Histone deacetylase inhibitors in Hodgkin lymphoma

Advances in Hodgkin's lymphoma pharmacotherapy: a focus on histone deacetylase inhibitors

INTRODUCTION

Classical Hodgkin lymphomas (cHL) usually have excellent cure rates. Yet, for patients with refractory or relapsed cHL, prognosis deteriorates as the disease becomes resistant to subsequent lines of therapies: autologous stem cell transplantation, brentuximab vedotin, and checkpoint inhibitors. Immune escape and drug resistance are hallmarks of Hodgkin Reed Sternberg cell survival, prompting the need for additional therapeutic strategies. Histone modification-based combination is an effective clinical strategy.

AREAS COVERED

In this review, we discuss the different histone deacetylase (HDAC) inhibitor molecules that have been developed and studied in cancer therapy with a focus on cHL. We review their preclinical and clinical activities both as single agents and in combination studies. Literature search was conducted in PubMed, Google Scholar, and ClinicalTrials.gov databases, using search terms 'Hodgkin lymphoma,' 'histone deacetylase inhibitor', and variations on such (e.g. 'HDAC' and individual drug names) in combination using operators 'AND,' 'OR,' and 'NOT' according to Boolean logic.

EXPERT OPINION

HDAC inhibitors alone will not be sufficient for the treatment of R/RcHL, but given their disease control capacity, synergistic interaction with currently approved drugs, and ability to overcome drug resistance, particularly PD-1 inhibitors, we believe that HDACinhibitors will eventually become incorporated into the treatment armamentarium of cHL.

Clinicopathological features and prediction values of HDAC1, HDAC2, HDAC3, and HDAC11 in classical Hodgkin lymphoma

Histone deacetylases (HDACs) are involved in multiple physical and pathological processes in classical Hodgkin lymphoma (cHL). The prognostic value of HDACs in cHL patients has not been discussed. The aim of the current study is to investigate the HDAC1, HDAC2, HDAC3, and HDAC11 expressions, and to evaluate the correlation of HDAC1, HDAC2, HDAC3, and HDAC11 expressions with the survival rate in cHL patients. We retrospectively analyzed clinicopathological data of 28 patients who were diagnosed with cHL between August 2002 and March 2010. Immunohistochemistry was used to detect the expression of HDAC1, HDAC2, HDAC3, and HDAC11 in these patients. The results showed that HDAC1, HDAC3, and HDAC11 were expressed at a higher level in Hodgkin Reed-Sternberg cells, whereas HDAC2 was expressed at a lower level in Hodgkin Reed-Sternberg cells. The expression of HDAC2 had a relationship with pathological type (P=0.012). There was also a correlation between the expression of HDAC11 and the erythrocyte sedimentation rate (P=0.054). Other clinicopathological parameters had no significant correlation with the expression of HDAC1, HDAC2, HDAC3, and HDAC11 in terms of survival (P>0.05). The 10-year total survival rate by Cox multivariate analysis, after taking into account all clinical and pathologic factors, showed that bulky disease retained significance (P=0.028). Higher expression of HDAC1 predicted shorter progression-free survival and overall survival (OS) in cHL patients (P<0.05, in both cases), and higher expression of HDAC11 might be correlated with lower OS (P=0.05). The study showed that the expressions of HDAC2 and HDAC11 have a particular relationship with the pathologic subtype. Increased expression of HDAC1 was correlated negatively with progression-free survival and OS, and increased expression of HDAC11 had a borderline relationship with the OS rate in patients with cHL.

BET bromodomain inhibitors and agonists of the beta-2 adrenergic receptor identified in screens for compounds that inhibit DUX4 expression in FSHD muscle cells

Background

Facioscapulohumeral dystrophy (FSHD) is a progressive muscle disease caused by mutations that lead to epigenetic derepression and inappropriate transcription of the double homeobox 4 (DUX4) gene in skeletal muscle. Drugs that enhance the repression of DUX4 and prevent its expression in skeletal muscle cells therefore represent candidate therapies for FSHD.

