Topical immunotherapy with diphencyprone for in transit and cutaneously metastatic melanoma

An overview of cyclopropenone derivatives as promising bioactive molecules

Cyclopropenone is a valuable electrophilic reagent that can react with electrophilic reagents, nucleophilic reagents, free radicals, organic metals, etc. Furthermore, cyclopropenone derivatives have shown significant biological activity in various diseases, such as triple-negative breast cancer (TNBC), melanoma, and alopecia areata (AA). The cyclopropenone analogue diphenylcyclopropenone (DPCP) has been approved for the treatment of AA. Given the potential therapeutic benefits of cyclopropenone derivatives, this review aims to systematically summarize the structures, synthesis routes, and potential pharmacological functions of cyclopropenone analogues in the hope of offering novel insights for further rational design of more drugs based on the cyclopropenone skeleton for the treatment of human diseases.

The Diagnosis and Management of Cutaneous Metastases from Melanoma

Melanoma is one of the deadliest skin tumors, accounting for almost 90% of skin cancer mortality. Although immune therapy and targeted therapy have dramatically changed the prognosis of metastatic melanoma, many patients experience disease progression despite the currently available new treatments. Skin metastases from melanoma represent a relatively common event as first sign of advanced disease or a sign of recurrence. Skin metastases are usually asymptomatic, although in advanced stages, they can present with ulceration, bleeding, and superinfection; furthermore, they can cause symptoms related to compression on nearby tissues. Treatments vary from simple surgery resections to topical or intralesional local injections, or a combination of these techniques with the most recent systemic immune or target therapies. New research and studies should focus on the pathogenesis and molecular mechanisms of the cutaneous metastases of melanoma in order to shed light on the mechanisms underlying the different behavior and prognoses of different patients.

Modulation of Inflammatory Proteins in Serum May Reflect Cutaneous Immune Responses in Cancer Immunotherapy

Diphencyprone (DPCP), a topical contact sensitizer, has shown efficacy in treating cutaneous melanoma metastases, including at times beyond the directly treated sites, but biomarkers indicative of treatment response have not been characterized. Thus, we performed a proteomic analysis of the skin and serum of five patients with cutaneous melanoma metastases treated with DPCP on days 0, 63, and 112 of the treatment course. In the serum, we found a significant upregulation (P < 0.05) in 13 of 96 assessed immuno-oncology proteins after DPCP treatment. Upregulated proteins included those of the T helper 1 axis (CXCL9, CXCL10), immune checkpoint proteins (PD-1), and various proteins with roles in promoting tumor immunity such as CD80 and TNFRSF4/9. Given the positive clinical response to topical treatment noted in the five patients studied, these proteins may represent prognostic biomarkers in the serum for evaluating the efficacy of DPCP treatment of cutaneous melanoma metastases. Because DPCP does not lead to nonspecific immune-related adverse events seen with immune checkpoint inhibitors, our study provides evidence for potential tumor-specific systemic immune activation and systemic antitumor effectors elicited by topical DPCP.

Proteomic profiling of a patient with cutaneous melanoma metastasis regression following topical contact sensitizer diphencyprone and immune checkpoint inhibitor treatment

Immune checkpoint inhibitors (ICIs) such as pembrolizumab have revolutionized the treatment of advanced melanoma, but many patients do not respond to ICIs alone, and thus there is need for additional treatment options. Topical immunomodulators such as diphencyprone (DPCP) also have clinical use in advanced melanoma, particularly in the treatment of cutaneous metastases. In a previous report, we characterized the enhanced clinical response to dual agent immunotherapy with pembrolizumab and DPCP in a patient with cutaneous melanoma metastases. To improve mechanistic understanding of this response, we analyzed proteomic data using the Olink immuno-oncology panel of 96 biomarkers from tissue and serum samples of this patient throughout his treatment course. Particular attention was paid to programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1), and lymphocyte-activation gene 3 (LAG-3) given they are all targeted by ICIs in clinical practice. These proteins were upregulated during the period of DPCP monotherapy, then downregulated during pembrolizumab monotherapy, and then robustly upregulated again during dual therapy. Although not exclusively, the induction of checkpoint inhibitor proteins in the presence of DPCP suggests potential synergy between this agent and ICIs in the treatment of cutaneous melanoma metastases. Large-scale investigation is warranted to further evaluate this potential novel combination therapeutic approach.

Use of Contact Immunotherapy in the Treatment of Skin Diseases Other than Alopecia Areata

For decades, contact immunotherapy with dinitrochlorobenzene, diphencyprone, and squaric acid dibutylester has played an important role in both clinical practice and scientific research. It is listed as the first-line treatment for extensive alopecia areata and was more recently approved for melanoma treatment as an orphan drug in the USA. Moreover, owing to the relative low cost and safety, topical immunotherapy has also been used in many infectious, neoplastic, and inflammatory dermatological diseases. It is especially valuable in vulnerable groups, for cosmetic/pain sensitive areas, or for multiple lesions. In this review, we summarize the current evidence supporting the use of contact immunotherapy for treatment of skin diseases, from articles collected from PubMed database. Owing to space limitation and already numerous studies focusing on alopecia areata, we include only skin diseases other than alopecia areata. In addition to diseases that have been reported to be treated by contact immunotherapy, the hypothesized mechanism, prognosis prediction, efficacy, and safety of these topical agents are discussed.

