Clinical potential of mechlorethamine gel for the topical treatment of mycosis fungoides-type cutaneous T-cell lymphoma: a review on current efficacy and safety data

Maintenance therapy for CTCL: importance for prevention of disease progression

There are no established maintenance protocols for cutaneous lymphomas. We aim to determine patient treatments and outcomes during the COVID-19 pandemic in order to uncover the most effective maintenance protocols for cutaneous lymphomas and impact of treatment interruption. Data was collected retrospectively from nine international institutions, including 149 patients. Younger patients had earlier stages of disease and were most frequently treated with skin-directed therapies including topical steroids, mechlorethamine gel, and phototherapy. Treatment interruption varied by treatment type and stage, with patients on topical therapies and earlier stages of disease being least likely to experience interruption. Treatment interruption was significantly associated with progression of disease and worse outcomes, with twice as many patients progressing who had interruption compared to those without interruption. This study may demonstrate the significance of continuous maintenance therapies, even in younger patients with early stages of disease.

Immunosequencing applications in cutaneous T-cell lymphoma

Immunosequencing has emerged as a newer clinical test for assessment of T-cell clonality in the blood and skin of cutaneous T-cell lymphoma (CTCL) patients. Utilization of immunosequencing, also known as high-throughput sequencing of the T-cell receptor (HTS-TCR), enables identification and quantification of the precise genetic signature of dominant T-cell clones. Although immunosequencing is more sensitive than commonly used methods such as polymerase chain reaction (PCR) paired with capillary electrophoresis or flow cytometry, it remains underutilized for CTCL management. Nonetheless, incorporation of HTS-TCR in clinical practice offers distinct advantages compared to other molecular analyses that may improve diagnostic evaluation, prognostication, and disease monitoring in CTCL. The objective of this comprehensive review is to provide a thorough explanation of the application of immunosequencing in the context of CTCL. We describe the significance of T-cell clonality and the methods used to detect it, including a detailed comparison between PCR paired with capillary electrophoresis and HTS-TCR. The utilization of immunosequencing in the blood and skin of CTCL patients is discussed in depth, specifically outlining how HTS-TCR can assist in diagnosing CTCL, predicting outcomes, and tracking disease progression. Finally, we address the potential applications of immunosequencing in clinical management and research as well as the novel challenges it presents.

Mechanism of action of chlormethine gel in mycosis fungoides

Mycosis fungoides (MF), the most common type of cutaneous T-cell lymphoma, is characterized by proliferation of malignant skin-tropic T cells. Progression from early-stage disease (skin patches and/or plaques) to more advanced stages (cutaneous tumours, erythroderma or extracutaneous involvement) occurs slowly and can be discontinuous. Prognosis is poor for the ~25% of patients who progress to advanced disease. Patients at any stage of MF may experience reduced health-related quality of life (QoL) via a spectrum of physically and psychologically debilitating symptoms that can impact many aspects of daily life. Allogeneic stem-cell transplantation is a curative treatment option for some patients with advanced disease, but otherwise there is currently no cure for MF; patients are often refractory to several treatments and require lifelong management. The goals of therapy are symptom control, prevention of disease progression, avoidance of treatment-related toxicity and maintenance/improvement of QoL. Although treatment regimens exist it can be difficult to know how to prioritize them, hence therapies are tailored according to patient needs and drug availabilities, following clinical recommendations. International consensus guidelines recommend skin-directed therapies (SDTs) as first-line treatment for early-stage disease, and SDTs combined with systemic therapy for advanced stages. Chlormethine (CL), also known as mechlorethamine, chlorethazine, mustine, HN2, caryolysine and embichin, is a synthetic deoxyribonucleic acid-alkylating agent that was used as a chemical weapon (mustard gas) during the First World War. Subsequent investigation revealed that survivors of mustard gas exposure had lymphocytopenia, and that CL could inhibit rapidly proliferating malignant T cells. CL has since been developed as a topical treatment for MF and prescribed as such for over 70 years. This review aims to summarize the current knowledge regarding the mechanism of action of CL in the cutaneous micro-environment, in the specific context of MF treatment.

