Low-dose oral bexarotene in combination with low-dose interferon alfa in the treatment of cutaneous T-cell lymphoma: clinical synergism and possible immunologic mechanisms

Topical and Systemic Formulation Options for Cutaneous T Cell Lymphomas

Although various anti-cutaneous T-cell lymphoma (CTCL) therapies are available for clinical use, appropriate chemotherapy lines for the treatment of CTCLs have yet to be established. Therefore, to date, various clinical trials for the treatment of advanced CTCLs are ongoing. In this review, we evaluate the therapeutic options that are available in clinical practice for treatment of early- and advanced-stage CTCLs (targeted therapies, histone deacetylase (HDAC) inhibitors, retinoids, interferons, cytotoxic drugs, etc.). We also examine clinical trials of novel regimens for the treatment of CTCLs.

The Use of Interferons in the Treatment of Cutaneous T-Cell Lymphoma

Interferons are polypeptides that naturally occur in the human body as a part of the innate immune response. By harnessing these immunomodulatory functions, synthetic interferons have shown efficacy in combating various diseases including cutaneous T-cell lymphoma. This article closely examines the qualities of interferon alfa and interferon gamma and the evidence behind their use in the 2 most common types of cutaneous T-cell lymphomas, namely, mycosis fungoides and Sézary syndrome.

Topical and oral bexarotene

Bexarotene is a retinoid that specifically binds retinoid X receptors and has numerous effects on cellular growth and differentiation. It is approved for the treatment of cutaneous T cell lymphoma both topically and systemically. Adverse effects include hyperlipidemia, central hypothyroidism, and neutropenia with bexarotene capsules, and an irritant dermatitis with bexarotene gel. With aggressive management of these potential side effects, bexarotene is an additional option in the armamentarium for management of cutaneous T cell lymphoma.

U.K. consensus statement on safe clinical prescribing of bexarotene for patients with cutaneous T-cell lymphoma

BACKGROUND

Bexarotene is a synthetic retinoid from the subclass of retinoids called rexinoids which selectively activate retinoid X receptors. It has activity in cutaneous T-cell lymphoma (CTCL) and has been approved by the European Medicines Agency since 1999 for treatment of the skin manifestations of advanced-stage (IIB-IVB) CTCL in adult patients refractory to at least one systemic treatment. In vivo bexarotene produces primary hypothyroidism which may be managed with thyroxine replacement. It also affects lipid metabolism, typically resulting in raised triglycerides, which requires prophylactic lipid-modification therapy. Effects on neutrophils, glucose and liver function may also occur. These side-effects are dose dependent and may be controlled with corrective therapy or dose adjustments.

OBJECTIVES

  To produce a U.K. statement outlining a bexarotene dosing schedule and monitoring protocol to enable bexarotene prescribers to deliver bexarotene safely for optimal effect.

METHODS

 Leaders from U.K. supraregional centres produced this consensus statement after a series of meetings and a review of the literature.

RESULTS

 The statement outlines a bexarotene dosing schedule and monitoring protocol. This gives instructions on monitoring and treating thyroid, lipid, liver, blood count, creatine kinase, glucose and amylase abnormalities. The statement also includes algorithms for a bexarotene protocol and lipid management, which may be used in the clinical setting.

CONCLUSION

 Clinical prescribing of bexarotene for patients with CTCL requires careful monitoring to allow safe administration of bexarotene at the optimal dose.

Evolving insights in the pathogenesis and therapy of cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome)

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of malignancies derived from skin-homing T cells. The most common forms of CTCL are Mycosis Fungoides (MF) and Sezary Syndrome (SS). Accurate diagnosis remains a challenge due to the heterogeneity of presentation and the lack of highly characteristic immunophenotypical and genetic markers. Over the past decade molecular studies have improved our understanding of the biology of CTCL. The identification of gene expression differences between normal and malignant T-cells has led to promising new diagnostic and prognostic biomarkers that now need validation to be incorporated into clinical practice. These biomarkers may also provide insight into the mechanism of development of CTCL. Additionally, treatment options have expanded with the approval of new agents, such as histone deacetylase inhibitors. A better understanding of the cell biology, immunology and genetics underlying the development and progression of CTCL will allow the design of more rational treatment strategies for these malignancies. This review summarizes the clinical epidemiology, staging and natural history of MF and SS; discusses the immunopathogenesis of MF and the functional role of the malignant T-cells; and reviews the latest advances in MF and SS treatment.