Non-Operative Options for Loco-regional Melanoma

Malignant melanoma is the 5th most common cancer and stage IV melanoma accounts for approximately 4% of new melanoma diagnoses in the United States. The prognosis for regionally advanced disease is poor, but there have been numerous recent advances in the medical management of melanoma in-transit metastases. The goal of this paper is to review currently accepted treatment options for in-transit metastases and introduce emerging therapies. Therapies to be discussed include limb perfusion and infusion, immunotherapy, checkpoint inhibitors, and radiation therapy.

Advances in non and minimal-invasive transcutaneous delivery of immunotherapy for cancer treatment

Cancer research has focused on figuring out what was the difference between cancer cells and the tissues within which cancer arose and developing targeted treatments for those differences. With FDA-approved treatments for more ten different cancers and more than thousand new clinical trials, immunotherapy has recently emerged as the most promising area of cancer research by improving efficacy and controlling the adverse effects. Transcutaneous delivery drug delivery offers a number of advantages for the patient because of not only its noninvasive and convenient nature but also factors such as avoidance of first-pass metabolism and prevention of gastrointestinal degradation. The purpose of this review was to highlight technological recent approaches to non and minimal-invasive delivery of immunotherapy for cancer treatment. Finally, some practical considerations and discussions for future studies in the field of transdermal immunomodulation are also included.

Lesional therapies for in-transit melanoma

BACKGROUND AND OBJECTIVES

To describe the outcomes of lesional therapy of in-transit melanoma (ITM) with interleukin-2 (IL-2), diphencyprone (DPCP), combination lesional therapy (IL-2, retinoid, and imiquimod; CLT), and imiquimod.

METHODS

Data was collected for consecutive patients with ITM receiving lesional therapies from 2008 to 2018 in a retrospective review. Included patients did not have metastatic disease at time of starting on lesional therapy and were not on systemic therapy. The primary outcome was complete pathologic response (pCR).

RESULTS

Of 83 patients, 57 (69%) started treatment with IL-2, 10 (12%) with DPCP, 12 (14%) with CLT, and 4 (5%) with imiquimod. pCR was achieved in 34 patients (41%) overall, including 44% starting on IL-2, 20% on DPCP, 58% on CLT, and none on imiquimod (P = .024). With a median follow-up of 45 months, cumulative one-year overall survival was 86%, with the best survival in the CLT group. Forty-eight percent experienced common terminology criteria for adverse events grade 1 or 2 toxicity. A quarter of patients on DPCP discontinued therapy due to toxicity (P = .002).

CONCLUSIONS

IL-2 may be considered for the treatment of ITM with multiple or rapidly developing lesions where there would otherwise be significant morbidity with surgery, given pCR rates and toxicity.

Quantitative and Spatial Analysis of CD8+/PD-1 Tumor-Infiltrating Lymphocytes as a Predictive Biomarker for Clinical Response of Melanoma In-Transit Metastases to Topical Immunotherapy

Background

Melanoma in-transit metastases (ITMs) are a challenge to treat and associated with systemic disease and poor prognosis. Topical diphencyprone (DPCP), a potent contact sensitizer, is an established treatment for melanoma ITMs. This exploratory study investigated the utility of BRAF mutation status, CD8, PD-1, PD-L1, and TILs distribution as biomarkers for response of ITMs to topical immunotherapy (DPCP).

Methods

The ITM deposits of 40 patients treated with DPCP were subjected to biomarker analysis for BRAF status, CD8 and PD-1 expression on tumor-infiltrating lymphocytes (TILs), and tumor PD-L1 expression. Response to DPCP and overall survival (OS) were compared by biomarker status.

Results

After 12 weeks, 10 patients (25%) had a complete response, 12 patients (30%) had a partial response, and 18 patients (45%) had no response. No significant association was found between any individual biomarker and response to DPCP or OS. The BRAF mutation rate was 25% (10/40). All the patients with a complete response had BRAF wild-type tumor. Peritumoral CD8+ T-cells were associated with complete response (P = 0.041). Both CD8+ and PD-1 expressions were highly correlated (P < 0.0001), and the highest levels of PD-1 expression were detected at the peritumoral interface (P = 0.0004). Only two cases were PD-L1-positive, and both had a complete response to DPCP (P = 0.043).

Conclusion

Patients who have BRAF wild-type tumor are more likely to experience a complete response to DPCP. Peritumoral TILs and PD-1 expressions may predict a better response to DPCP. Expression of PD-L1 may be associated with a complete response to DPCP. A larger prospective study is required.

Locoregional management of in-transit metastasis in melanoma: an Ontario Health (Cancer Care Ontario) clinical practice guideline

Objective

The purpose of this guideline is to provide guidance on appropriate management of satellite and in-transit metastasis (itm) from melanoma.