Methods

We screened an aggregated chemical library enriched for compounds with epigenetic activities and the Pharmakon 1600 library composed of compounds that have reached clinical testing to identify molecules that decrease DUX4 expression as monitored by the levels of DUX4 target genes in FSHD patient-derived skeletal muscle cell cultures.

Results

Our screens identified several classes of molecules that include inhibitors of the bromodomain and extra-terminal (BET) family of proteins and agonists of the beta-2 adrenergic receptor. Further studies showed that compounds from these two classes suppress the expression of DUX4 messenger RNA (mRNA) by blocking the activity of bromodomain-containing protein 4 (BRD4) or by increasing cyclic adenosine monophosphate (cAMP) levels, respectively.

Conclusions

These data uncover pathways involved in the regulation of DUX4 expression in somatic cells, provide potential candidate classes of compounds for FSHD therapeutic development, and create an important opportunity for mechanistic studies that may uncover additional therapeutic targets.

Electronic supplementary material

The online version of this article (doi:10.1186/s13395-017-0134-x) contains supplementary material, which is available to authorized users.

Advances in the pathophysiology and treatment of relapsed/refractory Hodgkin's lymphoma with an emphasis on targeted therapies and transplantation strategies

Hodgkin’s lymphoma (HL) is highly curable with first-line therapy. However, a minority of patients present with refractory disease or experience relapse after completion of frontline treatment. These patients are treated with salvage chemotherapy followed by autologous stem cell transplantation (ASCT), which remains the standard of care with curative potential for refractory or relapsed HL. Nevertheless, a significant percentage of such patients will progress after ASCT, and allogeneic hematopoietic stem cell transplantation remains the only curative approach in that setting. Recent advances in the pathophysiology of refractory or relapsed HL have provided the rationale for the development of novel targeted therapies with potent anti-HL activity and favorable toxicity profile, in contrast to cytotoxic chemotherapy. Brentuximab vedotin and programmed cell death-1-based immunotherapy have proven efficacy in the management of refractory or relapsed HL, whereas several other agents have shown promise in early clinical trials. Several of these agents are being incorporated with transplantation strategies in order to improve the outcomes of refractory or relapsed HL. In this review we summarize the current knowledge regarding the mechanisms responsible for the development of refractory/relapsed HL and the outcomes with current treatment strategies, with an emphasis on targeted therapies and hematopoietic stem cell transplantation.

Pembrolizumab in classical Hodgkin's lymphoma

Pembrolizumab is a humanized monoclonal antibody directed against programmed cell death protein 1 (PD-1), a key immune-inhibitory molecule expressed on T cells and implicated in CD4+ T-cell exhaustion and tumor immune-escape mechanisms. Classical Hodgkin's lymphoma (cHL) is a unique B-cell malignancy in the sense that malignant Reed-Sternberg (RS) cells represent a small percentage of cells within an extensive immune cell infiltrate. PD-1 ligands are upregulated on RS cells as a consequence of both chromosome 9p24.1 amplification and Epstein-Barr virus infection and by interacting with PD-1 promote an immune-suppressive effect. By augmenting antitumor immune response, pembrolizumab and nivolumab, another monoclonal antibody against PD-1, have shown significant activity in patients with relapsed/refractory cHL as well as an acceptable toxicity profile with immune-related adverse events that are generally manageable. In this review, we explore the rationale for targeting PD-1 in cHL, review the clinical trial results supporting the use of checkpoint inhibitors in this disease, and present future directions for investigation in which this approach may be used.

Histone deacetylase inhibitor givinostat: the small-molecule with promising activity against therapeutically challenging haematological malignancies

