adrenals, ovaries, pancreas, and bone. Six patients (26%) developed CNS involvement, two (9%) at presentation and four (27%) at relapse. All had extranodal disease, but only one had bone marrow involvement. Parenchymal and leptomeningeal CNS disease occurred in four and three patients, respectively.



CNS involvement in PMLCL is associated with extranodal involvement other than bone marrow and may reflect the unique biology of this disease. The propensity to involve the CNS parenchyma raises the concern that intrathecal prophylaxis may not be effective and suggests that CNS imaging should be considered in patients with extranodal disease.

title: Primary mediastinal B-cell lymphoma: high frequency of BCL-6 mutations and consistent expression of the transcription factors OCT-2, BOB.1, and PU.1 in the absence of immunoglobulins.
abstract: Although primary mediastinal (thymic) large B-cell lymphoma has been primarily studied, its precise phenotype, molecular characteristics, and histogenesis are still a matter of debate. The International Extranodal Lymphoma Study Group collected 137 such cases for extensive pathological review. Histologically, the lymphomatous growth was predominantly diffuse with fibrosis that induced compartmentalized cell aggregation. It consisted of large cells with varying degrees of nuclear polymorphism and clear to basophilic cytoplasm. On immunohistochemistry, the following phenotype was observed: CD45(+), CD20(+), CD79a(+), PAX5/BSAP(+), BOB.1(+), Oct-2(+), PU.1(+), Bcl-2(+), CD30(+), HLA-DR(+), MAL protein(+/-), Bcl-6(+/-), MUM1/IRF4(+/-), CD10(-/+), CD21(-), CD15(-), CD138(-), ), and CD3(-). Immunoglobulins were negative both at immunohistochemistry and in situ hybridization. Molecular analysis, performed in 45 cases, showed novel findings. More than half of the cases displayed BCL-6 gene mutations, which usually occurred along with functioning somatic IgV(H) gene mutations and Bcl-6 and/or MUM1/IRF4 expression. The present study supports the concept that a sizable fraction of cases of this lymphoma are from activated germinal center or postgerminal center cells. However, it differs from other aggressive B-cell lymphomas in that it shows defective immunoglobulin production despite the expression of OCT-2, BOB.1, and PU.1 transcription factors and the lack of IgV(H) gene crippling mutations.

title: CD30 expression is common in mediastinal large B-cell lymphoma.
abstract: Large B-cell lymphoma manifesting in the mediastinum shows distinctive clinical and immunophenotypic features and is recognized as a unique type of large B-cell lymphoma in the Revised European-American Lymphoma classification. Fifty-one cases of primary mediastinal large B-cell lymphoma were retrieved from the immunodiagnosis laboratory database files and were stained with anti-CD30 (Ber-H2). Of the 51 cases, 35 (69%) stained for CD30. This staining ranged from strong membrane staining of all or almost all of the neoplastic cells to positivity of rare individual cells. Eleven cases (22%) were negative; 4 (8%) were equivocal. Only 1 case was uninterpretable owing to B-5 fixation and lack of a positive internal control. Thus, the majority of mediastinal large B-cell lymphomas express the Hodgkin marker CD30. This finding may result in misdiagnosis of large cell lymphoma as Hodgkin disease.

title: Sobering realities of surviving Hodgkin lymphoma.
abstract: In this issue of Blood , Castellino and colleagues investigate morbidity and mortality in a cohort of long-term survivors of Hodgkin lymphoma (HL) from the Childhood Cancer Survivor Study. They observe frequent and serious late sequelae of therapy occurring even after 20 years of follow-up; their findings highlight the need to consider long-term implications when selecting therapeutic strategies for young patients with curable lymphomas.

title: Breast cancer risk after supradiaphragmatic radiotherapy for Hodgkin's lymphoma in England and Wales: a National Cohort Study.
abstract: To investigate breast cancer risk after supradiaphragmatic radiotherapy administered to young women with Hodgkin's lymphoma (HL) in a much larger cohort than previously to provide data for patient follow-up and screening individualized according to treatment type, age, and time point during follow-up.



Breast cancer risk was assessed in 5,002 women in England and Wales treated for HL with supradiaphragmatic radiotherapy at age < 36 years from 1956 to 2003, who underwent follow-up with 97% completeness until December 31, 2008.



Breast cancer or ductal carcinoma in situ developed in 373 patients, with a standardized incidence ratio (SIR) of 5.0 (95% CI, 4.5 to 5.5). SIRs were greatest for those treated at age 14 years (47.2; 95% CI, 28.0 to 79.8) and continued to remain high for at least 40 years. The maximum absolute excess risk was at attained ages 50 to 59 years. Alkylating chemotherapy or pelvic radiotherapy diminished the risk, but only for women treated at age ≥ 20 years, not for those treated when younger. Cumulative risks were tabulated in detail; for 40-year follow-up, the risk for patients receiving ≥ 40 Gy mantle radiotherapy at young ages was 48%.



This article provides individualized risk estimates based on large numbers for patients with HL undergoing follow-up after radiotherapy at young ages. Follow-up of such women needs to continue for 40 years or longer and may require more-intensive screening regimens than those in national general population programs. Special consideration is needed of potential measures to reduce breast cancer risk for girls treated with supradiaphragmatic radiotherapy at pubertal ages.

title: Dose-adjusted EPOCH-rituximab therapy in primary mediastinal B-cell lymphoma.
abstract: Primary mediastinal B-cell lymphoma is a distinct subtype of diffuse large-B-cell lymphoma that is closely related to nodular sclerosing Hodgkin's lymphoma. Patients are usually young and present with large mediastinal masses. There is no standard treatment, but the inadequacy of immunochemotherapy alone has resulted in routine consolidation with mediastinal radiotherapy, which has potentially serious late effects. We aimed to develop a strategy that improves the rate of cure and obviates the need for radiotherapy.



We conducted a single-group, phase 2, prospective study of infusional dose-adjusted etoposide, doxorubicin, and cyclophosphamide with vincristine, prednisone, and rituximab (DA-EPOCH-R) and filgrastim without radiotherapy in 51 patients with untreated primary mediastinal B-cell lymphoma. We used results from a retrospective study of DA-EPOCH-R from another center to independently verify the outcomes.



The patients had a median age of 30 years (range, 19 to 52) and a median tumor diameter of 11 cm; 59% were women. During a median of 5 years of follow-up, the event-free survival rate was 93%, and the overall survival rate was 97%. Among the 16 patients who were involved in the retrospective analysis at another center, over a median of 3 years of follow-up, the event-free survival rate was 100%, and no patients received radiotherapy. No late morbidity or cardiac toxic effects were found in any patients. After follow-up ranging from 10 months to 14 years, all but 2 of the 51 patients (4%) who received DA-EPOCH-R alone were in complete remission. The 2 remaining patients received radiotherapy and were disease-free at follow-up.



Therapy with DA-EPOCH-R obviated the need for radiotherapy in patients with primary mediastinal B-cell lymphoma. (Funded by the National Cancer Institute; ClinicalTrials.gov number, NCT00001337.).

title: Primary diffuse large B-cell lymphoma of the mediastinum: outcome following high-dose chemotherapy and autologous hematopoietic cell transplantation.
abstract: We performed a retrospective analysis of 35 patients with primary diffuse large B-cell lymphoma of the mediastinum treated with high-dose cyclophosphamide, carmustine, and etoposide (CBV) plus autologous hematopoietic cell transplantation to determine outcome and prognostic features for progression-free survival (PFS). Thirty-five patients with primary diffuse large B-cell lymphoma of the mediastinum in first response (complete remission [CR] or partial remission [PR]) with poor prognostic features, with primarily refractory disease, or with relapsed disease following conventional chemotherapy, were treated with CBV and autologous hematopoietic cell transplantation. PFS and overall survival were assessed by the Kaplan-Meier method. Patient characteristics before transplantation were examined by univariate analysis using the log-rank test and by Cox's proportional hazards regression analysis to determine predictors of PFS. Estimated 5-year PFS varied significantly with patient disease status at transplantation. Patients transplanted in first response had an estimated 5-year PFS rate of 83%, compared with 58% and 27% for primarily refractory and relapsed patients, respectively (P = .02). The strongest predictor of PFS was chemotherapy responsiveness immediately before transplantation. Patients with chemotherapy-responsive disease had a significantly greater PFS rate than patients with chemotherapy-nonresponsive disease (risk ratio, 3.60; 95% confidence interval [CI], 1.14 to 11.4). No other factors were found to be significant on univariate or multivariate analysis. Patients with primary diffuse large B-cell lymphoma of the mediastinum can achieve prolonged PFS following high-dose chemotherapy and autologous hematopoietic cell transplantation. Outcomes are strongly correlated with disease status (first response v refractory v relapsed) at transplantation and chemotherapy responsiveness immediately before transplantation.

title: High-dose chemotherapy followed by autologous stem cell transplantation for relapsed/refractory primary mediastinal large B-cell lymphoma
abstract: As a different entity of diffuse large B-cell lymphoma (DLBCL) according to the current World Health Organization classification,1 primary mediastinal large B-cell lymphoma (PMBL) is different from DLBCL in terms of clinical, immunohistochemical and genetic features.2 Despite a remarkable advance with first-line treatment of PMBL patients in the rituximab era,3, 4, 5, 6, 7 10–30% of patients still experience progression or relapse. Although patients with relapsed or refractory PMBL are often treated with high-dose therapy followed by autologous stem cell transplantation (HDT/ASCT) after salvage treatment, the progression-free survival (PFS) at 5 years of 27% is unsatisfactory compared with DLBCL in the pre-rituximab era.8, 9, 10 Moreover, information regarding outcomes after HDT/ASCT for relapsed or refractory PMBL is limited in the rituximab era. Therefore, clarifying the current role of HDT/ASCT is vital to establish the optimal treatment strategy.

