Novel therapies in peripheral T-cell lymphomas

Complete hematologic response after belinostat treatment and allogeneic stem cell transplantation for multiple relapsed/refractory angioimmunoblastic T-cell lymphoma: A case report

Key Clinical Message

This case report highlights the potential of belinostat for the treatment of relapsed/refractory peripheral T-cell lymphomas, for which effective therapies are still scarce.

Abstract

Peripheral T-cell lymphomas have an aggressive disease course associated with poor outcomes. We report a young patient with highly pretreated relapsed/refractory nodal follicular helper T-cell lymphoma (angioimmunoblastic-type [nTFHL-AI]), who successfully received an allogeneic stem cell transplantation following belinostat therapy. The complete hematologic response achieved has lasted more than 2 years.

Analysis of Peripheral T-cell Lymphoma Diagnostic Workup in the United States

BACKGROUND

With increased understanding of the unique entities, subtype-specific approaches for peripheral T-cell lymphoma (PTCL) are emerging, and more precise diagnoses are becoming increasingly important. PATIENTS AND METHODS: We analyzed the approach to the histopathologic diagnosis of PTCL using data from the comprehensive oncology measures of peripheral T-cell lymphoma (COMPLETE) study. The COMPLETE trial is a large prospective cohort study of patients with newly diagnosed PTCL in the United States.

RESULTS

A total of 499 patients were enrolled from 40 academic and 15 community-based centers. Baseline assessment forms were collected for 493 patients, of which 435 (88%) were available for analysis. The most common diagnoses were PTCL, not otherwise specified (PTCL-NOS), anaplastic large cell lymphoma, and angioimmunoblastic T-cell lymphoma (AITL). A mean of 10 markers (range, 0-21) was assessed per patient. CD30 was assessed frequently but not uniformly in cases that were not anaplastic large cell lymphoma. Only 17% of PTCL-NOS cases were assessed for PD1. CXCL13 was a relatively sensitive marker in AITL, expressed in 84% of tested cases; however, only 3% of PTCL-NOS cases were tested. T follicular helper cell marker assessment differed between academic and community practices, with PD1 more often evaluated by academic centers in cases of AITL (62% vs. 12%; P = .01).

CONCLUSION

The diagnostic workup for PTCL in the United States varies widely and often lacks important phenotypic information to fully characterize the lymphoma. Gaps in testing of selected markers should be filled, given the impending revision to the World Health Organization classification. The accuracy of diagnosis will become increasingly important as we enter the era of targeted treatment for PTCL.

Pitfalls and major issues in the histologic diagnosis of peripheral T-cell lymphomas: results of the central review of 573 cases from the T-Cell Project, an international, cooperative study

Peripheral T-cell lymphomas (PTCLs) comprise a heterogeneous group of neoplasms that are derived from post-thymic lymphoid cells at different stages of differentiation with different morphological patterns, phenotypes and clinical presentations. PTCLs are highly diverse, reflecting the diverse cells from which they can originate and are currently sub-classified using World Health Organization (WHO) 2008 criteria. In 2006 the International T-Cell Lymphoma Project launched the T-Cell Project, building on the retrospective study previously carried on by the network, with the aim to prospectively collect accurate data to improve knowledge on this group of lymphomas. Based on previously published reports from International Study Groups it emerged that rendering a correct classification of PTCLs is quite difficult because the relatively low prevalence of these diseases results in a lack of confidence by most pathologists. This is the reason why the T-Cell Project requested the availability of diagnostic material from the initial biopsy of each patient registered in the study in order to have the initial diagnosis centrally reviewed by expert hematopathologists. In the present report the results of the review process performed on 573 cases are presented. Overall, an incorrect diagnosis was centrally recorded in 13.1% cases, including 8.5% cases centrally reclassified with a subtype eligible for the project and 4.6% cases misclassified and found to be disorders other than T-cell lymphomas; 2.1% cases were centrally classified as T-Cell disorders not included in the study population. Thus, the T-Cell Project confirmed the difficulties in providing an accurate classification when a diagnosis of PTCLs is suspected, singled out the major pitfalls that can bias a correct histologic categorization and confirmed that a centralized expert review with the application of adequate diagnostic algorithms is mandatory when dealing with these tumours. Copyright © 2016 John Wiley & Sons, Ltd.

