Treatment of cutaneous T cell lymphoma with 2'-deoxycoformycin (pentostatin)

Potential and promising anticancer drugs from adenosine and its analogs

In recent years, many studies have shown that adenosine has efficacy for treating cancer. More importantly, some adenosine analogs have been successfully marketed to fulfill anticancer purposes. In this review, we summarize the anticancer effects of adenosine and its analogs in clinical trials and preclinical studies, with focus on their anticancer mechanisms. In addition, we link the anticancer activities of adenosine analogs with their structures through structure-activity relationship (SAR) analysis, and highlight additional promising anticancer drug candidates. We hope that this review will be of help in understanding the importance of adenosine and its analogs with anticancer activities and directing future research and development of such compounds.

Purine nucleoside analogues: fludarabine, pentostatin, and cladribine

Purpose. The primary objective of this article is to continue the discussion of the pharmacology, phar macokinetics, clinical use, and adverse effects of the currently approved adenosine analogues, focusing on pentostatin. This is part two of a three part series.

Data Sources. We reviewed the literature through a MEDLINE search from 1986 to 1996. Rele vant articles cited in the literature obtained by MED LINE searching also were considered. We searched the following terms: fludarabine, cladribine, pentosta tin, apoptosis, and adenosine analogues. The search was restricted to the English language.

Data Extraction. We have reviewed the current literature in regard to the chemistry, mechanisms of action and pharmacology, pharmacokinetics, clinical use, adverse effects, drug interactions, indications, formulation, dosage, administration, and pharmaceu tical issues of the currently approved adenosoine analogues, focusing on pentostatin.

Data Synthesis. The adenosine analogues are structurally similar agents used in the management of hematological malignancies. Pentostatin and cladrib ine are both active agents in the treatment of hairy cell leukemia. There are no comparative clinical trials between the agents, and we have provided compari sons based on pharmacology, clinical experience, adverse effects, and cost.

What's new in the management of cutaneous T-cell lymphoma?

The aetiology and clinical management of primary cutaneous T-cell lymphoma (CTCL) and specifically of mycosis fungoides and Sezary syndrome are poorly defined. Interesting new insights into CTCL disease biology as well as a number of emerging of novel therapeutic interventions make this an increasingly interesting area for dermatologists and oncologists involved in the treatment of CTCL. This review article covers much of this new information including new drugs, such as denileukin diftitox (Ontak) a targeted cytotoxic biological agent, Bexarotene an RXR selective retinoid, anti-CD4 monoclonal antibodies (mAb), new cytotoxics agents and vaccines.

Therapy of T cell lymphomas with pentostatin

Pentostatin is a highly lymphocytotoxic agent active in hairy cell leukemia. Several studies also suggest significant activity in T cell lymphomas manifested in the skin. Herein, we will review the studies of pentostatin in these lymphomas and our most recent trial of this agent in heavily pretreated patients with cutaneous and peripheral T cell lymphomas. Overall, the data suggest that pentostatin has significant antitumor activity in these patients, with response rates ranging from 33% to over 70%. Approximately one-third of the responses are complete. The most common side effects include granulocytopenia, nausea, and renal insufficiency. CD4 suppression occurs and may result in an increased risk of herpes zoster infection. Although prolonged remissions have been seen, most responses are short-lived. These observations suggest that further exploration of this agent, in combination with other drugs active in T cell lymphomas, is warranted in this group of diseases.

Primary cutaneous T-cell lymphoma: review and current concepts

PURPOSE

Primary cutaneous T-cell lymphomas (CTCLs) encompass a wide variety of lymphomas that are characterized by the localization of the malignant lymphocytes to the skin at presentation. Advances in molecular biologic techniques, including immunophenotyping and gene rearrangement studies to determine clonality, have led to more frequent diagnosis of CTCL as well as more consistent subclassification of these entities. However, there continues to be confusion in the classification, prognosis, and management of patients with CTCL. The purpose of this review is to present a summary of the diagnosis, prognosis, and treatment of CTCL, with specific emphasis on mycosis fungoides (MF) and Sézary syndrome (SS). We also present a detailed discussion of the entities that make up the differential diagnosis of CTCL.

DESIGN

We reviewed the medical literature on CTCL and other diseases that make up the differential diagnosis of CTCL.

