Melanotan I

Vitiligo: Pathogenesis and New and Emerging Treatments.

Vitiligo is a complex disease with a multifactorial nature and a high impact on the quality of life of patients. Although there are multiple therapeutic alternatives, there is currently no fully effective treatment for this disease. In the current era, multiple drugs are being developed for the treatment of autoimmune diseases. This review assesses the available evidence on the pathogenesis of vitiligo, and a comprehensive review of treatments available for vitiligo now and in the near future is provided. This qualitative analysis spans 116 articles. We reviewed the mechanism of action, efficacy and safety data of phototherapy, afamelanotide, cyclosporine, phosphodiesterase 4 inhibitors, trichloroacetic acid, basic fibroblast growth factor, tumor necrosis factor (TNF) inhibitors, secukinumab, pseudocatalase and janus kinase (JAK) inhibitors. At the moment, there is no clearly outstanding option or fully satisfactory treatment for vitiligo, so it is necessary to keep up the development of new drugs as well as the publication of long-term effectiveness and safety data for existing treatments.

Vitiligo, from Pathogenesis to Therapeutic Advances: State of the Art.

Vitiligo is an acquired hypopigmentation of the skin due to a progressive selective loss of melanocytes; it has a prevalence of 1-2% and appears as rounded, well-demarcated white macules. The etiopathology of the disease has not been well defined, but multiple factors contribute to melanocyte loss: metabolic abnormalities, oxidative stress, inflammation, and autoimmunity. Therefore, a convergence theory was proposed that combines all existing theories into a comprehensive one in which several mechanisms contribute to the reduction of melanocyte viability. In addition, increasingly in-depth knowledge about the disease's pathogenetic processes has enabled the development of increasingly targeted therapeutic strategies with high efficacy and fewer side effects. The aim of this paper is, by conducting a narrative review of the literature, to analyze the pathogenesis of vitiligo and the most recent treatments available for this condition.

From pathogenesis of acne vulgaris to anti-acne agents.

Acne vulgaris is a cutaneous chronic inflammatory disorder with complex pathogenesis. Four factors play vital roles in acne pathophysiology: hyperseborrhea and dysseborrhea, altered keratinization of the pilosebaceous duct, Cutibacterium acnes (C. acnes) and inflammation. The main hormones responsible for the development of acne vulgaris include androgens, insulin and insulin-like growth factor-1. Other factors involved in this process are corticotropin-releasing hormone, α-melanocyte-stimulating hormone and substance P. Wnt/β-catenin signaling pathway, phosphoinositide 3-kinase (PI3K)/Akt pathway, mitogen-activated protein kinase pathway, adenosine 5'-monophosphate-activated protein kinase pathway and nuclear factor kappa B pathway participate in the modulation of sebocyte, keratinocyte and inflammatory cell (e.g. lymphocytes, monocytes, macrophages, neutrophils) activity. Among all the triggers and pathways mentioned above, IGF-1-induced PI3K/Akt/Forkhead box protein O1/mammalian target of rapamycin (mTOR) C1 pathway is the most important signaling responsible for acne pathogenesis. Commonly used anti-acne agents include retinoids, benzoyl peroxide, antibiotics and hormonal agents (e.g. spironolactone, combination oral contraceptive and flutamide). New approaches including peroxisome proliferator-activated receptor γ modifier, melanocortin receptor antagonists, epigallocatechin-3-gallate, metformin, olumacostat glasaretil, stearoyl-CoA desaturase inhibitor omiganan pentahydrochloride, KDPT, afamelanotide, apremilast and biologics have been developed as promising treatments for acne vulgaris. Although these anti-acne agents have various pharmacological effects against the diverse pathogenesis of acne, all of them have a synergistic mode of action, the attenuation of Akt/mTORC1 signaling and enhancement of p53 signal transduction. In addition to drug therapy, diet with no hyperglycemic carbohydrates, no milk and dairy products is also beneficial for treatment of acne.

[Undesirable pigmentation].

Homogenous pigmentation can be induced by α-melanocyte-stimulating hormone (MSH) homologues. Cosmetically inacceptable pigmentation is mostly located on the face. Although afamelatonide is a prescription drug for the orphan disease erthropoetic protoporphyria, structurally related α-MSH derivatives are available via the internet. Preventive and therapeutical options are necessary for postinflammatory hyperpigmentation, melasma, and lentigines. Case reports address activation of dysplastic naevi by melanotan I. Wood's lamp is of some use in analyzing the level of hyperpigmentation. However, no guidelines have been established; thus, a summary of current studies is presented. Melanotan I leads to the activation of dysplastic nevi. The gold standard for hyperpigmentation is triple therapy with hydrochinon, tretinoin, and steroids, which can cause irritation and lead to ochronosis in some individuals. Tyrosinase inhibitors, substances that increase the cell turnover, and plant derivatives are less efficient but more tolerable. Melanotan I and bleaching creams, which may possibly contain mercury, are dangerous. Hyperpigmentation is best treated using a combination therapy that inhibits melanocyte activity and melanin synthesis, removes melanin, destroys melanin granules, and includes UV protection. Especially in Fitzpatrick skin types IV-VI, cryotherapy and laser are not the first line treatment options due to renewed posttreatment hyperpigmentation.

Treatment Advances in Vitiligo: An Updated Review.

