Phase I/II study of pralatrexate in Japanese patients with relapsed or refractory peripheral T-cell lymphoma

Peripheral T-cell lymphoma: From biology to practice to the future

Recent advancements in comprehending peripheral T-cell lymphomas (PTCLs) validate and broaden our perspective, highlighting their diverse nature and the varying molecular mechanisms underlying the entities. Based on a comprehensive accumulated understanding, the PTCLs currently overcome the most challenging features of any disease: rarity, incredible heterogeneity, and a lack of any established standard of care. The treatments deployed in the front-line are extrapolated from regimens developed for other diseases. The recent approval of the three drugs brentuximab vedotin (BV), pralatrexate, and belinostat for patients with relapsed or refractory disease has provided clues about pathophysiology and future directions, though challenges satisfying post-marketing requirements (PMR) for those accelerated approvals have led to one of those drugs being withdrawn and put the other two in jeopardy. Edits of the front-line regimens, often called CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-plus approaches, look more like CHOP-minus strategies, as the toxicity of five-drug regimens often reduces the dose intensity of the added 'novel' drug, nullifying any hope of an advance. The turmoil in the field produced by the aforementioned, coupled with an ever-changing classification, has left the field uncertain about the path forward. Despite these challenges, empiric findings from studies of novel drug approaches, coupled with a logic emerging from studies of PTCL lymphomagenesis, have begun to illuminate, albeit faintly for some, a potential direction. The empiric finding that drugs targeting the discrete components of the PTCL epigenome, coupled with the description of multiple mutations in genes that govern epigenetic biology, offers, at the very least, an opportunity to finally be hypothesis-driven. The most recent recognition that the only combination of drugs shown to markedly improve progression-free survival (PFS) in patients with relapsed disease is one based on dual targeting of different and discrete components of that epigenetic biology has established a possibility that circumnavigating chemotherapy addition studies is both plausible, feasible, and likely the best prospect for a quantum advance in this disease. Herein, we analyze PTCL through a 2025 lens, highlighting and underscoring walls that have impeded progress. We will critically explore all the clues and the panoramic view of PTCL research.

Pooled analysis of pralatrexate single-agent studies in patients with relapsed/refractory peripheral T-cell lymphoma

ABSTRACT

Patients with relapsed or refractory (R/R) mature natural killer cell and T-cell lymphoma have limited treatment options. To evaluate pralatrexate's performance and factors influencing its safety and efficacy in R/R peripheral T-cell lymphoma (PTCL), we performed a pooled analysis of data from 4 similarly designed, regulatory-mandated prospective clinical trials. Of 221 patients (median age, 59 years; 67.0% male) in the study population, 48.9% had PTCL not otherwise specified (PTCL-NOS), 21.3% angioimmunoblastic T-cell lymphoma, and 11.8% ALK-negative anaplastic large cell lymphoma (ALCL). Patients received pralatrexate for a median of 2.56 months (range, 0.03-24.18) and had a 40.7% objective response rate with a median duration of response of 9.1 months, progression-free survival 4.6 months, and overall survival 16.3 months. The most common treatment-related all-grade adverse events were stomatitis, thrombocytopenia, white blood cell count decrease, pyrexia, and vomiting. Subgroup exploratory analyses suggest improved efficacy with 1 prior line of chemotherapy vs 2 or ≥4 prior lines; PTCL-NOS or ALCL vs transformed mycosis fungoides; chemotherapy and transplant before pralatrexate vs chemotherapy alone or chemotherapy with other nontransplant treatments. In conclusion, these pooled analysis results further support using pralatrexate in patients with R/R PTCL. Prospective studies are needed to confirm the findings of subgroups analyses.

