Pharmacology of adapalene

Drug repurposing screen identifies novel anti-inflammatory activity of sunitinib in macrophages

Inflammation is a driver of human disease and an unmet clinical need exists for new anti-inflammatory medicines. As a key cell type in both acute and chronic inflammatory pathologies, macrophages are an appealing therapeutic target for anti-inflammatory medicines. Drug repurposing - the use of existing medicines for novel indications - is an attractive strategy for the identification of new anti-inflammatory medicines with reduced development costs and lower failure rates than de novo drug discovery. In this study, FDA-approved medicines were screened in a murine macrophage NF-κB reporter cell line to identify potential anti-inflammatory drug repurposing candidates. The multi-tyrosine kinase inhibitor sunitinib was found to be a potent inhibitor of NF-κB activity and suppressor of inflammatory mediator production in murine bone marrow derived macrophages. Furthermore, oral treatment with sunitinib in mice was found to reduce TNFα production, inflammatory gene expression and organ damage in a model of endotoxemia via inhibition of NF-κB. Finally, we revealed sunitinib to have immunomodulatory effects in a model of chronic cardiovascular inflammation by reducing circulating TNFα. This study validates drug repurposing as a strategy for the identification of novel anti-inflammatory medicines and highlights sunitinib as a potential drug repurposing candidate for inflammatory disease via inhibition of NF-κB signalling.

Adapalene and Doxorubicin Synergistically Promote Apoptosis of TNBC Cells by Hyperactivation of the ERK1/2 Pathway Through ROS Induction

Doxorubicin is a commonly used chemotherapeutic agent to treat several malignancies, including aggressive tumors like triple-negative breast cancer. It has a limited therapeutic index owing to its extreme toxicity and the emergence of drug resistance. As a result, there is a pressing need to find innovative drugs that enhance the effectiveness of doxorubicin while minimizing its toxicity. The rationale of the present study is that combining emerging treatment agents or repurposed pharmaceuticals with doxorubicin might increase susceptibility to therapeutics and the subsequent establishment of improved pharmacological combinations for treating triple-negative breast cancer. Additionally, combined treatment will facilitate dosage reduction, reducing the toxicity associated with doxorubicin. Recently, the third-generation retinoid adapalene was reported as an effective anticancer agent in several malignancies. This study aimed to determine the anticancer activity of adapalene in TNBC cells and its effectiveness in combination with doxorubicin, and the mechanistic pathways in inhibiting tumorigenicity. Adapalene inhibits tumor cell growth and proliferation and acts synergistically with doxorubicin in inhibiting growth, colony formation, and migration of TNBC cells. Also, the combination of adapalene and doxorubicin enhanced the accumulation of reactive oxygen species triggering hyperphosphorylation of Erk1/2 and caspase-dependent apoptosis. Our results demonstrate that adapalene is a promising antitumor agent that may be used as a single agent or combined with present therapeutic regimens for TNBC treatment.

Trifarotene: A Novel Therapeutic Option for Acne

Acne vulgaris, or acne, is a prevailing cutaneous predicament that customarily crops up on the face, neck, and trunk in the forms of comedones, papules, pustules, and nodules. According to epidemiologic explorations, acne affects 9.4% of the global population, making it the eighth most common disease globally. Acne perturbs up to 85% of adolescents, while it is periodically misconceived as an ailment that affects teenagers only; nonetheless, it also affects myriad adults. Acne has well-documented psychosocial ramifications, including adverse effects on self-perception, mental health, and social functioning. Trifarotene is basically a novel fourth-generation locally applied retinoid approved for the first time in the regimens of both face and truncal acnes. The exclusive topical retinoid that adheres precisely to RAR-gamma, the epidermis' most frequent isoform, is trifarotene, approved in October 2019. The current review evaluates the role of trifarotene in treating acne.

Transcriptomics Analysis Indicates Trifarotene Reverses Acne-Related Gene Expression Changes

Background and Objectives: Trifarotene is a topical retinoid selective for retinoic acid receptor gamma that was recently approved for treatment of acne vulgaris. We performed a gene expression analysis to identify the molecular and cellular impact of trifarotene treatment on acne papules. Methods: In this open-label prospective study, subjects with moderate inflammatory acne of the back were treated with trifarotene 0.005% or vehicle cream on dedicated areas for 27 days, and 4 biopsies were collected from each subject (1 from skin without a visible acne lesion and three at the site of an acne papule: one baseline, one after vehicle treatment, and one after trifarotene treatment). Large scale gene expression profiling of the biopsies was performed using Affymetrix technology, treatment-specific gene expression profiles were generated using statistical modeling, and pathway analysis was performed. Using single-cell RNAseq data, in silico deconvolution of transcriptomics data was performed to identify cellular signatures. Results: We discovered a unique set of 67 genes modulated by trifarotene that are primarily involved in cellular migration, inflammation, and extracellular matrix reorganization. Changes in cellular expression were similar in both trifarotene-treated and spontaneously-resolving lesions. However, only trifarotene treatment impacted SPP1⁺ macrophages, a subset of highly proliferative macrophages recently identified in fibrotic tissue. Conclusions: These results show that trifarotene has a novel action in acne treatment by affecting epidermal and immune components of acne pathogenesis.

