Cutaneous T-cell Lymphoma

GFI-1 overexpression promotes cell proliferation and apoptosis resistance in mycosis fungoides by repressing Bax and P21

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma. The majority of patients with advanced stage MF are resistant to conventional chemotherapy and thus have a poor prognosis. The transcriptional repressor growth factor independence-1 (GFI-1) serves an important role in the development of T-cells. The results of the present study demonstrated that the expression of GFI-1 at different clinical stages of MF was significantly higher compared with benign inflammatory dermatoses, and there was a significant association with disease progression. Gene knockdown of GFI-1 results in the inhibition of Hut-78 cell proliferation and clone formation in vitro, cell cycle arrest and spontaneous apoptosis, upregulation of cell cycle-related P21, as well as the apoptosis-related proteins Bax and Caspase-3, and downregulation of CDK2. Using luciferase assays, and mutational analysis, it was demonstrated that GFI-1 directly regulated the transcription of P21. The results of the present study highlighted a potential molecular therapeutic approach for the treatment of advanced MF.

Cutaneous T Cell Lymphoma: A Difficult Diagnosis Demystified

Cutaneous T cell lymphoma (CTCL) represents a heterogeneous group of extranodal non-Hodgkin lymphomas in which monoclonal T lymphocytes infiltrate the skin. The mechanism of CTCL development is not fully understood, but likely involves dysregulation of various genes and signaling pathways. A variety of treatment modalities are available, and although they can induce remission in most patients, the disease may recur after treatment cessation. Owing to relatively low incidence and significant chronicity of disease, and the high morbidity of some therapeutic regimens, further clinical trials are warranted to better define the ideal treatment option for each subtype of CTCL.

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.

Proteomic Approaches to Biomarker Discovery in Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma (CTCL) is the most frequently encountered type of skin lymphoma in humans. CTCL encompasses multiple variants, but the most common types are mycosis fungoides (MF) and Sezary syndrome (SS). While most cases of MF run a mild course over a period of many years, other subtypes of CTCL are very aggressive. The rapidly expanding fields of proteomics and genomics have not only helped increase knowledge concerning the carcinogenesis and tumor biology of CTCL but also led to the discovery of novel markers for targeted therapy. Although multiple biomarkers linked to CTCL have been known for a relatively long time (e.g., CD25, CD45, CD45RA, and CD45R0), compared to other cancers (lymphoma, melanoma, colon carcinoma, head and neck cancer, renal cancer, and cutaneous B-cell lymphoma), information about the antigenicity of CTCL remains relatively limited and no dependable protein marker for CTCL has been discovered. Considering the aggressive nature of some types of CTCL, it is necessary to identify circulating molecules that can help in the early diagnosis, differentiation from inflammatory skin diseases (psoriasis, nummular eczema), and aid in predicting the prognosis and evolution of this pathology. This review aims to bring together some of the information concerning protein markers linked to CTCL, in an effort to further the understanding of the convolute processes involved in this complex pathology.

TOX expression and role in CTCL

BACKGROUND

Cutaneous T-cell lymphomas (CTCL) are skin malignancies including mycosis fungoides (MF) and CD30(+) lymphoproliferative disorders (LPD). In early disease, CTCL can be difficult to diagnose, especially in MF for which there is no reliable diagnostic marker. MF/CTCL have increased expression of thymocyte selection-associated HMG box protein (TOX). Although TOX has been proposed to be a diagnostic marker for MF, further validation studies are needed. Moreover, it is unclear what drives TOX expression or its role in MF/CTCL.

OBJECTIVE

We hypothesize evaluation of TOX levels across a spectrum of CTCL, including MF precursor (large plaque parapsoriasis, LPP), will help elucidate the implications of altered TOX expression.

MATERIALS AND METHODS

TOX staining was performed in MF, CD30(+) LPD, LPP as well as benign inflammatory dermatoses (BID) and normal skin (NS). CTCL cell lines were utilized to evaluate the regulation of TOX.