title: Salvage chemotherapy and autologous stem cell transplantation are inferior for relapsed or refractory primary mediastinal large B-cell lymphoma compared with diffuse large B-cell lymphoma
abstract: Primary mediastinal large B-cell lymphoma (PMLCL) is an aggressive non-Hodgkin lymphoma with distinct clinical and gene expression profiles. Outcomes of salvage chemotherapy and autologous stem cell transplantation (ASCT) for relapsed or refractory disease (RR) have not been well characterised. We retrospectively identified 180 consecutive RR patients (37 PMLCL and a control group of 143 DLBCL) that underwent salvage chemotherapy. The overall response rate (ORR) to salvage chemotherapy (25% vs. 48%, p = 0.01) and 2-year OS after diagnosis of RR disease (15% vs. 34%, p = 0.018) was inferior in PMLCL patients. The 2-year post-ASCT OS (67% PMLCL vs. 53%, p = 0.78) and PFS (57% PMLCL vs. 36%, p = 0.64) were similar. RR PMLCL had an inferior ORR and survival compared with DLBCL but chemosensitive PMLCL and DLBCL patients have similar outcomes post-ASCT. Strategies for PMLCL should focus on identifying poor risk patients to test novel induction and salvage strategies.

title: Integrative analysis reveals selective 9p24.1 amplification, increased PD-1 ligand expression, and further induction via JAK2 in nodular sclerosing Hodgkin lymphoma and primary mediastinal large B-cell lymphoma.
abstract: Classical Hodgkin lymphoma (cHL) and mediastinal large B-cell lymphoma (MLBCL) are lymphoid malignancies with certain shared clinical, histologic, and molecular features. Primary cHLs and MLBCLs include variable numbers of malignant cells within an inflammatory infiltrate, suggesting that these tumors escape immune surveillance. Herein, we integrate high-resolution copy number data with transcriptional profiles and identify the immunoregulatory genes, PD-L1 and PD-L2, as key targets at the 9p24.1 amplification peak in HL and MLBCL cell lines. We extend these findings to laser-capture microdissected primary Hodgkin Reed-Sternberg cells and primary MLBCLs and find that programmed cell death-1 (PD-1) ligand/9p24.1 amplification is restricted to nodular sclerosing HL, the cHL subtype most closely related to MLBCL. Using quantitative immunohistochemical methods, we document the association between 9p24.1 copy number and PD-1 ligand expression in primary tumors. In cHL and MLBCL, the extended 9p24.1 amplification region also included the Janus kinase 2 (JAK2) locus. Of note, JAK2 amplification increased protein expression and activity, specifically induced PD-1 ligand transcription and enhanced sensitivity to JAK2 inhibition. Therefore, 9p24.1 amplification is a disease-specific structural alteration that increases both the gene dosage of PD-1 ligands and their induction by JAK2, defining the PD-1 pathway and JAK2 as complementary rational therapeutic targets.

title: Expression of Programmed Cell Death 1 Ligand 2 (PD-L2) Is a Distinguishing Feature of Primary Mediastinal (Thymic) Large B-cell Lymphoma and Associated With PDCD1LG2 Copy Gain
abstract: Primary mediastinal (thymic) large B-cell lymphoma (PMBL) and diffuse large B-cell lymphoma (DLBCL) are tumors with distinct clinical and molecular characteristics that are difficult to distinguish by histopathologic and phenotypic analyses alone. Programmed cell death 1 ligand 2 (PD-L2) is a cell surface protein expressed by activated macrophages and dendritic cells that binds PD-1 on T cells to inhibit immune responses. Amplification and/or translocations involving chromosome 9p24.1, a region that includes PDCD1LG2-encoding PD-L2, is a common event in PMBL but not DLBCL and suggests that PD-L2 expression might be a distinguishing feature of PMBL. We developed an assay for the immunohistochemical detection of PD-L2 protein in fixed biopsy specimens (PD-L2 IHC), which we applied to a cohort of PMBLs and DLBCLs. For a subset of cases, we correlated the results of PD-L2 IHC with PDCD1LG2 copy number (CN) as determined by quantitative polymerase chain reaction. Twenty-three of 32 (72%) PMBLs but only 1 of 37 (3%) DLBCLs were positive by PD-L2 IHC. Among PMBLs with PDCD1LG2 CN gain, all were positive by PD-L2 IHC. One PMBL without CN gain was positive by PD-L2 IHC. When expressed in PMBL, PD-L2 was restricted to tumor cells and not detected on intratumoral macrophages. We conclude that PD-L2 protein is robustly expressed by the majority of PMBLs but only rare DLBCLs and often associated with PDCD1LG2 copy gain. PD-L2 IHC may serve as a useful ancillary test for distinguishing PMBL from DLBCL and for the rational selection of patients for therapeutic antibodies that inhibit PD-1 signaling.

title: Programmed Death-1 Ligand Is Uniformly Expressed On Primary Mediastinal Diffuse Large B-Cell Lymphoma Cells with No Influence On Patient Survival.
abstract: Primary mediastinal diffuse large B-cell lymphoma (PMBCL) is an uncommon disease with an aggressive clinical course and potential curability. Growing evidence suggests that host antitumor immunity suppression may play a role in resistant cases. The most studied candidate molecules are ligands PD-L1 (CD 274) and PD-L2 (CD 273) expressed by lymphoma cells, which effectively suppress host T cells. The PD ligand genes are located on chromosome 9p24.1 close to Janus kinase 2 (JAK2) gene. The clinical impact of PD-L1/PD-L2 protein expression has not been described in PMBCL.  Tumor samples of 27 previously untreated patients were analyzed. Clinical characteristics were as follows: median age at diagnosis 35 years (20–74), female-to-male ratio 1.7:1, most patients (70%) had limited mediastinal disease and a mean tumor diameter of 10.7 cm. The IPI and aaIPI scores were low in 67% and 37%, intermediate-low in 26% and 41% and intermediate-high in 7% and 22%, respectively. No patients were assigned to a high risk group. All patients were treated with anthracycline-based chemotherapy 15% with CHOP and 85% with third-generation intensive regimen. Therapy was intensified in 70% of the cases with high-dose therapy and autologous stem cell transplantation. Most of the patients (70%) received rituximab and 15% were also treated with IF radiotherapy. Formalin-fixed and paraffin-embedded tissues were processed in routine tissue sections (approx. 5 micrometers) and placed on plus slides. After antigen retrieval with the use of the enzymatic or microwave oven processes, indirect immunohistochemistry with commercially available primary antibodies in optimized dilution was performed: CD20 clone L27, CD23 clone 1B12, CD30 clone Ber-H2, CD10 clone G27-P, Bcl-2 clone 100, Bcl-6 clone PGB6p, MUM1/IRF4 clone MUM1p, CD274 polyclonal, CD273 polyclonal, and HLADR clone TAL.1B5. For visualization, a secondary antibody with the standard avidin-biotin (ABC) method was applied. Results were expressed as a percentage of positive tumor cells and H-score (product of percentage of positive cells and staining intensity). Cytogenetic analysis with a locus-specific FISH probe (9p24) and arrayCGH was carried out in 15 (56%) of the patients.  Final treatment response was assessed in 26 (96%) patients (1 patient did not passed restaging procedures yet), CR was achieved in 22 (85%), PR in three and one patient progressed. After a median follow-up of 73 months (6.1 yrs), 22/26 (84%) patients are alive in the 1st CR, and only three patients died. Five-year PFS was 82.6% (95% CI 0.67–0.98) and five-year overall survival was 90.9% (95% CI 0.79–1.00). All samples expressed PD-L2 in (a median of) 80% of tumor cells with a median H-score of 90. PD-L2 protein expression was very low - six cases were negative and in positive cases, median expression was only 5% (H-score 5). HLA-DR expression was detected in all cases with a median positivity of 70% (H-score 140). Cytogenetic analysis detected amplification of 9p24.1 in 8/15 (53%) of the cases. When analyzing clinical characteristics, only correlation of high HLA-DR expression with limited clinical stage (p=0.04) and low IPI (p  Frontline intensive therapy is very effective in PMBCL patients. This is why no clear prognostic impact of protein expression of PD ligands or HLA expression was observed. There was constant high PD-L1 protein expression in PMBCL, low PD-2L expression and a high proportion of cases with JAK-2 gene amplification. Preliminary data show relationship between tumor immunogenicity (HLA-DR expression) and lymphoma aggressiveness. High PD-1L protein expression may probably influence treatment response quality. Further analyses are needed to clarify correlation between 9p24.1 amplification and PD-L protein expression. Supported by grants: MZ ER IGA NT 11103, LF-2012-007 and MSM 6198959205.  Travel grants Other.

title: Genomic rearrangements involving programmed death ligands are recurrent in primary mediastinal large B-cell lymphoma.
abstract: The pathogenesis of primary mediastinal large B-cell lymphoma (PMBCL) is incompletely understood. Recently, specific genotypic and phenotypic features have been linked to tumor cell immune escape mechanisms in PMBCL. We studied 571 B-cell lymphomas with a focus on PMBCL. Using fluorescence in situ hybridization here, we report that the programmed death ligand (PDL) locus (9p24.1) is frequently and specifically rearranged in PMBCL (20%) as compared with diffuse large B-cell lymphoma, follicular lymphoma, and Hodgkin lymphoma. Rearrangement was significantly correlated with overexpression of PDL transcripts. Utilizing high-throughput sequencing techniques, we characterized novel translocations and chimeric fusion transcripts involving PDLs at base-pair resolution. Our data suggest that recurrent genomic rearrangement events underlie an immune privilege phenotype in a subset of B-cell lymphomas.