Histone acetyl transferases and histone deacetylases (HDACs) are counteracting epigenetic enzymes regulating the turnover of histone acetylation thereby regulating transcriptional events in a precise manner. Deregulation of histone acetylation caused by aberrant expression of HDACs plays a key role in tumour onset and progression making these enzymes as candidate targets for anticancer drugs and therapy. Small-molecules namely histone deacetylase inhibitors (HDACi) modulating the biological function of HDACs have shown multiple biological effects including differentiation, cell cycle arrest and apoptosis in tumour models. HDACi in general have been described in plethora of reviews with respect to various cancers. However, no review article is available describing thoroughly the role of inhibitor givinostat (ITF2357 or [6-(diethylaminomethyl) naphthalen-2-yl] methyl N-[4-(hydroxycarbamoyl) phenyl] carbamate) in haematological malignancies. Thus, the present review explores the intricate role of novel inhibitor givinostat in the defined malignancies including multiple myeloma, acute myelogenous leukaemia, Hodgkin's and non-Hodgkin's lymphoma apart from myeloproliferative neoplasms. The distinct molecular mechanisms triggered by this small-molecule inhibitor in these cancers to exert cytotoxic effect have also been dealt with. The article also highlights the combination strategy that can be used for enhancing the therapeutic efficiency of this inhibitor in the upcoming future.

Lymphocyte Depleted Hodgkin's Lymphoma Presented with Haemolytic Anemia: A Case Report and Literature Review

Hodgkin's lymphoma accounts for ten per cent of all lymphomas. Lymphomas represent the third most frequent neoplasia on a worldwide scale and constitute 3 % of malignant tumors. In the United States, there are about 8,000 new cases every year. This case report describes a case of lymphocyte-depletion Hodgkin's lymphoma (LDHL) manifested by anemia. LDHL is the least common of the types of Hodgkin's disease, comprising less than 1 % of all cases of this cancer. A 19-year-old Indian male presented with complaint of huge asymptomatic swelling in the right lateral part of neck since 8 months. All the lymph nodes of the right side submandibular, submental, cervical and axillary lymph nodes were rubbery in consistency, tender and were palpable. The CBC revealed hemoglobin of 7.4 gm/dL and ESR count was highly raised up to 125 mm/first hour. Direct Coomb's test detected multiple antibodies IgG type, which was consistent with the diagnosis of Haemolytic anemia. Ultrasonography of the neck showed enlarged discrete lymph nodes on the right side of the neck. For further evaluation patient was subject for ultrasonography of the abdomen which revealed there was of enlargement of both spleen and liver. Lymph node FNAC revealed classic LDHL. Anemia and swelling resolved after completion of chemotherapy with adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD) after 6 cycles. The literature review and our case report discuss the optimal management of this Hodgkin's lymphoma. To our knowledge, this is the first case of LDHL with Haemolytic Anemia treated with only ABVD regime.

Entinostat, a novel histone deacetylase inhibitor is active in B-cell lymphoma and enhances the anti-tumour activity of rituximab and chemotherapy agents

Histone deacetylases (HDACs) inhibitors are active in T-cell lymphoma and are undergoing pre-clinical and clinical testing in other neoplasms. Entinostat is an orally bioavailable class I HDAC inhibitor with a long half-life, which is under evaluation in haematological and solid tumour malignancies. To define the activity and biological effects of entinostat in B-cell lymphoma we studied its anti-tumour activity in several rituximab-sensitive or -resistant pre-clinical models. We demonstrated that entinostat is active in rituximab-sensitive cell lines (RSCL), rituximab-resistant cell lines (RRCL) and primary tumour cells isolated from lymphoma patients (n = 36). Entinostat exposure decreased Bcl-XL (BCL2L1) levels and induced apoptosis in cells. In RSCL and RRCL, entinostat induced p21 (CDKN1A) expression leading to G1 cell cycle arrest and exhibited additive effects when combined with bortezomib or cytarabine. Caspase inhibition diminished entinostat activity in some primary tumour cells suggesting that entinostat has dual mechanisms-of-action. In addition, entinostat increased the expression of CD20 and adhesion molecules. Perhaps related to these effects, we observed a synergistic activity between entinostat and rituximab in a lymphoma-bearing severe combined immunodeficiency (SCID) mouse model. Our data suggests that entinostat is an active HDAC inhibitor that potentiates rituximab activity in vivo and supports its further clinical development in B-cell lymphoma.