New targets of therapy in T-cell lymphomas

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

Clinical and in vitro resistance to bexarotene in adult T-cell leukemia: loss of RXR-alpha receptor

The oral rexinoid bexarotene (Targretin) is widely used for treatment of cutaneous T-cell lymphomas (CTCL). We recently reported the first case of adult T-cell leukemia/lymphoma (ATLL) that responded rapidly to combination therapy of bexarotene and interferon (IFN)-alpha2b with complete clinical response. We demonstrated that bexarotene induced apoptosis of the patient's malignant peripheral blood T-cells in vitro. However, our patient developed skin and nodal relapse 180 days after starting treatment. We now demonstrate that his peripheral blood malignant T cells became resistant to bexarotene-induced apoptosis. We investigated potential mechanisms that may cause aberrations in the retinoid X receptor (RXR) subunits, RXR-alpha and RXR-beta, to account for these findings. Sequence analysis did not reveal acquisition of mutations in the genes encoding RXR-alpha and RXR-beta by resistant cells. We assessed RXR-alpha and RXR-beta expression by Western blot analysis and found that resistant cells had significantly decreased RXR-alpha expression compared with pretherapy bexarotene-sensitive cells. Our findings indicate that reduced expression of the RXR-alpha receptor subunit may represent a mechanism for resistance to bexarotene in T-cell malignancies.

Safety and efficacy of low-dose bexarotene and PUVA in the treatment of patients with mycosis fungoides

BACKGROUND

The new rexinoid bexarotene is a retinoid X receptor antagonist and immune response modifier. Although combinations of oral bexarotene and psoralen plus UVA (PUVA) have been tried in patients with all stages of mycosis fungoides (MF), the dosage of bexarotene used in these combination regimens has been variable.

OBJECTIVE

To assess the efficacy and safety of low-dose oral bexarotene and PUVA in patients with relapsed or treatment-refractory MF following monotherapy with multiple agents including PUVA, narrow-band UVB, interferon-alpha, oral bexarotene, and topical corticosteroids.

METHOD

Combination therapy with PUVA three times weekly and low-dose oral bexarotene (150 or 300 mg/day, depending on physicians' preference) was administered to 14 patients, seven men and seven women (median age 49.5 years, range 30-75 years), with relapsed or refractory MF stages I-III. All responders received maintenance treatment at the same bexarotene dose that induced remission until progression or unacceptable toxicity.

RESULTS

Low-dose oral bexarotene combined with PUVA was associated with an overall response rate (complete response or partial response) in 67% of the nine patients with refractory MF who completed the treatment course. Of these nine patients, four had a complete response, two had a partial response, one had stable disease, and two had progressive disease. Five patients withdrew because of hyperlipidemia. Oral bexarotene was continued as maintenance therapy in three of the four complete responders (one refused); two of these patients relapsed 2-10 months after PUVA discontinuation. Patients with partial response or stable disease received the combination for 3-5 months and were switched to another treatment regimen because of lack of further response. Therapy was fairly well tolerated.

CONCLUSION

In a select population of patients who had not responded to at least one monotherapy for early-stage MF, a combination of low-dose oral bexarotene and PUVA was successful in achieving a satisfactory overall response rate in 67% of patients who completed the treatment course and was fairly well tolerated. Limitations of the study include the small number of patients evaluated, its retrospective nature, and the fact that patients were commenced on different bexarotene starting doses (150 or 300 mg/day), depending on physicians' preference.

Results of a Phase II trial of oral bexarotene (Targretin) combined with interferon alfa-2b (Intron-A) for patients with cutaneous T-cell lymphoma

BACKGROUND

Bexarotene is one of the most active single agents for the treatment of recurring or refractory cutaneous T-cell lymphoma (CTCL). Interferon alfa has also been used for many years as an effective treatment for this disease. The results in recent case reports of the combination of bexarotene and interferon alfa have been promising. Based on more extensive results reported with the combination of other retinoids with interferon alfa, the present study attempted to determine the response rate, response duration, and safety of bexarotene (Targretin capsules, Ligand Pharmaceuticals, San Diego, Calif) alone and then with the addition of interferon alfa-2b (Intron-A, Schering-Plough, Kenilworth, NJ).

METHODS

Patients with biopsy-proven CTCL, TNM stages IB, IIA, IIB-IV, were treated with oral bexarotene 300 mg/m2/day for at least 8 weeks. If a complete response was not seen after 8 weeks, interferon alfa-2b 3 million units (MU) subcutaneously was added, and increased to 5 MU if tolerated, 3 times a week.

RESULTS

A total of 22 patients were enrolled at 5 sites, and 18 patients were assessable for response. Overall response rate for combined bexarotene and interferon alfa was 39% (95% confidence interval [CI]: 17%-64%), including 1 patient with a clinical complete response, 6 patients with partial response, 3 patients with stable disease, and 8 patients with progressive disease. Three partial responses were first noted during the bexarotene-alone phase. Adverse events were generally manageable, and only 1 patient was withdrawn from study for hypertriglyceridemia.