Methods

The guideline was developed by the Program in Evidence-Based Care (pebc) of Ontario Health (Cancer Care Ontario) and the Melanoma Disease Site Group. Recommendations were drafted by a Working Group based on a systematic review of publications in the medline and embase databases. The document underwent patient- and caregiver-specific consultation and was circulated to the Melanoma Disease Site Group and the pebc Report Approval Panel for internal review; the revised document underwent external review.

Recommendations

"Minimal itm" is defined as lesions in a location with limited spread (generally 1-4 lesions); the lesions are generally superficial, often clustered together, and surgically resectable. "Moderate itm" is defined as more than 5 lesions covering a wider area, or the rapid development (within weeks) of new in-transit lesions. "Maximal itm" is defined as large-volume disease with multiple (>15-20) 2-3 cm nodules or subcutaneous or deeper lesions over a wide area.■ In patients presenting with minimal itm, complete surgical excision with negative pathologic margins is recommended. In addition to complete surgical resection, adjuvant treatment may be considered.■ In patients presenting with moderate unresectable itm, consider using this approach for localized treatment: intralesional interleukin 2 or talimogene laherparepvec as 1st choice, topical diphenylcyclopropenone as 2nd choice, or radiation therapy as 3rd choice. Evidence is insufficient to recommend intralesional bacille Calmette- Guérin or CO2 laser ablation outside of a research setting.■ In patients presenting with maximal itm confined to an extremity, isolated limb perfusion, isolated limb infusion, or systemic therapy may be considered. In extremely select cases, amputation could be considered as a final option in patients without systemic disease after discussion at a multidisciplinary case conference.■ In cases in which local, regional, or surgical treatments for itm might be ineffective or unable to be performed, or if a patient has systemic metastases at the same time, systemic therapy may be considered.

Sequencing in management of in-transit melanoma metastasis: Diphencyprone versus isolate limb infusion

BACKGROUND

In-transit metastases (ITMs) in melanoma are associated with poor prognosis, however a significant proportion of these patients survive for extended periods without further disease progression. We routinely use locoregional treatment e.g. Diphencyprone (DPCP) and/or isolated limb infusion (ILI) as long-term palliation. This study aimed to identify correct sequencing of these therapies based on disease burden and progression.

METHOD

Retrospective evaluation of all melanoma patients with ITMs treated with DPCP/ILI/both from 2010 to 2017 at our Cancer Centre was performed. Patients were initially assessed in a multidisciplinary setting and empirically prescribed DPCP for low-disease burden, ILI for high-disease burden. Patient demographics, tumour characteristics, response to therapy, ITM progression and patient outcomes were analysed.

RESULTS

78 patients (M:F = 30:48), aged 47-95years (median 74years) treated with DPCP/ILI/both (n = 44/21/13) were identified. Progression-free survival (PFS) was significantly increased in patients responsive to DPCP or ILI as initial treatment. Patients who failed on DPCP and subsequently treated with ILI had a significantly increased PFS compared to DPCP alone (p = 0.026, HR = 0.048). This was not the case with patients who were treated with DPCP following failed ILI. All patients who failed to respond to the initial therapy progressed within 6 months.

CONCLUSION

Our study shows that careful stratification ITM patients according to disease burden is fundamental to optimal outcomes. High-disease burden patients benefit from initial ILI; low-disease burden patients should commence on DPCP. ILI can be considered in DPCP patients who fail early. Systemic therapy should be considered when locoregional therapies fail after 12 months or after rapid relapse following ILI.

The Landmark Series: Regional Therapy of Recurrent Cutaneous Melanoma

In-transit melanoma represents a distinct disease pattern in which melanoma recurs as dermal or subcutaneous nodules between the primary melanoma site and the draining regional lymph node basin. The disease pattern is often not amenable to complete surgical resection. Since the 1950s, regional therapies have been explored for the treatment of this disease entity, with the goal of maximizing delivery of the therapeutic agent to the tumor while minimizing systemic toxicity. We reviewed landmark studies describing and evaluating regional chemotherapy and intralesional therapies for patients with in-transit melanoma metastases.

Lithraea caustic (Litre) Extract Promotes an Antitumor Response Against B16 Melanoma

Melanoma immunotherapy, specifically the autotransplant of dendritic cells charged with tumors antigens, has shown promising results in clinical trials. The positive clinical effects of this therapy have been associated to increased Th17 response and delayed-type hypersensitivity (DTH) against to tumor antigens. Some synthetic compounds, such as diphenylcyclopropenone (DPCP), are capable of triggering a DTH response in cutaneous malignancies and also to induce clinically relevant effects against melanoma. In this work, we evaluated Litre extract (LExT), a standardized extract of a Chilean stinging plant, Lithraea caustic (Litre). As Litre plant is known to induce DTH, we used a murine B16 melanoma model to compare the topical and intratumor efficacy of LExT with synthetic DTH inducers (DPCP and 2,4-dinitrochlorobenzene [DNCB]). LExt contained mainly long chain catechols and sesquiterpenes. The intratumor injection of LExT induced a significant delay in tumor growth, similarly topical treatment of an established tumor with 0.1% LExT ointment induced a growth delay and even tumor regression in 15% of treated animals. No significant changes were observed on the T-cell populations associated to LExT treatment, and neither DNCB nor DPCP were capable to induce none of the LExT-induced antitumoral effects. Interestingly, our results indicate that LExT induces an antitumor response against melanoma in a mouse model and could bring a new –and affordable- treatment for melanoma in humans.