Vitiligo is a common disorder of depigmentation caused by the progressive destruction of melanocytes that affects the skin, hair, and mucous membranes, clinically presenting as depigmented macules and leukotrichia. This condition, affecting millions of people worldwide, has a significant psychosocial burden on patients' quality of life, particularly in relation to skin colour. The etiopathogenesis of this disorder is obscure, but multiple factors contribute to the loss of melanocytes in the skin, like oxidative stress, inflammation, genetics, and autoimmunity. The treatment of vitiligo has been challenging over the past years, but recent developments in understanding the etiopathogenesis of the disease have paved the way for the development of more effective and promising therapeutic treatment options. The aim of this review was to provide an overview of the underlying mechanisms and highlight the latest advances in the treatment of vitiligo. This review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Metanalyses) guidelines. A comprehensive search of the literature was carried out through the PubMed electronic database from inception to 31 December 2023 using the following search terms "vitiligo" AND "JAK inhibitors", "vitiligo" AND "prostaglandin", " vitiligo" AND " afamelanotide", "vitiligo" AND "antioxidants", "vitiligo" AND "vitamin D3", "vitiligo" AND "statins", "vitiligo" AND "TNF-alpha", "vitiligo" AND "interleukin", "vitiligo" AND "light therapy". Two independent reviewers screened titles, abstracts, and full texts to select papers dealing with vitiligo and its treatment. The advent of treatment modalities like Janus kinase inhibitors, prostaglandin analogues, antioxidants, TNF-α inhibitors, targeted phototherapy, and excimer lasers has revolutionized the therapeutic possibilities, offering a ray of hope to the individuals suffering from this devastating condition.

Phototherapy for Vitiligo.

Vitiligo is a common disorder with a severe impact on quality of life. The authors review recent advances in phototherapy for vitiligo focusing on narrowband ultraviolet B including mechanisms, treatment recommendations, and combination therapies. Phototherapy is the first-line treatment of choice for vitiligo with narrowband UVB preferred for widespread vitiligo and excimer used for localized lesions. However, unfamiliarity with prescribing phototherapy may be limiting clinicians from using it to its full potential. This article provides clinicians with the critical information needed to safely and effectively provide phototherapy for their patients with vitiligo.

Afamelanotide: A Review in Erythropoietic Protoporphyria.

Afamelanotide (SCENESSE(®)) is a synthetic α-melanocyte stimulating hormone analogue and first-in-class melanocortin-1 receptor agonist that is approved in the EU for the prevention of phototoxicity in adults with erythropoietic protoporphyria (EPP). It is administered subcutaneously as a biodegradable, controlled-release implant containing 16 mg of afamelanotide. This article reviews the clinical efficacy and tolerability of afamelanotide in EPP and summarizes its pharmacological properties. In the phase III trial, CUV039, afamelanotide treatment improved light tolerance in patients with EPP. Compared with placebo, afamelanotide treatment enabled patients to spend more time in direct sunlight without pain and increased the time to the appearance of the first symptoms of phototoxicity provoked by a standardized light source. Afamelanotide was generally well tolerated in this trial, with no drug-related serious adverse events reported. Commonly occurring adverse reactions included headache and implant-site reactions. Efficacy and safety data from earlier phase III trials are consistent with those from the CUV039 trial. Afamelanotide, approved in the EU for the prevention of EPP phototoxicity, represents a useful addition to the management of the disorder.

Afamelanotide: An Orphan Drug with Potential for Broad Dermatologic Applications.

Afamelanotide (SCENESSE®) is a synthetic analogue of α-melanocyte-stimulating hormone that is FDA-approved to increase pain-free sunlight exposure in adult patients with erythropoietic protoporphyria. Its dual photoprotective and anti-inflammatory effects also make it a promising therapy for other photosensitive dermatologic diseases that are resistant to treatment. The PubMed/MEDLINE and ClinicalTrials.gov databases were searched for literature and ongoing trials describing the use of afamelanotide in treating cutaneous diseases. There is randomized controlled trial (RCT) evidence for the successful use of afamelanotide in several conditions beyond erythropoietic protoporphyria, including polymorphic light eruption and vitiligo. Smaller studies have also demonstrated its efficacy in treating acne vulgaris, Hailey-Hailey disease, and solar urticaria. No serious adverse effects with afamelanotide use have been reported, though diffuse hyperpigmentation is experienced by almost all patients. Larger scale studies are needed to confirm the efficacy of afamelanotide in treating dermatologic conditions beyond erythropoietic protoporphyria, and further research should focus on determining the safety, efficacy, and optimal dosing of afamelanotide for pediatric patients.J Drugs Dermatol. 2021;20(3):290-294. doi:10.36849/JDD.5526.

[Porphyrias-what is verified?].

Porphyrias are caused by enzyme defects of heme biosynthesis. According to their clinical presentation and to each affected pathway, they are categorized into acute and non-acute as well as hepatic and erythropoietic porphyrias. Acute hepatic porphyrias, e.g. acute intermittent porphyria (AIP), porphyria variegata (VP), hereditary coproporphyria (HCP) and 5‑aminolevulinic acid dehydratase-deficient porphyria (ALADP) are characterized by accumulation of the porphyrin precursors 5‑aminolevulinic acid (ALA) and porphobilinogen (PBG) that correlate with severe abdominal, psychiatric, neurological or cardiovascular symptoms. Additionally, skin photosensitivity can occur in VP and less frequently, in HCP. Decisive for the diagnosis of acute hepatic porphyrias are a >4-fold elevated urinary excretion of ALA in ALADP and ALA and PBG in all other acute porphyrias. First-line treatment of an acute porphyria attack includes intensive care with pain management, sufficient caloric supply, strict avoidance of porphyrinogenic drugs and elimination of other triggering factors. Heme therapy is indispensable in case of developing neurological symptoms and clinical worsening despite first-line measures. Non-acute porphyrias, mainly porphyria cutanea tarda (PCT), erythropoietic protoporphyria (EPP) and X‑linked protoporphyria (XLP) display accumulation of porphyrins in the skin and/or liver resulting in photosensitivity up to possible liver damage. Patients with PCT benefit from iron depletion, low-dose chloroquine treatment and/or hepatitis C virus elimination. Afamelanotide is associated with better sunlight tolerance in patients with EPP and XLP. Moreover, innovative therapies that highly selectively address dysregulated steps of the heme biosynthetic pathway are currently under clinical trial.