Belinostat in Patients With Relapsed or Refractory Peripheral T-Cell Lymphoma: Results of the Pivotal Phase II BELIEF (CLN-19) Study

PURPOSE

Peripheral T-cell lymphomas (PTCLs) represent a diverse group of non-Hodgkin lymphomas with a poor prognosis and no accepted standard of care for patients with relapsed or refractory disease. This study evaluated the efficacy and tolerability of belinostat, a novel histone deacetylase inhibitor, as a single agent in relapsed or refractory PTCL.

PATIENTS AND METHODS

Patients with confirmed PTCL who experienced progression after ≥ one prior therapy received belinostat 1,000 mg/m(2) as daily 30-minute infusions on days 1 to 5 every 21 days. Central assessment of response used International Working Group criteria. Primary end point was overall response rate. Secondary end points included duration of response (DoR) and progression-free and overall survival.

RESULTS

A total of 129 patients were enrolled, with a median of two prior systemic therapies. Overall response rate in the 120 evaluable patients was 25.8% (31 of 120), including 13 complete (10.8%) and 18 partial responses (15%). Median DoR by International Working Group criteria was 13.6 months, with the longest ongoing patient at ≥ 36 months. Median progression-free and overall survival were 1.6 and 7.9 months, respectively. Twelve of the enrolled patients underwent stem-cell transplantation after belinostat monotherapy. The most common grade 3 to 4 adverse events were anemia (10.8%), thrombocytopenia (7%), dyspnea (6.2%), and neutropenia (6.2%).

CONCLUSION

Monotherapy with belinostat produced complete and durable responses with manageable toxicity in patients with relapsed or refractory PTCL across the major subtypes, irrespective of number or type of prior therapies. These results have led to US Food and Drug Administration approval of belinostat for this indication.

FDA Approval: Belinostat for the Treatment of Patients with Relapsed or Refractory Peripheral T-cell Lymphoma

On July 3, 2014, the FDA granted accelerated approval for belinostat (Beleodaq; Spectrum Pharmaceuticals, Inc.), a histone deacetylase inhibitor, for the treatment of patients with relapsed or refractory peripheral T-cell lymphoma (PTCL). A single-arm, open-label, multicenter, international trial in the indicated patient population was submitted in support of the application. Belinostat was administered intravenously at a dose of 1000 mg/m(2) over 30 minutes once daily on days 1 to 5 of a 21-day cycle. The primary efficacy endpoint was overall response rate (ORR) based on central radiology readings by an independent review committee. The ORR was 25.8% [95% confidence interval (CI), 18.3-34.6] in 120 patients that had confirmed diagnoses of PTCL by the Central Pathology Review Group. The complete and partial response rates were 10.8% (95% CI, 5.9-17.8) and 15.0% (95% CI, 9.1-22.7), respectively. The median duration of response, the key secondary efficacy endpoint, was 8.4 months (95% CI, 4.5-29.4). The most common adverse reactions (>25%) were nausea, fatigue, pyrexia, anemia, and vomiting. Grade 3/4 toxicities (≥5.0%) included anemia, thrombocytopenia, dyspnea, neutropenia, fatigue, and pneumonia. Belinostat is the third drug to receive accelerated approval for the treatment of relapsed or refractory PTCL.