Synthetic Retinoids Beyond Cancer Therapy

While the uses of retinoids for cancer treatment continue to evolve, this review focuses on other therapeutic areas in which retinoids [retinol (vitamin A), all-trans retinoic acid (RA), and synthetic retinoic acid receptor (RAR)α-, β-, and γ-selective agonists] are being used and on promising new research that suggests additional uses for retinoids for the treatment of disorders of the kidneys, skeletal muscles, heart, pancreas, liver, nervous system, skin, and other organs. The most mature area, in terms of US Food and Drug Administration-approved, RAR-selective agonists, is for treatment of various skin diseases. Synthetic retinoid agonists have major advantages over endogenous RAR agonists such as RA. Because they act through a specific RAR, side effects may be minimized, and synthetic retinoids often have better pharmaceutical properties than does RA. Based on our increasing knowledge of the multiple roles of retinoids in development, epigenetic regulation, and tissue repair, other exciting therapeutic areas are emerging. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Trifarotene: A Current Review and Perspectives in Dermatology

Retinoids have numerous applications in inflammatory, dyskeratotic, and oncohematology diseases. Retinoids have now reached the fourth generation, progressively reducing toxicity whilst increasing their efficacy. Trifarotene is a new fourth-generation retinoid with a selective action on RAR-γ. In this review, we reported the trials—both concluded and in progress—including the use of trifarotene in dermatological diseases. Studies were identified by searching electronic databases (MEDLINE, EMBASE, PubMed, Cochrane, Trials.gov) from 2012 to today and reference lists of respective articles. Only articles published in English language were included. Randomized trials evaluating trifarotene tolerability, safety, and efficacy in congenital ichthyosis and acne have demonstrated great results and mild side effects, leading to the approval by the FDA of trifarotene for the treatment of lamellar ichthyosis in 2014, and of acne vulgaris in October 2019. No high-quality randomized clinical trials have evaluated the treatment of primary cutaneous lymphomas with trifarotene. Finally, we are hypothesizing future perspectives in the treatment of non-melanoma skin cancers, fungal infections, photoaging, and hand-foot skin reactions with trifarotene.

Genetic Predictors of Severe Skin Toxicity in Patients with Stage III Colon Cancer Treated with Cetuximab: NCCTG N0147 (Alliance)

BACKGROUND

Cetuximab, an EGFR inhibitor used to treat multiple cancer types, including colon cancer, causes severe skin toxicity in 5%-20% of patients, leading to decreased quality of life and treatment delays. Our understanding of which patients have an increased risk of severe toxicities is limited. We conducted a genome-wide association study to identify germline variants predictive of cetuximab-induced severe skin toxicity.

METHODS

Our study included 1,209 patients with stage III colon cancer randomized to receive cetuximab plus 5-fluorouracil and oxaliplatin as part of the NCCTG N0147 (Alliance) clinical trial. Skin toxicity outcomes were collected using the Common Toxicity Criteria for Adverse Events version 3.0. We performed genotyping, evaluating approximately 10 million genetic variants. We used logistic regression to evaluate the association of each genetic variant and severe (grade ≥ 3) skin toxicity, adjusting for age, sex, and genetic ancestry. Genome-wide significance was defined as P < 5 × 10^-8.

RESULTS

Participants were predominantly middle-aged white men; 20% (n = 243) experienced severe skin toxicity. Two genetic variants in the retinoic acid receptor alpha (RARA) gene were significantly associated with severe skin toxicity [OR, 3.93; 95% confidence interval (CI), 2.47-6.25; P < 7.8 × 10^-9]. Functional annotations indicate these variants are in the RARA promoter. Additional significantly associated variants were identified in chromosome 2 intergenic regions.

CONCLUSIONS

Identified variants could represent a potential target for risk stratification of patients with colon cancer receiving cetuximab.

IMPACT

Retinoids have shown promise in the treatment of cetuximab-induced skin toxicity, so follow-up work could evaluate whether individuals with the RARA variant would benefit from retinoid therapy.

Trifarotene for the Treatment of Facial and Truncal Acne

OBJECTIVE

This article reviews clinical trials to assess the efficacy, safety, and clinical application of trifarotene 0.005% cream (Aklief).

DATA SOURCES

A systematic review of the literature was performed using the terms trifarotene OR Aklief OR CD5789 in MEDLINE (PubMed) and EMBASE databases. Articles prior to May 2020 were considered for inclusion. Bibliographies and ClinicalTrials.gov were also searched to identify further studies.

STUDY SELECTION AND DATA EXTRACTION

Relevant English language and human studies related to pharmacology, clinical trials, and safety were considered.

DATA SYNTHESIS

In the 52-week phase III trial, treatment success rates for facial acne (Investigator Global Assessment [IGA] rating of no or almost no acne) and truncal acne (Physician's Global Assessment [PGA] rating of no or almost no acne) were 65.1% and 66.9%, respectively. Overall success rates (IGA and PGA success in the same patient) were 57.9%; 52.8% of patients had a Dermatology Quality of Life Index score of 0 or 1, compared with 22.6% at baseline. Trifarotene was well tolerated, with pruritus, irritation, and sunburn as the most common adverse effects.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Trifarotene is a newly Food and Drug Administration-labeled fourth-generation topical retinoid that shows particular promise in the treatment of facial and truncal acne vulgaris. It is an effective and safe addition to currently available retinoids.

CONCLUSION

Trifarotene is effective and safe for treatment of facial and truncal acne. Future trials should compare its efficacy and tolerability with that of the older, clinically established retinoids. Despite efficacy, cost may be a prohibitive factor.

