Combination of 5% cysteamine and 4% nicotinamide in melasma: Efficacy, tolerability, and safety

Melasma is a chronic dermatosis that impacts the patient's quality of life and can present considerable challenges in terms of effective treatment.

hormonal influence, and genetic predisposition have been proposed to play a role in melasma development. 2,3gns of photoaging skin are influenced by genetic background and delayed in darker skin types.Solar elastosis, increased mast cell count and sebaceous glands, altered basal membrane, and enhanced vascularization are hallmarks of photoaging skin.Interestingly, accumulated epidemiological and pathophysiological data support the hypothesis that melasma is a photoaging disorder. 4eatment of melasma can be complex owing to its refractoriness and frequent relapses.Tyrosinase inhibitors are the most effective depigmenting agents, among which hydroquinone is the most investigated.In addition to tolerability, concerns regarding longterm topical hydroquinone application persist, given its melanocyte toxicity. 5,6her topical treatments such as retinoids, tranexamic acid, azelaic acid, alpha-hydroxy acids, and ascorbic acid typically exhibit minimal lightening effects when employed as monotherapy, and combination therapy has been deemed more successful. 7steamine is a thiol compound 8 and a promising agent for treating hyperpigmentation as an inhibitor of tyrosinase and peroxidase, primary enzymes involved in melanin biosynthesis. 5,9cordingly, cysteamine could be a non-hydroquinone topical agent for patients with melasma. 7Nicotinamide exhibits various biological effects and multiple mechanisms of action that could benefit depigmentation.1][12] The potent depigmenting properties of cysteamine have long been recognized, yet their application for human skin lightening was only recently developed.This delay was attributed to the difficulties associated with managing the substance's odor. 9The intricate nature of treating melasma with a robust depigmenting agent such as cysteamine, coupled with another agent such as nicotinamide that offers both depigmenting and anti-inflammatory advantages, prompted our undertaking of this study to evaluate the association of cysteamine with nicotinamide (ct-Amina, Libbs, Brazil).Due to these brightening skills, the combination of cysteamine and nicotinamide to treat melasma evaluating efficacy, tolerability, and safety is the main objective of this study.Written informed consent was obtained from all patients before enrollment.

| Patients and study design
We included healthy female participants, aged 18-50 years, Fitzpatrick skin types I through VI, with at least 12 months of melasma history, and moderate or severe melasma.The melasma severity was determined using the Melasma Severity Score. 10 Patients who were pregnant or lactating, who were diagnosed with COVID-19, who were considered to belong to risk groups for developing complications if they have COVID-19, who underwent melasma treatment up to 3 months before study enrollment, and who used the following topical or systemic medications: corticosteroids, immunosuppressants, and antihistamines were excluded.
All participants were instructed to apply an almond-sized amount of the investigational product daily, on the entire face (avoiding the eyes, eyelids, and lips), at night, after cleaning the skin with the standardized soap.Between V1 and visit 2 (V2, Day 30 ± 2 days), participants were instructed to apply and retain the product on their face for 60 min and then wash the face.This was followed by the application of the standardized facial moisturizer, retained overnight.Between V2 and visit 3 (V3, Day 60 ± 2 days), participants were instructed to maintain the product for 120 min; subsequently, between visits V3 and visit 4 (V4, Day 90 ± 2 days), the product was maintained for 180 min, followed by the same procedures mentioned above.Participants were instructed not to expose themselves to excessive sunlight during the study period and to use the SPF 50 sunscreen in the morning, followed by 2 reapplications.The activity and daily sun exposure of the patients were not recorded.
Photographs were obtained using the Visia® CR device (Canfield Scientific, Inc.) to calculate the spot surface area and skin homogeneity using the FrameScan software®.Additionally, a spot previously selected by the dermatologist and an adjacent area were subjected to instrumental colorimetry measurements using the Chroma Meter® CR-400 (Konica Minolta®), with the possibility of evaluating differences in skin color changes between these two areas using numerical data.Coordinates that describe the color were then obtained, the L coordinate being the lighting.To test the product efficacy for depigmenting melasma, the L parameter was evaluated in the area with melasma, the adjacent area, and the difference between the areas, representing the contrast between the spot and the adjacent area.The participants answered the quality of life assessment using the MELASQoL questionnaire 14 (on V1 and V4) and a questionnaire of perceived efficacy to evaluate spot color, homogeneity, revitalization, spot size, product smell, and satisfaction (on V2, V3, and V4).

| Study objectives
Herein, the primary objective was to evaluate the cutaneous acceptability, safety, and efficacy of topical 5% cysteamine combined with 4% nicotinamide in females with moderate and severe melasma.

| Statistical analysis
Numerical and ordinal efficacy results are summarized using descriptive measures such as mean, standard deviation, mean change from V1, and percent of participants who improved.The Student's t-test was used to compare measurements on V2, V3, and V4 with Day 0. A 5% significance level was used in all analyses.
The IGA and subjective questionnaire were descriptively evaluated; the IGA was assessed using the mean, standard deviation, and percentage of responses, and the subjective questionnaire used frequency estimation.The XLSTAT 2021 (Addinsoft, Paris, France) and MINITAB (version 14 Minitab, Pennsylvania, USA) software were used for analyses.