Topical and intralesional therapies for in-transitmelanoma

This report surveys the role of topical and intralesional agents in the management of in-transit melanoma. The extent and progression of in-transit disease is highly variable and many patients can have a protracted period of locoregional control. These agents are useful in the management of patients who have progressed beyond local surgical excision in whom more aggressive therapies, such as isolated limb infusion or use of talimogene laherparepvec, are not appropriate or have failed. In general, these agents are modestly effective and associated with frequent but only minor toxicity. As the mechanism of action of many of these agents includes initiation of a local immune response, combinations with immune checkpoint inhibitors are currently being explored.

Therapeutic vaccination immunomodulation: forming the basis of all cancer immunotherapy

Recent immunotherapy advances have convincingly demonstrated complete tumour removal with long-term survival. These impressive clinical responses have rekindled enthusiasm towards immunotherapy and tumour antigen vaccination providing 'cures' for melanoma and other cancers. However, many patients still do not benefit; sometimes harmed by severe autoimmune toxicity. Checkpoint inhibitors (anti-CTLA4; anti-PD-1) and interleukin-2 (IL-2) are 'pure immune drivers' of pre-existing immune responses and can induce either desirable effector-stimulatory or undesirable inhibitory-regulatory responses. Why some patients respond well, while others do not, is presently unknown, but might be related to the cellular populations being 'driven' at the time of dosing, dictating the resulting immune response. Vaccination is in-vivo immunotherapy requiring an active host response. Vaccination for cancer treatment has been skeptically viewed, arising partially from difficulty demonstrating clear, consistent clinical responses. However, this article puts forward accumulating evidence that 'vaccination' immunomodulation constitutes the fundamental, central, intrinsic property associated with antigen exposure not only from exogenous antigen (allogeneic or autologous) administration, but also from endogenous release of tumour antigen (autologous) from in-vivo tumour-cell damage and lysis. Many 'standard' cancer therapies (chemotherapy, radiotherapy etc.) create waves of tumour-cell damage, lysis and antigen release, thus constituting 'in-vivo vaccination' events. In essence, whenever tumour cells are killed, antigen release can provide in-vivo repeated vaccination events. Effective anti-tumour immune responses require antigen release/supply; immune recognition, and immune responsiveness. With better appreciation of endogenous vaccination and immunomodulation, more refined approaches can be engineered with prospect of higher success rates from cancer therapy, including complete responses and better survival rates.

Level of contact hypersensitivity response to diphencyprone and keratinocyte cancer

BACKGROUND

Keratinocyte cancers (KC) are common and pose a significant financial burden globally. Ultraviolet radiation is a significant factor in their development, through mutagenesis promotion but also through local and systemic immunosuppression. Although systemic immunosuppression is well understood, cutaneous immunity has been more difficult to evaluate.

OBJECTIVES

This study used a contact sensitizer, diphencyprone (DPCP), which elicits a contact hypersensitivity reaction in skin, to compare the degree of reactivity to DPCP in patients with a high KC burden versus those with a low KC burden.

METHODS

A prospective study was performed in immunocompetent patients aged 70 ± 5 years of age, comparing patients with a high KC burden (>10 previous KC) with those with a low KC burden (<2 previous KC). All patients were sensitized with 2% DPCP and then patch tested two weeks later with eight different concentrations of DPCP with the threshold concentration and total degree of reaction recorded.

RESULTS

Nine patients were recruited, 5 in the 'high cancer' group and 4 in the 'low cancer' group. All patients were Fitzpatrick skin type 1 or 2. All patients developed a reaction to DPCP. Patients in the low cancer group developed a reaction at a significantly lower threshold DPCP concentration than the high cancer group (P = 0.039). The cumulative intensity of reaction was higher in the low cancer group (P = 0.087).

CONCLUSION

Patients with a high KC burden required a higher threshold concentration of DPCP to elicit a hypersensitivity reaction, supporting the concept of a lower skin immunity in these patients. DPCP reactivity threshold could be a useful tool in the evaluation of skin immunity and propensity to develop keratinocyte cancers.

Application of CO2 laser evaporation in locally advanced melanoma

Aim

This study aims to investigate the role of CO₂ laser evaporation in the treatment of melanoma patients with satellite or in-transit metastases.

Materials & methods

Patients who underwent CO₂ laser evaporation were retrospectively included between November 2002 and August 2018. The Sharplan 40C CO₂ laser was used with a high pulse wave mode. Data concerning patient and tumor characteristics, CO₂ laser evaporation and subsequent therapies were collected.

Results

A total of 26 patients were included. Median duration of local control was 5.5 months. The median number of lesions evaporated per treatment was three (1-16); patients received a median of three (1-19) treatments.