Multidisciplinary Approach to the Diagnosis and Therapy of Mycosis Fungoides

Mycosis fungoides is the most common primary cutaneous T-cell lymphoma, characterized by skin-homing CD4+ T cells derivation, indolent course, and low-grade of malignancy. Mycosis fungoides's classic type typically onsets with cutaneous erythematous patches, plaque, and tumor. In WHO-EORTC classification, folliculotropic mycosis fungoides, pagetoid reticulosis, and granulomatous slack skin are recognized as distinct variants of mycosis fungoides, because of their clinical and histological features, behavior, and /or prognosis. Mycosis fungoides often shows diagnostic difficulties, due to its absence of specific features and lesional polymorphism. A patient's treatment requires staging. In about 10% of cases, mycosis fungoides can progress to lymph nodes and internal organs. Prognosis is poor at advanced stage and management needs a multidisciplinary team approach. Advanced stage disease including tumors, erythroderma, and nodal, visceral, or blood involvement needs skin directed therapy associated with systemic drugs. Skin directed therapy includes steroids, nitrogen mustard, bexarotene gel, phototherapy UVB, and photochemiotherapy, i.e., total skin electron radiotherapy. Systemic therapies include retinoids, bexarotene, interferon, histone deacetylase inhibitors, photopheresis, targeted immunotherapy, and cytotoxic chemotherapy. Complexity of mycosis fungoides associated with long-term chronic evolution and multiple therapy based on disease stage need a multidisciplinary team approach to be treated.

Topical Mechlorethamine for the Treatment of Psoriasis: A Report of Two Cases and Literature Review

INTRODUCTION

Psoriasis is a common inflammatory skin disease that significantly impacts patients' psychosocial wellbeing. Despite increasingly effective treatment options, the recurrence of plaques after discontinuation of therapy in many patients highlights the need for additional therapies.

METHODS

We report two cases of patients with concurrent psoriasis and mycosis fungoides who were treated with topical mechlorethamine (MCH). A literature review was performed by searching PubMed using the keywords psoriasis, mechlorethamine, chlormethine, and nitrogen mustard.

RESULTS

Both patients had significant improvement in their psoriasis following treatment with topical MCH gel, which was well tolerated and maintained clearance after 1 and 3 years of follow-up. Seven prospective cohort studies investigating the use of topical MCH were identified through literature review. Out of five studies reporting clinical outcomes by patient, 68 of 77 patients (88%) experienced an improvement in their psoriasis, with 47 of 77 (61%) achieving complete or near-complete clearance. The remaining two studies reported clinical outcomes by lesion, demonstrating improvement in 40 of 45 lesions (88%) and complete or near-complete clearance in 32 of 42 lesions (76%). Contact dermatitis was the most frequent adverse effect, observed in 56 of 125 patients (45%).

CONCLUSIONS

Topical MCH may be an option for patients with psoriasis who fail or have incomplete responses to other treatments. Published studies are limited by lack of standardized treatment regimens and well-defined outcome measures, highlighting the need for prospective clinical trials to better understand the utility of this topical agent in psoriasis.

Harnessing the immune system in the treatment of cutaneous T cell lymphomas

Cutaneous T cell lymphomas are a rare subset of non-Hodgkin's lymphomas with predilection for the skin with immunosuppressive effects that drive morbidity and mortality. We are now appreciating that suppression of the immune system is an important step in the progression of disease. It should come as no surprise that therapies historically and currently being used to treat these cancers have immune modulating functions that impact disease outcomes. By understanding the immune effects of our therapies, we may better develop new agents that target the immune system and improve combinatorial treatment strategies to limit morbidity and mortality of these cancers. The immune modulating effect of therapeutic drugs in use and under development for cutaneous T cell lymphomas will be reviewed.

Gene Regulations upon Hydrogel-Mediated Drug Delivery Systems in Skin Cancers-An Overview

The incidence of skin cancer has increased dramatically in recent years, particularly in Caucasian populations. Specifically, the metastatic melanoma is one of the most aggressive cancers and is responsible for more than 80% of skin cancer deaths around the globe. Though there are many treatment techniques, and drugs have been used to cure this belligerent skin cancer, the side effects and reduced bioavailability of drug in the targeted area makes it difficult to eradicate. In addition, cellular metabolic pathways are controlled by the skin cancer driver genes, and mutations in these genes promote tumor progression. Consequently, the MAPK (RAS-RAF-MEK-ERK pathway), WNT and PI3K signaling pathways are found to be important molecular regulators in melanoma development. Even though hydrogels have turned out to be a promising drug delivery system in skin cancer treatment, the regulations at the molecular level have not been reported. Thus, we aimed to decipher the molecular pathways of hydrogel drug delivery systems for skin cancer in this review. Special attention has been paid to the hydrogel systems that deliver drugs to regulate MAPK, PI3K-AKT-mTOR, JAK-STAT and cGAS-STING pathways. These signaling pathways can be molecular drivers of skin cancers and possible potential targets for the further research on treatment of skin cancers.

