Bexarotene - an alternative therapy for progressive cutaneous T-cell lymphoma? First experiences

Interventions for mycosis fungoides

BACKGROUND

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma, a malignant, chronic disease initially affecting the skin. Several therapies are available, which may induce clinical remission for a time. This is an update of a Cochrane Review first published in 2012: we wanted to assess new trials, some of which investigated new interventions.

OBJECTIVES

To assess the effects of interventions for MF in all stages of the disease.

SEARCH METHODS

We updated our searches of the following databases to May 2019: the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We searched 2 trials registries for additional references. For adverse event outcomes, we undertook separate searches in MEDLINE in April, July and November 2017.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of local or systemic interventions for MF in adults with any stage of the disease compared with either another local or systemic intervention or with placebo.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. The primary outcomes were improvement in health-related quality of life as defined by participants, and common adverse effects of the treatments. Key secondary outcomes were complete response (CR), defined as complete disappearance of all clinical evidence of disease, and objective response rate (ORR), defined as proportion of patients with a partial or complete response. We used GRADE to assess the certainty of evidence and considered comparisons of psoralen plus ultraviolet A (PUVA) light treatment as most important because this is first-line treatment for MF in most guidelines.

MAIN RESULTS

This review includes 20 RCTs (1369 participants) covering a wide range of interventions. The following were assessed as either treatments or comparators: imiquimod, peldesine, hypericin, mechlorethamine, nitrogen mustard and intralesional injections of interferon-α (IFN-α) (topical applications); PUVA, extracorporeal photopheresis (ECP: photochemotherapy), and visible light (light applications); acitretin, bexarotene, lenalidomide, methotrexate and vorinostat (oral agents); brentuximab vedotin; denileukin diftitox; mogamulizumab; chemotherapy with cyclophosphamide, doxorubicin, etoposide, and vincristine; a combination of chemotherapy with electron beam radiation; subcutaneous injection of IFN-α; and intramuscular injections of active transfer factor (parenteral systemics). Thirteen trials used an active comparator, five were placebo-controlled, and two compared an active operator to observation only. In 14 trials, participants had MF in clinical stages IA to IIB. All participants were treated in secondary and tertiary care settings, mainly in Europe, North America or Australia. Trials recruited both men and women, with more male participants overall. Trial duration varied from four weeks to 12 months, with one longer-term study lasting more than six years. We judged 16 trials as at high risk of bias in at least one domain, most commonly performance bias (blinding of participants and investigators), attrition bias and reporting bias. None of our key comparisons measured quality of life, and the two studies that did presented no usable data. Eighteen studies reported common adverse effects of the treatments. Adverse effects ranged from mild symptoms to lethal complications depending upon the treatment type. More aggressive treatments like systemic chemotherapy generally resulted in more severe adverse effects. In the included studies, CR rates ranged from 0% to 83% (median 31%), and ORR ranged from 0% to 88% (median 47%). Five trials assessed PUVA treatment, alone or combined, summarised below. There may be little to no difference between intralesional IFN-α and PUVA compared with PUVA alone for 24 to 52 weeks in CR (risk ratio (RR) 1.07, 95% confidence interval (CI) 0.87 to 1.31; 2 trials; 122 participants; low-certainty evidence). Common adverse events and ORR were not measured. One small cross-over trial found once-monthly ECP for six months may be less effective than twice-weekly PUVA for three months, reporting CR in two of eight participants and ORR in six of eight participants after PUVA, compared with no CR or ORR after ECP (very low-certainty evidence). Some participants reported mild nausea after PUVA but no numerical data were given. One participant in the ECP group withdrew due to hypotension. However, we are unsure of the results due to very low-certainty evidence. One trial comparing bexarotene plus PUVA versus PUVA alone for up to 16 weeks reported one case of photosensitivity in the bexarotene plus PUVA group compared to none in the PUVA-alone group (87 participants; low-certainty evidence). There may be little to no difference between bexarotene plus PUVA and PUVA alone in CR (RR 1.41, 95% CI 0.71 to 2.80) and ORR (RR 0.94, 95% CI 0.61 to 1.44) (93 participants; low-certainty evidence). One trial comparing subcutaneous IFN-α injections combined with either acitretin or PUVA for up to 48 weeks or until CR indicated there may be little to no difference in the common IFN-α adverse effect of flu-like symptoms (RR 1.32, 95% CI 0.92 to 1.88; 82 participants). There may be lower CR with IFN-α and acitretin compared with IFN-α and PUVA (RR 0.54, 95% CI 0.35 to 0.84; 82 participants) (both outcomes: low-certainty evidence). This trial did not measure ORR. One trial comparing PUVA maintenance treatment to no maintenance treatment, in participants who had already had CR, did report common adverse effects. However, the distribution was not evaluable. CR and OR were not assessable. The range of treatment options meant that rare adverse effects consequently occurred in a variety of organs.

AUTHORS' CONCLUSIONS

​​There is a lack of high-certainty evidence to support decision making in the treatment of MF. Because of substantial heterogeneity in design, missing data, small sample sizes, and low methodological quality, the comparative safety and efficacy of these interventions cannot be reliably established on the basis of the included RCTs. PUVA is commonly recommended as first-line treatment for MF, and we did not find evidence to challenge this recommendation. There was an absence of evidence to support the use of intralesional IFN-α or bexarotene in people receiving PUVA and an absence of evidence to support the use of acitretin or ECP for treating MF. Future trials should compare the safety and efficacy of treatments to PUVA, as the current standard of care, and should measure quality of life and common adverse effects.

Chemical evaluation and cytotoxic mechanism investigation of Clinacanthus nutans extract in lymphoma SUP-T1 cells

Clinacanthus nutans has been used as herbal medicine with antidiabetic, blood pressure lowering, and diuretic properties in Singapore, Thailand, and Malaysia. The in vitro cellular study showed the chloroform extract possessed significant cytotoxicity against leukemia K562 and lymphoma Raji cells. The clinical study reported that administration of plant could treat or prevent relapse in 12 cancer patients. However, detailed mechanism of the anticancer effects and chemical profiles are not thoroughly studied. The chemical study did show that the acetone extract (MHA) exerted the highest antiproliferative effect on human leukemia MOLT-4 cells and lymphoma SUP-T1 cells in dose-dependent cytotoxicity. We found that the use of MHA increased apoptosis by 4.28%-43.65% and caused disruption of mitochondrial membrane potential (MMP) by 11.79%-26.93%, increased reactive oxygen species (ROS) by 19.54% and increased calcium ion by 233.83%, as demonstrated by annexin-V/PI, JC-1, H₂ DCFDA, and Flou-3 staining assays, respectively. MHA-induced ER stress was confirmed by increase expression of CHOP and IRE-1α with western blotting assay. In conclusion, we identified good bioactivity in Clinacanthus nutans and recognize its potential effect on cancer therapy, but further research is needed to determine the use of the plant.

New insights into the molecular biology and targeted therapy of cutaneous T-cell lymphomas

Cutaneous T-cell lymphoma is an extra-nodal non-Hodgkin lymphoma of mature T cells. These tumor cells home to and persist in the skin,producing a broad spectrum of clinical entities. Recent results of basic research on tumor biology and tumor immunology as well as molecular genetics of cutaneous T-cell lymphoma have fostered the development of new therapeutic approaches. Several clinical trials testing these targeted therapies have shown encouraging results. This article provides an overview of recent research developments and therapeutic strategies for cutaneous T-cell lymphoma.