Conclusion

In a selected group of melanoma patients with satellite or in-transit metastases, CO₂ laser evaporation should be considered as treatment for local control.

Recent advances in localized immunotherapy of skin cancers

Skin cancer is the most frequent malignancy in humans. The immune system has long been known to have an important role in defeating cancer. Immunotherapy, which includes various strategies to enhance tumor immunity, currently represents an exciting option for the treatment of skin cancers. Local immunotherapy is a promising therapeutic approach and may improve response rates without inducing systemic toxicity. Here, we review the main localized immunotherapies for the management of skin cancer with a special focus on advanced melanoma, nonmelanoma skin cancer and primary cutaneous lymphoma.

Tissue Resident CD8 Memory T Cell Responses in Cancer and Autoimmunity

Resident memory (T_RM) cells are a distinct tissue-localized T cell lineage that is crucial for protective immunity in peripheral tissues. While a great deal of effort has focused on defining their role in immunity to infections, studies now reveal T_RM cells as a vital component of the host immune response to cancer. Characterized by cell-surface molecules including CD103, CD69, and CD49a, T_RM-like tumor-infiltrating lymphocytes (TILs) can be found in a wide range of human cancers, where they portend improved prognosis. Recent studies in mouse tumor models have shown that T_RM cells are induced by cancer vaccines delivered in peripheral tissue sites, or by the depletion of regulatory T cells. Such tumor-specific T_RM cells are recognized as both necessary and sufficient for long-lived protection against tumors in peripheral tissue locations. T_RM responses against tumor/self-antigens can concurrently result in the development of pathogenic T_RM responses to self, with a growing number of autoimmune diseases and inflammatory pathologies being attributed to T_RM responses. This review will recount the path to discovering the importance of resident memory CD8 T cells as they pertain to cancer immunity. In addition to highlighting key studies that directly implicate T_RM cells in anti-tumor immunity, we will highlight earlier work that implicitly suggested their importance. Informed by studies in infectious disease models, and instructed by a clear role for T_RM cells in autoimmunity, we will discuss strategies for therapeutically promoting T_RM responses in settings where they don't naturally occur.

Management of in-transit melanoma metastases: a review

In-transit metastases (ITM) of cutaneous melanoma are locoregional recurrences confined to the superficial lymphatics that occur in 3.4-6.2% of patients diagnosed with melanoma. ITM are a heterogeneous disease that poses a therapeutic dilemma. Patients may have a prolonged disease trajectory involving multiple or repeat treatment modalities for frequent recurrences. The management of ITM has evolved without the development of a standardized protocol. Owing to the variability of the disease course there are few dedicated clinical trials, with a number of key trials in stage III melanoma excluding ITM patients. Thus, there is a paucity of quality data on the efficacy of the treatment modalities available for ITM and even fewer studies directly comparing modalities. At present the mainstay of ITM treatment is surgical resection, with intralesional therapies, isolated limb infusion and radiotherapy utilized as second-line measures. The developing role of targeted therapies and immunotherapy has yet to be explored completely in these patients. This review addresses the evidence base of the efficacy of the various treatment modalities available and those factors that have impacted their clinical uptake.

Diphencyprone as a therapeutic option in cutaneous metastasis of melanoma. A single-institution experience

Diphencyprone has been reported as a local immunotherapy for cutaneous melanoma metastases. We aim to report cases of melanoma patients treated with diphencyprone in a single Brazilian institution and highlight their outcomes. Since 2012, we have treated 16 melanoma patients with cutaneous metastases with topical diphencyprone. To date, we have had 37.5% of complete response, 25% of partial responses, and 31.25% patients without any response. Treatment was well tolerated and local toxicity was easily controlled. We believe topical diphencyprone is a feasible treatment that can be another option for treating melanoma patients, especially in cases of in-transit or extensive disease.

Anti-Melanoma immunity and local regression of cutaneous metastases in melanoma patients treated with monobenzone and imiquimod; a phase 2 a trial

Vitiligo development in melanoma patients during immunotherapy is a favorable prognostic sign and indicates breakage of tolerance against melanocytic/melanoma antigens. We investigated a novel immunotherapeutic approach of the skin-depigmenting compound monobenzone synergizing with imiquimod in inducing antimelanoma immunity and melanoma regression. Stage III-IV melanoma patients with non-resectable cutaneous melanoma metastases were treated with monobenzone and imiquimod (MI) therapy applied locally to cutaneous metastases and adjacent skin during 12 weeks, or longer. Twenty-one of 25 enrolled patients were evaluable for clinical assessment at 12 weeks. MI therapy was well-tolerated. Partial regression of cutaneous metastases was observed in 8 patients and stable disease in 1 patient, reaching the statistical endpoint of treatment efficacy. Continued treatment induced clinical response in 11 patients, including complete responses in three patients. Seven patients developed vitiligo-like depigmentation on areas of skin that were not treated with MI therapy, indicating a systemic effect of MI therapy. Melanoma-specific antibody responses were induced in 7 of 17 patients tested and melanoma-specific CD8+T-cell responses in 11 of 15 patients tested. These systemic immune responses were significantly increased during therapy as compared to baseline in responding patients. This study shows that MI therapy induces local and systemic anti-melanoma immunity and local regression of cutaneous metastases in 38% of patients, or 52% during prolonged therapy. This study provides proof-of-concept of MI therapy, a low-cost, broadly applicable and well-tolerated treatment for cutaneous melanoma metastases, attractive for further clinical investigation.