Afamelanotide in protoporphyria and other skin diseases: a review.

Afamelanotide is a synthetic alpha melanocyte stimulating hormone presenting a higher activity than natural hormones. Its main properties are related to the enhanced production of eumelanin by agonistically binding to the melanocortin-1 receptor. Since 2016 afamelanotide has been especially applied to treat cases of erythropoietic porphyria (EPP), where painful photosensitivity has been observed since early childhood. The positive effect of afamelanotide in EPP administered subcutaneously improved tolerance to artificial white light and increased pain-free time spent in direct sunlight. In this review we summarize the possible use of afamelanotide in dermatology, with special emphasis on EPP and encourage including afamelanotide as a treatment option in patient care.

Targeting the central melanocortin system for the treatment of metabolic disorders.

A large body of preclinical and clinical data shows that the central melanocortin system is a promising therapeutic target for treating various metabolic disorders such as obesity and cachexia, as well as anorexia nervosa. Setmelanotide, which functions by engaging the central melanocortin circuitry, was approved by the FDA in 2020 for use in certain forms of syndromic obesity. Furthermore, the FDA approvals in 2019 of two peptide drugs targeting melanocortin receptors for the treatment of generalized hypoactive sexual desire disorder (bremelanotide) and erythropoietic protoporphyria-associated phototoxicity (afamelanotide) demonstrate the safety of this class of peptides. These approvals have also renewed excitement in the development of therapeutics targeting the melanocortin system. Here, we review the anatomy and function of the melanocortin system, discuss progress and challenges in developing melanocortin receptor-based therapeutics, and outline potential metabolic and behavioural disorders that could be addressed using pharmacological agents targeting these receptors.

Afamelanotide for prevention of phototoxicity in erythropoietic protoporphyria.

Introduction: In erythropoietic protoporphyria (EPP), an inherited disorder of heme biosynthesis, accumulation of protoporphyrin IX results in acute phototoxicity. EPP patients experience severe burning pain after light exposure, which results in a markedly reduced quality of life. Afamelanotide is the first effective approved medical treatment for EPP, acting on melanocortin-1 receptors. This article aims to review afamelanotide.Areas covered: This review summarizes the chemical properties, pharmacokinetics, safety, preclinical and clinical data on afamelanotide in EPP, and post-marketing surveillance. PubMed search, manufacturers' websites, and relevant articles used for approval by authorities were used for the literature search.Expert opinion: Afamelanotide is an α-melanocyte-stimulating hormone analog. It can activate eumelanogenesis without exposure to UV radiation. Clinical studies in EPP showed that afamelanotide treatment significantly increased exposure to sunlight and QoL. In our clinical experience afamelanotide treatment is much more effective in clinical practice than demonstrated in clinical trials and should be made available for all EPP patients meeting inclusion criteria. The 60-day interval period was not based on effectiveness studies, and therefore for some of the patients the maximum of four implants per year with the 60-day interval is insufficient. Afamelanotide is well tolerated; common adverse events were headache, fatigue, and nausea.

Pharmacokinetics and Pharmacodynamics of Afamelanotide and its Clinical Use in Treating Dermatologic Disorders.

Afamelanotide, the first α-melanocyte-stimulating hormone (MSH) analogue, synthesized in 1980, was broadly investigated in all aspects of pigmentation because its activity and stability were higher than the natural hormone. Afamelanotide binds to the melanocortin-1 receptor (MC1R), and MC1R signaling increases melanin synthesis, induces antioxidant activities, enhances DNA repair processes and modulates inflammation. The loss-of-function variants of the MC1R present in fair-skinned Caucasians are less effectively activated by the natural hormone. Afamelanotide was the first α-MSH analogue to be applied to human volunteers. Ten daily doses of between 0.08 and 0.21 mg/kg in saline injected subcutaneously resulted in long-lasting skin pigmentation and enabled basic pharmacokinetics. Subcutaneous application had full bioavailability, but neither oral nor transdermal application resulted in measurable plasma concentrations or pigmentation response. Two trials in human volunteers showed that neither MC1R variants nor fair skin reduced the afamelanotide-induced increase in skin pigmentation. A controlled-release formulation optimizes administration in man and is effective at a lower dose than the daily saline injections. Promising therapeutic results were published in polymorphic light eruption, erythropoietic protoporphyria (EPP), solar urticaria, Hailey-Hailey disease and vitiligo. In 2014, afamelanotide was approved by the European Medicines Agency for the prevention of phototoxicity in adult patients with EPP. No late effects were reported in volunteers 25 years after the first exposure or after continuous long-term application of up to 8 years in EPP patients, and an immunogenic potential has been excluded. Generally, adverse effects were benign in all trials.

Advances in the management of erythropoietic protoporphyria - role of afamelanotide.

Erythropoietic protoporphyria (EPP) and the phenotypically similar disease X-linked protoporphyria (XLPP) are inherited cutaneous porphyrias characterized clinically by acute non-blistering photosensitivity, intolerance to sunlight, and significantly reduced quality of life. They are due to marked overproduction of protoporphyrin (PP) chiefly by erythroblasts and reticulocytes. In EPP, the underlying genetic defect is in the ferrochelatase gene, which encodes the final enzyme in the heme synthetic pathway. In XLPP, the genetic defect is a gain-of-function mutation, usually a four-base deletion, in the gene that encodes the enzyme 5-aminolevulinic acid synthase-2, the first and rate-controlling enzyme of heme synthesis in developing red blood cells. The excess PP causes acute and painful photosensitivity, being activated by light in the long ultraviolet to blue spectrum (380-420 nm, the Soret band). Although several treatments have been proposed, presently no very effective treatment exists for EPP or XLPP. Afamelanotide (Scenesse®) is a first-in-class synthetic analog of α-melanocyte stimulating hormone. Afamelanotide mimics the naturally occurring hormone to increase skin pigmentation by increasing melanin production in melanocytes, resulting in increased sunlight tolerance in those with EPP/XLPP. Afamelanotide is currently approved for use in the European Union and Switzerland, and it is under review in the United States by the Food and Drug Administration for use in patients with EPP/XLPP. This paper provides a review of the clinical characteristics and current therapies for EPP/XLPP. We discuss the pharmacology, clinical efficacy, safety, and tolerability of afamelanotide and summarize the results of several key Phase II and III clinical trials. These data indicate that afamelanotide is a promising therapy for those with these debilitating diseases.