title: Evaluation of the diagnostic and prognostic value of PDL1 expression in Hodgkin and B-cell lymphomas.
abstract: Activation of the programmed death 1 (PD1)/PD1 ligand (PDL1) pathway is important for tumor cells to escape from immune control. The clinical efficacy of therapeutic modulation of the PD1-PDL1 pathway has been recently shown in classical Hodgkin lymphoma (cHL), but little is known about the frequency and diagnostic and prognostic importance of PDL1 expression in lymphomas. The available anti-PDL1 antibody clones E1L3N and SP142 were compared, and a large cohort of Hodgkin lymphomas (n=280) and B-cell lymphomas (n=619) was examined for PDL1 using E1L3N. The results were correlated with the expression of other phenotypic markers, interphase fluorescence in situ hybridization data of the 9p24.1 region (PDL1 locus), and the clinical outcome. PDL1 was expressed on more than 5% of tumor cells in 70% of cHL, 54% of nodular lymphocyte-predominant Hodgkin lymphoma, and 35% of primary mediastinal B-cell lymphomas; in the latter, PDL1 expression correlated with PDL1 gains (ρ=0.573). PDL1 was expressed in 31% of primary diffuse large B-cell lymphomas (DLBCLs), whereas most other entities did not express PDL1. In cHL, expression of PDL1 correlated with increased numbers of granzyme+ T cells (ρ=0.251) and CD68+ macrophages (ρ=0.221) but with decreased numbers of FoxP3+ T cells (ρ=0.145). In activated B-cell-like DLBCL, PDL1 positively correlated with PD1+ T cells, whereas an inverse correlation with FoxP3+ T cells was seen in the germinal center B-cell-like DLBCL. PDL1 expression can be diagnostically valuable in some gray zones around DLBCL and cHL; it identifies an "immune escape" cluster of cHL and activated B-cell-like DLBCL with increased granzyme+ and PD1+ T cells and macrophages and decreased regulatory T cells.

title: Expression pattern of PD‐L1 and PD‐L2 in classical Hodgkin lymphoma, primary mediastinal large B‐cell lymphoma, and gray zone lymphoma
abstract: We aimed at investigating the relationship between classical Hodgkin lymphoma (cHL), primary mediastinal large B‐cell lymphoma (PMBL), and gray zone lymphoma (GZL) with intermediate characteristics between cHL and PMBL, from the perspective of the aberration in programed cell death 1 and the programed death ligands (PDLs) network.

title: Programmed Death Ligand 1 Is Expressed by Non–Hodgkin Lymphomas and Inhibits the Activity of Tumor-Associated T Cells
abstract: Programmed death ligand 1 (PD-L1) is expressed on antigen-presenting cells and inhibits activation of T cells through its receptor PD-1. PD-L1 is aberrantly expressed on some epithelial malignancies and Hodgkin lymphomas and may prevent effective host antitumor immunity. The role of PD-L1 in non–Hodgkin lymphomas (NHL) is not well characterized.  Functional activity of PD-L1 was studied by incubating irradiated lymphoma cells with allogeneic T cells with or without anti-PD-L1 blocking antibody; T-cell proliferation and IFN-γ secretion served as measures of T-cell activation. Similar experiments were conducted using cultures of primary lymphoma specimens containing host T cells.  PD-L1 was expressed uniformly by anaplastic large cell lymphoma (ALCL) cell lines, but rarely in B-cell NHL, confined to a subset of diffuse large B-cell lymphomas (DLBCL) with activated B-cell features (3 of 28 cell lines and 24% of primary DLBCL). Anti-PD-L1 blocking antibody boosted proliferation and IFN-γ secretion by allogeneic T cells responding to ALCL and DLBCL cells. In autologous cultures of primary ALCL and DLBCL, PD-L1 blockade enhanced secretion of inflammatory cytokines IFN-γ, granulocyte macrophage colony-stimulating factor, interleukin (IL)-1, IL-6, IL-8, IL-13, TNF-α, and macrophage inflammatory protein-1α. In establishing cell lines from an aggressive PD-L1+ mature B-cell lymphoma, we also noted that PD-L1 expression could be lost under certain in vitro culture conditions.  PD-L1 may thwart effective antitumor immune responses and represents an attractive target for lymphoma immunotherapy.

title: JAK/STAT signaling in hematological malignancies
abstract: The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is central to signaling by cytokine receptors, a superfamily of more than 30 transmembrane proteins that recognize specific cytokines, and is critical in blood formation and immune response. Many of those receptors transmit anti-apoptotic, proliferative and differentiation signals, and their expression and functions are critical for the formation of blood lineages. Several cancers, including blood malignancies, have been associated with constitutive activation of members of the STAT family, which normally require JAK-mediated tyrosine phosphorylation for transcriptional activation. More recently, human myeloproliferative neoplasms were discovered to be associated with a unique acquired somatic mutation in JAK2 (JAK2 V617F), rare exon 12 JAK2 mutations, or thrombopoietin receptor mutations that constitutively activate wild-type JAK2. Prompted by these observations, many studies have explored the possibility that JAKs, cytokine receptors, or other components of the JAK/STAT pathway are mutated or upregulated in several hematological malignancies. This has been observed in certain pediatric acute lymphoblastic leukemias and adult T-cell lymphoblastic leukemias, and overexpression of JAK2 seems to be important in Hodgkin lymphoma. Here we discuss the nature and respective contribution of mutations dysregulating the JAK/STAT pathway in hematological malignancies and present examples in which such mutations drive the disease, contribute to the phenotype, or provide a survival and proliferative advantage. JAK inhibitors are making their way into the therapeutic arsenal (for example, in myelofibrosis), and we discuss the possibility that other hematological diseases might benefit from treatment with these inhibitors in combination with other agents.

title: Constitutive STAT6 activation in primary mediastinal large B-cell lymphoma.
abstract: Primary mediastinal large B-cell lymphoma (PMBL), currently recognized as a diffuse large B-cell lymphoma (DLBCL) subtype, shows increased expression of interleukin 4 (IL-4)/IL-13 signaling effectors and targets, suggesting constitutive activation of these pathways. We therefore investigated the functional state of the signal transducer and activator of transcription 6 (STAT6), mediating IL-4/IL-13 transcriptional effects. Constitutive STAT6 phosphorylation and DNA-binding activity were detected in PMBL cell lines but not DLBCL cell lines. Moreover, immunohistochemical analysis revealed nuclear phosphorylated STAT6 (P-STAT6) in 8 of 11 PMBL, compared with 1 of 10 DLBCL primary tumors (P =.01). IL-4 and IL-13 transcripts were absent in PMBL cell lines and expressed at low levels in tumors, indicating that, contrary to classical Hodgkin lymphoma (cHL), STAT6 activation is not due to an autocrine IL-4/IL-13 secretion. We demonstrated an amplification of the JAK2 gene in 2 of 6 PMBL cases, and showed higher JAK2 mRNA levels in PMBL compared with DLBCL (P =.005). The Janus kinase 2 (JAK2) was constitutively phosphorylated in the PMBL MedB1 cell line. MedB1 treatment with JAK2 inhibitor AG490 partially decreased STAT6 phosphorylation, suggesting that JAK2 is partially involved in STAT6 activation in these cells. Our findings highlight phosphorylated STAT6 as a characteristic distinguishing PMBL from DLBCL, but a common feature to PMBL and cHL, supporting the hypothesis of common pathogenic events in these 2 lymphomas.

title: Selective JAK2 Inhibition Specifically Decreases Hodgkin Lymphoma and Mediastinal Large B-cell Lymphoma Growth In Vitro and In Vivo
abstract: Classical Hodgkin lymphoma (cHL) and primary mediastinal large B-cell lymphoma (MLBCL) share similar histologic, clinical, and genetic features. In recent studies, we found that disease-specific chromosome 9p24.1/JAK2 amplification increased JAK2 expression and activity in both cHL and MLBCL. This prompted us to assess the activity of a clinical grade JAK2 selective inhibitor, fedratinib (SAR302503/TG101348), in in vitro and in vivo model systems of cHL and MLBCL with defined JAK2 copy numbers.  We used functional and immunohistochemical analyses to investigate the preclinical activity of fedratinib and associated biomarkers in cell lines and murine xenograft models of cHL and MLBCL with known 9p24.1/JAK2 copy number.  Chemical JAK2 inhibition decreased the cellular proliferation of cHL and MLBCL cell lines and induced their apoptosis. There was an inverse correlation between 9p24.1/JAK2 copy number and the EC50 of fedratinib. Chemical JAK2 inhibition decreased phosphorylation of JAK2, STAT1, STAT3, and STAT6 and reduced the expression of additional downstream targets, including PD-L1, in a copy number–dependent manner. In murine xenograft models of cHL and MLBCL with 9p24.1/JAK2 amplification, chemical JAK2 inhibition significantly decreased JAK2/STAT signaling and tumor growth and prolonged survival. In in vitro and in vivo studies, pSTAT3 was an excellent biomarker of baseline JAK2 activity and the efficacy of chemical JAK2 inhibition.  In in vitro and in vivo analyses, cHL and MLBCL with 9p24.1/JAK2 copy gain are sensitive to chemical JAK2 inhibition suggesting that clinical evaluation of JAK2 blockade is warranted.