Protocol for the TIDAL Melanoma Study: topical imiquimod or diphenylcyclopropenone for the management of cutaneous in-transit melanoma metastases-a phase II, single centre, randomised, pilot study

INTRODUCTION

Patients with in-transit melanoma metastases present a therapeutic challenge. Complete surgical excision of localised disease is considered as the gold standard; however, surgery is not always acceptable and alternatives are required. Treatment results reported using imiquimod and diphenylcyclopropenone (DPCP) suggest that topical immunotherapies can be used to successfully treat select patients with melanoma metastases. A phase II, randomised, single centre, pilot study was designed to assess the clinical efficacy and safety of DPCP and imiquimod for the treatment of superficial, cutaneous in-transit melanoma metastases.

METHODS AND ANALYSIS

This is an open-label, non-superiority, pilot study with no treatment cross-over. Eligible patients are randomised in a 1:1 ratio to receive topical therapy for up to 12 months with a minimum follow-up period of 12 months. The target sample size is 30 patients, with 15 allocated to each treatment arm. The primary endpoint is the number of patients experiencing a complete response of treated lesions as determined clinically using Response Evaluation Criteria in Solid Tumours. This trial incorporates health-related quality of life measures and biological tissue collection for further experimental substudies. The study will also facilitate a health economic analysis.

ETHICS AND DISSEMINATION

Approval was obtained from the Human Research Ethics Committee at the participating centre, and recruitment has commenced. The results of this study will be submitted for formal publication within a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

Prospectively registered on 16 October 2015 with the Australian New Zealand Clinical Trials Registry (ACTRN12615001088538). This study conforms to WHO Trial Registration Data Set.

Diphenylcyclopropenone for the treatment of cutaneous in-transit melanoma metastases - results of a prospective, non-randomized, single-centre study

BACKGROUND

Current treatments for in-transit melanoma (ITM) metastases are frequently invasive and do not improve overall survival. Recently, there has been increasing investigation into the use of topical agents. Diphenylcyclopropenone or diphencyprone (DPCP) is a novel, topical therapy that has been reported to have immune-sensitizing properties useful in the treatment of ITM.

OBJECTIVE

To assess the clinical outcomes of patients treated within a prospective, non-randomized, non-comparative study using DPCP for cutaneous ITM metastases.

METHODS

A review was conducted assessing the outcomes of 58 patients prospectively treated using DPCP. Patients had satellite or in-transit disease (stage IIIB+), with all lesion morphology types included. The patients were treated through a single, specialized clinic with regular outpatient follow-up. DPCP was topically applied as an aqueous cream in 0.005-1% concentrations once to twice per week for up to 24-48 h of duration. To assess variables associated with response, a per-protocol statistical analysis was performed.

RESULTS

Fifty-four patients were treated who satisfied eligibility criteria for analysis. The overall response rates were as follows: complete response 22%, partial response 39%, stable disease 24% and progressive disease 15%. The mean time to complete response was 10.5 months, mean duration (disease-free interval) 12.3 months and recurrence rate in complete responders 41%. Lesion morphology was predictive of clinical benefit with a higher response in epidermotropic disease (P < 0.05).

CONCLUSIONS

DPCP provided a well-tolerated, convenient and efficacious treatment for cutaneous ITM metastases. Identifying patterns of response may assist treatment selection and improve patient-rated outcomes.

Acute Truncal Lymphedema Secondary to Axillary Metastatic Melanoma Presenting Like Cellulitis

There are reported cases of diphencyprone used in treating cutaneous metastases of melanoma. Here, we report a patient with previous primary melanoma on his left back treated with surgical excision and lymphadenectomy, followed by radiotherapy for the recurrent tumor on the primary site. Despite radiotherapy and treatment with dabrafenib and trametinib, in-transit metastases have developed and topical diphencyprone was applied to these metastases. Six weeks later, the patient developed fever and a spreading erythematous tender indurated plaque covering the left side of the body including axillae, back, and flank, clinically suggestive of cellulitis. Systemic antibiotic therapy did not improve the condition and a biopsy showed sparse lymphocytic infiltrate. With the diagnosis of possible acute lymphedema, a CT scan was requested that showed significant axillary lymph node metastasis. The fever was considered secondary to dabrafenib and trametinib therapy. This case highlights that, in patients with lymphadenectomy, atypical forms of lymphedema on the body may appear. Truncal lymphedema is an infrequent event.