Afamelanotide for Erythropoietic Protoporphyria.

Erythropoietic protoporphyria is a severe photodermatosis that is associated with acute phototoxicity. Patients with this condition have excruciating pain and a markedly reduced quality of life. We evaluated the safety and efficacy of an α-melanocyte-stimulating hormone analogue, afamelanotide, to decrease pain and improve quality of life. We conducted two multicenter, randomized, double-blind, placebo-controlled trials of subcutaneous implants containing 16 mg of afamelanotide. Patients in the European Union (74 patients) and the United States (94 patients) were randomly assigned, in a 1:1 ratio, to receive a subcutaneous implant containing either afamelanotide or placebo every 60 days (a total of five implants in the European Union study and three in the U.S study). The type and duration of sun exposure, number and severity of phototoxic reactions, and adverse events were recorded over the respective 180-day and 270-day study periods. Quality of life was assessed with the use of validated questionnaires. A subgroup of U.S. patients underwent photoprovocation testing. The primary efficacy end point was the number of hours of direct exposure to sunlight without pain. In the U.S. study, the duration of pain-free time after 6 months was longer in the afamelanotide group (median, 69.4 hours, vs. 40.8 hours in the placebo group; P=0.04). In the European Union study, the duration of pain-free time after 9 months was also longer in the afamelanotide group than in the placebo group (median, 6.0 hours vs. 0.8 hours; P=0.005), and the number of phototoxic reactions was lower in the the afamelanotide group (77 vs. 146, P=0.04). In both trials, quality of life improved with afamelanotide therapy. Adverse events were mostly mild; serious adverse events were not thought to be related to the study drug. Afamelanotide had an acceptable side-effect and adverse-event profile and was associated with an increased duration of sun exposure without pain and improved quality of life in patients with erythropoietic protoporphyria. (Funded by Clinuvel Pharmaceuticals and others; ClinicalTrials.gov numbers, NCT01605136 and NCT00979745.).

Silica-Assisted Solid-Phase Peptide Synthesis (SiPPS).

Non-swelling silica-based resin was used for peptide synthesis. The strategy used is similar to that of solid-phase peptide synthesis (SPPS), referred to as silica-assisted solid-phase peptide synthesis (SiPPS). A 2-h coupling seemed to favor the coupling compared to that of 1-h standard coupling. The use of this non-swelling resin allows a 50% reduction in the consumption of solvents. The strategy was well demonstrated for the synthesis of H-YSSFL-NH2, linear oxytocin, angiotensin II, and afamelanotide using a silica-based support (Fmoc-Rink amide SiliaBond manufactured from SiliCycle Inc.). The peptides were found to have more than acceptable purity, although there was a loss in overall yields.

Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review.

Recently, the unregulated use of untested synthetic alpha-melanocyte-stimulating hormone (α-MSH) analogues, commonly known as melanotan I and II, appears to have increased. These analogues are primarily used for their tan-stimulating effects. Dermatologists see many patients in their clinic who tan. This review provides an overview of the risks of the unregulated use of these substances. Other topics discussed here include the history and safety of afamelanotide, which is the only α-MSH analogue that is approved for use in a limited number of medical indications. Although afamelanotide has been thoroughly tested and deemed safe, illegal melanotans are likely risky for several reasons. There are questions regarding the preparation, administration, and dosage of these substances. In addition to these general risks, increasing numbers of case reports indicate that the unregulated use of both melanotan I and II is associated with cutaneous complications, particularly melanocytic changes in existing moles and newly emerging (dysplastic) nevi. Four case reports have described melanomas emerging from existing moles either during or shortly after the use of melanotan. Although conclusive evidence linking these phenomena is lacking, publications have stressed the importance of awareness that melanotan is a part of a 'tanning culture' in certain subpopulations. Multiple national health organizations have issued safety warnings regarding the use of melanotan I and II.

Interventional treatments for Hailey-Hailey disease.

Hailey-Hailey disease or familial benign chronic pemphigus is a rare blistering dermatosis that is characterized by recurrent erythematous plaques with a predilection for the skin folds. For extensive Hailey-Hailey disease that is recalcitrant to conventional therapy, laser ablation, photodynamic therapy, electron beam radiotherapy, botulinum toxin type A, dermabrasion, glycopyrrolate, and afamelanotide have been reported as useful treatments, but comparative trials are lacking. This review discusses the various treatment modalities for Hailey-Hailey disease and a summary of the evidence for the most recommended treatments.

Erythropoietic protoporphyrias: Pathogenesis, diagnosis and management.