RESULTS

Positive TOX expression was identified in 73.6% of MF cases and in 31.6% of BID/NS. TOX had a positive predictive value (PPV) for MF of 86.7% and a negative predictive value (NPV) of 48.1%. TOX expression in MF was detected more commonly in Black patients (P = 0.015) and less commonly in transformed MF (P = 0.045). LPP had positive TOX staining in 70.0%. In CTCL cells, GATA3 knockdown decreased TOX mRNA and protein expression. TOX expression also decreased in the presence of CTCL therapeutics.

CONCLUSION

Our data indicate that TOX is useful as a diagnostic marker in MF. Moreover, TOX expression was evident in LPP, indicating it may have a previously unappreciated role in the development of MF. Finally, our data suggest that GATA3 regulates TOX, revealing insight into TOX regulation.

Romidepsin for the treatment of relapsed/refractory cutaneous T-cell lymphoma (mycosis fungoides/Sézary syndrome): Use in a community setting

Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of rare non-Hodgkin lymphomas that arise in the skin. In advanced stages, CTCL becomes systemic and is associated with poor prognosis. Diagnosis of CTCL and treatment of early-stage disease with topical therapies often occurs under the care of a dermatologist. Community oncologists see few patients with CTCL due to direct referrals from dermatologists to academic or lymphoma specialty centers. However, some patients will continue to be managed in a community setting. Currently there is no evidence-based stepwise algorithm for treatment of patients with CTCL, and guidelines suggest a wide range of systemic therapies, including biologics, targeted agents, and more traditional chemotherapies. To provide optimal care in a community setting, oncologists must become familiar with newer nonchemotherapeutic treatment options. This review highlights romidepsin, a histone deacetylase inhibitor approved for the treatment of patients with CTCL who have received ≥1 prior systemic therapy.

Vorinostat-An Overview

Vorinostat is a new drug used in the management of cutaneous T cell lymphoma when the disease persists, gets worse or comes back during or after treatment with other medicines. It is an efficacious and well tolerated drug and has been considered a novel drug in the treatment of this condition. Currently apart from cutaneous T cell lymphoma the role of Vorinostat for other types of cancers is being investigated both as mono-therapy and combination therapy.

Skin Recurrence of Transformed Mycosis Fungoides Postumbilical Cord Blood Transplant despite Complete Donor Chimerism

Background. Allogeneic stem cell transplant is the treatment of choice for systemic cutaneous T-cell lymphoma (CTCL) which provides graft-versus-lymphoma effect. Herein we discuss a case of recurrence of CTCL skin lesions after cord blood transplant in a patient who continued to have 100% donor chimerism in bone marrow. Case Presentation. A 48-year-old female with history of mycosis fungoides (MF) presented with biopsy proven large cell transformation of MF. PET scan revealed multiple adenopathy in abdomen and chest suspicious for lymphoma and skin biopsy showed large cell transformation. She was treated with multiple cycles of chemotherapy. Posttherapy PET scan showed resolution of lymphadenopathy. Later she underwent ablative preparative regimen followed by single cord blood transplant. Bone marrow chimerism studies at day +60 after transplant showed 100% donor cells without presence of lymphoma. However 5 months after transplant she had recurrence of MF with the same genotype as prior skin lesion. Bone marrow chimerism study continued to show 100% donor cells. Conclusion. A differential graft-versus-lymphoma effect in our case prevented lymphoma recurrence systemically but failed to do so in skin. We hypothesize that this response may be due to presence of other factors in the bone marrow and lymph node microenvironments preventing recurrence in these sites.