title: Induced expression of PD‐1, a novel member of the immunoglobulin gene superfamily, upon programmed cell death.
abstract: The classical type of programmed cell death is characterized by its dependence on de novo RNA and protein synthesis and morphological features of apoptosis. We confirmed that stimulated 2B4.11 (a murine T‐cell hybridoma) and interleukin‐3 (IL‐3)‐deprived LyD9 (a murine haematopoietic progenitor cell line) died by the classical type of programmed cell death. Assuming that common biochemical pathways might be involved in the deaths of 2B4.11 and LyD9, we isolated the PD‐1 gene, a novel member of the immunoglobulin gene superfamily, by using subtractive hybridization technique. The predicted PD‐1 protein has a variant form of the consensus sequence found in cytoplasmic tails of signal transducing polypeptides associated with immune recognition receptors. The PD‐1 gene was activated in both stimulated 2B4.11 and IL‐3‐deprived LyD9 cells, but not in other death‐induced cell lines that did not show the characteristic features of the classical programmed cell death. Expression of the PD‐1 mRNA in mouse was restricted to the thymus and increased when thymocyte death was augmented by in vivo injection of anti‐CD3 antibody. These results suggest that activation of the PD‐1 gene may be involved in the classical type of programmed cell death.

title: Expression of the PD-1 antigen on the surface of stimulated mouse T and B lymphocytes.
abstract: A mAb J43 has been produced against the product of the mouse PD-1 gene, a member of the Ig gene superfamily, which was previously isolated from an apoptosis-induced T cell hybridoma (2B4.11) by using subtractive hybridization. Analyses by flow cytometry and immunoprecipitation using the J43 mAb revealed that the PD-1 gene product is a 50-55 kDa membrane protein expressed on the cell surface of several PD-1 cDNA transfectants and 2B4.11 cells. Since the molecular weight calculated from the amino acid sequence is 29, 310, the PD-1 protein appears to be heavily glycosylated. Normal murine lymphoid tissues such as thymus, spleen, lymph node and bone marrow contained very small numbers of PD-1(+) cells. However, a significant PD-1(+) population appeared in the thymocytes as well as T cells in spleen and lymph nodes by the in vivo anti-CD3 mAb treatment. Furthermore, the PD-1 antigen expression was strongly induced in distinct subsets of thymocytes and spleen T cells by in vitro stimulation with either anti-CD3 mAb or concanavalin A (Con A) which could lead T cells to both activation and cell death. Similarly, PD-1 expression was induced on spleen B cells by in vitro stimulation with anti-IgM antibody. By contrast, PD-1 was not significantly expressed on lymphocytes by treatment with growth factor deprivation, dexamethasone or lipopolysaccharide. These results suggest that the expression of the PD-1 antigen is tightly regulated and induced by signal transduction through the antigen receptor and do not exclude the possibility that the PD-1 antigen may play a role in clonal selection of lymphocytes although PD-1 expression is not required for the common pathway of apoptosis.

title: Development of lupus-like autoimmune diseases by disruption of the PD-1 gene encoding an ITIM motif-carrying immunoreceptor.
abstract: PD-1, a 55 kDa transmembrane protein containing an immunoreceptor tyrosine-based inhibitory motif, is induced in lymphocytes and monocytic cells following activation. Aged C57BL/6(B6)-PD-1(-/-) congenic mice spontaneously developed characteristic lupus-like proliferative arthritis and glomerulonephritis with predominant IgG3 deposition, which were markedly accelerated by introduction of a Fas mutation (lpr). Introduction of a PD-1 null mutation into the 2C-TCR (anti-H-2Ld) transgenic mice of the H-2(b/d) background resulted in the chronic and systemic graft-versus-host-like disease. Furthermore, CD8+ 2C-TCR+ PD-1(-/-) T cells exhibited markedly augmented proliferation in vitro in response to H-2d allogenic cells. Collectively, it is suggested that PD-1 is involved in the maintenance of peripheral self-tolerance by serving as a negative regulator of immune responses.

title: B7-H1, a third member of the B7 family, co-stimulates T-cell proliferation and interleukin-10 secretion
abstract: The B7 family members B7-1 and B7-2 interact with CD28 and constitute an essential T-cell co-stimulatory pathway in the initiation of antigen-specific humoral and cell-mediated immune response. Here, we describe a third member of the B7 family, called B7-H1 that does not bind CD28, cytotoxic T-lymphocyte A4 or ICOS (inducible co-stimulator). Ligation of B7-H1 co-stimulated T-cell responses to polyclonal stimuli and allogeneic antigens, and preferentially stimulated the production of interleukin-10. Interleukin-2, although produced in small amounts, was required for the effect of B7-H1 co-stimulation. Our studies thus define a previously unknown co-stimulatory molecule that may be involved in the negative regulation of cell-mediated immune responses.

title: Engagement of the Pd-1 Immunoinhibitory Receptor by a Novel B7 Family Member Leads to Negative Regulation of Lymphocyte Activation
abstract: PD-1 is an immunoinhibitory receptor expressed by activated T cells, B cells, and myeloid cells. Mice deficient in PD-1 exhibit a breakdown of peripheral tolerance and demonstrate multiple autoimmune features. We report here that the ligand of PD-1 (PD-L1) is a member of the B7 gene family. Engagement of PD-1 by PD-L1 leads to the inhibition of T cell receptor–mediated lymphocyte proliferation and cytokine secretion. In addition, PD-1 signaling can inhibit at least suboptimal levels of CD28-mediated costimulation. PD-L1 is expressed by antigen-presenting cells, including human peripheral blood monocytes stimulated with interferon γ, and activated human and murine dendritic cells. In addition, PD-L1 is expressed in nonlymphoid tissues such as heart and lung. The relative levels of inhibitory PD-L1 and costimulatory B7-1/B7-2 signals on antigen-presenting cells may determine the extent of T cell activation and consequently the threshold between tolerance and autoimmunity. PD-L1 expression on nonlymphoid tissues and its potential interaction with PD-1 may subsequently determine the extent of immune responses at sites of inflammation.

title: PD-1 and its ligands in tolerance and immunity.
abstract: Programmed death 1 (PD-1) and its ligands, PD-L1 and PD-L2, deliver inhibitory signals that regulate the balance between T cell activation, tolerance, and immunopathology. Immune responses to foreign and self-antigens require specific and balanced responses to clear pathogens and tumors and yet maintain tolerance. Induction and maintenance of T cell tolerance requires PD-1, and its ligand PD-L1 on nonhematopoietic cells can limit effector T cell responses and protect tissues from immune-mediated tissue damage. The PD-1:PD-L pathway also has been usurped by microorganisms and tumors to attenuate antimicrobial or tumor immunity and facilitate chronic infection and tumor survival. The identification of B7-1 as an additional binding partner for PD-L1, together with the discovery of an inhibitory bidirectional interaction between PD-L1 and B7-1, reveals new ways the B7:CD28 family regulates T cell activation and tolerance. In this review, we discuss current understanding of the immunoregulatory functions of PD-1 and its ligands and their therapeutic potential.

title: Tumor-associated B7-H1 promotes T-cell apoptosis: A potential mechanism of immune evasion
abstract: B7-H1, a recently described member of the B7 family of costimulatory molecules, is thought to be involved in the regulation of cellular and humoral immune responses through the PD-1 receptor on activated T and B cells. We report here that, except for cells of the macrophage lineage, normal human tissues do not express B7-H1. In contrast, B7-H1 is abundant in human carcinomas of lung, ovary and colon and in melanomas. The pro-inflammatory cytokine interferon-γ upregulates B7-H1 on the surface of tumor cell lines. Cancer cell–associated B7-H1 increases apoptosis of antigen-specific human T-cell clones in vitro, and the apoptotic effect of B7-H1 is mediated largely by one or more receptors other than PD-1. In addition, expression of B7-H1 on mouse P815 tumor increases apoptosis of activated tumor-reactive T cells and promotes the growth of highly immunogenic B7-1+ tumors in vivo. These findings have implications for the design of T cell–based cancer immunotherapy.

title: Involvement of PD-L1 on tumor cells in the escape from host immune system and tumor immunotherapy by PD-L1 blockade
abstract: PD-1 is a receptor of the Ig superfamily that negatively regulates T cell antigen receptor signaling by interacting with the specific ligands (PD-L) and is suggested to play a role in the maintenance of self-tolerance. In the present study, we examined possible roles of the PD-1/PD-L system in tumor immunity. Transgenic expression of PD-L1, one of the PD-L, in P815 tumor cells rendered them less susceptible to the specific T cell antigen receptor-mediated lysis by cytotoxic T cells in vitro, and markedly enhanced their tumorigenesis and invasiveness in vivo in the syngeneic hosts as compared with the parental tumor cells that lacked endogenous PD-L. Both effects could be reversed by anti-PD-L1 Ab. Survey of murine tumor lines revealed that all of the myeloma cell lines examined naturally expressed PD-L1. Growth of the myeloma cells in normal syngeneic mice was inhibited significantly albeit transiently by the administration of anti-PD-L1 Ab in vivo and was suppressed completely in the syngeneic PD-1-deficient mice. These results suggest that the expression of PD-L1 can serve as a potent mechanism for potentially immunogenic tumors to escape from host immune responses and that blockade of interaction between PD-1 and PD-L may provide a promising strategy for specific tumor immunotherapy.

title: Safety and activity of anti-PD-L1 antibody in patients with advanced cancer.
abstract: Programmed death 1 (PD-1) protein, a T-cell coinhibitory receptor, and one of its ligands, PD-L1, play a pivotal role in the ability of tumor cells to evade the host's immune system. Blockade of interactions between PD-1 and PD-L1 enhances immune function in vitro and mediates antitumor activity in preclinical models.