Intravenously Administered, Retinoid Activating Nanoparticles Increase Lifespan and Reduce Neurodegeneration in the SOD1G93A Mouse Model of ALS

Dysregulation of the retinoic acid (RA) signaling pathway is observed in amyotrophic lateral sclerosis (ALS) and other neurodegenerative disorders. Here, we investigated the therapeutic potential of retinoid activation via the RA receptor β (RARβ) in the SOD1^G93A mouse model of ALS. Our approach utilized the RARβ agonist adapalene, which we previously found to be neuroprotective in vitro. Adapalene, like most retinoids, is poorly water soluble, which has thus far prevented effective drug delivery in vivo. To address this challenge, we encapsulated adapalene within nanoparticles (Adap-NPs) composed of poly(lactic acid)-poly(ethylene glycol) (PLA-PEG). Our data demonstrate that intravenous administration of Adap-NPs robustly activates retinoid signaling in the CNS. Chronic administration of Adap-NPs resulted in improved motor performance, prolonged lifespan, and neuroprotection in SOD1^G93A mice. This study highlights retinoid signaling as a valuable therapeutic approach and presents a novel nanoparticle platform for the treatment of ALS.

Staphylococcus epidermidis: A Potential New Player in the Physiopathology of Acne?

Background: Cutibacterium acnes has been identified as one of the main triggers of acne. However, increasing knowledge of the human skin microbiome raises questions about the role of other skin commensals, such as Staphylococcus epidermidis, in the physiopathology of this skin disease. Summary: This review provides an overview of current knowledge of the potential role of S. epidermidis in the physiopathology of acne. Recent research indicates that acne might be the result of an unbalanced equilibrium between C. acnes and S. epidermidis,according to dedicated interactions. Current treatments act on C. acnesonly. Other treatment options may be considered, such as probiotics derived from S. epidermidis to restore the naturally balanced microbiota or through targeting the regulation of the host’s AMP mediators. Key Messages: Research seems to confirm the beneficial role of S. epidermidis in acne by limiting C. acnes over-colonisation and inflammation.

Adapalene-loaded poly(ε-caprolactone) microparticles: Physicochemical characterization and in vitro penetration by photoacoustic spectroscopy

Adapalene (ADAP) is an important drug widely used in the topical treatment of acne. It is a third-generation retinoid and provides keratolytic, anti-inflammatory, and antiseborrhoic action. However, some topical adverse effects such as erythema, dryness, and scaling have been reported with its commercial formula. In this sense, the microencapsulation of this drug using polyesters can circumvent its topical side effects and can lead to the enhancement of drug delivery into sebaceous glands. The goal of this work was to obtain ADAP-loaded poly(ε-caprolactone) (PCL) microparticles prepared by a simple emulsion/solvent evaporation method. Formulations containing 10 and 20% of ADAP were successfully obtained and characterized by morphological, spectroscopic, and thermal studies. Microparticles presented encapsulation efficiency of ADAP above 98% and showed a smooth surface and spherical shape. Fourier transform infrared spectroscopy (FTIR) results presented no drug-polymer chemical bond, and a differential scanning calorimetry (DSC) technique showed a partial amorphization of the drug. ADAP permeation in the Strat-M membrane for transdermal diffusion testing was evaluated by photoacoustic spectroscopy (PAS) in the spectral region between 225 and 400 nm after 15 min and 3 h from the application of ADAP-loaded PCL formulations. PAS was successfully used for investigating the penetration of polymeric microparticles. In addition, microencapsulation decreased the in vitro transmembrane diffusion of ADAP.

Nonclinical and human pharmacology of the potent and selective topical retinoic acid receptor-γ agonist trifarotene

BACKGROUND

First- and third-generation retinoids are the main treatment for acne. Even though efficacious, they lack full selectivity for retinoic acid receptor (RAR) γ, expressed in the epidermis and infundibulum.

OBJECTIVES

To characterize the in vitro metabolism and the pharmacology of the novel retinoid trifarotene.

MATERIALS AND METHODS

In vitro assays determined efficacy, potency and selectivity on RARs, as well as the activity on the expression of retinoid target genes in human keratinocytes and ex vivo cultured skin. In vivo studies investigated topical comedolytic, anti-inflammatory and depigmenting properties. The trifarotene-induced gene expression profile was investigated in nonlesional skin of patients with acne and compared with ex vivo and in vivo models. Finally, the metabolic stability in human keratinocytes and hepatic microsomes was established.

RESULTS

Trifarotene is a selective RARγ agonist with > 20-fold selectivity over RARα and RARβ. Trifarotene is active and stable in keratinocytes but rapidly metabolized by human hepatic microsomes, predicting improved safety. In vivo, trifarotene 0·01% applied topically is highly comedolytic and has anti-inflammatory and antipigmenting properties. Gene expression studies indicated potent activation of known retinoid-modulated processes (epidermal differentiation, proliferation, stress response, retinoic acid metabolism) and novel pathways (proteolysis, transport/skin hydration, cell adhesion) in ex vivo and in vivo models, as well as in human skin after 4 weeks of topical application of trifarotene 0·005% cream.

CONCLUSIONS

Based on its RARγ selectivity, rapid degradation in human hepatic microsomes and pharmacological properties including potent modulation of epidermal processes, topical treatment with trifarotene could result in good efficacy and may present a favourable safety profile in acne and ichthyotic disorders.

