How I treat the peripheral T-cell lymphomas

Baseline and interim functional imaging with PET effectively risk stratifies patients with peripheral T-cell lymphoma

The prognosis of peripheral T-cell lymphoma (PTCL) is heterogenous. Baseline or interim imaging characteristics may inform risk-adapted treatment paradigms. We identified 112 patients with PTCL who were consecutively treated with cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP)/CHOP-like regimens with the intent to consolidate with an autologous transplant. Baseline (n = 93) and interim (after 4 cycles, n = 99) positron emission tomography (PET) images were reevaluated, and we calculated baseline total metabolic tumor volume (TMTV). Interim PET (iPET) responses were graded visually by 5-point score (i5PS) and by percentage change of standardized uptake value. By univariate analysis, predictors of event-free survival (EFS) included Prognostic Index for Peripheral TCL (PIT) higher than 1 (hazard ratio [HR], 1.83; P = .021), International Prognostic Index (IPI) higher than 3 (HR, 2.01; P = .021), high TMTV (>125 cm³; HR, 3.92; P = .003), and positive iPET (HR, 3.57; P < .001). By multivariate analysis, high baseline TMTV predicted worse overall survival (OS; HR, 6.025; P = .022) and EFS (HR, 3.861; P = .005). Patients with i5PS of 1 to 3 had a longer median OS and EFS (104 months, 64 months) than those with i5PS of 4 to 5 (19 months, 11 months; P < .001). Four-year OS and EFS for patients with i5PS of 1 to 3 and PIT of 1 or less were 85% and 62%, respectively. However, 4-year OS and EFS for those with i5PS of 4 to 5 and PIT higher than 1 were both 0% (P < .001). In multivariate analysis, after controlling for IPI and PIT, i5PS was independently prognostic for EFS (HR, 3.400 95% confidence interval, 1.750-6.750; P < .001) and OS (HR, 10.243; 95% confidence interval, 4.052-25.891; P < .001). In conjunction with clinical parameters, iPET helps risk stratify patients with PTCL and could inform risk-adapted treatment strategies. Prospective studies are needed to confirm these findings.

Pralatrexate in patients with recurrent or refractory peripheral T-cell lymphomas: a multicenter retrospective analysis

Peripheral T-cell lymphomas (PTCL) are a heterogeneous group of non-Hodgkin’s lymphomas with poor clinical outcomes. Pralatrexate showed efficacy and safety in recurrent or refractory PTCLs. The purpose or this study was to investigate the efficacy and safety of pralatrexate in relapsed or refractory PTCLs in real-world practice. This was an observational, multicenter, retrospective analysis. Between December 2012 and December 2016, a total of 38 patients with relapsed or refractory PTCLs were treated with pralatrexate at 10 tertiary hospitals in Korea. Patients received an intravenous infusion of pralatrexate at a dose of 30 mg/m²/week for 6 weeks on a 7-week schedule. Modified dosing and/or scheduling was allowed according to institutional protocols. Median patient age was 58 years (range, 29–80 years) and the most common subtype was peripheral T-cell lymphoma, not otherwise specified (n = 23, 60.5%). The median dosage of pralatrexate per administration was 25.6 mg/m²/wk (range, 15.0–33.0 mg/m²/wk). In intention-to-treat analysis, 3 patients (7.9%) showed a complete response and 5 patients (13.2%) showed a partial response, resulting in an overall response rate (ORR) of 21.1%. The median duration of response was 7.6 months (range, 1.6–24.3 months). The median progression-free survival (PFS) was 1.8 months (95% confidence interval [CI], 1.7–1.8 months) and the median overall survival was 7.7 months (95% CI, 4.4–9.0 months). The most common grade 3/4 adverse events were thrombocytopenia (n = 13, 34.2%), neutropenia (n = 7, 23.7%), and anemia (n = 7, 18.4%). Our study showed relatively lower ORR and shorter PFS in patients with recurrent or refractory PTCLs treated with pralatrexate in real-world practice. The toxicity profile was acceptable and manageable. We also observed significantly lower dose intensity of pralatrexate in real-world practice.

Diagnostic delay in a case of T-cell neurolymphomatosis

A 69-year-old woman presented with severe subacute painful meningoradiculoneuritis. Neurophysiology showed a patchy, proximal axonal process with widespread denervation. Cerebrospinal fluid (CSF) was lymphocytic (normal T-cell predominant) with negative cytology. MRI revealed multiple sites of enhancement, but fluorodeoxyglucose positron emission tomography was negative. Bone marrow aspirate and trephine (BMAT) showed no evidence of a lymphoproliferative condition. Right brachial plexus biopsy demonstrated mixed T-cell/B-cell endoneurial inflammation not fulfilling criteria for vasculitis. She was stabilised with high-dose steroids and cyclophosphamide, followed by mycophenolate for inflammatory myeloradiculoneuritis. However, symptoms recurred when prednisolone was weaned. Although T-cell receptor gene analysis from the initial CSF demonstrated clonal rearrangements, it was only when the same clones were identified on two repeat BMATs and CSF that T-cell neurolymphomatosis, an exceedingly rare condition, was diagnosed. This case highlights the diagnostic challenge in peripheral neurolymphomatosis related to patchy disease, variable sensitivity and specificity of investigative tools, and the influence of therapies on traditional cytological definitions of lymphoma. The clinical picture, exhaustive exclusion of alternative causes and the persistence of an abnormal T-cell clone ultimately lead to a diagnostic consensus between specialist neurology and haematology clinicians.

Reproducing the molecular subclassification of peripheral T-cell lymphoma-NOS by immunohistochemistry

Peripheral T-cell lymphoma (PTCL) is a heterogeneous group of mature T-cell malignancies; approximately one-third of cases are designated as PTCL-not otherwise specified (PTCL-NOS). Using gene-expression profiling (GEP), we have previously defined 2 major molecular subtypes of PTCL-NOS, PTCL-GATA3 and PTCL-TBX21, which have distinct biological differences in oncogenic pathways and prognosis. In the current study, we generated an immunohistochemistry (IHC) algorithm to identify the 2 subtypes in paraffin tissue using antibodies to key transcriptional factors (GATA3 and TBX21) and their target proteins (CCR4 and CXCR3). In a training cohort of 49 cases of PTCL-NOS with corresponding GEP data, the 2 subtypes identified by the IHC algorithm matched the GEP results with high sensitivity (85%) and showed a significant difference in overall survival (OS) (P = .03). The IHC algorithm classification showed high interobserver reproducibility among pathologists and was validated in a second PTCL-NOS cohort (n = 124), where a significant difference in OS between the PTCL-GATA3 and PTCL-TBX21 subtypes was confirmed (P = .003). In multivariate analysis, a high International Prognostic Index score (3-5) and the PTCL-GATA3 subtype identified by IHC were independent adverse predictors of OS (P = .0015). Additionally, the 2 IHC-defined subtypes were significantly associated with distinct morphological features (P < .001), and there was a significant enrichment of an activated CD8+ cytotoxic phenotype in the PTCL-TBX21 subtype (P = .03). The IHC algorithm will aid in identifying the 2 subtypes in clinical practice, which will aid the future clinical management of patients and facilitate risk stratification in clinical trials.

