Pentostatin in T-cell malignancies--a phase II trial of the EORTC. Leukemia Cooperative Group

Current understandings on T-cell prolymphocytic leukemia and its association with TCL1 proto-oncogene

T-cell prolymphocytic leukemia (T-PLL) is a rare mature T cell leukemia with aggressive clinical course, poor response to conventional therapies and high mortality rates. Classical cytogenetics and various genetic techniques have observed complex karyotypes and associated genes involved in the molecular pathogenesis of T-PLL, among which the proto-oncogene T-cell leukemia/lymphoma 1 (TCL1) as a hallmark of malignancy is hyper-activated and abnormally expressed in many T-PLL cases. Progress has been made to identify the presence of chromosomal rearrangements and subsequent changes in key molecular pathways typically involving Akt, which may hint cytogenetic mechanisms underlying the pathogenesis of T-PLL and indicate new treatment targets. In this article, we describe current insights of T-PLL with an emphasis on the potential role of TCL1 gene disorders and TCL1-Akt interactions in cell transformation and disease progression, followed by discussion on current treatment options and novel therapeutic approaches based on cytogenetics, which still remains to be explored for the effective management of T-PLL and other TCL1-driven hematological malignancies.

Advances in the understanding and management of T-cell prolymphocytic leukemia

T-prolymphocytic leukemia (T-PLL) is a rare T-cell neoplasm with an aggressive clinical course. Leukemic T-cells exhibit a post-thymic T-cell phenotype (Tdt-, CD1a-, CD5+, CD2+ and CD7+) and are generally CD4+/CD8-, but CD4+/CD8+ or CD8+/CD4- T-PLL have also been reported. The hallmark of T-PLL is the rearrangement of chromosome 14 involving genes for the subunits of the T-cell receptor (TCR) complex, leading to overexpression of the proto-oncogene TCL1. In addition, molecular analysis shows that T-PLL exhibits substantial mutational activation of the IL2RG-JAK1-JAK3-, STAT5B axis. T-PLL patients have a poor prognosis, due to a poor response to conventional chemotherapy. Monoclonal antibody therapy with antiCD52-alemtuzumab has considerably improved outcomes, but the responses to treatment are transient; hence, patients who achieve a response to therapy are considered for stem cell transplantation (SCT). This combined approach has extended the median survival to four years or more. Nevertheless, new approaches using well-tolerated therapies that target growth and survival signals are needed for most patients unable to receive intensive chemotherapy.

Cutaneous T-cell lymphoma: 2017 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell lymphoproliferative disorders involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multi-disciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or blood involvement are generally approached with biologic-response modifiers or histone deacetylase inhibitors prior to escalating therapy to include systemic, single-agent chemotherapy. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Cutaneous T-cell lymphoma: 2016 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell lymphoproliferative disorders involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multidisciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral, or blood involvement are generally approached with biologic-response modifiers or histone deacetylase inhibitors before escalating therapy to include systemic, single-agent chemotherapy. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Cutaneous T-cell lymphoma: 2014 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell lymphoproliferative disorders involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, and blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multidisciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or blood involvement are generally approached with biologic-response modifiers or histone deacetylase inhibitors prior to escalating therapy to include systemic, single-agent chemotherapy. Multiagent chemotherapy (e.g., CHOP) may be employed for those patients with extensive visceral involvement requiring rapid disease control. In highly selected patients, allogeneic stem-cell transplantation may be considered.

Cutaneous T-cell lymphoma: 2011 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell lymphoproliferative disorders involving the skin, the majority of which may be classified as Mycosis fungoides (MF) or Sézary syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

Tumor, node, metastasis, and blood (TNMB) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multidisciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral, or blood involvement are generally approached with biologic-response modifiers, denileukin diftitox, and histone deacetylase inhibitors before escalating therapy to include systemic, single-agent chemotherapy. Multiagent chemotherapy may be used for those patients with extensive visceral involvement requiring rapid disease control. In highly-selected patients with disease refractory to standard treatments, allogeneic stem-cell transplantation may be considered.

Pentostatin for treatment of steroid-refractory acute GVHD: a retrospective single-center analysis

Acute GVHD (aGVHD) remains a major cause of mortality in patients undergoing allo-SCT. In particular, the outcome of those patients who fail first-line therapy with glucocorticosteroids is poor. Preliminary reports suggested that the purine analogue pentostatin might be effective for treatment of steroid-refractory aGVHD. Here, we report on our single-center experience with pentostatin in this condition. From 2005 to 2008, a total of 24 consecutive patients, who had undergone first-line salvage treatment for steroid-refractory aGVHD of the gastrointestinal tract with pentostatin, were identified from 301 patients allografted during that period and retrospectively analyzed. Response to treatment, defined as CR or very good PR (VGPR), was observed in nine patients (38%), with a median time to response of 10 days. Although pentostatin was associated with only moderate myelosuppressive toxicity, if any, 2-year survival was only 17% with five of the nine responders dying from infection (four patients) or recurrent GVHD (one patient). We conclude that pentostatin is a moderately effective therapy for steroid-refractory aGVHD, showing response and outcome rates similar to other clinically used regimens.