Why Topical Retinoids Are Mainstay of Therapy for Acne

Acne-focused dermatology expert groups have consistently recommended that most patients with acne be treated with a combination of topical retinoid and antimicrobial therapy. This is based on clinical data as well as evidence that these drug classes have different and complementary mechanisms of action that target multiple aspects of acne's complex pathophysiology. Recent evidence-based guidelines for acne, including those from the American Academy of Dermatology (AAD) and the European Dermatology Forum (EDF), have agreed that retinoids have an essential role in this widespread disease. The AAD states "retinoids are the core of topical therapy for acne because they are comedolytic, resolve the precursor microcomedone lesion, and are anti-inflammatory;" further, they "allow for maintenance of clearance." Despite uniform recommendation for use of topical retinoids, a recent study of prescribing practices from 2012 to 2014 indicated that dermatologists prescribed retinoids just 58.8% of the time while non-dermatologists prescribed them for only 32.4% of cases. In this article, we review the reasons supporting retinoids as the mainstay of acne therapy and discuss some of the perceived barriers that may be limiting use of this important drug class. Further, we discuss how and when titrating retinoid concentrations may be utilized in clinical practice.

FUNDING

Galderma International.

Fixed-Combination Gels of Adapalene and Benzoyl Peroxide Provide Optimal Percutaneous Absorption Compared to Monad Formulations of These Compounds: Results from Two In Vitro Studies

Introduction

Adapalene 0.1%/benzoyl peroxide 2.5% (0.1% A/BPO) and adapalene 0.3%/BPO 2.5% (0.3% A/BPO) gels are fixed-combination options for the topical treatment of acne. However, the active compounds of these combinations are also available as monads, to be used in association or as monotherapy. These two in vitro studies determined the effect of different treatment regimens on the percutaneous absorption of adapalene (0.1% and 0.3%) gels and BPO 2.5% gel in ex vivo human skin.

Methods

In vitro percutaneous absorption studies were conducted using full-thickness human skin from six donors. Treatment regimens included the application of 0.1% A/BPO, 0.3% A/BPO, or four free-combination regimens of the monads. Skin samples were incubated for 24 h. Concentrations of adapalene and BPO equivalent (BPO-eq) (i.e. benzoic acid after chemical transformation of BPO) were measured using high-performance liquid chromatography. Comparison of regimens was performed using a bioequivalence criterion (estimated ratio bewteen 0.8 and 1.25).

Results

The fixed combination 0.3% A/BPO regimen demonstrated more than three times higher absorption of adapalene versus the fixed-combination 0.1% A/BPO. Based on the bioequivalence acceptance criterion, all four free-combination regimens were different from 0.1% A/BPO and 0.3% A/BPO, with higher adapalene release delivered by the fixed combinations versus the free combinations. For BPO-eq, the results showed that the free-combination regimens where adapalene 0.1% was applied first were different from 0.1% A/BPO, with lower BPO-eq release delivered by these regimens compared to the fixed combination. The regimen adapalene 0.3% for 10 h followed by BPO 2.5% delivered lower BPO-eq release compared to the fixed combination.

Conclusion

The fixed-combination A/BPO gels provide optimal percutaneous absorption of the active compounds compared to free combinations of adapalene 0.1%, adapalene 0.3%, and BPO 2.5%. The higher concentration of adapalene in the 0.3% A/BPO gel and the resulting higher absorption may explain higher clinical efficacy.

Treatment of Inflammatory Acne with a Combination Therapy with Lymecycline and Adapalene Followed by Maintenance Treatment with Adapalene

Oral antibiotics, especially tetracyclines, are commonly used to treat moderate to moderately severe acne vulgaris. There are hints suggesting that a combination treatment with oral tetracyclines and topical retinoids can cause a greater and prompter improvement of acne than monotherapy with tetracyclines. We evaluated the clinical activity of a 12-week combined therapy with oral lymecycline (300mg/day for 2 weeks and then 150mg/day) and topical adapalene (gel or cream) in 419 patients with inflammatory acne. A significant reduction in the number of acne lesions was noted at 4 and 12 weeks (P<0.0001). Thereafter, 400 patients underwent a maintenance treatment with adapalene alone for 12 weeks. At week 24 a relevant improvement of acne lesions still persisted (P<0.0001) in most patients. Only 16 patients relapsed and required additional use of oral lymecycline which proved again successful. No substantial differences were noted in the magnitude of clinical response between patients treated with adapalene gel and those treated with cream formulation. Treatment was well tolerated. Local adverse reactions occurred in 11.7 % of patients and resulted in premature discontinuation of treatment in 1.4 %. Systemic (gastrointestinal) untoward effects developed in 1.2 % of patients and caused treatment interruption in 0.7 % of cases. No serious adverse events occurred.

Moderate and Severe Inflammatory Acne Vulgaris Effectively Treated with Single-Agent Therapy by a New Fixed-Dose Combination Adapalene 0.3 %/Benzoyl Peroxide 2.5 % Gel: A Randomized, Double-Blind, Parallel-Group, Controlled Study

Background

A need exists for topical treatments in managing more severe inflammatory acne.

Objectives

The objectives of this study were to evaluate the efficacy and safety of adapalene 0.3 %/benzoyl peroxide 2.5 % (0.3 % A/BPO) topical gel in subjects with moderate and severe inflammatory acne.