The Role of PI3K Inhibition in Lymphoid Malignancies

PURPOSE OF REVIEW

The outcome of patients with lymphoid malignancies has markedly improved in recent years which is likely due to a combination of advances in supportive care, and therapeutic options. In this article, we will provide an overview over the role PI3-kinase signalling, one of the most important dysregulated pathways in cancer, and its successful inhibition in lymphoma.

RECENT FINDINGS

PI3-kinase inhibitors have shown remarkable activity in an increasing subset of patients with non-Hodgkin lymphomas. The first drug to be approved was idelalisib for patients with relapsed/refractory follicular lymphoma and CLL/SLL as monotherapy, or in combination with rituximab, respectively. After an initial setback related to increased toxicity including deaths observed in several upfront studies, there has been a resurgence in interest in this pathway following the promising efficacy of second-generation PI3K inhibitors including in patients with T cell lymphomas. PI3K inhibition continues to be an invaluable tool in the therapy of patients with lymphoid malignancies if managed cautiously. Preclinical models are helpful in predicting possible side effects and identifying new lymphoma subtypes that may be susceptible to this class of agents. The future will likely involve rationally designed combinatorial approaches to deepen the response rate and prevent the emergence of resistance.

Cyclin-dependent kinase 7 inhibitor THZ1 in cancer therapy

Current cancer therapies have encountered adverse response due to poor therapeutic efficiency, severe side effects and acquired resistance to multiple drugs. Thus, there are urgent needs for finding new cancer-targeted pharmacological strategies. In this review, we summarized the current understanding with THZ1, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7), which demonstrated promising anti-tumor activity against different cancer types. By introducing the anti-tumor behaviors and the potential targets for different cancers, this review aims to provide more effective approaches to CDK7 inhibitor-based therapeutic agents and deeper insight into the diverse tumor proliferation mechanisms.

Proliferative, pro-inflammatory, and angiogenesis regulator gene expression profile defines prognosis in different histopathological subtypes of nodal peripheral T-cell lymphoma

Nodal peripheral T-cell lymphoma (PTCL) is an aggressive and heterogeneous malignancy with poor prognosis. We studied the prognostic impact of the expression profile of genes related to cell proliferation (CCNA2, TOP2A, and CHEK1), pro-inflammatory activity (NFkB1 and IKBkB), and angiogenesis (VEGF1) in nodal PTCL outcomes, as well as the ability of this genomic panel to discriminate different histological subtypes. We investigated the relative expression of regulator genes in 63 nodal PTCL patients. CCNA2, TOP2A, CHEK1, and NF-kB1 proteins were also assessed by immunohistochemistry. The median patient age was 47 years, 57.1% were male, 34.9% were diagnosed with PTCL-NOS, 28.6% with ALK-/ALCL, 22.2% with ALK+/ALCL, and 14.3% with AITL. The proliferative genes were associated with worse 3-year OS and PFS in PTCL-NOS and better 3-year PFS in ALK-/ALCL. Expression of CCNA2≥median and overexpression of CHEK1 protein (HR 3.793; p = 0.007) were associated with worse OS for all the cohort of nodal PTCL (HR 1.418; p = 0.001). The genomic expression profile tested in this study was not able to discriminate the different subtypes of nodal PTCL, although it showed a distinct prognostic significance between PTCL-NOS and ALCL-ALK. Overexpression of the CCNA2 gene and CHEK1 protein were associated with poor prognosis in the total nodal PTCL cohort.

The role of autologous stem cell transplantation in peripheral T cell lymphoma: a long-term follow-up single-center experience

PURPOSE

Peripheral T cell lymphomas (PTCL) are a rare and heterogeneous group of aggressive non-Hodgkin lymphomas, showing a generally poor prognosis. In this retrospective analysis, we aimed to investigate the impact of autologous stem cell transplantation (autoSCT) in PTCL.

METHODS

A retrospective analysis of 58 consecutive unselected PTCL patients aged 21-71 years undergoing autoSCT as first-line consolidation as well as in the relapse setting was performed.

RESULTS

The median follow-up time was 67 months. A 5-year overall survival (OS) of 53% and a 5-year progression-free survival (PFS) after autoSCT of 44% was achieved. The overall relapse rate after autoSCT was 50%. On multivariate analysis, standard baseline characteristics such as age, disease stage and international prognostic index (IPI) score failed to predict outcome in our cohort. First-line treatment with autoSCT was not associated with a benefit in OS when compared to patients receiving autoSCT at relapse. Notably, autoSCT seemed to be a suitable approach even for older transplant-eligible patients (aged ≥ 60 years), with a similar 5-year OS of 49% when compared to younger patients.

CONCLUSIONS

Our study suggests that autoSCT can achieve long-term survival in PTCL patients even after relapse and should also be considered for eligible older patients.

Outcomes for Relapsed and Refractory Peripheral T-Cell Lymphoma Patients after Front-Line Therapy from the COMPLETE Registry

BACKGROUND

Outcomes for patients with peripheral T-cell lymphoma (PTCL) who fail to achieve complete response (CR) or relapse after front-line therapy are poor with lack of prospective outcomes data.

OBJECTIVES

COMPLETE is a prospective registry of 499 patients enrolled at academic and community sites in the United States detailing patient demographics, treatment and outcomes for patients with aggressive T cell lymphomas. We report results for patients with primary refractory and relapsed disease.

METHODS

Primary refractory disease was defined as an evaluable best response to initial treatment (induction ± maintenance or consolidation/transplant) other than CR, and included a partial response, progressive disease, or no response/stable disease. Relapsed disease was defined as an evaluable best response to initial treatment of CR, followed by disease progression at a later date, irrespective of time to progression. Patients were included in the analysis if initial treatment began within 30 days of enrollment and treatment duration was ≥4 days.