Role of Single-Agent Purine Analogues in Therapy of Peripheral T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) comprise a heterogeneous group of lymphomas with different clinical presentation and morphologic, immunophenotypic, and cytogenetic markers. Many of these malignancies follow an aggressive course and current therapeutic strategies are limited. The prognosis for these patients is usually very poor. The purine analogues are a class of drugs that have been shown to be active in patients who have T-cell lymphoma. T cells have a very high concentration of adenosine deaminase (ADA), a key enzyme in the purine degradation pathway, which is blocked by this class of agent. Pentostatin has been the most extensively studied of these drugs in PTCL and has shown variable response rates. However, many of the reports are limited to small single-center studies. Larger prospective randomized trials will be necessary to examine this therapy and to further explore combination regimens, which may result in increased responses.

Purine Analogues in Advanced T-Cell Lymphoid Malignancies

T-cell lymphomas account for 10% to 15% of all lymphoid malignancies. In advanced stages of T-cell lymphoma, single or multiagent chemotherapy and bioimmunotherapeutic agents have been used. Purine analogues have demonstrated activity in both refractory cutaneous T-cell lymphoma and peripheral T-cell lymphoma with response rates ranging from 20% to 70%. Response rates have been higher with pentostatin (60%) than with the other compounds in this class. The potential limitation to this therapy is the prolonged immunosuppression, which increases the risk of opportunistic injections in patients who are already at heightened risk for infections. Patients should be monitored closely with CD4 counts and surveillance for opportunistic infections. Future studies of purine analogues should evaluate patients who are less heavily pretreated and combination therapy with other agents such as alemtuzumab should be investigated in order to prolong the duration of disease remission.

Pentostatin and purine analogs for indolent lymphoid malignancies

Pentostatin has been shown to be active in a variety of B- and T-cell malignancies. The drug is a tight inhibitor of adenosine deaminase, a key degradative enzyme of purine metabolism present in all human tissues, with the highest levels found in the lymphoid system. Early clinical trials indicated that this agent was highly active in acute lymphoblastic leukemias with high intracellular adenosine deaminase levels. Relatively high doses of the drug were needed, which was associated with severe adverse events. Through the efforts of a few investigators, better tolerated, low-dose regimens have been shown to be extremely active in lymphoproliferative diseases with very low intracellular adenosine deaminase levels such as hairy cell leukemia, B- and T-cell chronic leukemias, T-cell cutaneous lymphomas and low-grade non-Hodgkin lymphomas. Clinical as well as experimental data have indicated that this drug induces lymphocyte-specific cytotoxicity, and myelosuppressive adverse events have been minimal. Although all the purine analogs have shown similar activity, the advantage of pentostatin is the relatively specific cytotoxicity against lymphocytes, which permits treatment even in patients with severe cytopenias. Although no direct comparisons of the purine analogs have been performed, pentostatin may be preferred due to this property.

Gemcitabine as frontline treatment for cutaneous T-cell lymphoma

BACKGROUND

Based on the activity of gemcitabine in heavily pretreated patients with cutaneous T-cell lymphoma (CTCL), the objective of the current study was to determine the role of gemcitabine in the treatment of patients with advanced, untreated CTCL.

METHODS

Between June 2002 and February 2004, 32 untreated patients with mycosis fungoides (MF) (n = 26 patients); peripheral T-cell lymphoma, unspecified (PTCLU) with exclusive skin involvement (n = 5 patients); and Sezary syndrome (SS) (n = 1 patient) were enrolled in a 7-institution, Phase II trial and treated with gemcitabine. This drug was given on Days 1, 8, and 15 of a 28-day schedule at a dose of 1200 mg/m2 intravenously over 30 minutes for a total of 6 cycles.

RESULTS

Of the 32 patients studied, 7 (22%) achieved a complete response (CR) and 17 (53%) achieved a partial response (PR), whereas the remaining 8 patients showed no benefit from the treatment. Five of the CRs were confirmed histologically. The CR and PR rates were found to be the same for patients with MF and PTCLU, respectively. The median duration of CR was 10 months (range, 4-22 mos). Treatment appeared to be well tolerated; hematologic toxicity was mild and no nausea/emesis or organ toxicity was noted.