Methods

This was a multicenter, randomized, double-blind, parallel-group study. Randomization was stratified by acne severity (50 % moderate and 50 % severe). Subjects received 0.3 % A/BPO, 0.1 % A/BPO (benchmark), or vehicle (comparator) once daily for 12 weeks. Co-primary efficacy endpoints were success rate at week 12 (the percentage of subjects rated ‘clear’ or ‘almost clear’ with at least a 2-grade improvement on Investigator’s Global Assessment [IGA]) and change in inflammatory (IN) and noninflammatory (NIN) lesion counts from baseline to week 12. Secondary efficacy endpoints were percent changes in IN and NIN lesion counts. Safety endpoints were incidence of adverse events (AEs) and local tolerability signs/symptoms.

Results

A total of 503 subjects were randomized: 217, 217, and 69 subjects in the 0.3 % A/BPO, 0.1 % A/BPO, and vehicle groups, respectively. For success rate (subjects rated ‘clear’ or ‘almost clear’ with ≥2-grade improvement in IGA), 0.3 % A/BPO was superior to vehicle, with a treatment difference of 22.7 % (33.7 vs. 11.0 %; 95 % confidence interval [CI] 12.8–32.6, p < 0.001). At week 12, 0.3 % A/BPO was superior to vehicle for mean reduction from baseline in IN (27.0 vs. 14.4) and NIN lesion counts (40.2 vs. 18.5), as well as for percentage reduction from baseline in IN (68.7 vs. 39.2 %) and NIN lesion counts (68.3 vs. 37.4 %) (all p < 0.001). Among subjects with severe inflammatory acne (IGA = 4), 0.1 % A/BPO did not reach statistical significance for success rate compared with vehicle (p = 0.443), whereas 0.3 % A/BPO demonstrated significantly greater efficacy (p = 0.029, requiring ≥3-point IGA improvement). Additionally, 0.3 % A/BPO was safe and well-tolerated.

Conclusions

Results of this clinical trial demonstrate the significantly greater efficacy of adapalene 0.3 % A/BPO topical gel compared with vehicle as well as a good safety profile in the treatment of moderate to severe inflammatory non-nodulocystic acne, which increases patients’ treatment options.

Clinicaltrials.gov identifier

NCT01880320.

How does our increased understanding of the role of inflammation and innate immunity in acne impact treatment approaches?

A supplement article recently published in the Journal of the European Academy of Dermatology and Venereology by Dréno et al., members of the Global Alliance to Improve Outcomes in Acne group, summarized the data for the emerging concept that inflammation in general and the innate immune system specifically play a central role in the pathogenesis of acne. This review, entitled "Understanding innate immunity and inflammation in acne: implications for management", also discusses the impact of different treatment options on the innate immune response and inflammation. The aim of the present summary is to provide a synopsis of the key points made in the paper, from the members of the Global Alliance, as relevant to the main article within this supplement: "Recent advances in the use of adapalene 0.1%/benzoyl peroxide 2.5% to treat acne patients with moderate to severe acne".

Multicenter study for efficacy and safety evaluation of a fixeddose combination gel with adapalen 0.1% and benzoyl peroxide 2.5% (Epiduo® for the treatment of acne vulgaris in Brazilian population

BACKGROUND

The current options for the treatment of acne vulgaris present many mechanisms of action. For several times, dermatologists try topical agents combinations, looking for better results.

OBJECTIVES

To evaluate the efficacy, tolerability and safety of a topical, fixed-dose combination of adapalene 0.1% and benzoyl peroxide 2.5% gel for the treatment of acne vulgaris in the Brazilian population.

METHODS

This is a multicenter, open-label and interventionist study. Patients applied 1.0 g of the fixed-dose combination of adapalene 0.1% and benzoyl peroxide 2.5% gel on the face, once daily at bedtime, during 12 weeks. Lesions were counted in all of the appointments, and the degree of acne severity, overall improvement, tolerability and safety were evaluated in each visit.

RESULTS

From 79 recruited patients, 73 concluded the study. There was significant, fast and progressive reduction of non-inflammatory, inflammatory and total number of lesions. At the end of the study, 75.3% of patients had a reduction of >50% in non-inflammatory lesions, 69.9% in inflammatory lesions and 78.1% in total number of lesions. Of the 73 patients, 71.2% had good to excellent response and 87.6% had satisfactory to good response. In the first week of treatment, erythema, burning, scaling and dryness of the skin were frequent complaints, but, from second week on, these signals and symptoms have reduced.

CONCLUSION

The fixed-dose combination of adapalene 0.1% and benzoyl peroxide 2.5% gel is effective, safe, well tolerated and apparently improves patient compliance with the treatment.

Topical therapies for skin cancer and actinic keratosis

The global incidence of skin cancer and actinic keratosis (AK) has increased dramatically in recent years. Although many tumours are treated with surgery or radiotherapy topical therapy has a place in the management of certain superficial skin neoplasms and AK. This review considers skin physiology, non-melanoma skin cancer (NMSC), the relationship between AK and skin cancer and drugs administered topically for these conditions. The dermal preparations for management of NMSC and AK are discussed in detail. Notably few studies have examined drug disposition in cancerous skin or in AK. Finally, recent novel approaches for targeting of drugs to skin neoplasms and AK are discussed.

Topical acne treatments in Europe and the issue of antimicrobial resistance

Acne vulgaris (acne) is a chronic inflammatory disease of the sebaceous gland, characterized by follicular hyperkeratinization, excessive colonization by Propionibacterium acnes (P. acnes) as well as immune reactions and inflammation. Despite an armamentarium of topical treatments available including benzoyl peroxide, retinoids and azelaic acid, topical antibiotics in monotherapies, especially erythromycin and clindamycin, are still used in Europe to treat acne. This intensive use led to antimicrobial-resistant P. acnes and staphylococci strains becoming one of the main health issues worldwide. This is an update on the current topical acne treatments available in Europe, their mechanism of action, their potential to induce antimicrobial resistance and their clinical efficacy and safety.