RESULTS

Of 420 evaluable patients, 97 met the definition for primary refractory and 58 with relapsed disease. In the second-line setting, relapsed patients received single-agent therapies more often than refractory patients (52 vs. 28%; p = 0.01) and were more likely to receive single-agent regimens (74 vs. 53%; p = 0.03). The objective response rate to second-line therapy was higher in relapsed patients (61 vs. 40%; p = 0.04) as was the proportion achieving a CR (41 vs. 14%; p = 0.002). Further, relapsed patients had longer overall survival (OS) compared to refractory patients, with a median OS of 29.1 versus 12.3 months.

CONCLUSIONS

Despite the availability of newer active single agents, refractory patients were less likely to receive these therapies and continue to have inferior outcomes compared to those with relapsed disease. PTCL in the real world remains an unmet medical need, and improvements in front-line therapies are needed.

Prognostic factors and the impact of frontline therapy in peripheral T-cell lymphoma: 10 years of 'real-world' experience from Western Australia

We present an analysis of 98 consecutive patients with peripheral T-cell lymphoma (PTCL) treated over a 10-year period within Western Australia. The most common frontline therapies were CHO(E)P (47%), HyperCVAD (21%), and reduced intensity therapy or supportive care alone (19%). Median and 4-year overall survival (OS) for the whole cohort were 1.59 years and 34%. Amongst CHO(E)P and HyperCVAD-treated patients, elevated LDH, advanced stage, IPI >1, and non-ALK + ALCL histology predicted inferior progression-free survival (PFS). Inferior OS was predicted by elevated LDH, age >60, IPI >1, and non-ALK + ALCL histology. Response rates and PFS were not significantly different between patients treated with CHO(E)P or HyperCVAD. OS was longer in the HyperCVAD group, however this was not significant on multivariable analysis and appears to relate to the younger age and more aggressive therapy at relapse in this group. Our data confirmed the prognostic utility of the IPI in patients with PTCL and do not demonstrate a clear benefit of HyperCVAD.

Single agents vs combination chemotherapy in relapsed and refractory peripheral T-cell lymphoma: Results from the comprehensive oncology measures for peripheral T-cell lymphoma treatment (COMPLETE) registry

Single agents have demonstrated activity in relapsed and refractory (R/R) peripheral T-cell lymphoma (PTCL). Their benefit relative to combination chemotherapy remains undefined. Patients with histologically confirmed PTCL were enrolled in the Comprehensive Oncology Measures for Peripheral T-cell Lymphoma Treatment (COMPLETE) registry. Eligibility criteria included those with R/R disease who had received one prior systemic therapy and were given either a single agent or combination chemotherapy as first retreatment. Treatment results for those with R/R disease who received single agents were compared to those who received combination chemotherapy. The primary endpoint was best response to retreatment. Fifty-seven patients met eligibility criteria. At first retreatment, 46% (26/57) received combination therapy and 54.5% (31/57) received single agents. At median follow up of 2 years, a trend was seen towards increased complete response rate for single agents versus combination therapy (41% vs 19%; P = .02). There was also increased median overall survival (38.9 vs 17.1 months; P = .02) and progression-free survival (11.2 vs 6.7 months; P = .02). More patients receiving single agents received hematopoietic stem-cell transplantation (25.8% vs 7.7%, P = .07). Adverse events of grade 3 or 4 occurred more frequently in those receiving combination therapy, although this was not statistically significant. The data confirm the unmet need for better treatment in R/R PTCL. Despite a small sample, the analysis shows greater response and survival in those treated with single agents as first retreatment in R/R setting, while maintaining the ability to achieve transplantation. Large, randomized trials are needed to identify the best strategy.

Peripheral T-Cell Lymphoma: Moving Toward Targeted Therapies

Therapeutic advances for peripheral T-cell non-Hodgkin lymphoma (PTCL) have lagged behind their B-cell NHL counterparts in part because novel agents to treat PTCL have been developed empirically. The recent clinical success of brentuximab-vedotin suggests that novel therapies for PTCL can significantly improve outcomes when properly targeted. Aberrancies in T-cell receptor, Jak/STAT, and DNA methylation pathways play critical roles in T-NHL pathogenesis based on genomic studies and preclinical experimental validation. New strategies targeting these pathways in patients with PTCL are underway, and this clinical trial experience will possibly contribute to additional improvements in outcome for patients with these diseases.

Autologous transplantation as consolidation for high risk aggressive T-cell non-Hodgkin lymphoma: a SWOG 9704 intergroup trial subgroup analysis

Phase II data suggest a benefit to autotransplantation for aggressive T-cell non-Hodgkin lymphoma (T-NHL) in first remission; randomized trials have yet to validate this. We performed a retrospective analysis of aggressive T-NHL patients in the intergroup randomized consolidative autotransplant trial (SWOG 9704). Of the 370 enrolled, 40 had T-NHL: 12 were not randomized due to ineligibility (n = 1), choice (n = 2), or progression (n = 9), leaving 13 randomized to control and 15 to autologous stem cell transplantation (ASCT). Two ASCT patients refused transplant and one failed mobilization. The 5-year landmark PFS/OS estimates for ASCT vs. control groups were 40% vs. 38% (p = .56), and 40% vs. 45% (p = .98), respectively. No difference was seen based on IPI, or histologic subtype. Only 1/7 receiving BCNU-based therapy survived vs. 4/5 receiving TBI. Aggressive T-NHL autotransplanted in first remission did not appear to benefit from consolidative ASCT. This and the 30% who dropped out pre-randomization mostly to progression, suggests that improved induction regimens be developed.

Transplantation

Mature T-cell non-Hodgkin lymphomas (T-cell NHL) are a heterogeneous group of lymphoid malignancies including NK/T-cell lymphomas. Hematopoietic cell transplantation (HCT) is an important component of the management of T-cell NHL; however, the optimal timing and type of transplant for each different subtype is an ongoing debate. For the purpose of this chapter, PTCL will be classified as (1) systemic PTCL that includes nodal as well as non-nodal histologies in PTCL (2) CTCL-or cutaneous T-cell lymphomas that arise primarily in the skin and (3) NK/T-cell lymphomas both nasal and extranasal types. It is difficult to do any large trials in PTCL as they are rare diseases with variable clinical and biological characteristics and most patients are not transplant eligible due to various reasons including poor disease control. There are no randomized trials in transplant for PTCL but there is an experience based on retrospective as well as some well-designed prospective trials that have helped outline the role of HSCT in the treatment paradigm of PTCL. High-dose therapy and autologous HCT is recommended in first complete remission for most systemic (non-cutaneous) nodal subtypes, or peripheral T-cell lymphomas (PTCL). Autologous HCT can provide long-term remission for relapsed PTCL but is ineffective for refractory/chemoresistant disease. Allogeneic stem cell transplantation harnesses the graft-versus-lymphoma effect, providing long-term remission for relapsed PTCL. AlloHCT is also being used successfully to provide long-term disease control for advanced cutaneous T-cell lymphoma (CTCL). The use of transplant in NK/T-cell lymphoma is increasingly being recommended in the relapsed setting only as there are more effective treatments available for the upfront setting in limited stage disease.