CONCLUSIONS

The results of the current Phase II study demonstrate the activity of gemcitabine as a single agent in untreated CTCL patients. Further studies using gemcitabine in combination, either contemporary or sequentially, with other drugs in patients with advanced stage, untreated CTCL are needed.

Therapy for mycosis fungoides

Treatment of mycosis fungoides (MF) is indicated to reduce symptoms, improve clinical appearance, prevent secondary complications, and prevent progression of disease, all of which may have an impact on survival. Treatment of MF includes topical and systemic therapies, which can be administered alone or in combination. Psoralen and ultraviolet A radiation is effective in early-stage MF, inducing complete remissions in most patients. Psoralen and ultraviolet A radiation may also be combined with low doses of interferon (IFN)-alpha to treat stage I/II disease. However, early aggressive therapy with radiation and chemotherapy does not improve the prognosis. Local radiotherapy or total skin electron beam irradiation has been used with success to control advanced skin disease. Extracorporeal photopheresis may also be used successfully, but it is not generally available. Once the disease becomes refractory to topical therapy, IFN-alpha single-agent or combination chemotherapy may be administered, but the duration of response is often less than 1 year and ultimately all patients will relapse and become refractory. Among chemotherapeutic agents, pentostatin, gemcitabine, and liposomal doxorubicin seem to be particularly effective. Response rates after combined modality therapy with total skin electron beam irradiation and chemotherapy/IFN-alpha appear similar to response rates of chemotherapy alone. Therefore, there is a great need for the further development of novel emerging treatment modalities, such as retinoids (ie, bexarotene) and immunotherapeutic agents (ie, cytokines, tumor vaccines, and monoclonal antibodies), all of which appear to have significant therapeutic potential in patients with MF. Biologically based therapies may reduce the need for genotoxic therapies, such as cytostatics and radiotherapy.

Phase II study of pentostatin in advanced T-cell lymphoid malignancies

BACKGROUND

The goal of the current study was to assess the toxicity, safety, and efficacy of pentostatin in patients with T-cell lymphoid malignancies.

METHODS

Patients were eligible if they had biopsy-proven T-cell lymphoma or leukemia and failure to respond to previous therapy or an expected complete response rate to conventional therapy of < 20%. Pentostatin was administered at an initial dose of 3.75 or 5.0 mg/m(2) by intravenous bolus daily over a consecutive 3-day period every 3 weeks.

RESULTS

Forty-two of 44 patients enrolled in the study were evaluable. The median age of the patients was 62 years (range, 38-86 years). Patients received a median of 3 previous therapies (range, 0-10 previous therapies). Of these patients, 32 (76%) had mycosis fungoides/Sézary syndrome and 10 patients (24%) had other T-cell leukemias or lymphomas. The overall response rate was 54.8% (complete remission, 6 patients [14.3%]; partial remission, 17 patients [40.5%]). Durable responses were observed mainly in patients with Sézary syndrome or peripheral T-cell lymphoma. The median follow-up period for surviving patients was 20 months (range, 1-83+ months). The median duration of response was 4.3 months (range, 1-61 months). The most common toxicities were neutropenia, nausea, and CD4 suppression. A transient early "flare" of disease was observed in some responders.

CONCLUSIONS

At these doses, pentostatin was reasonably well tolerated and is an effective drug for the treatment of T-cell lymphomas.

Deoxycoformycin-containing combination chemotherapy for adult T-cell leukemia-lymphoma: Japan Clinical Oncology Group Study (JCOG9109)

Aggressive adult T-cell leukemia-lymphoma (ATL) generally has a very poor prognosis. Deoxycoformycin (DCF, pentostatin), an inhibitor of adenosine deaminase, has shown promising therapeutic efficacy for ATL. To develop a new effective therapy against aggressive ATL, we carried out a multicenter phase II study of DCF-containing combination chemotherapy. Sixty-two previously untreated patients with ATL (34, 21, and 7 patients with diseases of the acute, lymphoma, and unfavorable chronic types, respectively) were enrolled, but 2 were ineligible because they were judged to be favorable chronic types. A regimen of 1 mg/m2 vincristine intravenously on days 1 and 8, 40 mg/m2 doxorubicin intravenously on day 1, 100 mg/m2 etoposide intravenously on days 1 through 3, 40 mg/m2 prednisolone orally on days 1 and 2, and 5 mg/m2 DCF intravenously on days 8, 15, and 22 was administered every 28 days for 10 cycles unless disease progression or toxic complications occurred. Fifty-two percent of 60 eligible patients responded (95% confidence interval [CI], 38%-65%), with 17 patients (28%) achieving a complete response (CR) (95% CI, 17%-41%) and 14 achieving a partial response. The CR rate was inferior to those of both the previous Japan Clinical Oncology Group (JCOG) study (JCOG8701, 43%), a 9-drug combination chemotherapy of the second generation, and the subsequent JCOG9303 study (35%), a granulocyte colony-stimulating factor-supported, dose-intensified, 9-drug regimen. The median survival time of the 60 eligible patients in JCOG9109 was 7.4 months, and the estimated 2-year survival rate was 15.5%; these results were identical with those of JCOG8701 but inferior to those of JCOG9303. Grade 4 neutropenia and infection of grade 3 or greater were frequent (67% and 22%, respectively), and treatment-related death was observed in 4 patients (7%), septicemia in 2, and cytomegalovirus pneumonia in 2. We conclude that DCF-containing combination chemotherapy is not a promising regimen against aggressive ATL.