The erythropoietic protoporphyrias consist of three ultra-rare genetic disorders of the erythroid heme biosynthesis, including erythropoietic protoporphyria (EPP1), X-linked protoporphyria (XLEPP) and CLPX-protoporphyria (EPP2), which all lead to the accumulation of protoporphyrin IX (PPIX) in erythrocytes. Affected patients usually present from early childhood with episodes of severe phototoxic pain in the skin exposed to visible light. The quantification of PPIX in erythrocytes with a metal-free PPIX ≥3 times the upper limit of normal confirms the diagnosis. Protoporphyria-related complications include liver failure, gallstones, mild anaemia and vitamin D deficiency with reduced bone mineral density. The management is focused on preventing phototoxic reactions and treating the complications. Vitamin D should be supplemented, and DEXA scans in adults should be considered. In EPP1, even in cases of biochemically determined iron deficiency, supplementation of iron may stimulate PPIX production, resulting in an increase in photosensitivity and the risk of cholestatic liver disease. However, for patients with XLEPP, iron supplementation can reduce PPIX levels, phototoxicity and liver damage. Because of its rarity, there is little data on the management of EPP-related liver disease. As a first measure, any hepatotoxins should be eliminated. Depending on the severity of the liver disease, phlebotomies, exchange transfusions and ultimately liver transplantation with subsequent haematopoietic stem cell transplantation (HSCT) are therapeutic options, whereby multidisciplinary management including porphyria experts is mandatory. Afamelanotide, an alpha-melanocyte-stimulating hormone analogue, is currently the only approved specific treatment that increases pain-free sunlight exposure and quality of life.

An overview of the cutaneous porphyrias.

This is an overview of the cutaneous porphyrias. It is a narrative review based on the published literature and my personal experience; it is not based on a formal systematic search of the literature. The cutaneous porphyrias are a diverse group of conditions due to inherited or acquired enzyme defects in the porphyrin-haem biosynthetic pathway. All the cutaneous porphyrias can have (either as a consequence of the porphyria or as part of the cause of the porphyria) involvement of other organs as well as the skin. The single commonest cutaneous porphyria in most parts of the world is acquired porphyria cutanea tarda, which is usually due to chronic liver disease and liver iron overload. The next most common cutaneous porphyria, erythropoietic protoporphyria, is an inherited disorder in which the accumulation of bile-excreted protoporphyrin can cause gallstones and, rarely, liver disease. Some of the porphyrias that cause blistering (usually bullae) and fragility (clinically and histologically identical to porphyria cutanea tarda) can also be associated with acute neurovisceral porphyria attacks, particularly variegate porphyria and hereditary coproporphyria. Management of porphyria cutanea tarda mainly consists of visible-light photoprotection measures while awaiting the effects of treating the underlying liver disease (if possible) and treatments to reduce serum iron and porphyrin levels. In erythropoietic protoporphyria, the underlying cause can be resolved only with a bone marrow transplant (which is rarely justifiable in this condition), so management consists particularly of visible-light photoprotection and, in some countries, narrowband ultraviolet B phototherapy. Afamelanotide is a promising and newly available treatment for erythropoietic protoporphyria and has been approved in Europe since 2014.

Objective light exposure measurements and circadian rhythm in patients with erythropoietic protoporphyria: A case-control study.

Erythropoietic protoporphyria (EPP) patients suffer from painful phototoxicity. Sunlight-avoiding behaviour has not yet been quantified objectively in EPP patients. To study total white light exposure obtained with an actigraph device, before and during afamelanotide treatment, in EPP patients compared to healthy controls. Effects on circadian rhythm, pain and sleep were also investigated. Adult EPP patients visiting the Porphyria Center Rotterdam of the Erasmus MC were included in this single-center longitudinal case-control open-label intervention study. Controls were age and place of residence matched. Participants wore an actigraph (Actiwatch Pro) during two weeks for multiple periods. Afamelanotide was given to EPP patients as part of standard care. Twenty-six EPP patients and 23 matched controls participated. Controls were statistically significantly more exposed to white light than EPP patients off treatment during autumn (95.4%), spring (69.9%), and summer (105.4%; p&#xa0;=&#xa0;0.01). EPP patients on afamelanotide treatment had 71.6% more light exposure during spring compared to EPP patients off treatment (p&#xa0;<&#xa0;0.01). Afamelanotide treatment resulted in a reduction of painful moments in the morning (6.5% decrease) and the evening (8.1% decrease; p&#xa0;<&#xa0;0.05). Bedtime differed between EPP patients off treatment, controls and EPP patients on treatment (23:45&#xa0;h&#xa0;&#xb1;&#xa0;1:51 versus 23:02&#xa0;&#xb1;&#xa0;1:41 and 23:14&#xa0;&#xb1;&#xa0;1:29, respectively; p&#xa0;<&#xa0;0.0001). Actigraphy is a useful method to objectively measure white light exposure and treatment effects in EPP. In EPP patients afamelanotide treatment is associated with increased white light exposure during spring, and overall less pain. Treatment with afamelanotide is also associated with normalization of circadian rhythm.

Afamelanotide, an agonistic analog of &#x3b1;-melanocyte-stimulating hormone, in dermal phototoxicity of erythropoietic protoporphyria.

Afamelanotide, an &#x3b1;-melanocyte stimulating hormone (MSH) agonistic analog is a first-in-class therapeutic. Its application to protoporphyria (PP), a disease associated with absolute sunlight-intolerance is discussed. The genetics and existing therapy of the inherited disease PP comprising both erythropoietic protoporphyria and X-linked dominant protoporphyria. The physiological and pharmacological actions of &#x3b1;-MSH and afamelanotide including receptor-mediated intracellular signaling and effects of receptor polymorphisms. Adverse effects and safety issues. The clinical severity and the necessity for an effective therapy for the rare disease PP are illustrated by a short, up-to-date portrait. A condensed description of clinically important aspects of &#x3b1;-MSH signaling, physiological, pharmacological and safety issues of afamelanotide applied to humans and the rational for its potential efficacy in PP are given. The different trials of afamelanotide in PP and their most recent results are discussed. Although early, results of the first trials of afamelanotide for PP are promising and the risk-safety profile appears favorable today. We expect afamelanotide and analogs thereof to be a prospective therapeutic tool in light-related skin diseases, and in future this drug class might prove effectiveness in other medical conditions.

Afamelanotide Is Associated with Dose-Dependent Protective Effect from Liver Damage Related to Erythropoietic Protoporphyria.