Peripheral T-Cell Lymphoma, not Otherwise Specified (PTCL-NOS)

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) is a World Health Organization (WHO)-defined diagnostic category within the highly heterogeneous group of mature post-thymic T-cell neoplasms. It is the most common subtype of mature post-thymic T-cell neoplasms globally, accounting for up to 35% of PTCL cases in Europe and North America. PTCL-NOS is a diagnosis of exclusion, comprising several disease entities that differ in biology, clinical presentation, and outcome. The diagnosis of PTCL-NOS is made based on the presence of typical histopathological features of lymphoma, an aberrant T-cell immunophenotype, often with a loss of CD5 and CD7, and a clonal T-cell receptor (TCR) gene rearrangement, in the appropriate clinical context. Unlike other types of T-cell lymphoma, recurrent mutations to assist with the diagnosis have not been identified. Patients often present with advanced stage. Prognosis is poor, with a 5-year overall survival (OS) of 20-30%. Anthracycline-based combination chemotherapy remains the most frequently used frontline strategy, with overall response rates (ORR) of 50-60%, and complete response rates (CRR) of 20-30%. Prospective studies with intent-to-treat analyses have shown that consolidation with high-dose chemotherapy and autologous stem cell transplant (ASCT) results in progression-free survivals (PFS) that compare favorably with historical cohorts and may improve OS in selected patient populations. However, randomized data are still lacking. Over the past decade, therapeutic agents approved in the relapsed and refractory setting have produced response rates of up to 33% and median PFS up to 18 months. Overall, outcomes remain poor and there is a dire need for more effective treatments. This review discusses the latest information on the diagnosis and treatment of PTCL-NOS.

Angioimmunoblastic T-Cell Lymphoma

Angioimmunoblastic T-cell lymphoma (AITL) is one of the most common types of T-cell lymphoma, representing about 15-20% of cases of peripheral T-cell lymphoma (PTCL). It is characterized by a unique clinical presentation and distinct pathologic and molecular features. Classes of drugs particularly active in AITL are emerging; however, treatment of relapsed and refractory disease remains a challenge. This chapter reviews the epidemiology, clinical presentation, pathogenesis, diagnosis, and treatment of AITL.

Hematologic toxicity is rare in relapsed patients treated with belinostat: a systematic review of belinostat toxicity and safety in peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are an aggressive and diverse group of lymphomas with a T-cell origin. Most patients progress following initial treatment and require salvage therapy. The burden of symptoms is high due to its extra-nodal presentation, high rate of advanced disease, and associated cytopenias combined with its predilection for an elderly population. The disease is generally incurable at relapse in the absence of transplantation and treatment is aimed at prolonging life and reducing disease-related symptoms. Belinostat is a histone deacetylate inhibitor that was granted accelerated approval by the US Food and Drug Administration on July 3, 2014, for the treatment of relapsed PTCL. Here, a systemic review was conducted to assess the safety and efficacy of belinostat. A safety analysis involved 512 patients with relapsed malignancies, and an efficacy analysis focused on patients with relapsed PTCL and included a total of 144 patients. Common adverse events were noted including fatigue (35%), nausea (42.8%), and vomiting (28.5%), but comparatively low rates of grade 3/4 hematologic toxicity overall (6.4%). Efficacy analysis demonstrated an overall response rate of 25.7% and complete responses of 10.4% with the majority of discontinuations occurring for lack of efficacy. Ultimately, these results demonstrate that belinostat has comparable efficacy to other agents used in this setting and is well tolerated in regard to hematologic events, but there is limited data on patient-reported outcomes, reduction in disease-related symptoms, or quality of life.

Biomarker-driven strategy for MCL1 inhibition in T-cell lymphomas

There is a pressing need for more effective therapies to treat patients with T-cell lymphomas (TCLs), including first-line approaches that increase the response rate to cyclophosphamide, adriamycin, vincristine, and prednisone (CHOP) chemotherapy. We characterized the mitochondrial apoptosis pathway in cell lines and patient-derived xenograft (PDX) models of TCL and assessed the in vitro efficacy of BH3 mimetics, including the BCL2 inhibitor venetoclax, the BCL2/BCL-xL inhibitor navitoclax, and the novel MCL1 inhibitor AZD5991. The abundance of antiapoptotic BCL2 family members based on immunoblotting or RNA transcript levels correlated poorly with the activity of BH3 mimetics. In contrast, the functional approach BH3 profiling reliably predicted sensitivity to BH3 mimetics in vitro and in vivo. We used BH3 profiling to select TCL PDX that were dependent on MCL1. Mice xenografted with these PDX and treated with AZD5991 had markedly improved survival. The combination of AZD5991 and CHOP achieved synergy based on survival improvement beyond a mathematical "sum of benefits" model. Thus, MCL1 inhibition is a promising strategy as both a single agent and in combination with chemotherapy for patients with TCL and functional dependence on MCL1.

CAR T-cells for T-cell malignancies: challenges in distinguishing between therapeutic, normal, and neoplastic T-cells

Chimeric antigen receptor (CAR) T-cells targeting CD19 demonstrated remarkable efficacy for the treatment of B-cell malignancies. The development of CAR T-cells against T-cell malignancies appears more challenging due to the similarities between the therapeutic, normal and malignant T-cells. The obstacles include CAR T-cell fratricide, T-cell aplasia, and contamination of CAR T-cell products with malignant T-cells. Here, we review these challenges and propose solutions to overcome these limitations.

CAR T-cells for T-cell malignancies: challenges in distinguishing between therapeutic, normal, and neoplastic T-cells

Chimeric antigen receptor (CAR) T-cells targeting CD19 demonstrated remarkable efficacy for the treatment of B-cell malignancies. The development of CAR T-cells against T-cell malignancies appears more challenging due to the similarities between the therapeutic, normal and malignant T-cells. The obstacles include CAR T-cell fratricide, T-cell aplasia, and contamination of CAR T-cell products with malignant T-cells. Here, we review these challenges and propose solutions to overcome these limitations.