Pralatrexate inhibited the replication of varicella zoster virus and vesicular stomatitis virus: An old dog with new tricks

Varicella zoster virus (VZV) is associated with herpes zoster (HZ) or herpes zoster ophthalmicus (HZO). All antiviral agents currently licensed for the management of VZV replication via modulating different mechanisms, and the resistance is on the rise. There is a need to develop new antiviral agents with distinct mechanisms of action and adequate safety profiles. Pralatrexate (PDX) is a fourth-generation anti-folate agent with an inhibitory activity on folate (FA) metabolism and has been used as an anti-tumor drug. We observed that PDX possessed potent inhibitory activity against VZV infection. In this study, we reported the antiviral effects and the underlying mechanism of PDX against VZV infection. The results showed that PDX not only inhibited VZV replication in vitro and in mice corneal tissues but also reduced the inflammatory response and apoptosis induced by viral infection. Furthermore, PDX treatment showed a similar anti-VSV inhibitory effect in both in vitro and in vivo models. Mechanistically, PDX inhibited viral replication by interrupting the substrate supply for de novo purine and thymidine synthesis. In conclusion, this study discovered the potent antiviral activity of PDX with a novel mechanism and presented a new strategy for VZV treatment that targets a cellular metabolic mechanism essential for viral replication. The present study provided a new insight into the development of broad-spectrum antiviral agents.

Precise diagnosis and targeted therapy of nodal T-follicular helper cell lymphoma (T-FHCL)

Nodal T-follicular helper cell lymphoma (T-FHCL) derived from T-follicular helper (Tfh) cell falls into a heterogeneous category of peripheral T-cell lymphoma (PTCL). Due to the limited number of therapeutic regimens and limited first-line efficacy, T-FHCL has a poor prognosis, and there is an urgent need for effective targeted therapies. With advancements in sequencing technologies, especially single-cell sequencing and next-generation sequencing, more specific genetic aberrations characteristic of T-FHCL can be discovered, allowing for precise molecular diagnosis and specific research on novel agents. Many biomarker-targeting agents, used either alone or in combination, have been tested, and they have generally enhanced the therapeutic outcomes of T-FHCL. Histone deacetylase inhibitors achieve significant clinical benefits in the treatment of T-FHCL, especially in combination therapy. Chimeric antigen receptor T-cell (CAR-T-cell) immunotherapies, hematopoietic stem cell transplantation, and other potential agents merit further study.

Oral HDAC inhibitor tucidinostat in patients with relapsed or refractory peripheral T-cell lymphoma: phase IIb results

Tucidinostat (formerly known as chidamide) is an orally available, novel benzamide class of histone deacetylase (HDAC) inhibitor that selectively blocks class I and class IIb HDAC. This multicenter phase IIb study aimed to investigate the efficacy and safety of tucidinostat, 40 mg twice per week (BIW), in patients with relapsed/refractory (R/R) peripheral T-cell lymphoma (PTCL). The primary endpoint was overall response rate (ORR) assessed by an independent overall efficacy review committee. Between March 2017 and March 2019, 55 patients were treated, and 46 and 55 were evaluated for efficacy and safety, respectively. Twenty-one of 46 patients achieved objective responses with an ORR of 46% (95% confidence interval : 30.9-61.0), including five patients with complete response (CR). Responses were observed across various PTCL subtypes. In angioimmunoblastic T-cell lymphoma, there were two CR and five partial responses (PR) among eight patients, achieving an ORR of 88%. The disease control rate (CR + PR + stable disease) was 72% (33/46). The median progression-free survival, duration of response, and overall survival were 5.6 months, 11.5 months, 22.8 months, respectively. The most common adverse events (AE) (all grades) were thrombocytopenia, neutropenia, leukopenia, anemia, and diarrhea. The grade ≥3 AE emerging in ≥20% of patients included thrombocytopenia (51%), neutropenia (36%), lymphopenia (22%), and leukopenia (20%). Importantly, most of the AE were manageable by supportive care and dose modification. In conclusion, the favorable efficacy and safety profiles indicate that tucidinostat could be a new therapeutic option in patients with R/R PTCL (clinicaltrials gov. Identifier: NCT02953652).