In animal models, melanocyte-stimulating hormones (MSHs) protect the liver from various injuries. Erythropoietic protoporphyria (EPP), a metabolic disorder, leads to the accumulation of protoporphyrin (PPIX). In addition to the most prominent symptom of incapacitating phototoxic skin reactions, 20% of EPP patients exhibit disturbed liver functioning and 4% experience terminal liver failure caused by the hepatobiliary elimination of excess PPIX. Skin symptoms are mitigated through the application of the controlled-release implant afamelanotide, an &#x3b1;-MSH analog, every sixty days. Recently, we showed that liver function tests (LFTs) improved during afamelanotide treatment when compared to before treatment. The present study investigated whether this effect is dose-dependent, as the evidence of dose dependency would support a beneficial influence of afamelanotide. In this retrospective observational study, we included 2933 liver-function tests, 1186 PPIX concentrations and 1659 afamelanotide implant applications in 70 EPP patients. We investigated whether the number of days since the preceding afamelanotide dose or the number of doses during the preceding 365 days had an effect on LFTs and PPIX levels. In addition, we assessed the effect of global radiation. Inter-patient differences exerted the most prominent effect on PPIX and LFTs. In addition, PPIX increased significantly with an increase in the number of days since the last afamelanotide implant (p < 0.0001). ALAT and bilirubin decreased significantly with an increasing number of afamelanotide doses in the preceding 365 days (p = 0.012, p = 0.0299, respectively). Global radiation only influenced PPIX (p = 0.0113). These findings suggest that afamelanotide ameliorates both PPIX concentrations and LFTs in EPP in a dose-dependent manner.

Into the Light: Afamelanotide and the Treatment of Erythropoietic Protoporphyria in the United States.

Erythropoietic protoporphyria (EPP) is a rare disease that causes disabling cutaneous photosensitivity with pain and burning sensations. In 2019, afamelanotide, an &alpha;-melanocyte-stimulating hormone analogue, was approved in the United States for treatment of EPP. In this study, patients receiving afamelanotide filled out questionnaires assessing the benefit of treatment. Outcomes measured included: return to normal activities, experience of phototoxic reactions, effect on patient confidence, and more. Patients ranked their experience on a descriptive scale ranging from "very much" to "never". Prior to treatment, 75% of patients indicated that EPP affected their lives "very much" or "a lot". This number fell to 11% after the 1st implant and to 0% after each subsequent implant. The number of patients that willingly ventured outside increased with each subsequent implant. The results of this study clearly show that afamelanotide treatment can dramatically and positively impact the lives of EPP patients.&nbsp; Citation: Resnik SR, Targett D, Resnik BI. Into the light: afamelanotide and the treatment of erythropoietic protoporphyria in the United States. J Drugs Dermatol. 2023;22(9):941-949. doi:10.36849/JDD.7126R1.

Current and emerging treatments for vitiligo.

Clinicians should be aware that vitiligo is not merely a cosmetic disease and that there are safe and effective treatments available for vitiligo. It is important to recognize common and uncommon presentations and those with active disease, as well as their implications for clinical management; these were discussed in the first article in this continuing medical education series. Existing treatments include topical and systemic immunosuppressants, phototherapy, and surgical techniques, which together may serve to halt disease progression, stabilize depigmented lesions, and encourage repigmentation. We discuss how to optimize the currently available treatments and highlight emerging treatments that may improve treatment efficacy in the future.

Afamelanotide (CUV1647) in dermal phototoxicity of erythropoietic protoporphyria.

The application of afamelanotide, an &#x3b1;-melanocyte stimulating hormone agonistic analogue to protoporphyria, a disease with absolute sunlight-intolerance is discussed. The clinics, genetics and existing therapies of protoporphyria are described. The physiological receptor-mediated intracellular signaling of &#x3b1;-melanocyte stimulating hormone and effects of receptor variants are outlined. The pharmacological action of afamelanotide and the rationale behind its application in protoporphyria are given. The results of several Phase II and III and safety issues are discussed. The trial results were significant, although the effects were not very large in absolute terms, and the risk-safety profile is favorable today. Based on the high compliance rate and the excellent consistency in clinical effectiveness during six years of compassionate use program in Switzerland, we expect afamelanotide and analogues to become a prospective therapeutic tool. Moreover, we hope that dosage forms suitable for children will be developed in future, as children and adolescents suffer most in protoporphyria.

Efficacy of the melanocortin analogue Nle4-D-Phe7-&#x3b1;-melanocyte-stimulating hormone in the treatment of patients with Hailey-Hailey disease.

Hailey-Hailey disease (HHD) is a rare, chronic and recurrent blistering disorder, which is characterized clinically by erosions occurring primarily in intertriginous regions, and histologically by suprabasal acantholysis. Oxidative stress plays a specific role in the pathogenesis of HHD, by regulating the expression of factors playing an important role in keratinocyte proliferation and differentiation. Given the significance of oxidative stress in HHD, we investigated the potential effects of the antioxidant properties of an &#x3b1;-MSH analogue, Nle4-D-Phe7-&#x3b1;-MSH (afamelanotide), in HHD lesion-derived keratinocytes. Treatment of HHD-derived keratinocytes with afamelanotide contributed to upregulation of Nrf2 [nuclear factor (erythroid-derived 2)-like 2], a redox-sensitive transcription factor that plays a pivotal role in redox homeostasis during oxidative stress. Additionally, afamelanotide treatment restored the defective proliferative capability of lesion-derived keratinocytes. Our results show that Nrf2 is an important target of the afamelanotide signalling that reduces oxidative stress. Because afamelanotide possesses antioxidant effects, we also assessed the clinical potential of this &#x3b1;-MSH analogue in the treatment of patients with HHD. In a phase II open-label pilot study, afamelanotide 16 mg was administered subcutaneously as a sustained-release resorbable implant formulation to two patients with HHD, who had a number of long-standing skin lesions. For both patients, their scores on the Short Form-36 improved 30 days after the first injection of afamelanotide, and both had 100% clearance of HHD lesions 60 days after the first injection, independently of the lesion location. Afamelanotide is effective for the treatment of skin lesions in HHD.