Anti-CD37 chimeric antigen receptor T cells are active against B- and T-cell lymphomas

Chimeric antigen receptor (CAR) T cells have emerged as a novel form of treatment of patients with B-cell malignancies. In particular, anti-CD19 CAR T-cell therapy has effected impressive clinical responses in B-cell acute lymphoblastic leukemia and diffuse large B-cell lymphoma. However, not all patients respond, and relapse with antigen loss has been observed in all patient subsets. Here, we report on the design and optimization of a novel CAR directed to the surface antigen CD37, which is expressed in B-cell non-Hodgkin lymphomas, in chronic lymphocytic leukemia, and in some cases of cutaneous and peripheral T-cell lymphomas. We found that CAR-37 T cells demonstrated antigen-specific activation, cytokine production, and cytotoxic activity in models of B- and T-cell lymphomas in vitro and in vivo, including patient-derived xenografts. Taken together, these results are the first showing that T cells expressing anti-CD37 CAR have substantial activity against 2 different lymphoid lineages, without evidence of significant T-cell fratricide. Furthermore, anti-CD37 CARs were readily combined with anti-CD19 CARs to generate dual-specific CAR T cells capable of recognizing CD19 and CD37 alone or in combination. Our findings indicate that CD37-CAR T cells represent a novel therapeutic agent for the treatment of patients with CD37-expressing lymphoid malignancies.

Current and Investigational Agents Targeting the Phosphoinositide 3-Kinase Pathway

Prevalent molecular alterations of the phosphoinositide 3-kinase (PI3K) pathway are found on solid tumors and are expressed in leukocytes, making it a desirable target in both solid and hematologic malignancies. In recent years, two agents targeting this pathway have been approved by the United States Food and Drug Administration, idelalisib and copanlisib, with many others under investigation. Due to the off-target effects seen with these agents, those under development have varying isoform specificity that mitigates toxicity. In this review, we attempt to illustrate the varying differences among these agents, both mechanistically as well as highlight differences in their respective adverse effect profiles.

How I treat T-cell chronic active Epstein-Barr virus disease

T-cell chronic active Epstein-Barr virus (CAEBV) is a rare disease in which EBV is present predominantly in T cells that infiltrate the tissues; patients have high levels of EBV in the blood. If untreated, patients often develop liver failure, hemophagocytic lymphohistiocytosis, coronary artery aneurysms, EBV infiltrating T cells impairing organ function, or T-cell lymphomas refractory to treatment. At present, hematopoietic stem-cell transplantation is the only curative therapy, and it is critical to make a proper diagnosis and initiate transplantation before the disease progresses to an irreversible stage. Specific medications such as high-dose systemic corticosteroids or ganciclovir combined with either histone deacetylase inhibitors or bortezomib may temporarily reduce systemic toxicity associated with T-cell CAEBV and allow the patient time to receive a transplant. Relapses of the disease after transplantation have also occurred, and the use of donor-derived virus-specific T cells may help to treat these relapses.

Bendamustine for the treatment of relapsed or refractory peripheral T cell lymphomas: A French retrospective multicenter study

Peripheral T-cell lymphoma (PTCL) is a group of diseases with poor outcome and few therapeutic options. We aimed to assess the efficacy of bendamustine in real life cohort of patients.

Between November 2009 and March 2015, 138 PTCL patients were treated with bendamustine in 27 centers. Population median age was 64 (28-89) years with male/female ratio of 1.4. There were mainly angio-immunoblastic (AITL = 71), PTCL-not otherwise specified (PTCL-NOS = 40) and anaplastic large cell lymphoma (ALCL = 8). The majority of patients (96%) had disseminated disease and extranodal localizations (77%). Median number of chemotherapy lines prior to bendamustine was 2 (1-8). Median duration of response (DoR) after the last chemotherapy prior to bendamustine was 4.3 months (1-70) and 50% of patients had refractory disease.

Median number of administered bendamustine cycles was 2 (1-8) and 72 patients (52%) received less than 3 mostly because of disease progression. Median dose was 90 (50-150) mg/m². Overall response rate (ORR) was 32.6% with complete response (CR) rate of 24.6% and median DoR was 3.3 months (1-39). AITL patients were more sensitive than PTCL-NOS patients (ORR: 45.1 versus 20%, p = 0.01). Median PFS and OS were 3.1 (0.2-46.3) and 4.4 (0.2-55.4) months. On multivariate analysis, refractory disease (p = 0.001) and extranodal localization (p = 0.028) adversely influenced ORR. Grade 3-4 thrombocytopenia, neutropenia and infections were reported in 22, 17 and 23% of cases respectively.

Bendamustine as single agent could be considered as a therapeutic option for relapsed or refractory PTCL, particularly in chemosensitive or AITL patients. Combinations of bendamustine with other drugs warrant further evaluation.

Targeting T-cell malignancies using anti-CD4 CAR NK-92 cells

Peripheral T-cell lymphomas (PTCLs) are a group of very aggressive non-Hodgkin's lymphomas (NHLs) with poor prognoses and account for a majority of T-cell malignancies. Overall, the standard of care for patients with T-cell malignancies is poorly established, and there is an urgent clinical need for a new approach. As demonstrated in B-cell malignancies, chimeric antigen receptor (CAR) immunotherapy provides great hope as a curative treatment regimen. Because PTCLs develop from mature T-cells, these NHLs are commonly CD4+, and CD4 is highly and uniformly expressed. Therefore, CD4 is an ideal target for PTCL CAR immunotherapy. To that effect, we created a robust third-generation anti-CD4 CAR construct (CD4CAR) and introduced it into clonal NK cells (NK-92). CD4CAR NK-92 cells specifically and robustly eliminated diverse CD4+ human T-cell leukemia and lymphoma cell lines (KARPAS-299, CCRF-CEM, and HL60) and patient samples ex vivo. Furthermore, CD4CAR NK-92 cells effectively targeted KARPAS-299 cells in vivo that modeled difficult-to-access lymphoma nodules, significantly prolonging survival. In our study, we present novel targeting of CD4 using CAR-modified NK cells, and demonstrate efficacy. Combined, our data support CD4CAR NK cell immunotherapy as a potential new avenue for the treatment of PTCLs and CD4+ T-cell malignancies.