Japanese subgroup analysis in the Asian phase II study of darinaparsin in patients with relapsed or refractory peripheral T-cell lymphoma

A Japanese subgroup analysis from the Asian phase II study of darinaparsin in patients with relapsed or refractory peripheral T-cell lymphoma (PTCL) was performed to evaluate the efficacy and safety outcomes of the Japanese population. In this Asian phase II study, darinaparsin was administered to 65 patients, including 37 Japanese patients. In the Japanese population, the histopathological type of PTCL was PTCL, not otherwise specified in 26 patients (70.3%), angioimmunoblastic T-cell lymphoma in 9 patients (24.3%) and anaplastic large cell lymphoma, anaplastic lymphoma kinase (ALK) -negative in 2 patients (5.4%), and the median patient age was 70.0 (range: 43-85). 94.6% and 35.1% of the Japanese population had previously received multi-agent and single-agent regimen, respectively. The efficacy and safety were summarized and compared between the overall and Japanese populations. Based on central assessment, the overall response rate was 22.2% (8/36; 90% confidence interval [CI]: 11.6-36.5) in the Japanese population and 19.3% (11/57; 90% CI: 11.2-29.9) in the overall population. There were no essential differences in the safety profile of darinaparsin between the Japanese population and the overall population. The results of this subgroup analysis indicate that the efficacy and safety profiles of the Japanese subpopulation were broadly consistent with that of the overall population, and that darinaparsin is potentially an effective treatment with a manageable safety profile in Japanese patients with relapse or refractory PTCL.

Characterization of newly established Pralatrexate-resistant cell lines and the mechanisms of resistance

Background

Pralatrexate (PDX) is a novel antifolate approved for the treatment of patients with relapsed/refractory peripheral T-cell lymphoma, but some patients exhibit intrinsic resistance or develop acquired resistance. Here, we evaluated the mechanisms underlying acquired resistance to PDX and explored potential therapeutic strategies to overcome PDX resistance.

Methods

To investigate PDX resistance, we established two PDX-resistant T-lymphoblastic leukemia cell lines (CEM and MOLT4) through continuous exposure to increasing doses of PDX. The resistance mechanisms were evaluated by measuring PDX uptake, apoptosis induction and folate metabolism-related protein expression. We also applied gene expression analysis and methylation profiling to identify the mechanisms of resistance. We then explored rational drug combinations using a spheroid (3D)-culture assay.

Results

Compared with their parental cells, PDX-resistant cells exhibited a 30-fold increase in half-maximal inhibitory concentration values. Induction of apoptosis by PDX was significantly decreased in both PDX-resistant cell lines. Intracellular uptake of [¹⁴C]-PDX decreased in PDX-resistant CEM cells but not in PDX-resistant MOLT4 cells. There was no significant change in expression of dihydrofolate reductase (DHFR) or folylpolyglutamate synthetase (FPGS). Gene expression array analysis revealed that DNA-methyltransferase 3β (DNMT3B) expression was significantly elevated in both cell lines. Gene set enrichment analysis revealed that adipogenesis and mTORC1 signaling pathways were commonly upregulated in both resistant cell lines. Moreover, CpG island hypermethylation was observed in both PDX resistant cells lines. In the 3D-culture assay, decitabine (DAC) plus PDX showed synergistic effects in PDX-resistant cell lines compared with parental lines.

Conclusions

The resistance mechanisms of PDX were associated with reduced cellular uptake of PDX and/or overexpression of DNMT3B. Epigenetic alterations were also considered to play a role in the resistance mechanism. The combination of DAC and PDX exhibited synergistic activity, and thus, this approach might improve the clinical efficacy of PDX.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08607-9.