Phase 1 study of the oral histone deacetylase inhibitor abexinostat in patients with Hodgkin lymphoma, non-Hodgkin lymphoma, or chronic lymphocytic leukaemia

Background We determined the safety, pharmacokinetics, pharmacodynamics, and antitumour activity of abexinostat in B-cell lymphoma or chronic lymphocytic leukaemia. Patients and methods Thirty-five patients received oral abexinostat 30, 45, or 60 mg/m(2) bid in a 3 + 3 design in three 21-day schedules: 14 days on treatment in schedule 1 (D1-14); 10 days in schedule 2 (D1-5 and D8-12); and 12 days in schedule 3 (D1-4, D8-11, and D15-18). Safety, tumour response, plasma concentration, and histone H3 acetylation were measured. Results Two dose-limiting toxicities occurred in each schedule (one grade 3 febrile neutropenia; five grade 4 thrombocytopenia) at 60 mg/m(2) bid (maximal tolerated dose). The recommended dose was 45 mg/m(2) bid; schedule 1 was considered optimal. Non-haematological drug-related toxicities included grade 1 or 2 diarrhoea (43%), nausea (23%), and vomiting (11%); haematological toxicities included thrombocytopenia (31% grade 3, and 26% grade 4), which remained manageable and reversible on withdrawal. Of 29 evaluable patients, there were 2 complete and 6 partial responses; median duration of response was 14.6 months (range 3-16.5 months) (1 cycle is equivalent to 0.75 months). There was no evidence for nonlinear pharmacokinetics. There was a correlation between dose and histone acetylation. Conclusion Abexinostat has manageable toxicity and induced some durable complete and partial responses in B-cell lymphoma or chronic lymphocytic leukaemia. Our results suggest most favourable responses in patients with follicular lymphoma, though further research would be needed to confirm this finding.

Expression of histone deacetylases in diffuse large B-cell lymphoma and its clinical significance

BACKGROUND

Histone deacetylase inhibitors are a new class of drugs used in treatment of malignant tumors. Diffuse large B-cell lymphoma (DLBCL) is the most common type of B-cell lymphoma, and it accounts for more than 40% of all B-cell lymphomas. In this study, we aimed to determine the expression patterns of histone deacetylases (HDACs) in DLBCL, to examine whether HDAC expression patterns differ among cases, and to assess whether these findings have clinical significance.

MATERIALS AND METHODS

We selected 91 cases of DLBCL diagnosed at St. Vincent Hospital, The Catholic University of Korea, from 2001-2012. We performed a pathology slide review and collected clinical data including age, sex, tumor site, survival time, and mortality. Immunohistochemical analysis was performed using primary antibodies for HDACs, including HDAC1 and 2 of class I, HDAC4 and 5 of class IIa, and HDAC6 of class IIb. Expression site was determined to be nuclear, cytoplasmic, or both. Staining intensities were graded as low and high. We assessed correlations between HDAC expression levels and clinical data and survival analysis.

RESULTS

Of the 91 cases examined, 46 (50.5%) were men and 45 (49.5%) were women. Most of the patients were elderly, and 74 (81.3%) cases were older than 46 y. Forty-six (50.5%) cases showed lymph node involvement, and 45 (49.5%) cases showed lymphoma at extranodal sites. In nodal lymphoma, staining was strongly positive for HDAC2, whereas staining was weak or negative for HDAC4; however, there was no significant correlation with survival. But nodal lymphoma cases with high nuclear expression of HDAC2 and nodal lymphoma cases with high nuclear expression of HDAC2 and low nuclear expression of HDAC4 showed significantly shorter survival times compared with other cases.

CONCLUSIONS

High nuclear expression of HDAC2 may play an important role in survival of DLBCL patients, especially in those with nodal lymphoma, which is associated with a shorter survival time. Our results may have important implications for treatment of DLBCL by epigenetic regulation.

Histone deacetylase inhibition: an important mechanism in the treatment of lymphoma

Lymphomas encompass a group of malignancies that originate in the lymph nodes or other lymphoid tissues. Epigenetic modification, especially by histone deacetylase (HDACs), plays a key role during the occurrence and development of lymphomas. Consequently, HDAC inhibitors (HDACIs), a class of gene expression-modulating drugs, have emerged as promising mechanism-based agents for the treatment of lymphomas. This review presents the rationale of HDAC inhibition, describes the epigenetic-based mechanisms of action of HDACIs, discusses their clinical efficiency, and summarizes the current and future developments in this field.