Response to Chlormethine/Mechlorethamine gel Maintenance Treatment Regimen in Patients With Mycosis Fungoides: A Single-center Retrospective Study

BACKGROUND

Mycosis fungoides (MF), the most common subtype of Cutaneous T-cell lymphomas, is caused by malignant T-cell proliferations in the skin that can invade blood, lymph nodes, or viscera. Currently, data on efficacy of maintenance therapies in MF are lacking. We developed a unique protocol to use chlormethine/mechlorethamine 0.016% gel formulation as maintenance regimen for MF patients in remission.

PURPOSE

To determine progression-free survival and efficacy of chlormethine/mechlorethamine as maintenance and active treatment regimens for MF.

MATERIALS AND METHODS

A retrospective review of MF patients seen at Thomas Jefferson University from 2012 to 2020 was conducted. Patients of all stages treated with chlormethine/mechlorethamine as maintenance or active treatment with 2 consecutive mSWATs (modified Severity Weighted Assessment Tool) documented were included. Treatment outcomes were assessed by change in mSWAT and progression-free survival. Dermatology Life Quality Index surveys before and after treatment were analyzed.

RESULTS

Of 186 MF patients, 44 met inclusion criteria. Patients on maintenance therapy had a 65.22% progression-free survival rate with median time to progression of 29.45 months. By-time analysis for responders on active and maintenance treatment showed an increased response over time. Peak responses were seen at last mSWAT recorded. Both cohorts experienced improved quality-of-life scores from initiation to discontinuation of chlormethine/mechlorethamine.

CONCLUSION

Patients on maintenance and active chlormethine/mechlorethamine treatment regimens demonstrated improvement in mSWAT and quality-of-life. Chlormethine/mechlorethamine treatment showed progression-free survival for a median of 29.45 months, indicating this therapy may be an effective maintenance regimen.

The Nitrogen Mustards

The nitrogen mustards are powerful cytotoxic and lymphoablative agents and have been used for more than 60 years. They are employed in the treatment of cancers, sarcomas, and hematologic malignancies. Cyclophosphamide, the most versatile of the nitrogen mustards, also has a place in stem cell transplantation and the therapy of autoimmune diseases. Adverse effects caused by the nitrogen mustards on the central nervous system, kidney, heart, bladder, and gonads remain important issues. Advances in analytical techniques have facilitated the investigation of the pharmacokinetics of the nitrogen mustards, especially the oxazaphosphorines, which are prodrugs requiring metabolic activation. Enzymes involved in the metabolism of cyclophosphamide and ifosfamide are very polymorphic, but a greater understanding of the pharmacogenomic influences on their activity has not yet translated into a personalized medicine approach. In addition to damaging DNA, the nitrogen mustards can act through other mechanisms, such as antiangiogenesis and immunomodulation. The immunomodulatory properties of cyclophosphamide are an area of current exploration. In particular, cyclophosphamide decreases the number and activity of regulatory T cells, and the interaction between cyclophosphamide and the intestinal microbiome is now recognized as an important factor. New derivatives of the nitrogen mustards continue to be assessed. Oxazaphosphorine analogs have been synthesized in attempts to both improve efficacy and reduce toxicity, with varying degrees of success. Combinations of the nitrogen mustards with monoclonal antibodies and small-molecule targeted agents are being evaluated. SIGNIFICANCE STATEMENT: The nitrogen mustards are important, well-established therapeutic agents that are used to treat a variety of diseases. Their role is continuing to evolve.

Chlormethin-Gel-basierte komplette Remission einer CD30-positiven Mycosis fungoides-Plaque

Chlormethin-Gel ist seit Mai 2019 als Lokaltherapeutikum bei Erwachsenen für kutane T-Zell-Lymphome vom Typ Mycosis fungoides (MF) zugelassen. Die topische Anwendung erfolgt 1-mal täglich. Im Rahmen der Zulassungsstudie kam es nach einer mindestens 6-monatigen Behandlung mit Chlormethin-Gel bei 76,7 % der Patienten (69 von 90) zu einer ≥ 50 %-igen Verbesserung der klinischen Befunde, gemessen anhand der CAILS-Skala (Composite Assessment of Index Lesion Serverity). Eine komplette Remission wurde bei 19 % (17 von 90) der Patienten beschrieben. Etwas mehr als die Hälfte der behandelten Patienten zeigte lokale Nebenwirkungen mit Hautirritationen, Hautrötungen und auch Hautinfektionen. Weitere mögliche Hautreaktionen sind Pruritus, Blasenbildung und Geschwüre.