Updates in the Treatment of Peripheral T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of rare hematologic malignancies accounting for less than 10% of non-Hodgkin lymphomas. The 2016 classification of World Health Organization recognized 29 different entities of PTCLs. These subgroups are characterized by different molecular and genetic patterns. For nearly 30 years, little improvement in the treatment of PTCLs has been noticed due to the paucity of randomized trials and anthracycline-based chemotherapy remains the mainstay of first-line treatment. In front-line setting, ECHELON-2, the first randomized controlled Phase III clinical trial, recently met its primary endpoint of PFS demonstrating the superiority of BV containing regimen when compared to standard CHOP in patients with CD30 positive PTCLs. The role of therapeutic intensifications such as autologous or allogenic stem cell transplantations remains controversial in first-line setting and in relapsed/refractory disease due to the lack of studies clearly addressing this question and the recently published negative studies. PTCLs are often refractory to first-line chemotherapy and tend to relapse after an initial response. New agents have been approved for relapsed/refractory disease such as Histone deacetylase inhibitors, folate analogue metabolic inhibitor or CD30 antibody drug conjugated. Despite an acceptable response to these agents, progression-free survival remains very poor. New strategies such as combinations of different agents have been evaluated in order to improve outcomes. Innovative drugs in the fields of epigenetics, immunomodulation within the tumor microenvironment, and direct targeting of tumor cells to CD30 and T-cell receptor abnormalities open new perspectives to improve the treatment of PTCLs.

Biology and Molecular Pathogenesis of Mature T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) constitute a highly heterogeneous group of hematological diseases with complex clinical and molecular features consistent with the diversity of the T-cell type from which they originate. In the past several years, the systematic implementation of high-throughput genomic technologies for the analysis of T-cell malignancies has supported an exponential progress in our understanding of the genetic drivers of oncogenesis and unraveled the molecular complexity of these diseases. Recent findings have helped redefine the classification of T-cell malignancies and provided novel biomarkers to improve diagnosis accuracy and analyze the response to therapy. In addition, multiple novel targeted therapies including small-molecule inhibitors, antibody-based approaches, and immunotherapy have shown promising results in early clinical analysis and have the potential to completely change the way T-cell malignancies have been treated traditionally.

Pralatrexate for refractory mycosis fungoides in two Japanese patients

Pralatrexate has been approved for the treatment of relapsed/refractory peripheral T cell lymphomas. Studies in the U.S. also support the clinical efficacy of pralatrexate to treat advanced‐stage cutaneous T‐cell lymphomas, but outcomes in Japanese patients have not yet been reported. We herein describe two Japanese patients with heavily‐pretreated relapsed/refractory mycosis fungoides that were successfully controlled by pralatrexate.

Outlines of the Japanese guidelines for the management of primary cutaneous lymphomas 2020

Since the publication of the Japanese "Guidelines for the management of cutaneous lymphomas" in 2011, the World Health Organization (WHO) classification of hematolymphoid neoplasms and the WHO-European Organisation for Research and Treatment of Cancer classification for primary cutaneous lymphomas were updated and a number of novel systemic drugs for cutaneous T-cell lymphoma had been approved in Japan. In 2020, we revised the Japanese guidelines for the management of cutaneous lymphomas with consideration of the recent advances in the understanding of the pathophysiology and classification of cutaneous lymphomas together with the update of treatment strategies reflecting the advent of novel drugs. In addition to a brief explanation of epidemiology, diagnosis, staging system, prognosis and management of each subtype of cutaneous lymphomas, the recommendations for nine clinical questions regarding treatment options that can vary even among experts are also described. A systematic review process and determination of recommendations in answer to each clinical question have been performed in accordance with the Grading of Recommendations, Assessment, Development and Evaluation scheme by a multidisciplinary expert panel consisting of dermatologists, a hematologist and a radiation oncologist. In this article, we present the outlines of the revised Japanese "Guidelines for the management of cutaneous lymphomas".

Pralatrexate in relapsed/refractory T-cell lymphoma: a retrospective multicenter study

We present a retrospective multicenter study of pralatrexate treatment outcomes in an Australian practice setting for patients with relapsed/refractory T-cell lymphoma who had failed 1+ systemic therapies, treated via a compassionate access program. Endpoints assessed included response rates, toxicities, and subsequent therapies. Progression-free survival (PFS), time to next treatment (TTNT), event-free survival (EFS), overall survival (OS), and time to best response, were assessed by Kaplan-Meier analysis. The study included 31 patients, with median age 69 years. We demonstrated ORR of 35.5% (n = 11), including 4 complete responses (13%) and 7 partial responses (23%). The predicted median OS was 10 months, with EFS of 9 months, and PFS of 9 months. Median TTNT was 8 months. Mucositis was the most commonly observed toxicity. This study - the second largest real-world cohort reported to date - underscores the importance of pralatrexate in relapsed/refractory T-cell lymphoma, as well as its acceptable toxicity profile.