Comparative effects of retinoic acid or glycolic acid vehiculated in different topical formulations

Retinoids and hydroxy acids have been widely used due to their effects in the regulation of growth and in the differentiation of epithelial cells. However, besides their similar indication, they have different mechanisms of action and thus they may have different effects on the skin; in addition, since the topical formulation efficiency depends on vehicle characteristics, the ingredients of the formulation could alter their effects. Thus the objective of this study was to compare the effects of retinoic acid (RA) and glycolic acid (GA) treatment on the hairless mouse epidermis thickness and horny layer renewal when added in gel, gel cream, or cream formulations. For this, gel, gel cream, and cream formulations (with or without 6% GA or 0.05% RA) were applied in the dorsum of hairless mice, once a day for seven days. After that, the skin was analyzed by histopathologic, morphometric, and stereologic techniques. It was observed that the effects of RA occurred independently from the vehicle, while GA had better results when added in the gel cream and cream. Retinoic acid was more effective when compared to glycolic acid, mainly in the cell renewal and the exfoliation process because it decreased the horny layer thickness.

Pharmaceuticals that contain polycyclic hydrocarbon scaffolds

This review comprehensively explores approved pharmaceutical compounds that contain polycyclic scaffolds and the properties that these skeletons convey.

Efficacy of 0.1% adapalene in a non-inflammatory Kyoto Rhino Rat acne model

BACKGROUND

Acne vulgaris is a disorder of the pilosebaceous unit of the skin, and the underlying mechanism is still obscure. Kyoto rhino (krh/krh) rats were made by ethylnitrosourea (ENU) mutagenesis and harbor S413X nonsense mutation of the rat hairless (Hr) gene. Krh/krh rats develop comedones with hair loss on their back as they grow.

OBJECTIVE

Our purpose is to assess whether or not the krh/krh rat is a suitable model of non-inflammatory acne, and to investigate the comedolytic effects of adapalene in krh/krh rats.

METHODS

Krh/krh rats at 12weeks of age were topically treated with adapalene or a vehicle 6 times a week, for 12weeks. Skin lesions were clinically investigated and skin samples were obtained from treated skins from each animal after 6 and 12weeks of treatments.

RESULTS

Comedone was clinically enlarged in the control group compared with the adapalene group. The adapalene group showed significantly increased epidermal thickness as compared to the control group. Furthermore, open comedone areas were also significantly decreased in the adapalene group as compared to the control group. The adapalene group also showed reduced lipid production in open comedones as compared to the control group. Cytokine productions including IL-10 and IL-12a tended to increase in skin treated with adapalene as compared to the control group.

CONCLUSION

Krh/krh rats represented a new model for non-inflammatory acne with abnormalities in both hair follicles and sebaceous glands. It is hypothesized that adapalene is a superior drug to decrease open comedones by modifying lipid metaboism and cytokine production in krh/krh rats.

Active ingredients against human epidermal aging

The decisive role of the epidermis in maintaining body homeostasis prompted studies to evaluate the changes in epidermal structure and functionality over the lifetime. This development, along with the identification of molecular mechanisms of epidermal signaling, maintenance, and differentiation, points to a need for new therapeutic alternatives to treat and prevent skin aging. In addition to recovering age- and sun-compromised functions, proper treatment of the epidermis has important esthetic implications. This study reviews active ingredients capable of counteracting symptoms of epidermal aging, organized according to the regulation of specific age-affected epidermal functions: (1) several compounds, other than retinoids and derivatives, act on the proliferation and differentiation of keratinocytes, supporting the protective barrier against mechanical and chemical insults; (2) natural lipidic compounds, as well as glycerol and urea, are described as agents for maintaining water-ion balance; (3) regulation of immunological pathogen defense can be reinforced by natural extracts and compounds, such as resveratrol; and (4) antioxidant exogenous sources enriched with flavonoids and vitamin C, for example, improve solar radiation protection and epidermal antioxidant activity. The main objective is to provide a functional classification of active ingredients as regulatory elements of epidermal homeostasis, with potential cosmetic and/or dermatological applications.

Effects of adapalene-benzoyl peroxide combination gel in treatment or maintenance therapy of moderate or severe acne vulgaris: a meta-analysis

Background

An antibiotic-free, fixed-dose combination gel with adapalene (A) 0.1% and benzoyl peroxide (BPO) 2.5% has been developed for treatment of acne vulgaris.

Objective

To compare the clinical outcomes of A-BPO combination gel with vehicle gel for treatment or maintenance therapy of patients with acne vulgaris.

Methods

An electronic search of the database PubMed (1966 to September 2012), Embase (1984 to September 2012), and Cochrane Controlled Trials Register (CENTRAL; 3rd Quarter, 2012) was undertaken to identify relevant studies. Main clinical outcomes were success rate, treatment-related adverse events (AEs), AEs leading to discontinuation, satisfaction with the effectiveness, and overall satisfaction.

Results

Six studies were finally included in this meta-analysis. The A-BPO group yielded better clinical outcomes regarding the success rate (p<0.00001), satisfaction with the effectiveness of treatment (p=0.005), and overall satisfaction (p=0.005) compared to the vehicle group. The incidence of treatment-related AEs in the A-BPO group was comparable with that of vehicle group (p=0.09), while the A-BPO group was associated with a slightly increase in the incidence of AEs leading to discontinuation when compared with the vehicle group (p=0.02).