Intralesional treatment of metastatic melanoma: a review of therapeutic options

Intralesional therapy of melanoma patients with locally advanced metastatic disease is attracting increasing interest, not least due to its ability to lead to both direct tumor cell killing and the stimulation of both a local and a systemic immune response. An obvious pre-requisite for this type of approach is the presence of accessible metastases that are amenable to direct injection with the therapeutic agent of interest. Patients who present with these characteristics belong to stages IIIB/C or IV of the disease. Surgical resection with intention to cure is the standard of care for patients with limited tumor burden and confined spread of disease (resectable patients). However, this category of patients is at a high risk of further recurrences until the disease becomes inoperable (unresectable) or progresses to a more advanced stage with visceral organ involvement, after which the prognosis is particularly grim. Most of the intralesional treatments tested so far, including the recently approved oncolytic virus talimogene laherparepvec, target the subpopulation of patients with unresectable disease, but the possibility to use the intralesional treatment in a neoadjuvant setting for fully resectable patients is attracting considerable interest. The present article reviews approved products and advanced stage pharmaceutical agents in development for the intralesional treatment of melanoma patients.

Developments in Intralesional Therapy for Metastatic Melanoma

BACKGROUND

Locoregional advanced melanoma poses a complex clinical challenge that requires a multidisciplinary, patient-centered approach. Numerous agents have been studied for their suitability as intralesional therapy in the past decades, but few have successfully completed phase 3 clinical trial testing.

METHODS

The relevant medical literature was searched for articles regarding use of intralesional therapies in metastatic melanoma. Therapies with data from phase 2 or higher studies were selected for review. This review also summarizes the mechanisms of action, adverse-event profiles, and clinical data for these agents.

RESULTS

Intralesional therapies demonstrate promising effects in select patients with advanced melanoma. The optimal approach should be individually tailored and consist of a combination of intralesional therapies, regional perfusions, systemic immunotherapies, targeted therapies, and surgery, if necessary.

CONCLUSIONS

Due to its relatively good local response rates and tolerable adverse-event profile, intralesional therapy may be a treatment option for select patients with unresectable, locally advanced or metastatic melanoma.

Diagnosis and treatment of in-transit melanoma metastases

In transit metastases (ITM) from extremity or trunk melanomas are subcutaneous or cutaneous lymphatic deposits of melanoma cells, distant from the primary site but not reaching the draining nodal basin. Superficial ITM metastases develop in 5-10% of melanoma patients and are thought to be caused by cells spreading along lymphatics; ITM appear biologically different from distant cutaneous metastases, these probably due to a haematogenous dissemination. The diagnosis is usually clinical and by patients, but patients need to be adequately educated in the recognition of this clinical situation. Ultrasound or more sophisticated instrumental devices may be required if the disease develops more deeply in the soft tissues. According to AJCC 2009 staging classification, ITM are included in stages IIIb and IIIc, which are considered local advanced disease with quite poor 5-year survival rates and outcomes of 24-54% at 5 years.² Loco-regional recurrence is in fact an important risk factor for distant metastatic disease, either synchronous or metachronous. Therapy for this pattern of recurrence is less standardised then in most other clinical situations and options vary based on the volume and site of the disease. Definitive surgical resection remains the preferred therapeutic approach. However, when surgery cannot be performed with a reasonable cosmetic and functional outcome, other options must be utilized.^3-6 Treatment options are classified as local, regional or systemic. The choice of therapy depends on the number of lesions, their anatomic location, whether or not these are dermal or subcutaneous, the size and the presence or absence of extra-regional disease.

Intralesional PV-10 for in-transit melanoma-A single-center experience

BACKGROUND AND OBJECTIVES

Patients with in-transit melanoma metastasis have longer median survival than patients with distant metastatic disease. Furthermore, local disease control is an important endpoint for symptom management. The treatment of unresectable loco-regional recurrence or in-transit disease has been historically managed with a combination of treatments including surgery, radiotherapy, isolated limb infusion or perfusion as well as systemic therapies. Intralesional PV-10 has been used at Peter MacCallum Cancer Centre since 2010, and the current report presents a retrospective analysis of patient outcomes, reporting the response rates, durability of responses, and observed toxicities.

METHODS

Records were analyzed retrieving details of 19 patients treated with PV-10 over a 4-year period from 2010 to 2014. Medical records were reviewed for these patients and data extracted.

RESULTS

Nineteen patients with in-transit melanoma were treated with intralesional PV-10 between 2010 and 2014. Disease control (complete or partial response or disease stability) was achieved in 68% of patients with 26% having a complete response. This was achieved with minimal associated toxicity.

CONCLUSIONS

PV-10 is an effective, durable, well-tolerated treatment tool with an acceptable side effect profile for the management of unresectable in-transit melanoma. J. Surg. Oncol. 2016;114:380-384. © 2016 Wiley Periodicals, Inc.

Nonsteroidal Topical Immunomodulators in Allergology and Dermatology

The purpose of this study was to review currently available literature data concerning pathomechanisms of action, indications, treatment efficacy, as well as side effects of nonsteroidal immunomodulators used in dermatology, primarily for the treatment of allergic dermatoses. MEDLINE search was undertaken using the key words “Topical Immunomodulators, Dermatology and Allergy”. Full articles, and nothing but full articles, were used.