Treatment approaches in relapsed or refractory peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of rare and aggressive non-Hodgkin’s lymphomas. Clinical staging, prognostic scoring, and initial treatment strategies have historically been based on paradigms developed in B-cell lymphomas. Despite primary treatment protocols that are typically anthracycline-based and frequently involve consolidative autologous stem cell transplantation in first remission, many patients develop disease progression. There remains a high unmet medical need for improved treatment strategies in the relapsed or refractory setting. Salvage chemotherapy and stem cell transplantation in those who are suitable has traditionally been the accepted approach, but this remains a minority of the total patient population. As increasing knowledge is gleaned regarding the biological heterogeneity within the various PTCL subtypes, newer targeted agents have been developed, studied, and approved in this small, heterogeneous population of relapsed or refractory disease. Given its success and tolerability in this pretreated population, brentuximab vedotin, an anti-CD30 antibody drug conjugate, was brought earlier in the disease course and is a model for advances in the targeted treatment of PTCL. As others undergo further development in the relapsed setting and successes are brought earlier in the disease course, the outcome for PTCL patients is likely to improve. However, innovative clinical trial designs are crucial for the assessment of targeted agents in this highly heterogeneous population. This review explores the current treatment environment for patients with relapsed and refractory PTCL, including newer strategies such as targeted agents and immunotherapy.

Generation of pralatrexate resistant T-cell lymphoma lines reveals two patterns of acquired drug resistance that is overcome with epigenetic modifiers

While pralatrexate (PDX) has been successfully developed for the treatment of T-cell lymphoma, the mechanistic basis for its T-cell selectivity and acquired resistance remains elusive. In an effort to potentially identify synergistic combinations that might circumnavigate or delay acquired PDX resistance, we generated resistant cells lines over a broad concentration range. PDX-resistant cell lines H9-12 and H9-200 were developed, each exhibiting an IC50 of 35 and over 1000 nM, respectively. These lines were established in vitro from parental H9 cells. Expression analysis of the proteins known to be important determinants of antifolate pharmacology revealed increase expression of dihydrofolate reductase (DHFR) due to gene amplification, and reduced folate carrier1 downregulation, as the putative mechanisms of resistance in H9-12 and H9-200 cells. Cross resistance was only seen with methotrexate but not with romidepsin, azacitidine (AZA), decitabine, gemcitabine, doxorubicin, or bortezomib. Resistance to PDX was reversed by pretreatment with hypomethylating agents in a concentration-dependent fashion. Comparison of gene expression profiles of parental and resistant cell lines confirmed markedly different patterns of gene expression, and identified the dual specificity phosphatase four (DUSP4) as one of the molecular target of PDX activity. Reduced STAT5 phosphorylation following exposure to PDX was observed in the H9 but not in the H9-12 and H9-200 cells. These data suggest that combination with hypomethylating agents could be potent, and that DUSP4 and STAT5 could represent putative biomarkers of PDX activity.

Efficacy and safety of single-agent pralatrexate for treatment of angioimmunoblastic T-cell lymphoma after failure of first line therapy: a pooled analysis

Angioimmunoblastic T-cell lymphoma (AITL) is a histological subtype of peripheral T-cell lymphoma associated with a poor prognosis. This post-hoc pooled analysis aims to provide insight about the efficacy of pralatrexate monotherapy in a subset of twenty-nine patients with relapsed or refractory (r/r) AITL drawn from two prospective registration trials completed in China and Japan. After a median of two prior lines of therapy, an overall response rate of 52% (15/29 patients; 95% CI 0.34, 0.70) was demonstrated. The estimated median duration of response, progression free survival (PFS) and overall survival (OS) were 6.4 months (196 days), 5.0 months (151 days), and 18.0 months (548 days), respectively. Grades 1-3 mucositis was observed in twenty-three patients (79.3%); and hemato-toxicity in twenty-six (89.7%) patients. Results of this analysis corroborate with data from two previously reported US retrospective cohorts, supporting the potential benefits of pralatrexate monotherapy in patients with r/r AITL.