Structural insights into ligand recognition and activation of the melanocortin-4 receptor.

Melanocortin-4 receptor (MC4R) plays a central role in the regulation of energy homeostasis. Its high sequence similarity to other MC receptor family members, low agonist selectivity and the lack of structural information concerning MC4R-specific activation have hampered the development of MC4R-seletive therapeutics to treat obesity. Here, we report four high-resolution structures of full-length MC4R in complex with the heterotrimeric Gs protein stimulated by the endogenous peptide ligand &#x3b1;-MSH, FDA-approved drugs afamelanotide (Scenesse&#x2122;) and bremelanotide (Vyleesi&#x2122;), and a selective small-molecule ligand THIQ, respectively. Together with pharmacological studies, our results reveal the conserved binding mode of peptidic agonists, the distinctive molecular details of small-molecule agonist recognition underlying receptor subtype selectivity, and a distinct activation mechanism for MC4R, thereby offering new insights into G protein coupling. Our work may facilitate the discovery of selective therapeutic agents targeting MC4R.

A glimpse into the underground market of melanotan.

Melanotan-I and melanotan-II are alpha-melanocyte stimulating hormone (a-MSH) analogues that can be purchased illicitly online with relative ease and are injected subcutaneously to stimulate a tan. Little is known about the use of these unregulated substances. An observational survey was posted to an online forum in which participants share their experiences using melanotan-I or melanotan-II. Users were asked to complete this voluntary, anonymous survey, which had questions focusing on motivation and hesitation for and against using melanotan, difficulty in acquiring it, and plans for continuing to use melanotan in the future.

The effects of cholecalciferol and afamelanotide on vitamin D levels in erythropoietic protoporphyria: a&#xa0;multicentre cohort study.

Patients with erythropoietic protoporphyria experience lifelong painful photosensitivity resulting in a lack of sunlight exposure. Previous studies have shown that 47-63% of patients with EPP suffer from vitamin D deficiency and a high prevalence of osteoporosis. An effective treatment for EPP has been available since 2016: the &#x3b1;-melanocyte stimulating hormone analogue afamelanotide. So far, studies on vitamin D levels in EPP have only investigated patients who have not been treated with afamelanotide. To investigate the effects of afamelanotide treatment on vitamin D levels in EPP. A multicentre observational cohort study in adults with EPP from the Erasmus Medical Centre, the Netherlands, and the University Hospital D&#xfc;sseldorf, Germany, was carried out. Routinely collected vitamin D levels between 2005 and 2021 were used for analysis. Patient exposure to cholecalciferol or afamelanotide was categorized into four treatment groups: untreated, cholecalciferol, afamelanotide and combined treatment. A linear mixed model for longitudinal data was applied to measure the effect of the treatment groups compared with the untreated groups on vitamin D levels. A total of 230 patients and 1774 vitamin D measurements were included. The prevalence of vitamin D deficiency and severe deficiency remained high despite afamelanotide treatment (< 50&#x2005;nmol L-1 in 71.8% of patients and < 30&#x2005;nmol L-1 in 48.1%, respectively). Afamelanotide treatment alone did not lead to a significant average increase in vitamin D levels [&#x3b2; = 0.5, 95% confidence interval (CI) -3.2 to 4.2]. In contrast, cholecalciferol and combined therapy with afamelanotide led to a significant increase in vitamin D levels [&#x3b2; = 11.6 (95% CI 7.2-15.9) and &#x3b2; = 15.2 (95% CI 12.3-18.1), respectively]. Cholecalciferol remains essential for the treatment of vitamin D deficiency in EPP, irrespective of new treatment options like afamelanotide. Afamelanotide treatment did not affect vitamin D levels. We suggest that future guidelines include continuous monitoring of vitamin D and a prescription for cholecalciferol in all patients with EPP, including those treated with afamelanotide.

Insights into Tanning Biology and Tanning Products.

This systematic review aims to critically assess the literature on the mechanisms of action, clinical uses, formulation strategies, and adverse effects of self-tanning agents, with a focus on dihydroxyacetone (DHA), melanotan, forskolin, and carotenoids. A systematic literature review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were screened for relevance to the mechanisms of action, clinical applications, chemical formulations, or adverse effects of self-tanning molecules. A total of 68 peer-reviewed studies were included. DHA induces pigmentation via the Maillard reaction and has demonstrated additional dermatologic applications, including use in vitiligo and erythropoietic protoporphyria and as a potential topical antifungal. Concerns persist about DHA-related cytotoxicity, genotoxicity, and systemic absorption. Unregulated melanotan I and II use has caused serious adverse effects, including rhabdomyolysis, renal infarction, and priapism. While forskolin stimulates melanin production independently of melanocortin receptors and has demonstrated efficacy in animal models, carotenoids, when ingested orally, accumulate in skin and subcutaneous fat, creating a yellow-orange hue. Both agents remain underresearched in human populations. Limitations include lack of standardized reporting across included studies, variability in study outcomes, and limited long-term safety data. Sunless tanning agents offer UV-free alternatives for cosmetic pigmentation but are not without risk. While DHA and melanotan remain the dominant agents in current use, forskolin and carotenoids offer alternative pathways for pigmentation and photoprotection. Further clinical studies are necessary to evaluate long-term safety, efficacy across skin types, and formulation optimization. Regulatory frameworks and dermatologic guidance must evolve to reflect the expanding landscape of sunless tanning modalities.

Afamelanotide for Treatment of the Protoporphyrias: Impact on Quality of Life and Laboratory Parameters in a US Cohort.