Classification and clinical features in 88 cases of equine cutaneous lymphoma

Equine cutaneous lymphoma is an uncommon disease that can present with variable clinical signs, immunosuppression, and rapid systemic disease progression. Various subtypes of equine lymphoma have been described and classified according to a veterinary adaptation of the World Health Organization classification system, but little data is available regarding the association between lymphoma subtypes and epidemiological criteria and/or clinical outcome. The objective of the current study was to classify previously diagnosed cases of equine cutaneous lymphoma and correlate subtypes with clinical data to investigate epidemiological trends and prognostic implications. Results from the study confirm T-cell–rich, large B-cell lymphoma (TCRLBCL) as the predominant subtype in equine cutaneous lymphoma. Cutaneous T-cell lymphoma (CTCL) was the second most common phenotype in the current study. To the authors’ knowledge, a description of the morphological and immunohistochemical features of CTCL in horses, an epitheliotropic neoplasm similar to the cutaneous epitheliotropic lymphoma variant (mycosis fungoides) observed in human beings and canids, has not been previously described. Less common lymphoma subtypes identified in the study include diffuse large B-cell lymphoma and anaplastic large T-cell lymphoma. Quarter Horses almost exclusively developed TCRLBCL, while the frequency of CTCL was increased significantly in Thoroughbreds compared with other breeds. TCRLBCLs more frequently presented as multiple masses while CTCLs were more often solitary nodules. When multiple regions of the body were affected, 100% of cases were TCRBCL. Finally, there was an observable trend for longer survival in cases of TCRLBCL without local recurrence, suggesting adequate surgical excision may be an effective treatment modality.

Tolerability to romidepsin in patients with relapsed/refractory T-cell lymphoma

Background

Histone deacetylase inhibitor romidepsin has demonstrated durable clinical responses and tolerability in patients with relapsed/refractory peripheral and cutaneous T-cell lymphoma (PTCL, CTCL). Selection of novel drug therapies for patients with relapsed/refractory aggressive lymphoma requires not only considerations regarding efficacy but also careful evaluation of toxicities as well as overall clinical benefit. The purpose of this analysis was to examine common adverse events (AEs) reported in pivotal trials of romidepsin in relapsed/refractory PTCL or CTCL and to more clearly define the overall AE profile in these populations.

Methods

Patients with relapsed/refractory PTCL or CTCL were treated with romidepsin at 14 mg/m² as a 4-hour intravenous infusion on days 1, 8, and 15 of 28-day cycles for up to 6 cycles; patients with at least stable disease could extend therapy until progressive disease or another withdrawal criterion was met. All enrolled patients who received ≥ 1 dose of romidepsin were included in the AE analyses.

Results

Overall, safety profiles of common AEs were similar, although patients with relapsed/refractory PTCL had more frequent hematologic toxicities and grade ≥ 3 infections. In both patient populations, the greatest incidence of grade ≥ 3 AEs and the majority of discontinuations due to AEs occurred during cycles 1–2. Early discontinuations were primarily related to infection, thrombocytopenia, or electrocardiogram abnormalities, confirming the need to closely monitor patients with poor bone marrow reserve or other comorbidities. Despite this, 28% of patients with relapsed/refractory PTCL and 36% of patients with relapsed/refractory CTCL continued on romidepsin treatment for ≥ 6 cycles.

Conclusions

This study demonstrates that patients with relapsed/refractory PTCL or CTCL have similar AE profiles with romidepsin treatment, although patients with PTCL experienced more frequent and more severe hematologic toxicities and more frequent grade ≥ 3 infections. The greatest incidence of grade ≥ 3 AEs and the majority of discontinuations due to AEs occurred during treatment cycles 1–2. Extended dosing of romidepsin can be tolerated in responding patients.

Trial registration

NCT00426764,NCT00106431

Romidepsin for the treatment of T-cell lymphomas

PURPOSE

The pharmacology, pharmacokinetic and pharmacodynamic properties, and clinical data on a novel therapy for the treatment of cutaneous or peripheral T-cell lymphoma (CTCL, PTCL) are summarized.

SUMMARY

Romidepsin is the only bicyclic histone deacetylase (HDAC) inhibitor to undergo clinical development. A potent and specific inhibitor of class 1 HDACs, romidepsin has linear pharmacokinetics and is primarily metabolized by cytochrome P-450 isoenzyme 3A4. In two Phase II studies involving patients with relapsed or refractory CTCL, romidepsin therapy produced overall response rates of 34-35% (including patients with advanced and heavily pretreated disease), with a complete response seen in about 6% of patients in both studies; romidepsin responses were seen across all evaluated disease sites (skin, blood, lymph, viscera). In two Phase II studies in patients with relapsed or refractory PTCL, romidepsin produced overall response rates of 25-38%, and 15-18% of patients experienced a complete response; therapeutic responses were seen across major PTCL subtypes regardless of the number or types of previous therapies or refractoriness to the last prior therapy. In clinical trials to date, romidepsin therapy was generally well tolerated, with nausea, fatigue, and vomiting reported as the most common nonhematologic adverse events. However, thrombocytopenia and neutropenia are relatively common events, especially in patients with PTCL.