Quantitative Analysis of a Multiplexed Immunofluorescence Panel in T-Cell Lymphoma

Immunohistochemistry (IHC) provides clinically useful information on protein expression in cancer cells. However, quantification of colocalizing signals using conventional IHC and visual scores is challenging. Here we describe the application of quantitative immunofluorescence in angioimmunoblastic T-cell lymphoma (AITL), a peripheral T-cell lymphoma characterized by cellular heterogeneity that impedes IHC interpretation and quantification. A multiplexed immunofluorescence (IF) panel comprising T- and B-lymphocyte markers along with T-follicular helper (T_FH) markers was validated for appropriate cellular localization in sections of benign tonsillar tissue and tested in two samples of AITL, using a Vectra microscope for spectral imaging and InForm software for analysis. We measured the percentage positivity of the T_FH markers, BCL6 and PD1, in AITL CD4-positive cells to be approximately 26% and 45%, with 12% coexpressing both markers. The pattern is similar to CD4 cells within the germinal center of normal tonsils and clearly distinct from extragerminal CD4 cells. This study demonstrates the feasibility of automated and quantitative imaging of a multiplexed panel of cellular markers in formalin-fixed, paraffin-embedded tissue sections of a cellularly heterogenous lymphoma. Multiplexed IF allows the simultaneous scoring of markers in malignant and immune cell populations and could potentially increase accuracy for establishment of diagnostic thresholds.

Activity of the PI3K-δ,γ inhibitor duvelisib in a phase 1 trial and preclinical models of T-cell lymphoma

Duvelisib (IPI-145) is an oral inhibitor of phosphatidylinositol 3-kinase (PI3K)-δ/γ isoforms currently in clinical development. PI3K-δ/γ inhibition may directly inhibit malignant T-cell growth, making duvelisib a promising candidate for patients with peripheral (PTCL) or cutaneous (CTCL) T-cell lymphoma. Inhibition of either isoform may also contribute to clinical responses by modulating nonmalignant immune cells. We investigated these dual effects in a TCL cohort from a phase 1, open-label study of duvelisib in patients with relapsed or refractory PTCL (n = 16) and CTCL (n = 19), along with in vitro and in vivo models of TCL. The overall response rates in patients with PTCL and CTCL were 50.0% and 31.6%, respectively (P = .32). There were 3 complete responses, all among patients with PTCL. Activity was seen across a wide spectrum of subtypes. The most frequently observed grade 3 and 4 adverse events were transaminase increases (40% alanine aminotransferase, 17% aspartate aminotransferase), maculopapular rash (17%), and neutropenia (17%). Responders and nonresponders had markedly different changes in serum cytokine profiles induced by duvelisib. In vitro, duvelisib potently killed 3 of 4 TCL lines with constitutive phospho-AKT (pAKT) vs 0 of 7 lines lacking pAKT (P = .024) and exceeded cell killing by the PI3K-δ-specific inhibitor idelalisib. Administration of duvelisib to mice engrafted with a PTCL patient-derived xenograft resulted in a shift among tumor-associated macrophages from the immunosuppressive M2-like phenotype to the inflammatory M1-like phenotype. In summary, duvelisib demonstrated promising clinical activity and an acceptable safety profile in relapsed/refractory TCL, as well as preclinical evidence of both tumor cell-autonomous and immune-mediated effects. This trial was registered at www.clinicaltrials.gov as #NCT01476657.

Understanding the New WHO Classification of Lymphoid Malignancies: Why It's Important and How It Will Affect Practice

Improved delineation of lymphoid malignancy biology has prompted refinement of the 2008 World Health Organization (WHO) classification of hematopoietic and lymphoid tumors with a new framework introduced in 2016. This knowledge has provided valuable insights regarding management. Early clonal proliferations have been set apart given their limited potential for malignant dissemination. Increasing knowledge of molecular drivers of aggressive lymphomas has allowed subclassification and opportunity for clinical investigations to personalize therapy. New insights into T-cell pathophysiology has allowed grouping based on shared molecular and cellular features. This article will summarize the key changes in terms of diagnosis and histopathologic definitions, the impact of these changes on clinical management, and the challenges of future research in this field.

Co-targeting aurora kinase with PD-L1 and PI3K abrogates immune checkpoint mediated proliferation in peripheral T-cell lymphoma: a novel therapeutic strategy

Peripheral T-cell non-Hodgkin lymphoma (PTCL) are heterogeneous, rare, and aggressive diseases mostly incurable with current cell cycle therapies. Aurora kinases (AKs) are key regulators of mitosis that drive PTCL proliferation. Alisertib (AK inhibitor) has a response rate ∼30% in relapsed and refractory PTCL (SWOG1108). Since PTCL are derived from CD4⁺/CD8⁺ cells, we hypothesized that Program Death Ligand-1 (PD-L1) expression is essential for uncontrolled proliferation. Combination of alisertib with PI3Kα (MLN1117) or pan-PI3K inhibition (PF-04691502) or vincristine (VCR) was highly synergistic in PTCL cells. Expression of PD-L1 relative to PD-1 is high in PTCL biopsies (∼9-fold higher) and cell lines. Combination of alisertib with pan-PI3K inhibition or VCR significantly reduced PD-L1, NF-κB expression and inhibited phosphorylation of AKT, ERK1/2 and AK with enhanced apoptosis. In a SCID PTCL xenograft mouse model, alisertib displayed high synergism with MLN1117. In a syngeneic PTCL mouse xenograft model alisertib demonstrated tumor growth inhibition (TGI) ∼30%, whilst anti-PD-L1 therapy alone was ineffective. Alisertib + anti-PD-L1 resulted in TGI >90% indicative of a synthetic lethal interaction. PF-04691502 + alisertib + anti-PD-L1 + VCR resulted in TGI 100%. Overall, mice tolerated the treatments well. Co-targeting AK, PI3K and PD-L1 is a rational and novel therapeutic strategy for PTCL.

Clinical Practice Recommendations on Indication and Timing of Hematopoietic Cell Transplantation in Mature T Cell and NK/T Cell Lymphomas: An International Collaborative Effort on Behalf of the Guidelines Committee of the American Society for Blood and Marrow Transplantation