RESULTS AND CONCLUSION

MF and SS are the most common forms of CTCL. The etiology of this disease is still unknown. Patients may go for months to years with skin abnormalities before being diagnosed. MF/SS is an indolent disease and patients with T1 disease have a normal life expectancy. Patients who undergo transformation to large-cell lymphoma (8% to 23% of patients) have a poor prognosis, with mean survival ranging from 2 to 19 months. Treatment for MF/SS continues to be palliative. There are many new therapies that are currently being investigated in clinical trials, and the DAB(389)IL-2 fusion protein was recently approved for the treatment of refractory MF/SS.

Cutaneous T-cell lymphoma/leukemia

Effective treatment for cutaneous T-cell lymphomas (CTCL) requires an accurate and specific diagnosis based on the clinical presentation combined with evaluation of the histopathology, immunophenotyping, and gene rearrangement studies. Careful clinical and pathologic evaluation in centers familiar with the diverse forms of CTCL is most valuable for determining treatment options. The goals of treatment in mycosis fungoides (MF), which afflicts more than 50% of patients with CTCL, are the relief of symptoms and improvement in cosmetics. Despite some uncontrolled clinical trial results that have been reported to suggest "cures" in this disease, the general perception remains that this disease is not curable with standard therapies available today. Treatment is divided into topical (skin-directed) and systemic therapy. The most active systemic agent for the treatment of MF remains interferon-alpha, although many new modalities have recently been approved for the treatment of CTCL.

Pentostatin (2'-deoxycoformycin) in the treatment of cutaneous T-cell lymphoma

BACKGROUND

The treatment of patients with advanced or therapy-refractory cutaneous T-cell lymphoma (CTCL) remains a challenge. Pentostatin is a potent inhibitor of adenosine deaminase and is selectively toxic to lymphocytes. In a small number of patients with CTCL, it previously has been shown to be effective.

OBJECTIVE

Our purpose was to evaluate the efficacy and safety of pentostatin in the treatment of patients with advanced and/or therapy-refractory CTCL.

METHODS

Eighteen patients with stage I to IVb CTCL were treated with 4 to 5 mg/m2 of intravenous pentostatin every 1 to 4 weeks.

RESULTS

Two patients (11%) had complete responses of 4 months and 6 years, respectively. These patients had stage III and IVa CTCL and had previously received many different external or systemic treatments. Partial remission (50% to 99% clearing) lasting for 1.5 to 6 months occurred in five patients (28%) with stage IIa (n = 3), stage IIb, and stage IVa CTCL. These patients had received a median of three prior external or systemic treatments. No major side effects were observed, and bone marrow suppression was mild.

CONCLUSION

Single-agent pentostatin in intravenous doses of 4 to 5 mg/m2 is an effective systemic treatment of CTCL (39% objective response rate) with little toxicity.

2-Chlorodeoxyadenosine in cutaneous T-cell lymphoproliferative disorders

The efficacy and toxicity of 2-chlorodeoxyadenosine (2-CdA) in cutaneous T-cell lymphoproliferative disorders was examined. Between February 1991 and April 1996, 25 patients with relapsed or refractory cutaneous T-cell lymphoproliferative disorders (24 mycosis fungoides or Sezary syndrome, one Ki-1+ anaplastic large cell lymphoma) were treated with 2-CdA initially administered by continuous intravenous infusion at a dose of 0.1 mg/kg/d for 7 days (13 patients). The infusion duration was subsequently reduced to 5 days (9 patients) because of prohibitive hematologic toxicity. Three patients were treated at the same daily dose by bolus injection over two hours for 5 days. Cycles were administered at 28 day intervals. Seventeen patients received more than one cycle. An overall response rate of 24% was achieved. Three patients (12%) had a complete response with a median duration of 4.5 months (range, 2.5 to 16). Three (12%) had a partial response with a median duration of 2 months (range, 2 to 4). Nineteen patients (76%) had no response. The most significant toxicities encountered were myelosuppression (64%) and infectious complications (64%). 2-CdA has activity as a single agent in patients with previously treated relapsed T-cell lymphoproliferative disorders.