Im Folgenden wird von einer Patientin mit einer bekannten CD30+-Mycosis fungoides im Stadium IIB (ISCL/EORTC 2007) berichtet. Eine unter verschiedenen Systemtherapien (Bexaroten, Bade-PUVA, Brentuximab Vedotin) immer wieder rezidivierende, ca. handtellergroße Plaque an der Flanke links wurde mit Chlormethin-Gel behandelt.

Aufgrund bereits bekannter, langsam progredienter Größenzunahme und wiederholt schmerzhafter Mazerationen dieses Herdes erfolgte auch mit Blick auf mögliche Nebenwirkungen von Chlormethin-Gel die Behandlung in Absprache mit der Patientin nur jeden zweiten Tag.

Unter diesem Therapieregime zeigte sich, nach anfänglicher kurzzeitiger Hautreizung, bereits nach 3 Monaten eine komplette, histologisch gesicherte, aktuell 6 Monate anhaltende Remission der Läsion.

Diese Kasuistik soll einen eindrucksvollen Therapieverlauf unter Chlormethin-Gel in reduzierter Dosierung und bei guter Verträglichkeit präsentieren.

Diagnosis and Management of Cutaneous Lymphomas Including Cutaneous T-cell Lymphoma

The cutaneous lymphomas are malignancies of T-cell and B-cell lymphocytes in which the skin is the primary organ of involvement. The cutaneous T-cell lymphomas include variants that can mimic the presentation of common skin diseases or arthropod bites. Mycosis fungoides, the most common cutaneous T-cell lymphoma, usually presents as fixed asymptomatic patches or plaques in sun-protected areas. The cutaneous B-cell lymphomas have fewer variants that often present as papules or nodules that can mimic nonmelanoma skin cancers. Some therapies for cutaneous lymphoma have unique side effects such as central hypothyroidism, hyperlipidemia, and peripheral neuropathy.

Post hoc Analysis of a Randomized, Controlled, Phase 2 Study to Assess Response Rates with Chlormethine/Mechlorethamine Gel in Patients with Stage IA-IIA Mycosis Fungoides

BACKGROUND

Mycosis fungoides (MF) is the most common form of cutaneous T-cell lymphoma. Patients can be treated using chlormethine gel, a skin-directed therapy developed and approved for MF. In the randomized, controlled 201 trial, chlormethine gel was found to be noninferior to equal-strength chlormethine ointment. However, there remains a need to gain more insight into outcome measures after treatment.

OBJECTIVE

The aim of this study was to further investigate the potential of chlormethine gel treatment through a novel post hoc analysis of the 201 trial data (NCT00168064).

METHODS

Patients were randomized to chlormethine gel or ointment; response assessments included Composite Assessment of Index Lesion Severity (CAILS) and total body surface area (BSA). In this post hoc analysis, additional subgroup response analyses were performed for stage IA/IB-IIA MF. Very good partial response (75 to <100% improvement) was included as an additional response category. Time to response and overall response trends were determined. Finally, multivariate time-to-event analyses were performed to determine whether associations were observed between treatment frequency, response, and adverse events.

RESULTS

Response rates were significantly higher for patients with stage IA MF for CAILS (intent-to-treat [p = 0.0014] and efficacy-evaluable [EE; p = 0.0036] populations) and BSA (EE population [p = 0.0488]) treated with gel versus ointment. Time to first CAILS response and response trends were better for all-stage gel-treated patients overall. No association was seen between treatment frequency and response or occurrence of adverse events at the following visit. An association was observed between the occurrence of contact dermatitis and improved clinical response at the next visit (p = 0.0001).

CONCLUSION

This post hoc analysis shows that treatment with chlormethine gel may result in higher and faster response rates compared with chlormethine ointment, which confirms and expands results reported in the original analysis. The incidence of contact dermatitis may potentially be a prognostic indicator for clinical response; this needs to be confirmed in a larger population.