Outcome of autologous stem-cell transplantation in relapsed or refractory Hodgkin lymphoma patients in a centre from Turkey

PURPOSE

The aim of this study is to assess the predictors of outcome in patients with relapsed or refractory Hodgkin's lymphoma (HL) receiving autologous stem-cell transplantation (ASCT) MATERIALS AND METHODS: Fifty-two consecutive patients who received ASCT at the Stem Cell Transplantation Unit of Gazi University Hospital from February 2005 through June 2011 for relapsed or refractory HL were analysed retrospectively

RESULTS

Fifty-one patients could be evaluated after transplantation, as one of the patients died in the early post-transplantation period. Complete remission was obtained in 36 (71%), partial remission in 9 (18%), stable disease in 4 (8%), and progressive disease in 2 (3%) patients. After a median follow-up of 22 (range, 0.5-75) months, 46 (88%) patients were alive. The probability of overall survival (OS), progression free survival (PFS) and transplantation related mortality at 5 years were 87, 53, and 2%, respectively. Chemosensitive relapse had a positive impact on both OS and PFS CONCLUSION: ASCT remains to be the standard treatment of relapsed or refractory HL patients. Chemosensitive relapse is the most important prognostic factor determining the outcome of the ASCT.

Role of immune escape mechanisms in Hodgkin's lymphoma development and progression: a whole new world with therapeutic implications

Hodgkin's lymphoma represents one of the most frequent lymphoproliferative syndromes, especially in young population. Although HL is considered one of the most curable tumors, a sizeable fraction of patients recur after successful upfront treatment or, less commonly, are primarily resistant. This work tries to summarize the data on clinical, histological, pathological, and biological factors in HL, with special emphasis on the improvement of prognosis and their impact on therapeutical strategies. The recent advances in our understanding of HL biology and immunology show that infiltrated immune cells and cytokines in the tumoral microenvironment may play different functions that seem tightly related with clinical outcomes. Strategies aimed at interfering with the crosstalk between tumoral Reed-Sternberg cells and their cellular partners have been taken into account in the development of new immunotherapies that target different cell components of HL microenvironment. This new knowledge will probably translate into a change in the antineoplastic treatments in HL in the next future and hopefully will increase the curability rates of this disease.

Apoptosis induction by SAHA in cutaneous T-cell lymphoma cells is related to downregulation of c-FLIP and enhanced TRAIL signaling

Suberoylanilide hydroxamic acid (SAHA) has been approved for the treatment of cutaneous T-cell lymphoma (CTCL), but its mode of action remained largely elusive. As shown here in four CTCL cell lines, loss of cell viability correlated with significant time- and dose-dependent induction of apoptosis, whereas cytotoxicity was less pronounced. Both extrinsic and intrinsic apoptosis pathways were activated, as seen by processing of initiator caspases 8 and 9, loss of mitochondrial membrane potential, and cytochrome c release. Characteristically, antiapoptotic mediators such as Mcl-1, XIAP, survivin, and c-FLIP were downregulated. Consistent with its critical function, c-FLIP overexpression resulted in a significant decrease of SAHA-mediated apoptosis. Enhanced sensitivity to TRAIL (TNF-related apoptosis-inducing ligand) and enhanced TRAIL signaling was seen in CTCL cell lines with high sensitivity, whereas cell lines with moderate response were characterized by downregulation of TRAIL-R2 and weaker TRAIL expression. Comparable proapoptotic responses to SAHA and to the combination with TRAIL were seen in ex vivo tumor T cells of CTCL patients. Thus, activation of extrinsic apoptosis pathways, related to c-FLIP downregulation and enhanced TRAIL signaling, appeared as characteristic for CTCL cell responsiveness to SAHA. An improved understanding of the pathways may facilitate its targeted use and the selection of suitable combinations.

Mocetinostat for relapsed classical Hodgkin's lymphoma: an open-label, single-arm, phase 2 trial

BACKGROUND

The prognosis of patients with relapsed Hodgkin's lymphoma, especially those who relapse after stem-cell transplantation, is poor, and the development of new agents for this patient population is an unmet medical need. We tested the safety and efficacy of mocetinostat, an oral isotype-selective histone deacetylase inhibitor, in patients with relapsed classical Hodgkin's lymphoma.