Pralatrexate injection for the treatment of patients with relapsed or refractory peripheral T-cell lymphoma

INTRODUCTION

Peripheral T cell lymphomas (PTCL) are a heterogenous group of lymphoproliferative disorders which are generally not curable with conventional chemotherapy and associated with inferior outcomes. Pralatrexate is a novel folate analog, the first FDA approved drug) for the treatment of relapsed/refractory (R/R) PTCL.

AREAS COVERED

This paper provides a comprehensive review of PubMed literature describing the use of pralatrexate in R/R peripheral T-cell lymphoma. Pharmacokinetics and mechanism of action of pralatrexate are discussed as well as its clinical efficacy and safety in comparison to other agents available in R/R PTCL.

EXPERT OPINION

Pralatrexate is an active agent in relapsed/refractory PTCL with lower response rates seen in patients with angioimmunoblastic T cell lymphomas. Mucositis is the most frequently observed adverse event and this can be mitigated by the use of leucovorin along with cyanocobalamin and folic acid.

Pralatrexate in Chinese Patients with Relapsed or Refractory Peripheral T-cell Lymphoma: A Single-arm, Multicenter Study

BACKGROUND

Peripheral T-cell lymphoma (PTCL) is associated with poor prognosis, particularly in patients with relapsed/refractory (R/R) disease. Pralatrexate, a folate analogue inhibitor, was the first drug approved to treat R/R PTCL.

OBJECTIVE

As the distribution of PTCL subtypes differs between populations and few patients in the pivotal trial of pralatrexate were Asian, this study investigated the safety and efficacy of pralatrexate as monotherapy in Chinese patients with R/R PTCL.

PATIENTS AND METHODS

In this single-arm, open-label, multicenter study, 71 patients with R/R PTCL (median [range] 2 [1-14] prior systemic treatments) were recruited from 15 centers in China and received pralatrexate IV 30 mg/m²/week for 6 weeks in 7-week cycles (with vitamin B₁₂/folate). The primary endpoint was objective response rate (ORR) per central review (null hypothesis: ORR < 15%).

RESULTS

The study's primary objective was met: ORR (95% CI) was 52% (40-64%) (p < 0.001) and responses were observed across pre-specified patient subgroups. Median (95% CI) duration of response was 8.7 (3.3-14.1) months and first response was observed in Cycle 1 for most (84%) patients. Median (95% CI) progression-free survival and overall survival was 4.8 (3.1-8.1) months and 18.0 (10.4-NA) months, respectively. The most common treatment-emergent adverse events were stomatitis (68% [Grade 3/4: 20%]), anemia (49% [Grade 3/4: 24%]) and alanine aminotransferase increase (41% [Grade 3/4: 4%]).

CONCLUSIONS

These results demonstrate that pralatrexate may represent a promising treatment option for Chinese patients with R/R PTCL. The ORR of 52% compared favorably with prior studies of pralatrexate in other populations and there were no unanticipated side effects.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03349333.

The rapidly changing landscape in mature T-cell lymphoma (MTCL) biology and management

Historical advances in the care of patients with non-Hodgkin lymphoma (NHL) have been restricted largely to patients with B-cell lymphoma. The peripheral T-cell lymphomas (PTCLs), which are rare and heterogeneous in nature, have yet to experience the same degree of improvement in outcome over the past 20 to 30 years. It is estimated that there are approximately 80,000 and 14,000 cases, respectively, of NHL and Hodgkin lymphoma per year in the United States. As a subgroup of NHL, the PTCLs account for 6% to 10% of all cases of NHL, making them exceedingly rare. In addition, the World Health Organization 2017 classification describes 29 distinct subtypes of PTCL. This intrinsic diversity, coupled with its rarity, has stymied progress in the disease. In addition, most subtypes carry an inferior prognosis compared with their B-cell counterparts, an outcome largely attributed to the fact that most treatment paradigms for patients with PTCL have been derived from B-cell neoplasms, a radically different disease. In fact, the first drug ever approved for patients with PTCL was approved only a decade ago. The plethora of recent drug approvals in PTCL, coupled with a deeper understanding of the molecular pathogenesis of the disease, has stimulated the field to pursue new avenues of research that are now largely predicated on the development of novel, targeted small molecules, which include a host of epigenetic modifiers and biologics. There is an expectation these advances may begin to favorably challenge the chemotherapy paradigms that have been used in the T-cell malignancies.