C6 Ceramide (d18:1/6:0) as a Novel Treatment of Cutaneous T Cell Lymphoma

Simple Summary

There is no curative treatment for mycosis fungoides and Sézary syndrome, which are the most frequent forms of cutaneous T cell lymphoma (CTCL). Short-chain ceramides like C6 Ceramide are known to induce cell death by both apoptosis and necrosis. Here, we demonstrate that C6 Ceramide strongly reduced cell viability and induced cell death in CTCL cell lines but not in HaCaT keratinocytes and primary human keratinocytes. C6 Ceramide was rapidly metabolized by both keratinocyte cell types but not by CTCL cells. These results provide the basis for further clinical trials with topical applicated C6 Ceramide against mycosis fungoides and Sézary syndrome.

Abstract

Cutaneous T cell lymphomas (CTCLs) represent a heterogeneous group of T cell lymphomas that primarily affect the skin. The most frequent forms of CTCL are mycosis fungoides and Sézary syndrome. Both are characterized by frequent recurrence, developing chronic conditions and high mortality with a lack of a curative treatment. In this study, we evaluated the effect of short-chain, cell-permeable C6 Ceramide (C6Cer) on CTCL cell lines and keratinocytes. C6Cer significantly reduced cell viability of CTCL cell lines and induced cell death via apoptosis and necrosis. In contrast, primary human keratinocytes and HaCaT keratinocytes were less affected by C6Cer. Both keratinocyte cell lines showed higher expressions of ceramide catabolizing enzymes and HaCaT keratinocytes were able to metabolize C6Cer faster and more efficiently than CTCL cell lines, which might explain the observed protective effects. Along with other existing skin-directed therapies, C6Cer could be a novel well-tolerated drug for the topical treatment of CTCL.

How do we treat cutaneous T-cell lymphoma?

Cutaneous T-cell lymphomas are a heterogeneous group of non-Hodgkin lymphomas which are based on the malignant proliferation of skin-related T lymphocytes. The clinical appearance, as well as the course and the associated therapeutic approach, are sometimes very different between the different subtypes. Since allogeneic stem cell transplantation is currently the only curative option, and the morbidity and mortality are not insignificant, a therapy concept should be developed that considers its often rather indolent but chronic course. This concept should enable a good disease control with as few side effects as possible and preserve or improve the quality of life. In the early stages of the disease, skin-oriented therapies are generally used first before systemic and increasingly aggressive therapeutic agents are used as the disease progresses. Considering the current guidelines, literature and subjective experience, we summarize in this review how we treat cutaneous T-cell lymphomas.

Nitrogen Mustards as Anticancer Chemotherapies: Historic Perspective, Current Developments and Future Trends

Nitrogen mustards, a family of DNA alkylating agents, marked the start of cancer pharmacotherapy. While traditionally characterized by their dose-limiting toxic effects, nitrogen mustards have been the subject of intense research efforts, which have led to safer and more effective agents. Even though the alkylating prodrug mustards were first developed decades ago, active research on ways to improve their selectivity and cytotoxic efficacy is a currently active topic of research. This review addresses the historical development of the nitrogen mustards, outlining their mechanism of action, and discussing the improvements on their therapeutic profile made through rational structure modifications. A special emphasis is made on discussing the nitrogen mustard prodrug category, with Cyclophosphamide (CPA) serving as the main highlight. Selected insights on the latest developments on nitrogen mustards are then provided, limiting such information to agents that preserve the original nitrogen mustard mechanism as their primary mode of action. Additionally, future trends that might follow in the quest to optimize these invaluable chemotherapeutic medications are succinctly suggested.

Management of mycosis fungoides-type cutaneous T-cell lymphoma (MF-CTCL): focus on chlormethine gel

Mycosis fungoides (MF) is a low-grade cutaneous lymphoma accounting for more than half of primary cutaneous T-cell lymphomas (CTCLs). Due to the rarity of CTCL, randomized studies are lacking, and treatment is based mainly on the recent published European Organisation for Research and Treatment of Cancer guidelines. Basically, early-stage MF is treated with skin-directed treatments, whereas advanced-stage MF requires more aggressive therapies. Among the skin-directed therapies, nitrogen mustard has been used for more than 50 years. A gel formulation was developed recently, showing a slight decrease in efficacy, counterbalanced by better tolerance (essentially due to a decrease in delayed hypersensitivity reactions). This review aims to summarize the current management of MF and the role of chlormethine gel in the treatment of the disease.