METHODS

Patients with relapsed or refractory classical Hodgkin's lymphoma aged 18 years or older were treated with mocetinostat administered orally three times per week, in 28-day cycles. Two doses were assessed (85 mg and 110 mg). Patients were treated until disease progression or prohibitive toxicity. The primary outcome was disease control rate, defined as complete response, partial response, or stable disease (for at least six cycles), analysed by intention to treat. This trial has been completed and is registered with ClinicalTrials.gov, number NCT00358982.

FINDINGS

51 patients were enrolled. Initially, 23 patients were enrolled in the 110 mg cohort. Subsequently, because toxicity-related dose reductions were necessary in the 110 mg cohort, we treated 28 additional patients with a dose of 85 mg. On the basis of intent-to-treat analysis, the disease control rate was 35% (eight of 23 patients) in the 110 mg group and 25% (seven of 28) in the 85 mg group. 12 patients (24%) discontinued treatment because of adverse events, nine (32%) in the 85 mg cohort and three (13%) in the 110 mg cohort. The most frequent treatment-related grade 3 and 4 adverse events were neutropenia (four patients [17%] in the 110 mg group, three [11%] in the 85 mg group); fatigue (five patients [22%] in the 110 mg group, three [11%] in the 85 mg group); and pneumonia (four patients [17%] in the 110 mg group, two [7%] in the 85 mg group). Four patients, all in the 110 mg cohort, died during the study, of which two might have been related to treatment.

INTERPRETATION

Mocetinostat, 85 mg three times per week, has promising single-agent clinical activity with manageable toxicity in patients with relapsed classical Hodgkin's lymphoma.

FUNDING

MethylGene Inc, Montreal, Canada; Celgene Corporation, Summit, NJ, USA; Tufts Medical Center, Boston, MA, USA.

Lymphocyte Rich Hodgkin's Lymphoma Presented with Warm Hemolytic Anemia: A Case Report and Literature Review

Hodgkin's lymphoma accounts for ten percent of all lymphomas. In the United States, there are about 8000 new cases every year. This paper describes a case of lymphocyte-rich Hodgkin's lymphoma (LRHL) manifested by autoimmune hemolytic anemia (AIHA). A 27-year-old Israeli male presented with dizziness associated with one month of low-grade fevers and night sweats; he also complained of persistent cough, pruritus, and ten-pound weight lost during this time. The CBC revealed hemoglobin of 5.9 gm/dL, and direct Coomb's test detected multiple nonspecific antibodies consistent with the diagnosis of AIHA. Chest, abdomen, and pelvic CT scan showed mediastinal lymphadenopathy and splenomegaly. Lymph node biopsy revealed classic LRHL. AIHA resolved after completion of the first cycle of chemotherapy with adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD); after six cycles, he went into complete remission. Although infrequent, AIHA can be responsible for the presenting symptoms of HL.

Evolving insights in the pathogenesis and therapy of cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome)

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of malignancies derived from skin-homing T cells. The most common forms of CTCL are Mycosis Fungoides (MF) and Sezary Syndrome (SS). Accurate diagnosis remains a challenge due to the heterogeneity of presentation and the lack of highly characteristic immunophenotypical and genetic markers. Over the past decade molecular studies have improved our understanding of the biology of CTCL. The identification of gene expression differences between normal and malignant T-cells has led to promising new diagnostic and prognostic biomarkers that now need validation to be incorporated into clinical practice. These biomarkers may also provide insight into the mechanism of development of CTCL. Additionally, treatment options have expanded with the approval of new agents, such as histone deacetylase inhibitors. A better understanding of the cell biology, immunology and genetics underlying the development and progression of CTCL will allow the design of more rational treatment strategies for these malignancies. This review summarizes the clinical epidemiology, staging and natural history of MF and SS; discusses the immunopathogenesis of MF and the functional role of the malignant T-cells; and reviews the latest advances in MF and SS treatment.