CONCLUSION

Romidepsin, a class 1-specific HDAC inhibitor, induces durable responses, with a manageable toxicity profile, in patients with relapsed or refractory CTCL or PTCL who have few therapeutic options.

Cutaneous T-cell lymphoma in patients with chronic lymphocytic leukemia: clinical characteristics, temporal relationships, and survival data in a series of 14 patients at Mayo Clinic

BACKGROUND

We examined the course of cutaneous T-cell lymphoma (CTCL), which has been associated with chronic lymphocytic leukemia (CLL) in patients with CLL.

MATERIALS AND METHODS

A search was conducted of the master diagnosis index at our institution to identify patients with both CLL and CTCL from 1980 to 2010. A retrospective chart review was then conducted.

RESULTS

Of the 14 patients with CTCL and CLL, eight had mycosis fungoides (MF; two with patch stage, two with plaque stage, two with tumor stage, and two with erythrodermic stage), four had Sézary syndrome, one had natural killer cell lymphoma involving the skin, and one had peripheral T-cell lymphoma involving the skin. Eight had concurrent diagnoses, five received a CLL diagnosis first, and one received a CTCL diagnosis first. Ten patients were deceased at the time of data abstraction due to unknown causes (n = 4), lymphoma (n = 2), pneumonia (n = 2), MF (n = 1), or respiratory failure (n = 1). Of the nine patients with concurrent or prior CTCL, seven were deceased, with a median time to death of 10.2 months (range, 6-89 months). Of the five patients with CLL prior to CTCL, three were deceased at 18, 27, and 47 months, respectively, after the CTCL diagnosis. The median survival for the two groups was 12 and 47 months, respectively.

CONCLUSIONS

Patients with CTCL concurrent with or prior to CLL have a worse overall survival than patients with CLL in whom CTCL later develops. Larger studies are needed.

Prevalence and treatment of palmoplantar keratoderma and tinea pedis in patients with Sézary syndrome

BACKGROUND

Mycosis fungoides (MF) and the Sézary syndrome (SS) are non-Hodgkin's lymphomas that present with cutaneous lesions. Sézary syndrome is characterized by blood involvement, exfoliative eryrthroderma, lymphadenopathy, pruritus, keratoderma, and immunosuppression. This study was to estimate the prevalence of palmoplantar keratoderma and tinea pedis in Sézary syndrome and to analyze the effectiveness of anti-fungal treatment.

METHODS

We conducted a retrospective review of 1562 prospectively collected patients at the MD Anderson Cancer Center Cutaneous Lymphoma Clinic over sixteen years. All patients' palms and soles were evaluated for clinical evidence of keratoderma (hyperkeratosis) and for dermatophytosis (tinea pedis or unguum) by examining scales under 10% potassium hydroxide by light microscopy for hyphae.

RESULTS

Of 138 Sézary syndrome patients (88 men, 50 women, median age at diagnosis 64 years), 85 (61.6%) had palmoplantar keratoderma; 45 of the 85 Sézary syndrome patients (52.9%) also had coexisting tinea pedis. Only 14 (10.1%) had tinea pedis without keratoderma. Treatment for tinea pedis resulted in microscopy cure of keratoderma in 12 of 45 (26.7%) patients and clinical improvement.

CONCLUSIONS

The prevalence of palmoplantar keratoderma in Sézary syndrome is 61.6%, with co-existing tinea pedis found in 52.9%. Palmoplantar keratoderma with tinea pedis showed clinical improvement with fungicidal therapy suggesting that tinea often contributes to the pathogenesis and severity of Sézary syndrome-related keratoderma.