In this multicenter phase 1 trial, we administered intravenous anti-PD-L1 antibody (at escalating doses ranging from 0.3 to 10 mg per kilogram of body weight) to patients with selected advanced cancers. Anti-PD-L1 antibody was administered every 14 days in 6-week cycles for up to 16 cycles or until the patient had a complete response or confirmed disease progression.



As of February 24, 2012, a total of 207 patients--75 with non-small-cell lung cancer, 55 with melanoma, 18 with colorectal cancer, 17 with renal-cell cancer, 17 with ovarian cancer, 14 with pancreatic cancer, 7 with gastric cancer, and 4 with breast cancer--had received anti-PD-L1 antibody. The median duration of therapy was 12 weeks (range, 2 to 111). Grade 3 or 4 toxic effects that investigators considered to be related to treatment occurred in 9% of patients. Among patients with a response that could be evaluated, an objective response (a complete or partial response) was observed in 9 of 52 patients with melanoma, 2 of 17 with renal-cell cancer, 5 of 49 with non-small-cell lung cancer, and 1 of 17 with ovarian cancer. Responses lasted for 1 year or more in 8 of 16 patients with at least 1 year of follow-up.



Antibody-mediated blockade of PD-L1 induced durable tumor regression (objective response rate of 6 to 17%) and prolonged stabilization of disease (rates of 12 to 41% at 24 weeks) in patients with advanced cancers, including non-small-cell lung cancer, melanoma, and renal-cell cancer. (Funded by Bristol-Myers Squibb and others; ClinicalTrials.gov number, NCT00729664.).

title: Safety, activity, and immune correlates of anti-PD-1 antibody in cancer.
abstract: Blockade of programmed death 1 (PD-1), an inhibitory receptor expressed by T cells, can overcome immune resistance. We assessed the antitumor activity and safety of BMS-936558, an antibody that specifically blocks PD-1.



We enrolled patients with advanced melanoma, non-small-cell lung cancer, castration-resistant prostate cancer, or renal-cell or colorectal cancer to receive anti-PD-1 antibody at a dose of 0.1 to 10.0 mg per kilogram of body weight every 2 weeks. Response was assessed after each 8-week treatment cycle. Patients received up to 12 cycles until disease progression or a complete response occurred.



A total of 296 patients received treatment through February 24, 2012. Grade 3 or 4 drug-related adverse events occurred in 14% of patients; there were three deaths from pulmonary toxicity. No maximum tolerated dose was defined. Adverse events consistent with immune-related causes were observed. Among 236 patients in whom response could be evaluated, objective responses (complete or partial responses) were observed in those with non-small-cell lung cancer, melanoma, or renal-cell cancer. Cumulative response rates (all doses) were 18% among patients with non-small-cell lung cancer (14 of 76 patients), 28% among patients with melanoma (26 of 94 patients), and 27% among patients with renal-cell cancer (9 of 33 patients). Responses were durable; 20 of 31 responses lasted 1 year or more in patients with 1 year or more of follow-up. To assess the role of intratumoral PD-1 ligand (PD-L1) expression in the modulation of the PD-1-PD-L1 pathway, immunohistochemical analysis was performed on pretreatment tumor specimens obtained from 42 patients. Of 17 patients with PD-L1-negative tumors, none had an objective response; 9 of 25 patients (36%) with PD-L1-positive tumors had an objective response (P=0.006).



Anti-PD-1 antibody produced objective responses in approximately one in four to one in five patients with non-small-cell lung cancer, melanoma, or renal-cell cancer; the adverse-event profile does not appear to preclude its use. Preliminary data suggest a relationship between PD-L1 expression on tumor cells and objective response. (Funded by Bristol-Myers Squibb and others; ClinicalTrials.gov number, NCT00730639.).

title: Phase I Study of Pembrolizumab (MK-3475; Anti–PD-1 Monoclonal Antibody) in Patients with Advanced Solid Tumors
abstract: This phase I study evaluated the safety, maximum tolerated dose, antitumor activity, and pharmacokinetics and pharmacodynamics of pembrolizumab in patients with advanced solid tumors.  In a 3 + 3 dose escalation study, 10 patients received pembrolizumab 1, 3, or 10 mg/kg intravenously every 2 weeks until progression or intolerable toxicity. Seven additional patients received 10 mg/kg every 2 weeks. Thirteen patients participated in a 3-week intrapatient dose escalation (dose range, 0.005–10 mg/kg) followed by 2 or 10 mg/kg every 3 weeks. Tumor response was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.  No dose-limiting toxicities were observed. Maximum administered dose was 10 mg/kg every 2 weeks. One patient with melanoma and one with Merkel cell carcinoma experienced complete responses of 57 and 56+ weeks' duration, respectively. Three patients with melanoma experienced partial responses. Fifteen patients with various malignancies experienced stable disease. One patient died of cryptococcal infection 92 days after pembrolizumab discontinuation, following prolonged corticosteroid use for grade 2 gastritis considered drug related. Pembrolizumab exhibited pharmacokinetic characteristics typical of humanized monoclonal antibodies. Maximum serum target engagement was reached with trough levels of doses greater than or equal to 1 mg/kg every 3 weeks. Mechanism-based translational models with a focus on intratumor exposure prediction suggested robust clinical activity would be observed at doses ≥2 mg/kg every 3 weeks.  Pembrolizumab was well tolerated and associated with durable antitumor activity in multiple solid tumors. The lowest dose with full potential for antitumor activity was 2 mg/kg every 3 weeks.  See related commentary by van Elsas et al., p.

title: Phase II Study of the Efficacy and Safety of Pembrolizumab for Relapsed/Refractory Classic Hodgkin Lymphoma.
abstract: 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.  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.  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.  Pembrolizumab was associated with high response rates and an acceptable safety profile in patients with rrHL, offering a new treatment paradigm for this disease.

title: Safety and tolerability of pembrolizumab in patients with relapsed/refractory primary mediastinal large B-cell lymphoma.
abstract: Treatment options for relapsed/refractory primary mediastinal large B-cell lymphoma (rrPMBCL) are limited, and prognosis is generally poor (overall response rate [ORR] 0% to 25%; 2-year overall survival 15%). PMBCL frequently involves PD-1 ligand overexpression, potentially making PMBCL particularly susceptible to PD-1 blockade. We evaluated safety and antitumor activity of pembrolizumab, an anti-PD-1 antibody, in rrPMBCL as part of the KEYNOTE-013 multicohort phase 1b trial. At time of data cutoff, 18 patients (median age 30 years; median 3 prior lines of therapy) had been enrolled and treated, of whom 17 were included in the efficacy analyses. Eleven patients (61%) experienced drug-related adverse events (mostly grade 1-2); none discontinued treatment due to adverse events. ORR was 41% (7/17); 6 additional patients (35%) had stable disease. Of patients evaluable by imaging, 13 out of 16 (81%) had decreases in target lesions. With a median follow-up of 11.3 months, median duration of response was not reached. Two patients reached the maximum 2-year treatment duration and remain in remission. Median overall survival was not reached for treated patients overall; all responders were still alive at data cutoff. These results in heavily pretreated rrPMBCL patients demonstrate that PD-1 blockade with pembrolizumab has a manageable safety profile and promising antitumor activity.