Peripheral T-cell lymphoma

Peripheral (post-thymic) T-cell lymphoma consists of a wide spectrum of disorders with marked differences in biology and behavior. Proper classification is pivotal for evaluating treatment results, and most studies performed a decade ago lump together different disease entities and cannot be interpreted. With improved use of immunophenotyping and molecular methods for these disorders, their exact nature is better defined in the Revised European-American Lymphoma and subsequent World Health Organization (WHO) classifications. The WHO classification of post- thymic T/natural killer (NK)-cell lymphoma consists of 15 entities, including about 30% that are unclassified cases. A wide range in incidence exists between different populations, but it is likely to be lower than previously estimated. Certain entities, like nasal/nasal-type T/NK-cell lymphoma and human T-cell leukemia/lymphoma virus 1, are much more prevalent in certain racial groups and show exquisite viral association. In these entities as a group, prognosis and treatment seem inferior to those of their B-cell counterparts, but treatment must be tailored to the exact pathologic diagnosis and prognostic index. Aggressive combination chemotherapy appears to be curative for certain entities (eg, anaplastic lymphoma kinase-positive), whereas purine analogues may be useful for low-grade entities. The role of autologous and allogeneic stem cell transplantation is still poorly defined. Specific antibody-based therapy is also on the horizon.

Treatment of refractory T-cell malignancies using gemcitabine

We have treated 10 patients with relapsed or refractory T-cell malignancies using gemcitabine. The drug was administered intravenously over 30 min at a dose of 1200 mg/m2 on d 1, 8 and 15 of each 28-d cycle. The mean age of the patients was 62 years and the mean number of administered cycles was three. Of the 10 patients, two achieved a complete response and four a partial response, for an overall response rate of 60% (95% confidence interval 20--35%). The toxicity of chemotherapy was mild and manageable in all patients. These encouraging results warrant further investigation of gemcitabine either as a single agent or in combination regimens as early salvage treatment for patients with refractory T-cell haematological neoplasms.

In vitro and in vivo effects of 2'-deoxycoformycin (Pentostatin) on tumour cells from human gammadelta+ T-cell malignancies

Hepatosplenic gammadelta+ T-cell lymphoma represents a rare neoplasm of post-thymic phenotype, characterized by an aggressive clinical course and a poor response to conventional chemotherapy. In the present study, we have examined the cytotoxic effects of the purine analogue 2'-deoxycoformycin (dCF) on cultured mononuclear cells and purified gammadelta+ tumour cells from bone marrow or peripheral blood of four patients with hepatosplenic gammadelta+ T-cell lymphoma. At a concentration of 10 microM, dCF, in the presence of 2'-deoxyadenosine (dAdo), displayed an early and selective cytotoxic effect on gammadelta+ tumour T cells. After 48 h of in vitro exposure to dCF, the absolute number of viable CD3+/gammadelta+ tumour T cells was reduced by more than 90% in all samples with respect to control cultures, with absolute counts of viable CD3+/alphabeta+ lymphocytes being reduced only by 6-40% of the initial cell input. Analysis of cultures after 5 d of exposure to dCF plus dAdo revealed the persistence of normal CD3+/alphabeta+ T cells, which accounted, however, for only 20-25% of the initial cell input. Accordingly, the combination of dCF (10-100 microM) plus dAdo was able to induce a dose-dependent inhibition of clonogenic growth and [3H]-thymidine incorporation in purified CD3+/CD4-/CD8- gammadelta+ tumour cells. We also report that one patient with hepatosplenic gammadelta+ T-cell lymphoma in terminal leukaemic phase showed a striking haematological response to single-agent dCF given as fourth-line treatment. In particular, the selective clearance of gammadelta+ tumour T cells in peripheral blood and bone marrow was observed starting after the second course of treatment. Our results suggest that dCF may represent a potentially active drug for the management of this aggressive form of T-cell lymphoma.