Phase I clinical trial of O6-benzylguanine and topical carmustine in the treatment of cutaneous T-cell lymphoma, mycosis fungoides type

OBJECTIVES

To evaluate the toxic effects and maximum tolerated dose of topical carmustine [1,3-bis(2-chloroethyl)-1-nitrosourea] following intravenous O6-benzylguanine in the treatment of cutaneous T-cell lymphoma (CTCL), and to determine pharmacodynamics of O6-alkylguanine DNA alkyltransferase activity in treated CTCL lesions.

DESIGN

Open-label, dose-escalation, phase I trial.

SETTING

Dermatology outpatient clinic and clinical research unit at a university teaching hospital.

PATIENTS

A total of 21 adult patients (11 male, 10 female)with early-stage (IA-IIA) refractory CTCL, mycosis fungoides type, treated with topical carmustine following intravenous O6-benzylguanine.

INTERVENTION

Treatment once every 2 weeks with 120 mg/m(2) intravenous O6-benzylguanine followed 1 hour later by whole-body, low-dose topical carmustine starting at 10 mg, with 10-mg incremental dose-escalation in 3 patient cohorts. Cutaneous T-cell lymphoma lesional skin biopsy specimens were taken at baseline and 6 hours, 24 hours, and 1 week after the first O6-benzylguanine infusion for analysis of O6-alkylguanine-DNA alkyltransferase activity.

MAIN OUTCOME MEASURES

Clinical response measured by physical examination and severity-weighted assessment tool measurements, safety data acquired by review of adverse events at study visits, and O6-alkylguanine-DNA alkyltransferase activity in treated lesion skin biopsy specimens.

RESULTS

A minimal toxic effect was observed through the 40-mg carmustine dose level with 76% of adverse events being grade 1 based on the National Cancer Institute Common Terminology Criteria for Adverse Events. Mean baseline O6-alkylguanine-DNA alkyltransferase activity in CTCL lesions was 3 times greater than in normal controls and was diminished by a median of 100% at 6 and 24 hours following O6-benzylguanine with recovery at 1 week. Clinical disease reduction correlated positively with O6-alkylguanine-DNA alkyltransferase activity at 168 hours (P=.02) and inversely with area under the curve of O6-alkylguanine-DNA alkyltransferase over 1 week (P=.01). Twelve partial responses and 4 complete responses were observed (overall response, 76% [95% CI, 0.55-0.89]). Five patients discontinued therapy owing to adverse events with a possible, probable, or definite relationship to the study drug.

CONCLUSION

O6-benzylguanine significantly depletes O6-alkylguanine-DNA alkyltransferase in CTCL lesions and in combination with topical carmustine is well tolerated and shows meaningful clinical responses in CTCL at markedly reduced total carmustine treatment doses.

Profile of mycosis fungoides in 43 Saudi patients

BACKGROUND AND OBJECTIVES

Mycosis fungoides (MF) is a rare disease; and to our knowledge, there are no reports on its profile in Arabs. The objective of this study was to preliminarily analyze the clinical characteristics of MF patients seen in our institution.

DESIGN AND SETTING

Retrospective review of 140 patients with pathologic or clinical diagnosis or differential diagnosis of MF for the period 2000-2006.

PATIENTS AND METHODS

Pathology reports with diagnosis or differential diagnosis of MF were retrieved and suspected cases were identified and reviewed. For pathologically confirmed cases, sociodemographic, clinical, laboratory, and radiological details were collected. Details of staging, treatment modalities, and disease status at the last follow-up were retrieved.

RESULTS

A total of 43 pathologically confirmed MF patients (skin phototypes IV and V) with a mean age at diagnosis of 33.5 years were reviewed. This comprised 29 males (M:F ratio, 2:1), and the majority (86%) of patients had early-stage (I and II) MF. Twenty-one (48.8%) patients had classic MF; 18 (41.8%), hypopigmented MF; and 4 (9.3%), other variants. The male-to-female ratio was higher in the hypopigmented (3.5:1) than in the classic variant (1.6:1). The mean age at diagnosis was lower in the hypopigmented compared to the classic variant (25 versus 38.8 years, P=.019). The mean duration of follow-up was 27.6 months (range, 1-98 months). At the final assessment, 4 (9.5%) patients recovered; whereas 35 (83.3%) had MF skin disease; 1 had (2.4%) extracutaneous disease; and 2 (4.8%) died of MF.

