Treatment of mycosis fungoides with bexarotene and psoralen plus ultraviolet A

Treatment of early-stage mycosis fungoides with oral bexarotene and phototherapy. A systematic review and meta-analysis

BACKGROUND

Mycosis fungoides (MF) is a rare subtype of non-Hodgkin lymphoma, for which no standard treatment exists.

OBJECTIVES

To provide evidence-based recommendations for adult patients with early-stage MF treated with oral bexarotene and phototherapy.

METHODS

A systematic review and meta-analysis was conducted utilizing studies identified via Embase, Pubmed, Web of Science, and the Cochrane Library from inception to April 2020 to evaluate the clinical efficacy and adverse events of oral bexarotene and phototherapy.

RESULTS

Of 645 abstracts retrieved, 17 full-text articles with 143 subjects were included for analysis. There were nine case reports, five retrospective cohort studies, two prospective cohort studies, and one randomized controlled trial. Most subjects were men (24.48%) with stage IB disease (54.4%), and the mean age at presentation was 63. One patient had folliculotropic disease. The retrospective studies' analysis included 67 subjects and indicated that the partial response was 40.36% (95% CI 18.24 to 64.92), complete response was 34.06% (95% CI 10.73 to 62.56), and overall response was 64.48% (95% CI 48.56 to 78.89). Side effects from bexarotene were hypertriglyceridemia (54%), hypothyroidism (50%), and hypercholesterolemia (46%). Similar results were noted in the prospective studies.

CONCLUSIONS

The literature consists mostly of uncontrolled studies which suggest that combination therapy with oral bexarotene and phototherapy is a therapeutic option. Future randomized control studies with longer follow-up and standardized definitions of treatment responses and dosages are needed to support the development of evidence-based approaches for the treatment of early-stage MF. This article is protected by copyright. All rights reserved.

Mycosis fungoides and Sézary syndrome: Role of chemokines and chemokine receptors

Mycosis fungoides is the most common form of cutaneous T-cell lymphoma (CTCL), and is characterized by a clonal expansion of malignant CD4⁺ T lymphocytes with skin-homing properties. Clinically and pathologically, mycosis fungoides can be categorized into patch, plaque and tumor stages. The clinical course of mycosis fungoides is usually chronic and indolent, but a proportion of patients may develop progressive disease with peripheral blood, lymph node and visceral organ involvement. Sézary syndrome is an aggressive leukemic form of CTCL characterized by a clonal population of malignant T cells in the peripheral blood. Various forms of skin-directed and systemic treatments are available for mycosis fungoides and Sézary syndrome. However, current treatments are generally not curative, and can only control the disease. Currently, the etiology and pathogenesis of mycosis fungoides and Sézary syndrome are not well defined. Proposed mechanisms include chronic antigenic stimulation by infectious agents, expression of specific adhesion molecules, altered cytokine production, mutations of oncogenes and tumor suppressor genes, and avoidance of apoptosis. In recent years, a number of chemokine receptors and their corresponding chemokine ligands have been found to contribute to the migration and survival of lymphoma cells in mycosis fungoides and Sézary syndrome, including CC chemokine receptor 4 (CCR4), CCR10, C-X-C chemokine receptor type 4 (CXCR4), CCR7, CCR3 and CXCR3. Since chemokines and chemokine receptors have been found to play important roles in the pathophysiology of mycosis fungoides and Sézary syndrome, they may be potentially useful targets for the development of new treatments for these diseases in the future.

Phototherapy of mycosis fungoides

BACKGROUND/PURPOSE

Among the primary cutaneous T-cell lymphomas, mycosis fungoides (MF) is the most common disease entity. Recently, an improved understanding of the pathology, clinical presentation, and prognosis of MF has lead to the development of new and practically useful classification and staging systems. In most patients, MF presents with patches and plaques and remains confined to the skin for years and decades, making it an ideal target for phototherapy. However, treatment schedules vary widely and this review describes the current knowledge about phototherapy of MF focusing mainly on narrow- and broadband UVB and 8-methoxypsoralen plus UVA, its indications, practical aspects, and clinical outcome.

METHODS

Review and summary of the pertinent literature.

RESULTS AND CONCLUSIONS

Since 1976, when the first report on phototherapy for MF was published, sufficient evidence has accumulated to make narrowband UVB and PUVA safe and effective treatment options for early stages of the disease. In refractory cases or more advanced stages, combination of phototherapy with systemic treatments including mainly interferons and retinoids might be valuable. Additional research is required to further define the optimal treatment schedules and the role of maintenance.

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.

Tratamiento de micosis fungoide con PUVA más bexaroteno

INTRODUCTION

The combined use of bexarotene and PUVA is a treatment that is currently being investigated. In this paper, six patients treated with this combination are presented.

OBJECTIVES

To assess the efficacy and safety of treatment with PUVA + bexarotene in patients with mycosis fungoides (MF). Patients, material and methods. Six patients diagnosed with MF in different stages, who received three sessions of PUVA treatment a week (initially 2.35 J/cm 2, with progressive increases to a maximum of 23.5 J/cm 2) + bexarotene (initial dose 300 mg/m 2/day, decreasing to 200, 150 or 75 mg/m 2 if signs of toxicity appeared). All received atorvastatin.

RESULTS

Stage at the start of treatment: two patients IIb, one patient Ib with B2 blood involvement, two patients Ib, one patient Ia. Five of the six patients responded to the treatment (three full remissions [FR], two partial remissions [PR]). One patient did not respond. In those in whom FR was achieved, the time required for the response was 10, 20 and 24 weeks. All presented with hypertriglyceridemia (maximum 1194 mg/ dL). It was necessary to administer thyroid hormone supplements to four of the patients. Two of them had alterations in the hepatic biochemistry values, and two others presented with alterations in the muscle profile analysis.

CONCLUSION

The combination of PUVA and bexarotene is a safe and effective treatment for MF. It will be necessary to await the results of the clinical trials currently underway to see if their combined use is better than treatment with PUVA alone. The response rate (RR) was 86 % (three FR and two PR out of six patients).

Bexarotene in the treatment of cutaneous T-cell lymphoma

Primary cutaneous T-cell lymphomas encompass a spectrum of non-Hodgkin's lymphomas that are characterised by clonal proliferation of skin-homing malignant T lymphocytes. Mycosis fungoides and the leukaemic variant Sézary syndrome, collectively referred to as cutaneous T-cell lymphomas, are the most common entities. No curative therapy exists and patients ultimately develop advanced or relapsed disease that is refractory to standard treatment options. Therefore, there is a great need for the development of novel emerging therapies. Bexarotene is the first synthetic nuclear retinoid X receptor-selective retinoid approved by the FDA for the treatment of refractory cutaneous T-cell lymphoma in all stages, as both an oral capsule and a topical gel formulation. Bexarotene was found to induce apoptosis in a variety of preclinical in vitro and in vivo models including cutaneous T-cell lymphoma cells, and has shown efficacy in two multi-centre, open-label Phase II - III clinical trials for early and advanced stages of cutaneous T-cell lymphoma in patients who have failed or were refractory to standard therapies. New insights into the immunomodulatory function of bexarotene have indicated opportunities for combined treatment with IFN-alpha, denileukin diftitox or phototherapy. This article reviews the biological properties, pharmacokinetics, clinical efficacy, safety and role of bexarotene in the treatment of cutaneous T-cell lymphoma.