Recognizing the significant biological and clinical heterogeneity of mature T cell and natural killer (NK)/T cell lymphomas, the American Society for Blood and Marrow Transplantation invited experts to develop clinical practice recommendations related to the role of autologous hematopoietic cell transplantation (auto-HCT) and allogeneic HCT (allo-HCT) for specific histological subtypes. We used the GRADE methodology to aid in moving from evidence to decision making and ultimately to generating final recommendations. Auto-HCT in front-line consolidation is recommended in peripheral T cell lymphoma not otherwise specified (PTCL-NOS), angioimmunoblastic T cell lymphoma (AITL), anaplastic large cell lymphoma-anaplastic lymphoma kinase (ALCL-ALK)-negative, NK/T cell (disseminated), enteropathy-associated T cell lymphoma (EATL), and hepatosplenic lymphomas. Auto-HCT in relapsed-sensitive disease is recommended for NK/T cell (localized and disseminated), EATL, subcutaneous panniculitis-like T cell, and ALCL-ALK-positive lymphomas. Auto-HCT is also recommended for PTCL-NOS, AITL, and ALCL-ALK-negative lymphomas if not performed as front-line therapy. Auto-HCT in refractory (primary or relapsed) disease is not recommended for any of the histological subtypes discussed. Allo-HCT in front-line consolidation is recommended for NK/T cell (disseminated), adult T cell leukemia/lymphoma (ATLL; acute and lymphoma type), and hepatosplenic lymphomas. Allo-HCT for relapsed-sensitive disease is recommended for PTCL-NOS, AITL, ALCL-ALK-negative, ALCL-ALK-positive, NK/T cell (localized and disseminated), ATLL (acute, lymphoma type, smoldering/chronic), mycosis fungoides/Sezary syndrome (advanced stage IIB-IVB or tumor stage/extracutaneous), EATL, subcutaneous panniculitis-like T cell, and hepatosplenic lymphoma. Allo-HCT in refractory (primary or relapsed refractory) disease is recommended for any aforementioned histological subtypes. Emerging novel therapies will likely be incorporated into the pretransplantation, peritransplantation, and post-transplantation algorithms (auto-HCT or allo-HCT) with the goals of optimizing efficacy and improving outcomes. We acknowledge that there are unique clinical scenarios not covered by these recommendations that may require individualized decisions.

Redefining the role of etoposide in first-line treatment of peripheral T-cell lymphoma

Peripheral T-cell lymphomas (PTCLs) have an aggressive biological course and poor clinical outcomes. Despite producing somewhat less-than-satisfactory results, the combination of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) remains the de facto standard in PTCL treatment. Addition of etoposide to CHOP backbone to overcome such unsatisfactory results has yielded contradictory information. We aimed to thoroughly analyze the impact of incorporating etoposide into first-line treatment. Using merged data from the Korean National Health Insurance Service and National Cancer Registry, a total of 1933 patients (median age, 58 years) were evaluated for clinical characteristics and treatment outcomes. Thirty-eight percent (n = 748) of the 1933 patients received CHOP or CHOP-like regimen, 35.1% (n = 678) received CHOP-like regimen plus etoposide, 5.9% (n = 113) received other backbone chemotherapy plus etoposide, and 20.3% (394) received other treatments in the first-line setting. When we divided the patients into 3 groups according to regimen (group 1, CHOP or CHOP-like regimen; group 2, CHOP or CHOP-like regimen plus etoposide; group 3, all others), group 1 was associated with longest progression-free survival (PFS; P < .001) and overall survival (OS; P < .001). This lack of benefit with etoposide addition was observed across different PTCL subtypes and age groups. Adding etoposide led to longer hospitalizations and cytopenias requiring more transfusion. Upfront hematopoietic stem-cell transplantation led to better OS. Addition of etoposide to CHOP-like regimens does not result in better PFS or OS for patients with PTCL. Overall, Asian patients with PTCL do not benefit from chemotherapy intensification of first-line treatment. We hereby provide crucial information on establishing standardized PTCL treatment.

Autologous and Allogeneic Hematopoietic Cell Transplantation in Peripheral T/NK-cell Lymphomas: A Histology-Specific Review

Peripheral T-cell lymphoma and natural killer/T-cell lymphomas (PT/NKCL) make up a diverse subgroup of non-Hodgkin's lymphomas characterized by an aggressive clinical course. The use of hematopoietic stem cell transplantation (HSCT) in the treatment of PT/NKCL remains controversial because of the absence of randomized controlled trials. The best available data suggest that certain subtypes of PT/NKCL may benefit more from the application of HSCT than other subtypes and that this benefit results from their unique clinical characteristics and underlying biology. Ultimately, however, prospective randomized controlled trials are needed to clarify the optimal type and timing of HSCT in patients with PT/NKCL.

Toward a Biology-Driven Treatment Strategy for Peripheral T-cell Lymphoma

T-cell and natural killer–cell lymphomas are a relatively rare and heterogeneous group of diseases that are difficult to treat and usually have poor outcomes. To date, therapeutic interventions are of limited efficacy and there is a pressing need to find better treatments. In recent years, advances in molecular biology have helped to elucidate the underlying genetic complexity of this group of diseases and to identify mutations and signaling pathways involved in lymphomagenesis. In this review, we highlight the unique biological characteristics of some of the different subtypes and discuss how these may be targeted to provide more individualized and effective treatment approaches.

An audit of patients with mature T-cell non-Hodgkin lymphoma by transplant status in Tasmania

This retrospective audit of patients diagnosed with mature T-cell lymphoma across a 10-year period provides contemporary information on the outcomes and treatment patterns of an Australian cohort. Forty-two patients diagnosed with mature T-cell lymphoma were identified from the Tasmanian Cancer Registry and analysed using medical records and simple statistical analysis. The demographics and outcomes of patients in this cohort were comparable to large international studies with treatment patterns in line with the best available evidence.

THZ1 targeting CDK7 suppresses STAT transcriptional activity and sensitizes T-cell lymphomas to BCL2 inhibitors

Peripheral T-cell lymphomas (PTCL) are aggressive diseases with poor response to chemotherapy and dismal survival. Identification of effective strategies to target PTCL biology represents an urgent need. Here we report that PTCL are sensitive to transcription-targeting drugs, and, in particular, to THZ1, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7). The STAT-signalling pathway is highly vulnerable to THZ1 even in PTCL cells that carry the activating STAT3 mutation Y640F. In mutant cells, CDK7 inhibition decreases STAT3 chromatin binding and expression of highly transcribed target genes like MYC, PIM1, MCL1, CD30, IL2RA, CDC25A and IL4R. In surviving cells, THZ1 decreases the expression of STAT-regulated anti-apoptotic BH3 family members MCL1 and BCL-XL sensitizing PTCL cells to BH3 mimetic drugs. Accordingly, the combination of THZ1 and the BH3 mimetic obatoclax improves lymphoma growth control in a primary PTCL ex vivo culture and in two STAT3-mutant PTCL xenografts, delineating a potential targeted agent-based therapeutic option for these patients.

T-cell lymphomas are aggressive diseases associated with poor outcome. Here, the authors show that the THZ1, a CDK7 inhibitor, suppresses STAT transcriptional activity leading to apoptosis and sensitization to BCL2 inhibitors in T-cell lymphomas.