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare disorders of heme biosynthesis characterized by severe cutaneous phototoxicity. Afamelanotide, an &#x3b1;-melanocyte-stimulating hormone analogue, is the only approved treatment for protoporphyria and leads to increased light tolerance and improved quality of life (QoL). However, published experience with afamelanotide in the US is limited. Here, we report on all adults who received at least one dose of afamelanotide at the Massachusetts General Hospital Porphyria Center from 2021 to 2022. Changes in the time to phototoxic symptom onset, QoL, and laboratory parameters were assessed before and during treatment with afamelanotide. A total of 29 patients with protoporphyria were included, 26 of whom (72.2%) received &#x2265;2 afamelanotide implants. Among the patients who received &#x2265;2 implants, the median time to symptom onset following sunlight exposure was 12.5 min (IQR, 5-20) prior to the initiation of afamelanotide and 120 min (IQR, 60-240) after treatment (p < 0.001). Improvements in QoL during afamelanotide treatment were measured using two QoL tools, with good correlation observed between these two instruments. Finally, we found no improvements in the median levels of metal-free erythrocyte protoporphyrin, plasma protoporphyrin, or liver biochemistries during versus prior to the initiation of afamelanotide treatment. This study highlights a dramatic clinical benefit of afamelanotide in relation to light tolerance and QoL in protoporphyria, albeit without improvement in protoporphyrin levels or measures of liver function.

Current challenges in photoprotection.

Electromagnetic radiation in the ultraviolet, visible, and infrared ranges all produce biologic effects. Ultraviolet filters are the most well-studied photoprotective measure for the adverse effects of ultraviolet radiation. Because of the reported endocrinologic effects of oxybenzone in animal studies, its effects on coral reefs, and its photocontact allergy potential, its use has been minimized in many countries worldwide. New developments in topical antioxidants and oral and subcutaneous agents (eg, Polypodium leucotomos extract, afamelanotide, nicotinamide) with photoprotective and antiphotocarcinogenic properties could potentially provide addition modalities for protection against the effects&#xa0;of visible light and infrared radiation.

Use of melanotan I and II in the general population.

Erythropoietic protoporphyria in the Netherlands: Clinical features, psychosocial impact and the effect of afamelanotide.

Erythropoietic protoporphyria (EPP) patients experience severe burning pain after light exposure, which results in a markedly reduced quality of life. However, there is limited information on the psychosocial aspects of EPP. To investigate the clinical features and social aspects of living with EPP, before and during afamelanotide treatment in the Netherlands. A single-center prospective longitudinal study of adult patients with EPP attending the Erasmus MC Rotterdam. Patients completed questionnaires, comprising demographic, clinical and social details, including two generic (DS-14 and SF-36) and a disease specific (EPP-QoL) QoL questionnaires. 121 adult EPP patients were included. The educational level of EPP patients seemed higher compared to the Dutch population (36% vs. 30% high-education, 42% vs. 37% middle-education). At baseline 5% of the EPP patients were unemployed, none were unemployed during afamelanotide treatment. Full- and part-time employment rate increased from 59.5% to 69.9% on afamelanotide treatment (p&#x2009;>&#x2009;0.05). EPP-QoL improved from 44% to 75% on afamelanotide treatment (p&#x2009;<&#x2009;0.001). Type-D personality was present in 27.4% of patients; their social inhibition scores improved significantly on afamelanotide treatment (p&#xa0;=&#xa0;0.019). EPP patients scored low on the social functioning domain (SF-36) compared to the Dutch population (74.4&#x2009;&#xb1;&#x2009;27.3 vs. 84.0&#x2009;&#xb1;&#x2009;22.4; respectively), and improved during afamelanotide treatment (84.3&#x2009;&#xb1;&#x2009;20.9, p&#xa0;=&#xa0;0.001). EPP has a significant negative impact on social aspects, with less employment despite a higher education level. Afamelanotide treatment improves quality of life, social functioning and possibly employment rate. It is important to recognize the impact of EPP on social life, although, more research is needed.

Polymorphism of Melanocortin Receptor Genes-Association with Inflammatory Traits and Diseases.

Melanocortin receptors (MCRs) are responsible for various functions ranging from skin pigmentation, regulation of appetite, stress response and cognition, steroid synthesis, and energy balance to cellular regeneration and immunomodulation. The genetic polymorphism with tissue distribution ranging from the brain, limbic system, and adrenal cortex to neutrophils, monocytes, and macrophages is evident in MCRs. The mutations in MC1R, MC2R, MC3R, and MC4R genes are associated with risk of melanoma, familial glucocorticoid deficiency, obesity, and type 2 diabetes mellitus, respectively. Meanwhile, MC1R, MC2R, and MC5R genes are involved in the risk of major depressive disorder. Melanocortin receptors are involved in different inflammatory disorders, i.e., atopic dermatitis, autoimmune uveitis, sarcoidosis, respiratory diseases, multiple sclerosis, scleroderma, inflammatory bowel disease, amyotrophic lateral sclerosis, Alzheimer's disease, arthritis, and reperfusion injury. Several newer therapeutic agents related to MCRs have numerous advantages over the current anti-inflammatory drugs, demonstrating therapeutic relevance. Among them, &#x3b1;-MSH analogs play a role in atopic dermatitis and scleroderma, and MC1R agonist Dersimelagon has shown effectiveness in systemic sclerosis. The FDA has recently approved the repository corticotropin injection (RCI) to treat sarcoidosis. The FDA has also approved various melanocortin agonists, i.e., Bremelanotide, Afamelanotide, and Setmelanotide, for the treatment of hypoactive sexual desire disorder, Erythropoietic protoporphyria, and obesity, due to pro-opiomelanocortin and leptin receptor deficiency, respectively. Therefore, this review aims to summarize the function and genetic polymorphism of melanocortin receptors, regulatory pathways involving MCRs, and the existing evidence of the prime effect of MCRs on inflammatory responses via different mechanisms and their potential therapeutic use in inflammatory diseases.