Conclusion

A-BPO combination gel yields better clinical outcomes including success rate, satisfaction with the effectiveness, and overall satisfaction compared to vehicle gel, despite an increased incidence of AEs leading to discontinuation. The A-BPO combination agent most likely contributes to the treatment of moderate acne vulgaris rather than severe acne vulgaris, but it may be useful in maintenance therapy of patients with severe acne vulgaris.

New frontiers in promoting tumour cell death: targeting apoptosis, necroptosis and autophagy

Cancer is a multifaceted disease comprising a combination of genetic, metabolic and signalling aberrations, which severely disrupt the normal homeostasis of cell growth and death. Many oncogenic events while promoting tumour development also increase the sensitivity of cells to cell death stimuli including chemotherapeutic drugs. As a result, tumour cells often acquire the ability to evade death by inactivating cell death pathways that normally function to eliminate damaged and harmful cells. The impairment of cell death function is also often the reason for the development of chemotherapeutic resistance encountered during treatment. It is therefore necessary to achieve a comprehensive understanding of existing cell death pathways and the relevant regulatory components involved, with the intention of identifying new strategies to kill cancer cells. This review provides an insightful overview of the common forms of cell death signalling pathways, the interactions between these pathways and the ways in which these pathways are deregulated in cancer. We also discuss the emerging therapies targeted at activating or restoring cell death pathways to induce tumour cell death, which are currently being tested in clinical trials.

Combined pharmaceuticals in the external treatment of acne: modern data

The article contains data on the efficiency of ready combined pharmaceuticals in acne treatment and discusses the synergic effect of the new adapalene / benzoyl peroxide combination.

Adapalene 0.1%/benzoyl peroxide 2.5% gel: a review of its use in the treatment of acne vulgaris in patients aged ≥ 12 years

Adapalene 0.1%/benzoyl peroxide 2.5% gel (Epiduo™, Tactuo™) is the only fixed-dose combination product available that combines a topical retinoid with benzoyl peroxide; it targets three of the four main pathophysiologic factors in acne. This article reviews the therapeutic efficacy and tolerability of topical adapalene 0.1%/benzoyl peroxide 2.5% gel in the treatment of patients aged ≥ 12 years with acne vulgaris, as well as summarizing its pharmacologic properties. In three 12-week trials in patients aged ≥ 12 years with moderate acne, success rates were significantly higher with adapalene 0.1%/benzoyl peroxide 2.5% gel than with adapalene 0.1% gel or benzoyl peroxide 2.5% gel alone, and combination therapy had an earlier onset of action. In addition, significantly greater reductions in total, inflammatory, and noninflammatory lesion counts were seen in patients receiving adapalene 0.1%/benzoyl peroxide 2.5% gel than in those receiving adapalene 0.1% gel or benzoyl peroxide 2.5% gel alone. Adapalene 0.1%/benzoyl peroxide 2.5% gel did not significantly differ from clindamycin 1%/benzoyl peroxide 5% gel in terms of the reduction in the inflammatory, noninflammatory, or total lesion counts in patients with mild to moderate acne, according to the results of a 12-week trial. Twelve-week studies showed that topical adapalene 0.1%/benzoyl peroxide 2.5% gel in combination with oral lymecycline was more effective than oral lymecycline alone in patients with moderate to severe acne, and topical adapalene 0.1%/benzoyl peroxide 2.5% gel in combination with oral doxycycline hyclate was more effective than oral doxycycline hyclate alone in patients with severe acne. In patients with severe acne who responded to 12 weeks' therapy with topical adapalene 0.1%/benzoyl peroxide 2.5% gel plus oral doxycycline hyclate or oral doxycycline hyclate alone, an additional 6 months' therapy with adapalene 0.1%/benzoyl peroxide 2.5% gel was more effective than vehicle gel at maintaining response, with further improvement seen in adapalene 0.1%/benzoyl peroxide 2.5% gel recipients. A noncomparative study also demonstrated the efficacy of 12 months' therapy with adapalene 0.1%/benzoyl peroxide 2.5% gel in patients with acne vulgaris. Topical adapalene 0.1%/benzoyl peroxide 2.5% gel was generally well tolerated in patients with acne. In 12-week trials, the most commonly occurring treatment-related adverse events included erythema, scaling, dryness, and stinging/burning; these dermatologic treatment-related adverse events were usually of mild to moderate severity, occurred early in the course of treatment, and resolved without residual effects. Topical adapalene 0.1%/benzoyl peroxide 2.5% gel was generally well tolerated in the longer term, with dry skin being the most commonly occurring treatment-related adverse event over 12 months of treatment. In conclusion, adapalene 0.1%/benzoyl peroxide 2.5% gel is a valuable agent for the first-line treatment of acne vulgaris.

Successful treatment of Darier's disease with adapalene gel

We report a 12-year-old Japanese boy with a 3-year history of skin lesions that had been unsuccessfully treated with topical steroids. We initiated two different topical treatments with adapalene gel 0.1% (Differin(®) Gel 0.1%) and high-concentration vitamin D3 (tacalcitol) ointment; the lesions treated with adapalene gel improved dramatically in the first 2 months, whereas the high-concentration vitamin D3 ointment resulted in little improvement. Topical adapalene gel 0.1% may be a promising choice as a topical treatment of Darier's disease because of its high efficiency and lack of adverse effects.