CONCLUSIONS

The addition of interferon alfa-2b did not increase the response rate that would have been expected with bexarotene alone.

Off-label uses of biologics in dermatology: Interferon and intravenous immunoglobulin (Part 1 of 2)

The introduction of a number of biologic therapies into the market has revolutionized the practice of dermatology. These therapies include interferons, intravenous immunoglobulin, infliximab, adalimumab, etanercept, efalizumab, alefacept, and rituximab. Most dermatologists are familiar with the Food and Drug Administration-approved indications of these medications. However, numerous off-label uses have evolved. As part 1 of a 2-part series, this article will review the literature regarding the off-label uses of the interferons and intravenous immunoglobulin in dermatology.

Juvenile mycosis fungoides treated with bexarotene and PUVA

A 14-year-old Caucasian boy presented with a 4-month history of a slightly pruritic eruption that began on the hips and later extended to the trunk and upper and lower limbs. The patient did not present fever, weight loss, or asthenia. Physical examination revealed multiple, red, desquamative, oval patches with areas of healthy skin between them, which covered nearly 50% of the body surface area. The palms, soles, face, and mucosa were not affected. In addition, he presented two violet-colored infiltrated plaques on the left thigh and right buttock (Fig. 1). There were multiple, > 1 cm, freely mobile, axillary and inguinal nodes. In follow-up, the patient developed two red-colored, mobile, well-delimited cutaneous nodules of 2.5 cm in diameter in the right hemithorax and lumbar area. The lumbar nodule regressed spontaneously before treatment. The clinical diagnosis was mycosis fungoides. We obtained three skin biopsies, one from a patch lesion and the others from a nodule; the third was sent to a reference hospital to determine the rearrangement. Histologic examination was similar in the three biopsies and revealed an atypical lymphoid infiltrate in the superficial dermis with epidermotropism and a tumoral nodule of atypical, small-sized lymphocytes in the deep dermis and subcutaneous level (Fig. 2). The atypical infiltrate was CD3+, CD4+, CD8-, T-cell intracellular antigen (TIA)+/-, Epstein-Barr-encoded RNA (EBER)-, and CD56-. The biopsy of one left axillary adenopathy was compatible with mycosis fungoides (Fig. 3). Amongst the additional tests carried out was a blood analysis showing 5300 leukocytes (neutrophils, 35%; lymphocytes, 40.7%; monocytes, 16.8%; eosinophils, 6.40%) without Sézary cells, normal lactate dehydrogenase (LDH), immunoglobulin E (IgE) of 497 U/mL (normal, 3-100 U/mL), and beta2-microglobulin of 3.09 mg/L (normal, 1.64 +/- 0.58 mg/L). A bone marrow study and a thoraco-abdomino-pelvic scan were normal. The rearrangement in the skin was monoclonal, whereas in peripheral blood and lymph nodes it was polyclonal. With the diagnosis of mycosis fungoides stage IVA (according to the TNM classification), treatment was initiated with psoralen plus ultraviolet light A (PUVA), three times a week, plus oral bexarotene at a dose of 300 mg/m2/day. The parents were informed that this treatment was not approved for this age group and informed consent was obtained. The clinical tolerance to bexarotene was very good, although low doses of atorvastatin (10 mg/day) and 75-100 mg of thyroxine were needed to control the expected adverse reactions to oral retinoid. After 32 sessions of PUVA and 6 months of treatment with oral bexarotene, the skin patches regressed, except for the plaque on the left buttock and the nodule on the right hemithorax (Fig. 4). There was no evidence of lymphadenopathy clinically or via sonographic evaluation. Bexarotene was discontinued after patient clearance and resolution of adenopathies. Nevertheless, 5 months after discontinuation of oral treatment, the patient developed multiple, scaling, nonconfluent macules on the trunk and arms affecting almost 30% of the body surface area, which disappeared with the application of methylprednisolone aceponate. He did not present significant lymphadenopathies.

Mycosis fungoides and sezary syndrome: An update

Mycosis fungoides (MF), and the associated leukemic variant Sezary Syndrome (SS), are the most common group of cutaneous T-cell lymphomas. MF/SS is a non-Hodgkin's lymphoma of mature, skin-homing, clonal, malignant T lymphocytes that initially presents in the skin as patches, plaques, tumors, or generalized erythema (erythroderma) and can involve the lymph nodes and peripheral blood. Much progress has been made in recent years in understanding the origin of the malignant T cell in MF/SS and the pathophysiology and immunology of the disease. This recent work has made a great impact on diagnosis, prognostication, and treatment. In this review, we survey the MF/SS published literature over the past year and highlight some of the important advances.