title: Efficacy and Safety of Pembrolizumab in Relapsed/Refractory Primary Mediastinal Large B-Cell Lymphoma (rrPMBCL): Updated Analysis of the Keynote-170 Phase 2 Trial
abstract: In rrPMBCL, treatment outcomes with current therapies remain poor. Similar to classical Hodgkin lymphoma, PMBCL frequently exhibits 9p24.1/ PD-L1 / PD-L2 copy number alterations and rearrangements with associated PD-L1 and/or PD-L2 overexpression, which may facilitate immune evasion. The genetics of PMBCL could thus make it particularly susceptible to PD-1 blockade. In the phase 1 KEYNOTE-013 (NCT01953692) trial, the anti-PD-1 antibody pembrolizumab showed promising antitumor activity against rrPMBCL. KEYNOTE-170 (NCT02576990) is an ongoing, two-cohort, multicenter, Phase 2 study evaluating the efficacy and safety of pembrolizumab in patients with rrPMBCL and in patients with Richter syndrome. Here we report updated interim results and biomarker data from the rrPMBCL cohort of KEYNOTE-170.  This independent cohort of KEYNOTE-170 enrolled patients with rrPMBCL who relapsed after or were ineligible for autologous stem cell transplant (auto SCT); patients ineligible for auto SCT had to have relapsed or refractory disease after ≥ 2 lines of prior therapy. Patients received pembrolizumab 200 mg IV every 3 weeks until disease progression, unacceptable toxicity, or completion of 35 treatment cycles (i.e., 2 years). Tumors were biopsied prior to initiation of therapy and the tissue evaluated for relevant biomarker expression. Treatment response was assessed every 12 weeks by positron emission tomography and computed tomography using IWG 2007 response criteria. The primary end point was objective response rate (ORR) by blinded independent central review (BICR). Key secondary end points were complete response rate, ORR by investigator assessment, duration of response, overall survival (OS), and safety/tolerability. The safety population consisted of all patients who received ≥ 1 dose of study drug and the efficacy population of all safety patients who were expected to have ≥ 24 weeks of follow-up by the analysis cut-off date.  Patients were enrolled at 14 sites in 9 countries. At the analysis cutoff date (14 April 2017), 49 patients were treated in the rrPMBCL cohort (safety population): median age 33 years (range: 20 - 61), 55% female, median 3 lines of prior therapy (range: 2 - 8), 31% with prior radiation, 100% with prior rituximab, and 70% auto SCT ineligible due to chemorefractory disease. In total, 29 patients (59%) were PD-L1 positive, 2 (4%) PD-L1 negative, and 18 (37%) had missing baseline PD-L1 status. Median follow-up duration was 6.6 mos (range: 0.1 - 13.6); 29 patients discontinued treatment due to clinical or radiological progression (n=24), AE (n=3), or physician decision (n=2). In the efficacy population (i.e., patients expected to have reached the 24 week response assessment; n=29), ORR was 41% by BICR and 38% by investigator assessment. By BICR, responses were: 4 complete response (14%), 8 partial response (28%), 3 stable disease (10%), 8 progressive disease (28%), and 6 (21%) no assessment (i.e., discontinued or died prior to the 24 week imaging assessment). Of the patients in the efficacy population, 22 (76%) were positive for PD-L1, 1 (3%) were PD-L1 - negative, and 6 (21%) had missing biomarker data. Among all 22 evaluable patients, 16 (73%) had target lesion reductions (Figure). Median time to response was 2.9 mos (range: 2.4 - 8.5). Median duration of response was not reached (range: 1.1 - 8.2 mos); 10 responses were ongoing (range: 1.9 to 8.2 mos) at data cut-off. Median OS was also not reached; 12-months OS was 62%. In total, 12/49 patients (25%) experienced serious AEs and 26/49 (53%) experienced treatment-related adverse events (TRAEs). Grade 3 TRAEs were neutropenia (n=5 patients), increased hepatic enzymes (n=2), Clostridium difficile infection (n=1), tumor flare (n=1), asthenia (n=1), and pneumonia (n=1). One patient had a grade 4 TRAE (neutropenia). There were no treatment-related deaths. Updated data will be presented at the meeting.  In this ongoing global trial, PD-1 blockade with pembrolizumab showed promising antitumor activity and a manageable safety profile in patients with rrPMBCL, similar to results of the Phase 1b KEYNOTE-013 trial. Support. Merck & Co., Inc., Kenilworth, New Jersey, United States. Disclosures Zinzani: ​Celgene, Roche, Janssen, Gilead, Takeda, BMS, MSD, Servier, Sandoz, Mundipharma: Honoraria; Celgene, Janssen, Gilead, Roche, Takeda, BMS, MSD, Sandoz, Servier, Mundipharma: Speakers Bureau;  Consultancy, Other: Advisory board.  Bayer: Membership on an entity9s Board of Directors or advisory committees; Abbvie: Membership on an entity9s Board of Directors or advisory committees; Janssen: Membership on an entity9s Board of Directors or advisory committees; Celgene: Membership on an entity9s Board of Directors or advisory committees; Roche: Membership on an entity9s Board of Directors or advisory committees,  Consultancy, Honoraria, Other: travel costs,  Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria;  Consultancy, Honoraria;  Research Funding. Fogliatto: Roche: Honoraria, Other: Travel Support; accomodations; Novartis: Honoraria, Other: Travel support;  Travel Support.  Research Funding; Merck & Co.,  Research Funding; Seattle-Genetics: Research Funding; Janssen: Research  Research  Research Funding; Janssen: Research Funding; MSD: Research Funding; BMS: Honoraria, Other: Travel Accomodation; Roche: Honoraria, Other: Travel Accomodation; Abbvie: Other: Travel Accomodation;  Travel Accomodation; : travel accomodation, Research Funding; Bayer: Research Funding. Salles: Amgen, BMS, Celgene, Gilead, Janssen, Kite, Merck & Co., Inc., Morphosys, Novartis, Roche,  Honoraria;  Scientific Advisory Board;  Scientific Advisory Board; Bayer: Research Funding; Bristol-Myers Squibb: Membership on an entity9s Board of Directors or advisory committees,  Merck & Co., Inc.: Employment, Other: stock/stock options.  Merck & Co., Inc.: Employment, Other: stock/stock options.  Merck & Co., Inc.: Employment, Other: stock/stock options.   Research  Research Funding; Tensha: Research Funding; Genmab: Consultancy;  Research Funding; Otsuka: Research Funding.

title: Treatment outcome and prognostic factors for primary mediastinal (thymic) B-cell lymphoma: a multicenter study of 106 patients.
abstract: To define clinicopathologic features, response to treatment, and prognostic factors of primary mediastinal B-cell lymphoma (MBL), a CD20+ tumor recognized as a distinct entity among non-Hodgkin's lymphomas (NHL).



One hundred six patients presented with disease confined to thorax (86%), bulky mediastinum (73%), superior vena cava syndrome (47%), and contiguous infiltration (57%). Ninety-nine received doxorubicin-containing chemotherapy (CHT).



Thirty-five of 99 patients were primarily CHT-resistant, and 64 responded: 23 achieved complete response (CR) and 41 achieved response with residual mediastinal abnormality. Seventy-seven percent of responders received mediastinal radiotherapy (RT). Of 64 responders, 18 (28%) relapsed: none of 23 CR patients and 18 of 41 (44%) with residual mediastinal abnormality. Relapse-free survival rate of responders was 71% at 3 years. Actuarial 3-year survival rate was 52% for all patients and 82% for responders. Predictive factors of poor outcome were identified by logistic regression; Cox survival analysis was performed on death and relapse. Pericardial effusion (P < .001) and Eastern Cooperative Oncology Group (ECOG) performance status > or = 2 (P = .009) predicted nonresponse (NR) and affected survival. Less than partial midway response to CHT predicted NR to subsequent therapies. Bulky disease was related to persistent mediastinal abnormality and risk of relapse (P = .025).



MBL is an aggressive NHL with unique clinicopathologic aspects, often refractory to current CHT designed for high-grade NHL. Poor performance status and pericardial effusion predict NR and poor survival. Inadequate response after the first courses of front-line CHT predicts failure of subsequent treatment. Responders with bulky mediastinum or residual mediastinal abnormality after CHT are at risk of relapse. These factors should help to select high-risk patients for intensive treatments.

title: PD-1/CTLA-4 Blockade Inhibits Epstein-Barr Virus-Induced Lymphoma Growth in a Cord Blood Humanized-Mouse Model
abstract: Epstein-Barr virus (EBV) infection causes B cell lymphomas in humanized mouse models and contributes to a variety of different types of human lymphomas. T cells directed against viral antigens play a critical role in controlling EBV infection, and EBV-positive lymphomas are particularly common in immunocompromised hosts. We previously showed that EBV induces B cell lymphomas with high frequency in a cord blood-humanized mouse model in which EBV-infected human cord blood is injected intraperitoneally into NOD/LtSz-scid/IL2Rγnull (NSG) mice. Since our former studies showed that it is possible for T cells to control the tumors in another NSG mouse model engrafted with both human fetal CD34+ cells and human thymus and liver, here we investigated whether monoclonal antibodies that block the T cell inhibitory receptors, PD-1 and CTLA-4, enhance the ability of cord blood T cells to control the outgrowth of EBV-induced lymphomas in the cord-blood humanized mouse model. We demonstrate that EBV-infected lymphoma cells in this model express both the PD-L1 and PD-L2 inhibitory ligands for the PD-1 receptor, and that T cells express the PD-1 and CTLA-4 receptors. Furthermore, we show that the combination of CTLA-4 and PD-1 blockade strikingly reduces the size of lymphomas induced by a lytic EBV strain (M81) in this model, and that this anti-tumor effect requires T cells. PD-1/CTLA-4 blockade markedly increases EBV-specific T cell responses, and is associated with enhanced tumor infiltration by CD4+ and CD8+ T cells. In addition, PD-1/CTLA-4 blockade decreases the number of both latently, and lytically, EBV-infected B cells. These results indicate that PD-1/CTLA-4 blockade enhances the ability of cord blood T cells to control outgrowth of EBV-induced lymphomas, and suggest that PD-1/CTLA-4 blockade might be useful for treating certain EBV-induced diseases in humans.

title: Nivolumab plus ipilimumab in advanced melanoma.
abstract: In patients with melanoma, ipilimumab (an antibody against cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4]) prolongs overall survival, and nivolumab (an antibody against the programmed death 1 [PD-1] receptor) produced durable tumor regression in a phase 1 trial. On the basis of their distinct immunologic mechanisms of action and supportive preclinical data, we conducted a phase 1 trial of nivolumab combined with ipilimumab in patients with advanced melanoma.



We administered intravenous doses of nivolumab and ipilimumab in patients every 3 weeks for 4 doses, followed by nivolumab alone every 3 weeks for 4 doses (concurrent regimen). The combined treatment was subsequently administered every 12 weeks for up to 8 doses. In a sequenced regimen, patients previously treated with ipilimumab received nivolumab every 2 weeks for up to 48 doses.



A total of 53 patients received concurrent therapy with nivolumab and ipilimumab, and 33 received sequenced treatment. The objective-response rate (according to modified World Health Organization criteria) for all patients in the concurrent-regimen group was 40%. Evidence of clinical activity (conventional, unconfirmed, or immune-related response or stable disease for ≥24 weeks) was observed in 65% of patients. At the maximum doses that were associated with an acceptable level of adverse events (nivolumab at a dose of 1 mg per kilogram of body weight and ipilimumab at a dose of 3 mg per kilogram), 53% of patients had an objective response, all with tumor reduction of 80% or more. Grade 3 or 4 adverse events related to therapy occurred in 53% of patients in the concurrent-regimen group but were qualitatively similar to previous experience with monotherapy and were generally reversible. Among patients in the sequenced-regimen group, 18% had grade 3 or 4 adverse events related to therapy and the objective-response rate was 20%.