T-cell lymphoma cell lines (HUT102 and HUT78) established at the National Cancer Institute: history and importance to understanding the biology, clinical features, and therapy of cutaneous T-cell lymphomas (CTCL) and adult T-cell leukemia-lymphomas (ATLL)

Efforts at the National Cancer Institute to generate continuous in vitro cultures from patients with mycosis fungoides and the Sezary syndrome, neoplasms with a mature T-helper phenotype, led to the establishment of two cell lines, HUT78 and HUT102. Further characterization of these cell lines led to the identification of the first human retrovirus, HTLV-1, in the HUT102 cells, and the clinical description of the syndrome of HTLV-1 associated acute T-cell leukemia/lymphoma; the serum antibody test to screen for this virus was developed from the serum of the patient from whom the cell line was derived. The HUT78 cell line was pivotal in the identification and characterization of the HIV retrovirus in that a subclone, H9, proved to be permissive for replication of HIV in vitro. Propagation of HIV in vitro in H9 cells allowed for the development of immunological reagents to screen blood supplies for the presence of the virus. Further biologic and molecular studies of these lines have led not only to a better understanding of the underlying diseases but also to the development of rational therapeutic approaches.

Mycosis fungoides and the Sézary syndrome: pathology, staging, and treatment

Mycosis fungoides and the Sézary syndrome are forms of cutaneous T-cell lymphoma. Mycosis fungoides is an uncommon disease: only about 500 new cases are diagnosed in the United States annually. The median age of onset is 55 years and there is a 2:1 male predominance. The etiology of mycosis fungoides is unknown. Although occupational exposures have been implicated, case control studies fail to support this hypothesis. Mycosis fungoides is typified by cutaneous plaques which may evolve into tumors over the course of time. It is often preceded by a lengthy pre-mycotic phase prior to the time of definitive diagnosis. In its earliest diagnostic phase, there may only be slightly scaling patches with a limited distribution. Indurated lesions evolve into plaques, which may become more generalized in their distribution. As the severity of skin involvement increases, there is an increasing likelihood of spread to extracutaneous sites. The pathology of this disease is marked by involvement of the epidermis (Pautrier microabscesses). Immunologic studies characterize these cells as belonging to the helper T-cell subset. Genotypic analysis demonstrates monoclonal rearrangements of the T-cell receptors of the infiltrating cells. The staging system for mycosis fungoides considers the extent of skin involvement, presence of lymph node or visceral disease, and detection of abnormal cells in the peripheral blood. Patients with disease limited to the skin (90% of newly diagnosed cases) are treated best with topical or cutaneous therapies. Common modalities include psoralen photochemotherapy (PUVA), topical chemotherapy (nitrogen mustard) and total skin electron beam therapy. Both topical nitrogen mustard and electron beam therapy have good initial response rates (73% and 100%) and may achieve long-term disease-free survival, especially in patients with initially limited disease. Even if the response is incomplete or relapse occurs, substantial and very important palliation is generally achieved with topical therapy. Recurrent or resistant cutaneous disease will require the use of sequential topical treatment. The median survival time of patients who present with disease limited to the skin is greater than 10 years, and many deaths in this group are from intercurrent causes, especially in patients with limited or generalized plaque disease. If cutaneous tumors are present, the majority of these patients will eventually die from disease-related causes. The prognosis of patients who develop extracutaneous disease is exceedingly poor (median survival time, approximately 1 year).(ABSTRACT TRUNCATED AT 400 WORDS)

Sézary syndrome: diagnosis, prognosis, and critical review of treatment options

Sézary syndrome is a form of leukemia-lymphoma characterized clinically by erythroderma, pruritus, adenopathy, and circulating atypical cells with cerebriform nuclei. Histologically, atypical lymphocytes in the dermis and Pautrier's microabscesses are often present in skin biopsy specimens. Immunologic findings that support a diagnosis of Sézary syndrome include a predominance of CD4+ lymphocytes in both skin biopsy specimens and peripheral blood. Cytogenetic studies that demonstrate aneuploidy and DNA probe analysis that shows gene rearrangement for the beta-subunit of the T cell receptor are the latest, most sensitive, and specific methods for identifying the clonal nature of the disease. Various staging systems are used. We review the various treatments for Sézary syndrome, including the newer, biologically based investigational therapies, (e.g., antithymocyte globulin, monoclonal antibodies and other immunostimulants, retinoids, cyclosporine, interferon, and extracorporeal photopheresis). Extracorporeal photopheresis and some chemotherapeutic agents appear to produce the best results in terms of response and remission duration with minimal toxicity. However, more multicenter controlled clinical trials are needed to determine the most effective single or combined therapeutic regimen.