Treatment of cutaneous T-cell lymphoma with retinoids

Retinoids are biologic regulators of differentiation, proliferation, apoptosis, and immune response. Retinoids (all-trans retinoic acid, 13-cis-retinoic acid, and the synthetic analogs isotretinoin, etretinate, and acitretin) have been used for years as monotherapy and/or in combination for treatment of cutaneous T-cell lymphomas (CTCL). Orally administered bexarotene, the first synthetic highly selective retinoid X receptor retinoid to be approved by the Food and Drug Administration for CTCL, was shown to be active against the cutaneous manifestations of all stages of CTCL. The topical gel formulation was also effective for early cutaneous manifestations of CTCL or as an adjunct to systemic or phototherapy. Use of retinoids in future long-term clinical trials and their eventual application in CTCL regiments will require strategies to decrease the side effects of existing retinoids, identify novel receptor subtype-selective retinoids with better therapeutic index, and explore biologically based synergistic combination therapies with other active agents.

Cutaneous T-cell lymphoma

OBJECTIVE

To review recent information on the epidemiology, etiology, clinical presentation, staging, treatment approaches, and nursing management of CTCL.

DATA SOURCES

Research and review articles and textbooks.

CONCLUSION

Identifying the etiology and finding a cure for cutaneous T-cell lymphoma is promising as our knowledge and understanding of the T-cell biology evolves, creating more options for innovative therapies or treatment modalities.

IMPLICATIONS FOR NURSING PRACTICE

It is essential for the oncology nurse to understand the disease process, treatment modalities, and side effect profiles to provide astute nursing assessment, establishment of treatment goals, management of cutaneous symptoms, treatment of side effects, and pain control while preventing infection and providing psychological/social support throughout the course of the disease.

Treatment of Mycosis Fungoides with Denileukin Diftitox and Oral Bexarotene

Cutaneous T-cell lymphomas, including mycosis fungoides and Sezary syndrome, are often responsive to treatment, but current therapies have not been shown to increase survival, and in advanced stages, durable remissions are hard to achieve. We present a patient who was initially misdiagnosed with psoriasis and, 16 years later, was diagnosed with mycosis fungoides. Denileukin diftitox was used as a tumor debulking agent to give a partial response that was further improved with a combination of systemic interferon/oral bexarotene and skin-directed psorlen plus UV-A. The purpose of this case report is to show the value of sequential combination therapy for improving overall response.

The Role of Alemtuzumab in the Management of T-Cell Malignancies

T-cell malignancies are rare, making up 10% to 15% of all lymphoid neoplasms in adults. They include many different types of disorders such as T-cell prolymphocytic leukemia, T-cell large granular lymphocytic leukemia, adult T-cell leukemia/lymphoma, cutaneous T-cell lymphoma, and peripheral T-cell lymphoma, which are themselves divided into multiple subcategories. Most T-cell malignancies arise as a result of chromosomal abnormalities, including T-cell receptor rearrangement anomalies. Viral infections are implicated in the development of adult T-cell leukemia/lymphoma and some cases of peripheral T-cell lymphoma have been linked to Epstein-Barr virus or human immunodeficiency virus infection. With the possible exception of T-cell large granular lymphocytic leukemia, which often has an indolent course, T-cell malignancies have not responded well to conventional chemotherapeutic treatment. The introduction of monoclonal antibodies for the treatment of cancer has changed the outlook for patients with T-cell malignancies. Recent studies with single-agent alemtuzumab, an anti-CD52 monoclonal antibody, have shown improved response rates and survival in patients with T-cell prolymphocytic leukemia and cutaneous T-cell lymphoma. Preliminary data also suggest that alemtuzumab may have activity in patients with heavily pretreated peripheral T-cell lymphoma who are refractory to conventional chemotherapy. Preclinical studies with mice bearing human adult T-cell leukemia/lymphoma cells suggest that alemtuzumab may have a potential therapeutic role in this setting. Treatment of T-cell hematologic malignancies with alemtuzumab appears promising. Earlier treatment and combination with chemotherapeutic agents may improve treatment outcome for patients with these malignancies and allow for consolidation with stem cell transplant strategies in selected patients.