CONCLUSIONS

MF tends to affect younger Saudi patients. The hypopigmented variant constitutes a significant proportion of MF cases, especially in younger patients.

Loss of nuclear pro-IL-16 facilitates cell cycle progression in human cutaneous T cell lymphoma

Cutaneous T cell lymphomas (CTCLs) represent a heterogeneous group of non-Hodgkin lymphomas that affect the skin. The pathogenesis of these conditions is poorly understood. For example, the signaling mechanisms contributing to the dysregulated growth of the neoplastic T cells are not well defined. Here, we demonstrate that loss of nuclear localization of pro-IL-16 facilitates CTCL cell proliferation by causing a decrease in expression of the cyclin dependent-kinase inhibitor p27Kip1. The decrease in p27Kip1 expression was directly attributable to an increase in expression of S-phase kinase-associated protein 2 (Skp2). Regulation of Skp2 is in part attributed to the nuclear presence of the scaffold protein pro-IL-16. T cells isolated from 11 patients with advanced CTCL, but not those from healthy controls or patients with T cell acute lymphocytic leukemia (T-ALL), demonstrated reduction in nuclear pro-IL-16 levels. Sequence analysis identified the presence of mutations in the 5' end of the PDZ1 region of pro-IL-16, a domain required for association of pro-IL-16 with the nuclear chaperone HSC70 (also known as HSPA8). HSC70 knockdown led to loss of nuclear translocation by pro-IL-16 and subsequent increases in Skp2 levels and decreases in p27Kip1 levels, which ultimately enhanced T cell proliferation. Thus, our data indicate that advanced CTCL cell growth is facilitated, at least in part, by mutations in the scaffold protein pro-IL-16, which directly regulates Skp2 synthesis.

Romidepsin: evidence for its potential use to manage previously treated cutaneous T cell lymphoma

Introduction:

Cutaneous T cell lymphoma (CTCL) encompasses a heterogeneous group of neoplasms of skin-homing T cells, which includes mycosis fungoides, the most common form, and Sézary syndrome, the leukemia equivalent of mycosis fungoides. Histone deacetylase inhibitors are currently under investigation for their therapeutic value in a variety of conditions. Through multiple mechanisms, they induce apoptosis or inhibition of tumor cell growth. Some studies have also shown histone deacetylase inhibitors to have synergistic activity with existing therapeutic agents in selected conditions. Romidepsin is a histone deacetylase inhibitor with a promising efficacy and safety profile that may represent a valuable treatment alternative for patients with treatment-resistant mycosis fungoides and Sézary syndrome.

Aims:

To review emerging evidence regarding the use of romidepsin in the management of treatment-resistant CTCL.

Evidence review:

There is evidence that romidepsin can induce significant and durable responses in patients with refractory CTCL. In two independent Phase II trials including a total of 167 patients with CTCL, there was an overall response rate of 34% with a partial response of 28% and complete response rate of 6%. The most frequent toxicities reported from the Phase II trials were nausea, vomiting, fatigue, anorexia, and dysgeusia.

Clinical potential:

Romidepsin may be an effective therapeutic option for patients with CTCL who have had treatment failure with multiple standard treatment modalities.

Predictors of response to extracorporeal photopheresis in advanced mycosis fungoides and Sézary syndrome

BACKGROUND

Extracorporeal photopheresis (ECP) has been utilized for more than 20 years to treat cutaneous T-cell lymphoma (CTCL), but a clinical response can take up to 9 months to manifest. This study was undertaken to determine whether clinical features, laboratory values, cytokine levels, or gene expression levels of tumor markers are useful to predict the subsequent response to ECP in CTCL patients with blood involvement.