Identification of radiation-induced expression changes in nonimmortalized human T cells

In the event of a radiation accident or attack, it will be imperative to quickly assess the amount of radiation exposure to accurately triage victims for appropriate care. RNA-based radiation dosimetry assays offer the potential to rapidly screen thousands of individuals in an efficient and cost-effective manner. However, prior to the development of these assays, it will be critical to identify those genes that will be most useful to delineate different radiation doses. Using global expression profiling, we examined expression changes in nonimmortalized T cells across a wide range of doses (0.15-12 Gy). Because many radiation responses are highly dependent on time, expression changes were examined at three different times (3, 8, and 24 h). Analyses identified 61, 512 and 1310 genes with significant linear dose-dependent expression changes at 3, 8 and 24 h, respectively. Using a stepwise regression procedure, a model was developed to estimate in vitro radiation exposures using the expression of three genes (CDKN1A, PSRC1 and TNFSF4) and validated in an independent test set with 86% accuracy. These findings suggest that RNA-based expression assays for a small subset of genes can be employed to develop clinical biodosimetry assays to be used in assessments of radiation exposure and toxicity.

Hesperidin promotes cyclobutane pyrimidine dimer repair in UVB-exposed mice epidermis

PURPOSE

To investigate whether topical application of hesperin affords protection to Balb/C mice epidermis from UVB-induced cyclobutane pyrimidine dimers (CPDs).

METHODS

A DNA damage model of UVB irradiation-induced mice epidermis was established. The immunohistochemical staining and southwestern dot blotting were used for CPDs detection; western blotting was used for P53 detection.

RESULTS

Topical application of hesperidin on Balb/C mice skin significantly decreased the amount of epidermal CPDs 24 and 48 h after 180 mJ/cm(2) of UVB irradiation as compared to untreated mice. UVB-induced p53 expression was more pronounced in hesperidin-treated mice epidermis compared to that of untreated mice.

CONCLUSION

Taken together, these results suggest that topical hesperidin application promotes DNA photo-damage repair. Hesperidin is therefore a promising protective substance against UVB radiation.

A successful maintenance approach in inflammatory acne with adapalene gel 0.1% after an initial treatment in combination with clindamycin topical solution 1% or after monotherapy with clindamycin topical solution 1%

BACKGROUND

METHODS

A total of 300 acne subjects entered this multicentre, randomized, investigator-blinded study comparing the efficacy and safety of adapalene gel 0.1% plus clindamycin topical solution 1% versus clindamycin topical solution 1% alone. In the second part of the study (weeks 12-24), completed by 241 subjects, the efficacy and safety of adapalene gel 0.1% alone as a maintenance therapy was investigated.

RESULTS

A statistically significant greater reduction was observed from week 4 until week 12 in total lesion counts and from week 8 on for inflammatory and non-inflammatory lesion counts during the initial treatment for combination therapy compared with monotherapy. Results at week 24 for the reduction in all lesion counts during the maintenance phase were statistically significant in favour of adapalene (41.6%) compared with an increase for all lesion counts in the control group (92.1%). Adapalene alone or in combination with clindamycin topical solution was well tolerated. Few adverse events occurred, all of them during the initial treatment phase. Most of these local events were mild or moderate.

CONCLUSION

The present study confirmed the importance of a maintenance therapy after a successful initial treatment and underlined the benefit of a combination therapy with a topical retinoid such as adapalene and a topical antibiotic in the treatment of inflammatory acne.

A comparative trial of two retinoids commonly used in the treatment of acne vulgaris

BACKGROUND

Topical retinoids are highly effective treatments for acne vulgaris. The various formulations and concentrations available allow physicians to tailor therapies to individual patient's needs and minimize the cutaneous irritation that is often observed with the use of these drugs.

OBJECTIVE

To compare the efficacy and safety of tretinoin gel microsphere 0.1% with adapalene gel 0.1% in the treatment of acne vulgaris.

METHODS

A 12-week double-blind study was conducted, and patients were evaluated at baseline and at weeks 2, 3, 4, 6, 8, 10, and 12.

RESULTS

Although the two drugs displayed similar efficacy in the resolution of acne lesions at 12 weeks, a significantly greater reduction in the number of comedones was seen at week 4 among patients treated with tretinoin gel microsphere (p = 0.047). Patients receiving tretinoin gel microsphere had an increased incidence of dryness (weeks 8 and 10) and peeling (weeks 3, 6, 8, and 10) compared with those patients treated with adapalene gel, but the two groups were comparable with respect to erythema, burning/stinging, and itching.

CONCLUSION

Both drugs have similar efficacy in the resolution of acne lesions but tretinoin gel microsphere may result in a faster onset of action in the reduction of comedones compared to adapalene.

Evaluation of four topical preparations for the treatment of cannon hyperkeratosis in a horse

The response to treatment with four topical preparations was evaluated in an 11-year-old Morgan horse mare with histologically confirmed quadrilateral cannon hyperkeratosis. Each limb was treated for 30 days with 0.1% tacrolimus ointment, 0.1% adapalene gel, 0.2% phytosphingosine spray or a water-based emollient. Response to treatment was evaluated both histologically and visually. A water-based emollient and 0.1% tacrolimus ointment produced encouraging clinical responses. Pre-treatment histopathology identified marked, mostly compact, hyperkeratosis and follicular hyperkeratosis, most prominent in the infundibular area. Following treatment, histopathology identified a mild reduction in follicular keratin production and stratum corneum thickness.