Hepatosplenic γδ T-cell lymphoma: an overview

Peripheral T-cell lymphomas are a heterogeneous group of lymphoid malignancies. Among these, hepatosplenic γδ T-cell lymphoma (HTCL) represents an aggressive and treatment-resistant subgroup for which new avenues of treatment are critically needed. HTCL is characterized by primary extranodal distribution of the malignant cells with typical intrasinusoidal infiltration of the liver, spleen, and bone marrow, which results in hepatosplenomegaly and peripheral blood cytopenias. Another characteristic feature is the expression of γδ T-cell receptors. HTCL exhibits a rapid progressive course and an extremely poor response to currently known therapeutic strategies, with a 5-year overall survival rate of only 7%. In this review, we discuss the clinical, pathologic, and molecular characteristics of this disease, along with the challenges that are associated with its diagnosis and treatment.

Pralatrexate in patients with relapsed or refractory peripheral T-cell lymphoma: results from the pivotal PROPEL study

PURPOSE

Peripheral T-cell lymphoma (PTCL) is a poor prognosis subtype of non-Hodgkin's lymphoma with no accepted standard of care. This study evaluated the efficacy and tolerability of pralatrexate, a novel antifolate with promising activity.

PATIENTS AND METHODS

Patients with independently confirmed PTCL who progressed following ≥ 1 line of prior therapy received pralatrexate intravenously at 30 mg/m(2)/wk for 6 weeks in 7-week cycles. Primary assessment of response was made by independent central review using the International Workshop Criteria. The primary end point was overall response rate. Secondary end points included duration of response, progression-free survival (PFS), and overall survival (OS).

RESULTS

Of 115 patients enrolled, 111 were treated with pralatrexate. The median number of prior systemic therapies was three (range, 1 to 12). The response rate in 109 evaluable patients was 29% (32 of 109), including 12 complete responses (11%) and 20 partial responses (18%), with a median DoR of 10.1 months. Median PFS and OS were 3.5 and 14.5 months, respectively. The most common grade 3/4 adverse events were thrombocytopenia (32%), mucositis (22%), neutropenia (22%), and anemia (18%).

CONCLUSION

To our knowledge, PROPEL (Pralatrexate in Patients with Relapsed or Refractory Peripheral T-Cell Lymphoma) is the largest prospective study conducted in patients with relapsed or refractory PTCL. Pralatrexate induced durable responses in relapsed or refractory PTCL irrespective of age, histologic subtypes, amount of prior therapy, prior methotrexate, and prior autologous stem-cell transplant. These data formed the basis for the US Food and Drug Administration approval of pralatrexate, the first drug approved for this disease.

New targets of therapy in T-cell lymphomas

T-cell lymphomas (TCL) are characterized by poor response to chemotherapy and generally poor outcome. While molecular profiling has identified distinct biological subsets and therapeutic targets in B-cell lymphomas, the molecular characterization of TCL has been slower. Surface markers expressed on malignant T-cells, such as CD2, CD3, CD4, CD25, and CD52 were the first TCL-specific therapeutic targets to be discovered. However, the presence of these receptors on normal T-cells means that monoclonal antibody (mAb)- or immunotoxin (IT)-based therapy in TCL inevitably results in variable degrees of immunosuppression. Thus, although some mAbs/IT have significant activity in selected subsets of TCL, more specific agents that target signaling pathways preferentially activated in malignant T-cells are needed. One such novel class of agents is represented by the histone deacetylase (HDAC) inhibitors. These molecules selectively induce apoptosis in a variety of transformed cells, including malignant T-cells, both in vitro and in vivo. Several HDAC inhibitors have been studied in TCL with promising results, and have recently been approved for clinical use. Immunomodulatory drugs, such as interferons and Toll Receptor (TLR) agonists have significant clinical activity in TCL, and are particularly important in the treatment of primary cutaneous subtypes (CTCL). Although most classical cytotoxic drugs have limited efficacy against TCL, agents that inhibit purine and pyrimidine metabolism, known as nucleoside analogues, and novel antifolate drugs, such as pralatrexate, are highly active in TCL. With improved molecular profiling of TCL novel pharmacological agents with activity in TCL are now being discovered at an increasingly rapid pace. Clinical trials are in progress and these agents are being integrated in combination therapies for TCL, both in the relapsed/refractory setting as well as front line.