Autologous stem cell transplantation as frontline strategy for peripheral T-cell lymphoma: A single-centre experience

Objective To determine the efficacy and prognosis of autologous hematopoietic stem cell transplantation (ASCT) as frontline treatment for peripheral T cell lymphoma (PTCL). Methods Clinical data from 46 PTCL patients who achieved complete (CR) or partial remission (PR) after ASCT from October 1996 to July 2014 were analysed retrospectively. Results Median patient age was 32 (range: 15-68) years. Disease types included PTCL, unspecified type, in 23 patients, anaplastic large cell lymphoma in eight, angioimmunoblastic lymphoma in eight, extranodal NK/T-cell lymphoma in five, and hepatosplenic T-cell lymphoma and enteropathy associated T-cell lymphoma in one each. Of these patients, 80% had Prognostic Index for Peripheral T-cell Lymphoma scores ≥1. Thirty-four patients had pre-transplantation CR and 12 had PR. Median follow up was 37 (6-176) months. The 5-year overall survival (OS) and progression-free survival (PFS) rates were 77.1% and 61.9%, respectively. Multivariate analysis showed that pre-transplantation CR was an independent risk factor for survival, and CR was more common than PR (OS 81% vs 59.3%; PFS 71.8% vs 17.8%). Conclusion Frontline consolidation treatment with ASCT was associated with favourable outcomes in patients with PTCL. Pre-transplantation CR was a prognostic factor for survival, suggesting that ASCT may be favoured as front-line consolidation therapy after first complete remission.

Understanding the New WHO Classification of Lymphoid Malignancies: Why It's Important and How It Will Affect Practice

Improved delineation of lymphoid malignancy biology has prompted refinement of the 2008 World Health Organization (WHO) classification of hematopoietic and lymphoid tumors with a new framework introduced in 2016. This knowledge has provided valuable insights regarding management. Early clonal proliferations have been set apart given their limited potential for malignant dissemination. Increasing knowledge of molecular drivers of aggressive lymphomas has allowed subclassification and opportunity for clinical investigations to personalize therapy. New insights into T-cell pathophysiology has allowed grouping based on shared molecular and cellular features. This article will summarize the key changes in terms of diagnosis and histopathologic definitions, the impact of these changes on clinical management, and the challenges of future research in this field.

How I manage peripheral T-cell lymphoma, not otherwise specified and angioimmunoblastic T-cell lymphoma: current practice and a glimpse into the future

Peripheral T-cell lymphoma (PTCL), not otherwise specified (NOS) and angioimmunoblastic T-cell lymphoma (AITL) are the most frequent of more than 20 mature PTCL entities featuring a broad spectrum of morphological, immunophenotypic, molecular and clinical characteristics. Unfortunately, recent progress in understanding the (epi)genetic background of PTCL has not been met with similar advances in treatment. Thus, CHO(E)P [cyclophosphamide, doxorubicin, vincristine, and prednisone (plus etoposide)] remains standard first-line therapy. Patients without comorbidities achieving complete or partial remission proceed to autologous stem cell transplantation. With this approach about 50% of patients survive long-term. Patients relapsing after or progressing during first-line therapy have a dismal prognosis. They receive salvage gemcitabine-therapy followed by allogeneic transplantation whenever possible. After allografting, approximately half of the patients survive long-term; any other treatment is palliative. New drugs investigated in phase II studies achieved response rates between 10% and 30%; long-term remissions are the exception to the rule. While most new drugs are not licensed and not readily available, a plethora of other innovative drugs targeting (epi-)genetic abnormalities are in early development. These, together with combinations of new and old drugs, will hopefully increase response to first-line therapy, bridge more patients to transplantation, and finally improve prognosis for all patients with PTCL.

[Comparison of allogeneic or autologous hematopoietic stem cell transplant for high-risk peripheral T cell lymphomas]

Objective: To evaluate the efficacy of auto-HSCT and allo-HSCT in the treatment of high risk peripheral T cell lymphoma (PTCL). Methods: From July 2007 to July 2014, 60 cases of high risk PTCL were analyzed retrospectively. Results: All 60 patients were at high risk group (carried with IPI≥3), with a median age of 31 (12-58) years old. Of the 60 cases, 22 were PTCL-not otherwise specified (PTCL-NOS), 22 ALK negative anaplastic large cell lymphoma (ALK-negative ALCL) and 16 angioimmunoblastic T-cell lymphoma (AITL). Twenty-one patients (21/60) received allo-HSCT, and thirty-nine (39/60) auto-HSCT. Before receiving transplantation, 40/60 patients were in complete remission (CR), 2/60 patients partial remission (PR) and 18/60 patients not remission (NR). In the 40 CR patients before transplant, 10 patients received allo-HSCT and 30 patients auto-HSCT, respectively. In the 20 PR/NR patients before transplant, 11 patients received allo-HSCT and 9 patients auto-HSCT, respectively. After a median follow-up of 39 (range 1-96) months, the K-M analysis showed that the 5-year PFS by auto-HSCT and allo-HSCT were 61% and 60% (P=0.724) , respectively. The 5-year OS by auto-HSCT and allo-HSCT were 62% and 61% (P=0.724) , respectively. There were no statistically significant differences between auto-HSCT and allo-HSCT. And the cumulative TRM of auto-HSCT and allo-HSCT were 22.7% and 41.8% (P=0.250) , respectively within 5-years after transplantation. At the end of the last follow-up, 7 and 2 patients relapsed in auto-HSCT and allo-HSCT groups respectively, the 5-year cumulative recurrence rates of auto-HSCT and allo-HSCT transplantation were 37.2% and 10.1% (P=0.298), respectively. Conclusion: There was no significant difference in the long-term survival between auto-HSCT and allo-HSCT for high risk PTCL patients. Outcome by allo-HSCT may be better for NR patients.

Targeting histone deacetylases in T-cell lymphoma

Histone deacetylase inhibitors (HDACi) are epigenetic modifiers with single-agent activity in patients with cutaneous and peripheral T-cell lymphoma (CTCL, PTCL). The mechanisms for this preferential activity remain unclear, and although some would term this as 'class effect,' there are differences in efficacy and safety, likely a result of the varying chemical structures/classes, histone and non-histone targets, potencies, and clinical dosing for each. Three HDACi have single-agent approval in relapsed/refractory TCL in the United States: romidepsin in CTCL and PTCL, vorinostat in CTCL, and belinostat in PTCL. Although comparison of these agents is difficult due to differences in patient populations, through this review we aimed to provide a detailed overview of the clinical data for HDACi in TCL and their use in clinical practice. Despite early concerns, data demonstrate the cardiac safety of HDACi, while highlighting the need to maintain electrolytes in the normal range and monitor QT interval when initially co-administering antiemetics or other drugs that prolong QT. To further improve response rates and durability of responses, HDACi are under clinical investigation in combination with chemotherapy regimens and various novel agents.