Concurrent therapy with nivolumab and ipilimumab had a manageable safety profile and provided clinical activity that appears to be distinct from that in published data on monotherapy, with rapid and deep tumor regression in a substantial proportion of patients. (Funded by Bristol-Myers Squibb and Ono Pharmaceutical; ClinicalTrials.gov number, NCT01024231.).

title: First‐Line Atezolizumab plus Chemotherapy in Extensive‐Stage Small‐Cell Lung Cancer
abstract: Enhancing tumor‐specific T‐cell immunity by inhibiting programmed death ligand 1 (PD‐L1)–programmed death 1 (PD‐1) signaling has shown promise in the treatment of extensive‐stage small‐cell lung cancer. Combining checkpoint inhibition with cytotoxic chemotherapy may have a synergistic effect and improve efficacy.  We conducted this double‐blind, placebo‐controlled, phase 3 trial to evaluate atezolizumab plus carboplatin and etoposide in patients with extensive‐stage small‐cell lung cancer who had not previously received treatment. Patients were randomly assigned in a 1:1 ratio to receive carboplatin and etoposide with either atezolizumab or placebo for four 21‐day cycles (induction phase), followed by a maintenance phase during which they received either atezolizumab or placebo (according to the previous random assignment) until they had unacceptable toxic effects, disease progression according to Response Evaluation Criteria in Solid Tumors, version 1.1, or no additional clinical benefit. The two primary end points were investigator‐assessed progression‐free survival and overall survival in the intention‐to‐treat population.  A total of 201 patients were randomly assigned to the atezolizumab group, and 202 patients to the placebo group. At a median follow‐up of 13.9 months, the median overall survival was 12.3 months in the atezolizumab group and 10.3 months in the placebo group (hazard ratio for death, 0.70; 95% confidence interval [CI], 0.54 to 0.91; P=0.007). The median progression‐free survival was 5.2 months and 4.3 months, respectively (hazard ratio for disease progression or death, 0.77; 95% CI, 0.62 to 0.96; P=0.02). The safety profile of atezolizumab plus carboplatin and etoposide was consistent with the previously reported safety profile of the individual agents, with no new findings observed.  The addition of atezolizumab to chemotherapy in the first‐line treatment of extensive‐stage small‐cell lung cancer resulted in significantly longer overall survival and progression‐free survival than chemotherapy alone. (Funded by F. Hoffmann–La Roche/Genentech;

title: Interim results of brentuximab vedotin in combination with nivolumab in patients with relapsed or refractory Hodgkin lymphoma.
abstract: In this phase 1/2 study, brentuximab vedotin (BV) and nivolumab (Nivo) administered in combination were evaluated as initial salvage therapy in patients with relapsed or refractory (R/R) classical Hodgkin lymphoma (HL). Patients received up to 4 cycles of combination treatment, with BV administered on day 1 and Nivo on day 8 of the first cycle. For cycles 2 to 4, BV and Nivo were both administered on day 1. After study treatment, responses were evaluated by investigators per the 2014 Lugano classification, and patients could proceed to autologous stem cell transplantation (ASCT). Sixty-two patients were enrolled; the complete response rate among all treated patients (n = 61) was 61%, with an objective response rate of 82%. Before ASCT, adverse events (AEs) occurred in 98% of patients, mostly grades 1 and 2. Infusion-related reactions (IRRs) occurred in 44% of patients overall, with 41% of patients experiencing an IRR during at least 1 infusion of BV. Five patients (8%) were treated with systemic steroids for immune-related AEs. A reduction of peripheral T-cell subsets including regulatory T cells was observed after the first dose of BV, and reduced serum levels of thymus- and activation-regulated chemokine concurrent with an increase in proinflammatory cytokines and chemokines were seen after the first BV plus Nivo infusions. The combination of BV plus Nivo was an active and well-tolerated first salvage regimen, potentially providing patients with R/R HL an alternative to traditional chemotherapy.

title: 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.
abstract: Malignant cells of classical Hodgkin's lymphoma are characterised by genetic alterations at the 9p24.1 locus, leading to overexpression of PD-1 ligands and evasion of immune surveillance. In a phase 1b study, nivolumab, a PD-1-blocking antibody, produced a high response in patients with relapsed and refractory classical Hodgkin's lymphoma, with an acceptable safety profile. We aimed to assess the clinical benefit and safety of nivolumab monotherapy in patients with classical Hodgkin's lymphoma after failure of both autologous stem-cell transplantation and brentuximab vedotin.



In this ongoing, single-arm phase 2 study, adult patients (aged ≥18 years) with recurrent classical Hodgkin's lymphoma who had failed to respond to autologous stem-cell transplantation and had either relapsed after or failed to respond to brentuximab vedotin, and with an Eastern Cooperative Oncology Group performance status score of 0 or 1, were enrolled from 34 hospitals and academic centres across Europe and North America. Patients were given nivolumab intravenously over 60 min at 3 mg/kg every 2 weeks until progression, death, unacceptable toxicity, or withdrawal from study. The primary endpoint was objective response following a prespecified minimum follow-up period of 6 months, assessed by an independent radiological review committee (IRRC). All patients who received at least one dose of nivolumab were included in the primary and safety analyses. 
Among 80 treated patients recruited between Aug 26, 2014, and Feb 20, 2015, the median number of previous therapies was four (IQR 4-7). At a median follow-up of 8·9 months (IQR 7·8-9·9), 53 (66·3%, 95% CI 54·8-76·4) of 80 patients achieved an IRRC-assessed objective response. The most common drug-related adverse events (those that occurred in ≥15% of patients) included fatigue (20 [25%] patients), infusion-related reaction (16 [20%]), and rash (13 [16%]). The most common drug-related grade 3 or 4 adverse events were neutropenia (four [5%] patients) and increased lipase concentrations (four [5%]). The most common serious adverse event (any grade) was pyrexia (three [4%] patients). Three patients died during the study; none of these deaths were judged to be treatment related.



Nivolumab resulted in frequent responses with an acceptable safety profile in patients with classical Hodgkin's lymphoma who progressed after autologous stem-cell transplantation and brentuximab vedotin. Therefore, nivolumab might be a new treatment option for a patient population with a high unmet need. Ongoing follow-up will help to assess the durability of response.



Bristol-Myers Squibb.

title: Results of a pivotal phase II study of brentuximab vedotin for patients with relapsed or refractory Hodgkin's lymphoma.
abstract: Brentuximab vedotin is an antibody-drug conjugate (ADC) that selectively delivers monomethyl auristatin E, an antimicrotubule agent, into CD30-expressing cells. In phase I studies, brentuximab vedotin demonstrated significant activity with a favorable safety profile in patients with relapsed or refractory CD30-positive lymphomas.



In this multinational, open-label, phase II study, the efficacy and safety of brentuximab vedotin were evaluated in patients with relapsed or refractory Hodgkin's lymphoma (HL) after autologous stem-cell transplantation (auto-SCT). Patients had histologically documented CD30-positive HL by central pathology review. A total of 102 patients were treated with brentuximab vedotin 1.8 mg/kg by intravenous infusion every 3 weeks. In the absence of disease progression or prohibitive toxicity, patients received a maximum of 16 cycles. The primary end point was the overall objective response rate (ORR) determined by an independent radiology review facility.



The ORR was 75% with complete remission (CR) in 34% of patients. The median progression-free survival time for all patients was 5.6 months, and the median duration of response for those in CR was 20.5 months. After a median observation time of more than 1.5 years, 31 patients were alive and free of documented progressive disease. The most common treatment-related adverse events were peripheral sensory neuropathy, nausea, fatigue, neutropenia, and diarrhea.



The ADC brentuximab vedotin was associated with manageable toxicity and induced objective responses in 75% of patients with relapsed or refractory HL after auto-SCT. Durable CRs approaching 2 years were observed, supporting study in earlier lines of therapy.