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.

Pralatrexate for Prolonged Treatment of Refractory Peripheral T-Cell Lymphoma, Not Otherwise Specified, with Prophylactic Leucovorin

Peripheral T-cell lymphomas (PTCLs) are a rare and heterogenous group of hematological malignancies involving T or NK cells. PTCLs are generally associated with an aggressive course and poor prognosis. Pralatrexate (PDX) is the first FDA-approved agent for the treatment of refractory/recurrent PTCL. It has single-agent activity against PTCLs; however, oral mucositis represents dose-limiting toxicity in clinical practice. We report on the case of a patient administered with modified THP-COP therapy (pirarubicin [tetrahydropyranyl adriamycin], cyclophosphamide, and prednisone), who had bone or bone marrow as the primary lesion, which was treated successfully with PDX for an extended period of 1 year, with prophylactic use of leucovorin for oral mucositis. The maintenance dose of PDX was 30 mg/m² IV, over 3 consecutive weeks dosing with a 1-week rest period due to bone marrow suppression. The patient also received leucovorin 5 mg PO 3 times daily from days 2 to 6 after each PDX administration. Disease activity was well controlled, stable, and no oral mucositis was observed over the course of treatment.

Pralatrexate induced durable response in a relapsed/refractory peripheral T-cell lymphoma patient with a history of autologous stem cell transplantation: Case report of a patient followed-up over 3 years under pralatrexate treatment

RATIONALE

Relapsed or refractory peripheral T-cell lymphomas are aggressive diseases. Pralatrexate is an antimetabolite. Hereby, we are reporting a pralatrexate induced durable response in a relapsed/refractory peripheral T-Cell lymphoma patient with a history of autologous stem cell transplantation.

PATIENT CONCERNS

A male patient born in February 1947 was diagnosed with lymphoma based on his cervical lymph node excisional biopsy.

DIAGNOSES

He was diagnosed with PTCL-NOS on February 19, 2013.

INTERVENTIONS

The patient received 6 cycles of CHOP (Cyclophosphamide, doxorubicine, vincristine, methylprednisolone) chemotherapy, which achieved a complete remission. The patient underwent autologous stem cell transplantation in December 2013. After relapse was detected in the third month of the transplantation, the patient was treated with 2 cycles of ViGePP (vinorelbine, gemcitabine, procarbazine, prednisone/ methylprednisolone) chemotherapy. The patient was considered refractory to treatment after the ViGePP chemotherapy, and he was given brentuximab vedotin. Once a full response to treatment was achieved after 2 cycles, the patient received 6 cycles of brentuximab vedotin treatment. After 6 cycles, a skin biopsy was performed and the patient was diagnosed with relapsed/refractory PTCL-NOS. Pralatrexate therapy was then started on February 1, 2016 at a dose of 30 mg/m once weekly for 6 weeks in 7-week cycles.

OUTCOMES

The patient responded to pralatrexate treatment. And he has been under pralatrexate treatment over 3 years.

LESSONS

Pralatrexate should also be kept in mind as a treatment alternative in relapsed or refractory peripheral T-cell lymphoma patients.

Lymph node fine-needle cytology in the era of personalised medicine. Is there a role?