| Patient distribution and baseline demographic characteristics
Overall, 53 patients (age 27-50 years; mean age 41 years) participated in the intention-to-treat (ITT) analysis, of which 35 completed the study and were included in the treatment efficacy analyses (ITTe).Of the 18 patients who were withdrawn from the study, six belonged to risk groups for developing complications due to COVID-19, one became pregnant during the study, one was withdrawn due to intolerance to the use of the product and there was loss of follow-up in 10 volunteers.
Based on the IGA, positive effects of mild or moderate were observed in >90% of participants at all evaluated time points, specifically in 94.3, 91.4, and 97.2% of participants on V2, V3, and V4, respectively.
Spot analysis using images obtained with Visia® demonstrated significant improvements in total surface and Haralick homogeneity, indicating reduced spot size and improved skin homogeneity on V2, V3, and V4 when compared with those from V1 (Figure 4).Considering the questionnaire to evaluate the efficacy perceived by the participant, on V4, 94.3% of participants reported that spots appeared less pigmented, 85.7% noted that the skin was more homogeneous and uniform, and 74.3% stated that the skin appeared more radiant.Skin revitalization was reported by 88.6% of participants, decreased hyperpigmented areas by 97.1%; 94.3% stated progressively improved skin depigmentation, and 80% noted an overall improvement in skin appearance.Only 5.7% of participants stated that the product smell was pleasant, and 60% stated that the product smell was tolerable over time.Product satisfaction was reported by 88.6% of the subjects.
The MELASQoL showed significantly improved quality of life (p < 0.001) after 90 days of investigational product application, with mean scores of 51 ± 11.4 in V1 and 35 ± 18.4 in V4.

| Safety and tolerability
The safety assessment included the 53 patients in the ITT group.There were no reports of serious adverse events (AEs) during the study.
Most AEs occurred within the first 30 days after application, resolving during the use of the product.And not interfered in progressively increased exposure to the product.

| DISCUSS ION
The pathology of melasma extends beyond melanocytes, and recent literature highlights interactions between keratinocytes, mast cells, F I G U R E 2 Melasma.Clinical efficacy in participants treated with 5% cysteamine combined with 4% nicotinamide for 90 days.The Modified Melasma Area and Severity Index (mMASI) was performed on all visits under standard daylight (Pandya  et al., 2011).