Contact immunotherapy enhances the therapeutic effects of nivolumab in treating in-transit melanoma: Two cases reports

Because nivolumab significantly prolongs survival in patients with metastatic melanoma, enhancing its antitumor immune response is of great interest to dermato-oncologists. In this report, we describe two cases of metastatic melanoma successfully treated with nivolumab in combination with contact immunotherapy, using contact sensitizing agents, such as squaric acid dibutylester and diphencyprone. In addition, immunohistochemical staining supported one of the possible mechanisms of this combination therapy. Our present cases suggested a possible therapy for metastatic melanoma using nivolumab in combination with contact immunotherapy.

Diphencyprone Treatment of Alopecia Areata: Postulated Mechanism of Action and Prospects for Therapeutic Synergy with RNA Interference

Diphencyprone (DPCP) is a potent topical sensitizing agent that has been used since the late 1970s by physicians for the treatment of alopecia areata (AA), viral warts (human papillomavirus) and cutaneous metastases of melanoma. Although to date the compound is not approved as a drug by the FDA or EMA, physicians have continued to use DPCP because of its proven effects in these dermatological conditions. The use of the drug has been highly variable because of differences in compounding, and as a result, the literature reports vary widely in the concentrations used for sensitization and challenge treatment with DPCP. The efficacy of DPCP has generally been ascribed to immunological reactions by the host. Inducing inflammation with a contact sensitizer is counterintuitive to treating AA, an autoimmune disorder. We have hypothesized that the body's attempt to downregulate the inflammation caused by the contact sensitizer may also ameliorate AA. Studies using microarray and miRNA profiling may provide information about how DPCP induces inflammation in human skin at different times. Gene targets and microRNAs identified through these data may be modulated by an RNA interference approach to enhance DPCP efficacy and response rates. In addition, this approach may result in the discovery and development of drugs that are more potent and selective for the treatment of AA.

Unique microRNAs appear at different times during the course of a delayed-type hypersensitivity reaction in human skin

Diphencyprone (DPCP) is a hapten that induces delayed-type hypersensitivity (DTH) reactions. MicroRNAs (miRNAs) are short non-coding RNAs that negatively regulate gene expression and have been implicated in various inflammatory skin diseases, but their role in DTH reactions is not well understood. We generated global miRNA expression profiles (using next-generation sequencing) of DPCP reactions in skin of seven healthy volunteers at 3, 14 and 120 days after challenge. Compared to placebo-treated sites, DPCP-challenged skin at 3 days (peak inflammation) had 127 miRNAs significantly deregulated. At 14 days (during resolution of inflammation), 43 miRNAs were deregulated and, at 120 days (when inflammation had completely resolved), six miRNAs were upregulated. While some miRNAs have been observed in psoriasis or atopic dermatitis, most of the deregulated miRNAs have not yet been studied in the context of skin biology or immunology. Across the three time points studied, many but not all miRNAs were uniquely expressed. As various miRNAs may influence T cell activation, this may indicate that the miRNAs exclusively expressed at different time points function to promote or resolve skin inflammation, and therefore, may inform on the paradoxical ability of DPCP to treat both autoimmune conditions (alopecia areata) and conditions of ineffective immunity (melanoma).

Psoriasis is characterized by deficient negative immune regulation compared to transient delayed-type hypersensitivity reactions

Diphencyprone (DPCP) is a hapten that causes delayed-type hypersensitivity (DTH) reactions in human skin, and is used as a topical therapeutic for alopecia areata, warts, and cutaneous melanoma metastases.  We examined peak DTH reactions induced by DPCP (3 days post-challenge) by comprehensive gene expression and histological analysis.  To better understand how these DTH reactions naturally resolve, we compared our DPCP biopsies to those from patients with psoriasis vulgaris, a chronic inflammatory disease that does not resolve.  By both microarray and qRT-PCR, we found that psoriasis lesional skin has significantly lower expression of many negative immune regulators compared to peak DPCP reactions.  These regulators include: interleukin-10, cytotoxic T lymphocyte-associated 4 (CTLA4), programmed cell death 1 (PD1), programmed cell death 1 ligand 1 (PDL1), programmed cell death 1 ligand 2 (PDL2), and indoleamine 2,3-dioxygenase (IDO1).  Their decreased expression was confirmed at the protein level by immunohistochemistry.  To more completely determine the balance of positive vs. negative immune regulators in both DPCP reactions and psoriasis, we developed one comprehensive gene list for positive regulatory (inflammatory) genes, and another for negative regulatory (immunosuppressive) genes, through Gene Ontology terms and literature review.  With this approach, we found that DPCP reactions have a higher ratio of negative to positive regulatory genes (both in terms of quantity and expression levels) than psoriasis lesional skin.  These data suggest that the disease chronicity that distinguishes psoriasis from transient DTH reactions may be related to absence of negative immune regulatory pathways, and induction of these is therefore of therapeutic interest.  Further study of these negative regulatory mechanisms that are present in DPCP reactions, but not in psoriasis, could reveal novel players in the pathogenesis of chronic inflammation.  The DPCP system used here thus provides a tractable model for primary discovery of pathways potentially involved in immune regulation in peripheral tissues.