METHODS

Twenty-one patients with CTCL treated with ECP as monotherapy for at least 6 months were retrospectively identified. Laboratory and clinical data and blood obtained at baseline, 3, and 6 months of treatment were used for analysis.

RESULTS

In pretreatment blood specimens, a lower percentage of Sézary cells and a higher absolute eosinophil count were associated with a favorable clinical response. Clinical evidence of an early response after 3 months of ECP did not reliably predict a favorable response at 6 months or beyond. Comparison of cytokines, gene transcripts, and other laboratory measures of disease did not correlate with the subsequent clinical response, although lactate dehydrogenase levels tended to decrease progressively in ECP-responsive cases and increase progressively in ECP-non-responsive cases. Additionally, serum levels of TNF-alpha significantly increased from baseline to 6 months of ECP, but was not found to correlate with the clinical response.

CONCLUSIONS

Although we found that increased eosinophils and decreased percentage of Sézary cells were associated with a favorable clinical response to ECP, we were not able to identify the predictors of ECP response within the first 3 months of treatment.

Vorinostat: A novel therapy for the treatment of cutaneous T-cell lymphoma

PURPOSE

The pharmacology, pharmacokinetics, clinical efficacy, safety, adverse effects, dosage and administration, and role in therapy of vorinostat in the treatment of cutaneous T-cell lymphoma (CTCL) are reviewed.

SUMMARY

Vorinostat is a novel histone deacetylase (HDAC) inhibitor approved for the treatment of advanced CTCL. Its primary biochemical mechanism is to correct an aberrant balance between acetylated and deacetylated histones, the proteins involved in chromatin structure and organization. Vorinostat is metabolized and excreted following glucuronidation by the uridine diphosphate glucuronosyl-transferase (UGT) enzyme system. Polymorphisms in the gene encoding for this enzyme system, UGT1A1, may be an important predictor of vorinostat toxicity and response levels in individual patients. Vorinostat is not metabolized by and does not inhibit the cytochrome P-450 isoenzyme system, and only two drug interactions have been noted with vorinostat: warfarin and valproic acid or other HDAC inhibitors. In two Phase II studies, patients with CTCL treated with oral vorinostat demonstrated significant reductions in skin lesions and decreased disease progression. The overall response rate was approximately 30%, including one complete response and a time to response of approximately 10 weeks. At the approved 400-mg, once-daily dose, vorinostat was well tolerated, with the most common grade 1 or 2 adverse events being fatigue, nausea, and diarrhea. More-severe toxicities included thrombocytopenia, fatigue, and nausea and occurred in less than 6% of patients.

CONCLUSION

Vorinostat, a novel HDAC inhibitor, is efficacious and well tolerated in patients with CTCL and is being investigated for its efficacy and safety in other types of cancers and as a part of combination therapy.

Role of denileukin diftitox in the treatment of persistent or recurrent cutaneous T-cell lymphoma

Denileukin diftitox (Ontak(®)) is indicated for the treatment of patients with persistent or recurrent cutaneous T-cell lymphoma (CTCL), a rare lymphoproliferative disorder of the skin. Denileukin diftitox was the first fusion protein toxin approved for the treatment of a human disease. This fusion protein toxin combines the IL2 protein with diphtheria toxin, and targets the CD25 subunit of the IL2 receptor, resulting in the unique delivery of a cytocidal agent to CD-25 bearing T-cells. Historically, immunotherapy targeting malignant T-cells including monoclonal antibodies has been largely ineffective as cytocidal agents compared to immunotherapy directed against B-cells such as rituximab. This review will summarize the development of denileukin diftitox, its proposed mechanism of action, the pivotal clinical trials that led to its FDA approval, the improvements in quality of life, and the common toxicities experienced during the treatment of patients with CTCL. CTCL is often a chronic progressive lymphoma requiring the sequential use of treatments such as retinoids, traditional chemotherapy, or biological response modifiers. The incorporation of the immunotoxin denileukin diftitox into the sequential or combinatorial treatment of CTCL will also be addressed.