Cysteamine reportedly increases intracellular glutathione levels.
High intracellular glutathione levels have been associated with a switch from eumelanogenesis to pheomelanin synthesis, the latter considerably prolonged compared with the former; this causes melanogenesis to proceed at a slower pace. 9Cysteamine is a biological antioxidant in mammals and does not present mutagenic or carcinogenic risks. 17spite the high safety and efficacy profiles of cysteamine, this molecule has not been developed as a topical depigmenting agent for human use, given its highly offensive odor, especially in cream preparations.Since 2010, cysteamine stabilization and deodorization F I G U R E 3 Clinical Assessment after Treatment: Representative images illustrate the contrast in melasma before and after treatment with a 5% cysteamine and 4% nicotinamide cream.Pictures (A, B) display a volunteer with melasma on the frontal, nose, and cheek regions before and after 90 days of treatment (observe the spots in the left cheek and glabella areas).Pictures (C, D) feature a full-face melasma patient, highlighting the reduction in spot color intensity between Visit 1 (C) and Visit 4 (D).Picture (E) presents the pre-treatment image of a melasma patient with spots on the frontal, nose, and cheek regions.Picture (F) depicts the same patient after 90 days of treatment.
F I G U R E 4 Melasma.Clinical efficacy in participants treated with 5% cysteamine combined with 4% nicotinamide for 90 days.Progression of homogeneity and total surface of melasma using Visia® CR (Canfield Scientific, Inc.) image software analysis.
have been established, allowing application as a cream to effectively treat melasma topically. 18cotinamide, also known as vitamin B3 (niacinamide, nicotinic acid amide), is the amide form of the pyridine 3 carboxylic acid of niacin.
Nicotinamide is mainly involved in cellular energy metabolism, DNA repair, and regulation of transcription processes.Nicotinamide exhibits various biological effects and multiple mechanisms of action that could benefit depigmentation.Nicotinamide inhibits interleukin (IL)-12, tumor necrosis factorα, and IL-1 production by controlling nuclear factor-κB-mediated transcription and suppresses cytokine-mediated induction of nitric oxide synthase.[12] Herein, the participants applying 5% cysteamine with 4% nicotinamide showed significantly improved skin brightness, luminosity, and tone homogeneity.Our findings (Figure 1) revealed decreased spot color intensity and skin area with spots.Furthermore, the dryness pattern improved throughout follow-up, which can be attributed to niacinamide, affording a barrier repair effect and stimulating ceramide production. 11reover, mMASI scores (Figure 2) were significantly reduced in volunteers with facial melasma.The mMASI is a simple, reliable, and validated tool for assessing melasma severity. 19th investigators and subjects confirmed visible improvement, confirmed by clinical photography and chromametry using quantitative methods (Figure 4), demonstrating reduced spot surface, and indicating enhanced depigmentation in the spotted area, thereby improving skin tone homogeneity.Moreover, participants who applied a combination of 5% cysteamine and 4% nicotinamide to treat melasma reported improved quality of life.
More recently, cysteamine has been examined in some in vivo studies, as described in Table 1, with comparisons with placebo 16,9 and 4% hydroquinone, 5,7 as well as Kligman's formula. 18mpared with a placebo, cysteamine cream has shown promising results in parameters such as mMASI, MelasQoL, and Chromameter. 16,9 Mansouri et al study, the mean MASI score after 4 months was 7.2 ± 5.5 (58% reduction) in the cysteamine group and 11.6 ± 7.9 (16% reduction) in the placebo group.In our study mMASI score after 3 months was 2.8 ± 2.8 (58% reduction), that is, the same percentage reduction as that reported in the study by Mansouri et al for the cysteamine group. 9A similar result was found in the Farshi et al study and Karrabi et al, with a mean MASI score after 4 months of 8.03 ± 5.2 (56% reduction) and 6.0 ± 2.0 (51% reduction), respectively in the cysteamine group. 16,18In the Farshi et al study, there was a placebo group and the result was 12.2 ± 7.4 (8% reduction). 18lower percentage of MASI and mMASI reduction was found in studies Lima et al and Nguyen et al with a mean MASI score after 4 months of 5 (4-8) (38% reduction) and 5.6 ± 2.7 (21.3% reduction), respectively in the cysteamine group 5,7 In both studies, topical therapy was a 5% cysteamine cream, while our investigational product was a combination of 5% cysteamine and 4% nicotinamide.According to the above data, our study result for mMASI demonstrated a percentage reduction better than placebo and similar or better to the result of the cysteamine group in the published data.5,7,9,16,18 Compared with hydroquinone, cysteamine was reportedly safe and effective, with one study showing inferiority 5 and the other comparable results.7 Both studies noted that the melanotoxicity of hydroquinone and desired products were comparable with its efficacy.5,7,18 In the Kligman's formula trial, the mean mMASI score after 4 months was 7.04 and 6.09 in the Kligman's formula and cysteamine groups, respectively.At both prospective evaluation points (2 and 4 months), cysteamine cream afforded ~9% greater percentage reduction in mMASI score than Kligman's formula, and these differences were statistically significant (p = 0.005 and 0.001, respectively).6 Previous studies with cysteamine have shown erythema and burning as the main reported symptoms, ranging from 20% to 43%.
Erythema was deemed severe in 18%-20% of participants.Most AEs were transient and significantly reduced within 1 week of treatment initiation, followed by gradual disappearance. 5 this study, burning and erythema were the main Aes reported by participants, reaching a maximum of 16% of participants, with symptoms considered mild and moderate.Only 2% (one participant) experienced intense burning.As cysteamine tolerability is timedependent, symptoms should diminish with progressive cysteamine application. 9e present study performed continuous progressive application, reaching 3 h of product contact, with a reduced number and intensity of Aes.These improvements could be attributed to the new formulation combined with niacinamide, which, in addition to depigmenting properties, affords anti-inflammatory action, improving tolerability.
Although most participants tolerated more than 1 h of product application, the effect of overnight application should be further assessed. 5,9,16,20Efficacy over a prolonged duration should be examined, considering the safety profile of the formulation and the challenging pathology of melasma.

| LIMITATIONS
Long-term efficacy was not assessed and also unsure of the evaluation of melasma after stopping the treatment.This study has no placebo arm due to ethical recommendations by our Institutional Review Board.
Considering that the study was carried out during the COVID-19 pandemic, there was a higher discontinuation rate than expected.

| CON CLUS ION
A combination of 5% cysteamine with 4% nicotinamide affords a melasma treatment option with satisfactory results, safety, and tolerability.
TA B L E 1 Description of the use of the combination of cysteamine 5% and nicotinamide 4% study and other studies evaluating cysteamine for melasma treatment.
This single-center, quasi-experimental, prospective, open-label study was conducted following the principles of the Declaration of Helsinki and Good Clinical Practice at Allergisa Pesquisa Dermato-Cosmética, Campinas, São Paulo, Brazil.The study protocol was approved by the Research Ethics Committee before initiation.

1 (
Using the colorimetric instrumental assessment, we observed a statistically significant improvement (p < 0.001) in the luminosity parameter (L*) in the melasma spot area after 30, 60, and 90 days of product use compared to baseline (D0), with average variations of 1.4 (SE 0.3); 1.7 (SE 0.5), and 1.5 (SE 0.4) respectively, indicating a lightening of the spotted area.Regarding the adjacent area, the area without spots, the value of the parameter L* did not show a statistically significant difference (p = 0.080, p = 0.118, and p = 0.597) after 30, 60, and 90 days of use of the product concerning the baseline (D0), with average variations of 0.5 (SE 0.4); 0.5 (SE 0.5), and −0.SE 0.4) respectively.Considering the contrast between the spotted and adjacent areas, it indicates enhanced skin depigmentation in the spotted area and shows improved skin tone homogeneity.