Factors influencing response to ingenol mebutate therapy for actinic keratosis of face and scalp

Identification of differentially expressed genes in actinic keratosis samples treated with ingenol mebutate gel

Actinic keratosis is a common skin disease that may progress to invasive squamous cell carcinoma if left untreated. Ingenol mebutate has demonstrated efficacy in field treatment of actinic keratosis. However, molecular mechanisms on ingenol mebutate response are not yet fully understood. In this study, we evaluated the gene expression profiles of actinic keratosis lesions before and after treatment with ingenol mebutate using microarray technology. Actinic keratoses on face/scalp of 15 immunocompetent patients were identified and evaluated after treatment with topical ingenol mebutate gel 0.015%, applied once daily for 3 consecutive days. Diagnostic and clearance of lesions was determined by clinical, dermoscopic, and reflectance confocal microscopy criteria. Lesional and non-lesional skin biopsies were subjected to gene expression analysis profiled by Affymetrix microarray. Differentially expressed genes were identified, and enrichment analyses were performed using STRING database. At 8 weeks post-treatment, 60% of patients responded to ingenol mebutate therapy, achieving complete clearance in 40% of cases. A total of 128 differentially expressed genes were identified following treatment, and downregulated genes (114 of 128) revealed changes in pathways important to epidermal development, keratinocyte differentiation and cornification. In responder patients, 388 downregulated genes (of 450 differentially expressed genes) were also involved in development/differentiation of the epidermis, and immune system-related pathways, such as cytokine and interleukin signaling. Cluster analysis revealed two relevant clusters showing upregulated profile patterns in pre-treatment actinic keratoses of responders, as compared to non-responders. Again, differentially expressed genes were mainly associated with cornification, keratinization and keratinocyte differentiation. Overall, the present study provides insight into the gene expression profile of actinic keratoses after treatment with ingenol mebutate, as well as identification of genetic signatures that could predict treatment response.

Treatment responder analysis in actinic keratosis: can it lead the way to individualized choice of treatment?

BACKGROUND

It is unclear if there are any distinct AK patient populations that might respond best to a given treatment.

OBJECTIVE

To identify if a distinct subgroup of patients with AK might respond better to treatment with ingenol mebutate (IngMeb) versus diclofenac sodium (DS).

METHODS

Complete clearance of AK and mean lesion reduction at end of first treatment course and week 17 were evaluated within subgroups.

RESULTS

502 patients (255 IngMeb; 247 DS) were included in the analysis. At week 17, complete clearance was achieved by more patients treated with IngMeb versus DS within the majority of patient subgroups, including patients with <6 lesions and ≥6 lesions at baseline, aged ≥65 years, males, females, Fitzpatrick skin types II and III, and facial lesions. Mean lesion reduction at week 17 was greater with IngMeb than DS within the same subgroups, and in patients with scalp lesions.

CONCLUSIONS

This responder analysis did not identify any distinct population that responded more optimally than others with IngMeb or DS. More patients achieved complete clearance and higher lesion reduction of AK with IngMeb compared with DS in most subgroups.

Prevalence, Discontinuation Rate, and Risk Factors for Severe Local Site Reactions with Topical Field Treatment Options for Actinic Keratosis of the Face and Scalp

Actinic keratoses (AKs) are common lesions on chronically sun damaged skin, which are morphologically characterized by lower third to full thickness atypia of epidermal keratinocytes. These lesions carry a risk of progression towards invasive squamous cell carcinoma (SCC); therefore, treatment of visible lesions and the field in case of field cancerization is recommended. Treatment of AK includes the destruction of atypical keratinocytes that clinically presents with various degrees of erythema, scaling, crusting, erosion, and other visible and subjective symptoms. Such inflammatory reactions may have an impact on the patient’s social life and have shown to decrease compliance and adherence to therapy. Additionally, as various topical treatments have been proven to be effective in treating AK, tolerability of local site reactions (LSRs) might drive the decision for appropriate treatment in an individual scenario. Therefore, we aimed to review prevalence of severe LSRs among various topical treatments for AK. In addition, we summarized discontinuation rates due to LSRs and possible therapy-unrelated risk factors for the development of LSRs with increased severity.

Clinical utility of ingenol mebutate in the management of actinic keratosis: perspectives from clinical practice

Actinic keratoses (AKs) are epidermal cutaneous neoplasia observed predominantly in middle-aged and older subjects with mainly photo type I and photo type II on sun-exposed surfaces as a result of DNA damage. AKs have historically been characterized as being "precancerous"; however, now it is considered by many authors a carcinoma in situ that can persist or progress to invasive squamous cell carcinoma (SCC) with metastatic potential. Despite the advances in the recognition of typical clinic, dermoscopic and histologic patterns, currently it is not yet possible to predict which AKs will progress to SCC. For this reason, early diagnosis and effective therapy are recommended based on cost/risk/benefit analysis. Current treatment consists of lesion-directed or field-directed therapies or a combination of both. Among the topical field therapies, ingenol mebutate stands out for its therapeutic efficacy, both as directed lesion therapy and as field directed therapy. The aim of this review is to demonstrate the utility of ingenol mebutate in the management of AK in daily clinical practice and to highlight data from real world in order to confirm evidence from pivotal studies. In order to explore clinical data from real world, PubMed searches were performed with the search terms "clinical data ingenol mebutate" and "real world ingenol mebutate". The hits were examined for relevant articles using defaults criteria. The timeframe for the sample search started from the first publication on this topic in 2008 up to now. A total of 23 articles were found using the keywords specified above. The overview points out a low number of real-life studies on the effectiveness and tolerability of this novel treatment due to short period of clinical experience for its recent approval. Further real-life studies are required in order to better identify the efficacy, safety and adherence of the drug on a larger population.