The 2016 World Health Organisation revised classification of lymphoma has sub-classified well-defined entities and added a number of provisional entities on the basis of new knowledge on genetic, epigenetics and phenotypical data; prognostic and predictive features are also part of this classification. New knowledge on well-defined entities further enlightens the mechanisms of lymphomagenesis, which are more complex and multifactorial than once believed. Therapies are also more complex because traditional clinical trials have been integrated with new drugs and compounds with unique mechanisms of actions against distinct molecular targets. As lymphoma acquires additional genetic and phenotypic features over the time, pathological assessment is also necessary. Histological evaluation and tissue collection by surgical biopsies are necessary for phenotypical and molecular purposes; however, these are demanding procedures for both the patient and the health care system. At the same time, the choice of the best treatment for a specific entity, in different phases and different patients requires information that may not be available when the biopsy is performed. Fine needle aspiration cytology (FNAC) is successfully used in lymph nodes (LNs) in combination with different ancillary techniques and might be used to assess the phenotypic and genetic profile of specific targets and to get key information for therapy, in different phases and stages of the disease, with the option to re-check the same target over time, without surgical excision. This brief review describes LN-FNAC diagnostic criteria, current therapies for lymphomas and the potential role of LN-FNAC in selecting non-Hodgkin lymphomas patients for specific targeted treatments.

Novel and Future Therapeutic Drugs for Advanced Mycosis Fungoides and Sézary Syndrome

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common subtypes of cutaneous T-cell lymphoma. The majority of MF cases present with only patches and plaques and the lesions are usually limited to the skin. On the other hand, in some cases, patients show skin tumors or erythroderma followed by lymph node involvement and rarely visceral organ involvement. SS is a rare, aggressive cutaneous T-cell lymphoma marked by exfoliative erythroderma, lymphadenopathy, and leukemic blood involvement. Because patients with relapsed or refractory MF/SS display a poor prognosis and the current treatment options are characterized by high rates of relapse, there is unmet need for the efficient treatment. This review provides a discussion of the recent and future promising therapeutic approaches in the management of advanced MF/SS. These include mogamulizumab, brentuximab vedotin, alemtuzumab, immune checkpoint inhibitors, IPH4102 (anti-KIR3DL2 antibody), histone deacetylase inhibitors (vorinostat, romidepsin, panobinostat, belinostat, and resminostat), pralatrexate, forodesine, denileukin diftitox, duvelisib, lenalidomide, and everolimus.

Recent advances in understanding and managing T-cell lymphoma

Owing to the rarity of peripheral T-cell lymphoma (PTCL) and the heterogeneity of subtypes, there are no compelling data to guide the therapeutic approaches for such patients. Over the years, there have been remarkable advances in molecular subtyping and treatment of PTCL, although there are still many areas to be explored. In this review, we summarize recent updates on the evolution of understanding and treatment for PTCL.

Phase I/II study of pralatrexate in Japanese patients with relapsed or refractory peripheral T-cell lymphoma

Pralatrexate is a novel antifolate approved in the USA for the treatment of relapsed or refractory peripheral T‐cell lymphoma. To assess its safety, efficacy, and pharmacokinetics in Japanese patients with this disease, we undertook a phase I/II study. Pralatrexate was given i.v. weekly for 6 weeks of a 7‐week cycle. All patients received concurrent vitamin B₁₂ and folic acid. In phase I, three patients received pralatrexate 30 mg/m² and none experienced a dose‐limiting toxicity. In phase II, we treated 22 additional patients with that dose. The median number of treatment cycles was 1 (range, 1–9). Nine of 20 evaluable patients (45%) achieved an objective response by central review, including two complete responses. All responses occurred within the first treatment cycle. At the time of data cut‐off, median progression‐free survival was 150 days. Median overall survival was not reached. In the total population, the most commonly reported adverse events included mucositis (88%), thrombocytopenia (68%), liver function test abnormality (64%), anemia (60%), and lymphopenia (56%). Grade 3/4 adverse events included lymphopenia (52%), thrombocytopenia (40%), leukopenia (28%), neutropenia (24%), anemia (20%), and mucositis (20%). The pharmacokinetic profile showed no drug accumulation with repeat dosing. These results indicate that pralatrexate is generally well tolerated and effective in Japanese patients with relapsed or refractory peripheral T‐cell lymphoma. This trial was registered with ClinicalTrials.gov (NCT02013362).