Combination Treatment Modalities in Cutaneous T-Cell Lymphoma (CTCL)

A wide variety of cutaneous T-cell lymphoma therapies are now used in clinical practice. Treatment options include phototherapy, radiation, topical therapy, systemic mono-chemotherapy, combination chemotherapy, and combined modalities. Many patients fail or develop resistance to monotherapy, resulting in a need for combined treatment modalities to improve therapeutic results in terms of quality of life and duration of response. Recently, bexarotene, a selective antagonist of the retinoid X receptor, has been approved in the treatment of patients with cutaneous T-cell lymphoma. Bexarotene offers new opportunities for combination treatment strategies because of its novel and unique mechanism of action. In this article we review the rationale and examine key published evidence on combining these new treatment modalities.

Therapeutic Advances in Cutaneous T-Cell Lymphoma (CTCL): From Retinoids to Rexinoids

Retinoids comprise a family of polyisoprenoid lipids that include vitamin A (retinol) and its various natural and synthetic analogues. Retinoids are compounds with multiple actions. They are involved in the control of cell proliferation, cell differentiation, and embryonic development. Each retinoid has its own profile of pharmacologic properties that determines its usefulness in clinical dermatology or oncology. Although numerous synthetic retinoids have been synthesized, their biological activities are usually associated with clinical disadvantages such as toxicity and teratogenicity. Retinoids that bind to both the retinoic acid receptor and retinoid X receptor subtypes have shown clinical activity in hematologic malignancies and can mediate genes associated with both growth and differentiation. Retinoid X receptor-specific rexinoids have also shown efficacy in the treatment of cutaneous T-cell lymphomas, but their exact mechanism of action is unclear. This article summarizes the clinical relevance of both groups of compounds in this important patient population.

Tratamiento de linfomas cutáneos de células T con bexaroteno

INTRODUCTION

The choice of treatment in cutaneous T-cell lymphomas (CTCLs) depends on the clinical stage of the disease and the patient's general condition. To date, there is no curative treatment for this disease, and the objective is to control the symptoms and prevent the disease from progressing. Bexarotene is an X receptor-specific retinoid with anti-tumor activity. Its use as treatment for CTCLs refractory to at least one prior systemic therapy has been approved by the FDA.

PATIENTS AND METHODS

We carried out a descriptive study of 9 patients treated with bexarotene in the Lymphoma Unit of our department. We analyzed the clinical characteristics of the patients and the efficacy of the treatment, and we collected data on the side effects that appeared.

RESULTS

The overall response to the treatment was 44.4% (4/9). 2 patients had full remission and 2 had partial remission. Tolerance to the treatment was good, and the most frequent side effects were hypertriglyceridemia, hypercholesterolemia and central hypothyroidism.

CONCLUSIONS

Even though this is a series of only 9 patients, the results that we obtained are similar to ones previously described. Bexarotene is an effective therapeutic option in this heterogeneous group of diseases.

The spectrum of cutaneous T-cell lymphomas: new insights into biology and therapy

PURPOSE OF REVIEW

Cutaneous T-cell lymphomas represent clinically and biologically a heterogeneous group of non-Hodgkin lymphomas according to the new revised European Organization for Research and Treatment of Cancer and World Health Organization consensus classification for cutaneous lymphomas. Recent progress in immune and molecular biology and novel therapeutic targets have increased our understanding of these diseases and have led to novel treatment approaches. This review outlines the most recent advances.

RECENT FINDINGS

New immunologic and molecular findings may influence tumor phenotype and growth and provide a biologic basis for novel treatment approaches. Several reports have focused on new prognostic markers. Among the novel therapies for cutaneous T-cell lymphoma, interleukin-2 fusion toxins, monoclonal antibodies, histone deacetylase inhibitors, and immunomodulatory cytosine-phosphorothiolated guanine oligomers have shown promising results and are under further investigation.

SUMMARY

This review provides an update of recent findings of immunologic, molecular, and cytogenetic features and treatment approaches for patients with cutaneous T-cell lymphoma with special emphasis on mycosis fungoides and Sezary syndrome.

Immunopathogenesis and therapy of cutaneous T cell lymphoma

Cutaneous T cell lymphomas (CTCLs) are a heterogenous group of lymphoproliferative disorders caused by clonally derived, skin-invasive T cells. Mycosis fungoides (MF) and Sezary syndrome (SS) are the most common types of CTCLs and are characterized by malignant CD4(+)/CLA(+)/CCR4(+) T cells that also lack the usual T cell surface markers CD7 and/or CD26. As MF/SS advances, the clonal dominance of the malignant cells results in the expression of predominantly Th2 cytokines, progressive immune dysregulation in patients, and further tumor cell growth. This review summarizes recent insights into the pathogenesis and immunobiology of MF/SS and how these have shaped current therapeutic approaches, in particular the growing emphasis on enhancement of host antitumor immune responses as the key to successful therapy.