title: A Phase 1 Study of Nivolumab in Combination with Ipilimumab for Relapsed or Refractory Hematologic Malignancies (CheckMate 039)
abstract: Nivolumab (nivo) is a fully human IgG4 monoclonal antibody (mAb) targeting programmed death receptor-1 (PD-1). Nivo has demonstrated clinical activity and an acceptable safety profile in a phase 1b study (NCT01592370; CheckMate 039) in patients (pts) with relapsed/refractory hematologic malignancies. In pts diagnosed with Hodgkin lymphoma (HL), after a median 86 weeks of follow-up, 7/20 responders maintained a response for >1.5 years (Ansell S et al. Blood 2015;126:583), and after a median follow-up of 67 weeks, clinical activity (investigator-assessed objective response rate) was demonstrated in follicular lymphoma (FL; 40%), diffuse large B-cell lymphoma (DLBCL; 36%), mycosis fungoides (15%), and peripheral T-cell lymphoma (PTCL; 40%) (Lesokhin AM et al. J Clin Oncol 2016;34:2698). CheckMate 039 also included a cohort of pts who had received nivo in combination with ipilimumab (ipi), a fully human mAb targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4). Combination of CTLA-4 and PD-1 blockade has shown superior efficacy compared with nivo or ipi alone in preclinical studies and solid tumor malignancies (Wolchok JD et al.  Larkin JM et al.  2015;373:22; Antonia SJ et al. Lancet Oncol 2016;17:883). The aim of this cohort study was to evaluate the safety and efficacy of combined immune checkpoint blockade (nivo+ipi) in pts with the following hematologic malignancies: HL, B-cell non-Hodgkin lymphoma (B-NHL; FL and DLBCL), T-cell NHL (T-NHL; cutaneous T-cell lymphoma [CTCL] and PTCL]), and multiple myeloma (MM).  Nivo+ipi were given at 3 mg/kg IV and 1 mg/kg IV, respectively, every 3 weeks for 4 doses, followed by nivo monotherapy (3 mg/kg) every 2 weeks for up to 2 years. Pts with any of the above histologies, relapsed or refractory disease after ≥2 prior lines of therapy, and adequate organ function were included in the study. Prior systemic therapy may have included chemotherapy and autologous hematopoietic stem cell transplantation (auto-HSCT). Prior anti-PD-1 therapy and allogeneic (allo)-HSCT were not permitted. The primary endpoint was safety. Secondary endpoints included investigator-assessed objective response rate (ORR), best overall response, duration of response (DOR), and progression-free survival (PFS).  In total, 65 pts were treated with nivo+ipi (31 HL, 15 B-NHL, 11 T-NHL, 7 MM, and 1 with primary mediastinal B-cell lymphoma [PMBL] who was included in the overall safety cohort only). Median (range) number of prior systemic therapies was 4 (2, 10; HL), 3, (1, 16; B-NHL), 4 (1, 11; T-NHL), and 5 (2, 20; MM). Among patients with HL, only 13% (4/31) had prior auto-HSCT. 2 pts with HL and 1 with T-NHL proceeded to allo-HSCT after stopping study therapy. Across all cohorts, median follow-up was 11.4 months. 5 pts (8%) discontinued due to a drug-related adverse event (AE). The most common drug-related AEs of any grade were fatigue (17 pts [26%]), pyrexia (15 [23%]), and diarrhea (12 [18%]). 19 pts (29%) had a drug-related AE of grade ≥3. 31 pts (48%) had a serious AE. 24 pts (37%) died: HL 2 pts, B-NHL 11, T-NHL 6, MM 4, PMBL 1. Among those pts, 22 (34%) were from disease progression (HL 2 pts, B-NHL 10, T-NHL 5, MM 4, PMBL 1); no deaths were due to an AE. Clinical outcome data are presented (Table) .  These are the first reported data of combination checkpoint blockade therapy in hematologic malignancies. Overall, the combination of nivo+ipi in these heavily pretreated patients demonstrated a safety and efficacy profile similar to that previously reported for nivo monotherapy in HL, NHL, and MM. Additional follow-up may further clarify the role of ipi in this cohort of patients. In this predominantly transplant-naive group of patients with HL, the efficacy of nivo+ipi was similar to that seen in patients with relapsed/refractory HL treated with nivo alone.  Bayer Health Care Pharmaceuticals,  Traveling and Lodging- Food and Beverage; E.R. Squibb & Sons, LLC (Bristol Myers Squibb): Consultancy, Other: Travel and Lodging; Incyte Corporation: Consultancy;  Merck Sharp & Dohme Corporation: Consultancy, Other: Travel and Lodging; Pharmacyclics LLC,  Food and Beverage.  Cell Signaling: Honoraria; Bristol-  Seattle Genetics: Research Funding; Seattle Genetics,   Bristol- Research Funding, Speakers Bureau.  Bristol- Employment, Equity Ownership.

title: Brentuximab vedotin in relapsed primary mediastinal large B-cell lymphoma: results from a phase 2 clinical trial.
abstract: Primary mediastinal B cell lymphoma (PMBCL) is a rather infrequent aggressive lymphoma, putatively arising from a transformed thymic B cell. It accounts for <5% of all non-Hodgkin lymphomas and typically affects adolescents and young women in their third or fourth decade of life.[1][

title: Phase I study of a novel oral Janus kinase 2 inhibitor, SB1518, in patients with relapsed lymphoma: evidence of clinical and biologic activity in multiple lymphoma subtypes.
abstract: The Janus kinase 2/signal transducers and activators of transcription (JAK2/STAT) pathway plays an important role in the pathogenesis of hematologic malignancies. We conducted a phase I dose-finding and pharmacokinetic/pharmacodynamic study of SB1518, a potent JAK2 inhibitor, in patients with relapsed lymphoma.



Patients with relapsed or refractory Hodgkin or non-Hodgkin lymphoma of any type except Burkitt's or CNS lymphoma were enrolled. Patient cohorts received escalating doses of SB1518 orally once daily for 28-day cycles. Response was evaluated after 8 weeks.



Thirty-four patients received doses of 100 to 600 mg/d. The maximum tolerated dose was not reached. Treatment was well tolerated, with mostly grade 1 and 2 toxicities. Gastrointestinal toxicities were the most common treatment-related events. Cytopenias were infrequent and modest. Pharmacologically active concentrations were achieved at all doses. Dose-related linear increases in area under the concentration-time curve were seen on day 1, with no significant accumulation on day 15. Mean terminal half-life was 1 to 4 days, and mean time to peak concentration ranged from 5 to 9 hours. SB1518 inhibited JAK2 signaling at 4 hours postdose at all levels. Increases in fms-like tyrosine kinase-3 (FLT-3) ligand, reflecting FLT-3 inhibition, were seen in most patients. There were three partial responses (≥300 mg/d) and 15 patients with stable disease (SD), with most responses lasting longer than 2 months. Seven of 13 SDs had tumor reductions of 4% to 46%.



SB1518 has encouraging activity in relapsed lymphoma, providing the first proof-of-principle of the potential therapeutic value of targeting the JAK/STAT pathway in lymphoma in the clinical setting.

title: The Efficacy of JAK2 Inhibitor in Heavily Pretreated Classical Hodgkin Lymphoma: A Prospective Pilot Study of Ruxolitinib in Relapsed or Refractory Classical Hodgkin Lymphoma and Primary Mediastinal Large B-Cell Lymphoma
abstract: JAK2 expression and activity increased in classical Hodgkin lymphoma (HL) and primary mediastinal large B-cell lymphoma (PMBCL) because both of them were reported to have chromosome 9p24.1/JAK2 amplification. Thus, JAK2 has been suggested as a potential therapeutic target in both disease having similar clinical and genetic features, and a previous in vitro and in vivo study showed cHL and PMBCL with JAK2 amplification were sensitive to JAK2 inhibition. However, the efficacy of JAK2 inhibitor has never been evaluated in clinical trials with cHL and PMBCL patients. We performed a prospective pilot proof of concept study with JAK2 inhibitor, ruxolitinib in relapsed or refractory cHL and PMBCL to evaluate the effect of JAK2 inhibition.  This study enrolled only relapsed or refractory cHL and PMBCL. Subjects should experience at least two times of relapse or treatment failure before enrollment. We enrolled subjects who were more than 18 years and had at least one lesion of FDG-PET positive measureable disease. Ruxolitinib was administered orally at a dose of 20 mg twice a day of a 28-day cycle. Treatment cycles were repeated up to 16 cycles until disease progression or unacceptable toxicity occurred. The primary objective was to assess the overall disease control rate including the achievement of complete response (CR), partial response (PR) and stable disease (SD). Response evaluation was done according to the 2007 Cheson criteria, and the planned number of subjects was 20. Pathology review was done by the Korean Lymphoma Pathology Review Board after the enrollment was completed. The JAK2 amplification in tumor cells was independently analyzed by the Cancer Institute Hospital of Japanese Foundation for Cancer Research without clinical information. Details of the study were registered at ClinicalTrials.gov (NCT01965119).  We enrolled 20 patients (median age: 43, range: 19 - 76) including 14 cHL and 6 PMBCL between 2013 and 2015. The median number of prior therapies was four (range: 2 - 10). Eight patients underwent autologous stem cell transplantation, and ten patients received involved field radiotherapy during their treatment period. Four cHL (29%, 4/14) and four PMBCL (67%, 4/6) were primarily refractory to induction treatment. At the time of enrollment, 18 patients were refractory to salvage treatment, and two patients relapsed five years after their last treatment. The first response evaluation after the 2 nd cycle showed 40% (7/20) of overall disease control rate (1 CR, 6 PR, and 1 SD). However, one cHL case with PR was excluded from the analysis after the final diagnosis was changed to chronic active EBV infection by the pathology review board. The comparison between cHL and PMBCL showed more efficacy of ruxolitinib in cHL because all patients with PMBCL rapidly progressed after 1 st or 2 nd cycle whereas disease was controlled in seven patients with cHL (1 CR, 5 PR and 1 SD) out of 13 patients with cHL (54%, 7/13). Although the median number of treatment cycle of all patients was two (range: 1-10), six responders received on the average five cycles of treatment (range: 4-10), and the median duration of response was 5 months (range: 4 - 12+ months). The toxicity was manageable without any grade 3 or 4 hematologic and non-hematologic toxicity. Most non-hematologic toxicities including liver enzyme elevation and abdominal pain were grade 1 or 2. The analysis of JAK2 amplification by FISH was done in 9 patients whose tissue sample was available. Among three patients with high amplification (more than 10 signals), only one SD was observed whereas two patients achieved PR out of six cases with low or absent amplification.  The efficacy of ruxolitinib in heavily pretreated patients with relapsed or refractory cHL suggested JAK2 inhibition might be more effective for the treatment of cHL than PMBCL. A phase I/II study with larger study population should be warranted based on our results of pilot study.  Celltrion, Inc.: Consultancy, Honoraria.