Visualization and treatment of subclinical actinic keratoses with topical imiquimod 5% cream: an observational study

Multidrug Resistance in Cancer: Understanding Molecular Mechanisms, Immunoprevention and Therapeutic Approaches

Cancer is one of the leading causes of death worldwide. Several treatments are available for cancer treatment, but many treatment methods are ineffective against multidrug-resistant cancer. Multidrug resistance (MDR) represents a major obstacle to effective therapeutic interventions against cancer. This review describes the known MDR mechanisms in cancer cells and discusses ongoing laboratory approaches and novel therapeutic strategies that aim to inhibit, circumvent, or reverse MDR development in various cancer types. In this review, we discuss both intrinsic and acquired drug resistance, in addition to highlighting hypoxia- and autophagy-mediated drug resistance mechanisms. Several factors, including individual genetic differences, such as mutations, altered epigenetics, enhanced drug efflux, cell death inhibition, and various other molecular and cellular mechanisms, are responsible for the development of resistance against anticancer agents. Drug resistance can also depend on cellular autophagic and hypoxic status. The expression of drug-resistant genes and the regulatory mechanisms that determine drug resistance are also discussed. Methods to circumvent MDR, including immunoprevention, the use of microparticles and nanomedicine might result in better strategies for fighting cancer.

Cancer Immunoprevention: Current Status and Future Directions

Cancer is one of the most serious diseases affecting health and the second leading cause of death worldwide. Despite the development of various therapeutic modalities to deal with cancer, limited improvement in overall survival of patients has been yielded. Since there is no certain cure for cancer, detection of premalignant lesions, and prevention of their progression are vital to the decline of high morbidity and mortality of cancer. Among approaches to cancer prevention, immunoprevention has gained further attention in recent years. Deep understanding of the tumor/immune system interplay and successful prevention of virally-induced malignancies by vaccines have paved the way toward broadening cancer immunoprevention application. The identification of tumor antigens in premalignant lesions was the turning point in cancer immunoprevention that led to designing preventive vaccines for various malignancies including multiple myeloma, colorectal, and breast cancer. In addition to vaccines, immune checkpoint inhibitors are also being tested for the prevention of oral squamous cell carcinoma (SCC), and imiquimod which is an established drug for the prevention of skin SCC, is a non-specific immunomodulator. Herein, to provide a bench-to-bedside understanding of cancer immunoprevention, we will review the role of the immune system in suppression and promotion of tumors, immunoprevention of virally-induced cancers, identification of tumor antigens in premalignant lesions, and clinical advances of cancer immunoprevention.

Earliest stage treatment of actinic keratosis with imiquimod 3.75% cream: Two case reports-Perspective for non melanoma skin cancer prevention

Imiquimod 3.75% cream is licensed for the treatment of actinic keratosis (AK). Two case reports on the treatment of facial UV-exposed skin shall open the discussion if subclinical AKs can be detected by the use of imiquimod cream in UV-exposed areas even if no lesions can be found clinically. A 87-year old female showing small scaly AK lesions on her right cheek was treated with imiquimod 3.75% cream. A 59-year old female without obvious clinical signs of UV-damage on the face experimentally applied imiquimod 3.75% cream twice daily on the entire face for 2 weeks. In the 87-year old, inflammatory reaction developed from day 3 onward and showed field cancerization, the lesions healed without scarring. In the 59-year old at the end of the treatment phase, distinct signs of inflammation appeared, then taking 2 weeks for healing without sequalae. These results open the discussion if the use of imiquimod 3.75% cream could be recommended preventively in UV-exposed skin areas to obviate a later development of AKs/squamous cell carcinoma/nonmelanoma skin cancer.

Mediators of Inflammation in Topical Therapy of Skin Cancers

Taking into consideration that the immune system plays a very important role in the development of melanoma and non-melanoma skin cancers, which have a high prevalence in immunosuppressed patients and after prolonged ultraviolet radiation, the interest in developing novel therapies, in particular targeting the inflammation in cancer, has increased in the past years. The latest data suggest that therapies such as imiquimod (IMQ), ingenol mebutate (IM), 5-fluorouracil (5-FU), retinoids, and nonsteroidal anti-inflammatory drugs (NSAIDs) have been used with success in the topical treatment of some cancers. Herein, we review the topical treatment targeting the inflammation in skin cancer and the mechanisms involved in these processes. Currently, various associations have shown a superior success rate than monotherapy, such as systemic acitretin and topical IMQ, topical 5-FU with tretinoin cream, or IMQ with checkpoint inhibitor cytotoxic T lymphocyte antigen 4. Novel therapies targeting Toll-like receptor-7 (TLR-7) with higher selectivity than IMQ are also of great interest.

Imiquimod 2.5% and 3.75% Cream for the Treatment of Photodamage: A Meta-analysis of Efficacy and Tolerability in 969 Randomized Patients

Background: Ad-hoc reports within clinical studies of imiquimod for the treatment of actinic keratosis (AK) have suggested the drug can improve both skin texture and overall signs of photodamage. Objective: We sought to assess the efficacy and tolerability of imiquimod 3.75% and 2.5% cream for the treatment of photodamage in patients with AK of the full face or balding scalp. Methods: A meta-analysis of four identical multicenter, randomized, double-blind, vehicle-controlled studies was conducted. The studies included a total of 969 adult subjects (aged 33-91 years) with 5 to 20 visible lesions or palpable AKs in an area exceeding 25cm² on either the face or balding scalp. Patients were randomized to imiquimod 3.75%, imiquimod 2.5%, or vehicle cream (1:1:1). Up to two packets (250mg each) were applied per dose once daily for two two-week treatment cycles, separated by a two-week no-treatment interval. Photodamage improvement was assessed at study end based on subjects' baseline assessments using a seven-point scale. Local skin reactions were recorded throughout the study. Results: Combined Investigator's Global Integrated Photodamage (IGIP) score was "significantly" or "much" improved in 57.6 percent (n=175) of patients treated with imiquimod 2.5% cream and in 69.6 percent (n=208) of patients treated with imiquimod 3.75% cream versus in 25.7 percent (n=76) of patients treated with the vehicle. Mean IGIP scores at end of study were 1.67, 1.98, and 0.73, respectively (both actives P<0.0001 versus vehicle). Conclusion: Both imiquimod 2.5% and 3.75% creams showed a positive effect on photodamage when compared with the vehicle cream.

Actinic keratosis - review for clinical practice

Actinic keratosis (AK) is a lesion that arises as a result of excessive exposure to solar radiation and appearing predominantly on Fitzpatrick phototype I and II skin. Given that some AKs evolve into squamous cell carcinoma, these lesions are considered premalignant in nature, occurring mostly in elderly men and immunosuppressed individuals chronically exposed to ultraviolet (UV) radiation. There are several mechanisms for the formation of AKs; among them are oxidative stress, immunosuppression, inflammation, altered proliferation and dysregulation of cell growth, impaired apoptosis, mutagenesis, and human papillomavirus (HPV). Through the understanding of these mechanisms, several treatments have emerged. Among the options for AK treatment, the most commonly used include 5-fluorouracil (5-FU), cryotherapy, diclofenac, photodynamic therapy (PDT), imiquimod (IQ), retinoids, and ingenol mebutate (IM). There have been recent advances in the treatment options that have seen the emergent use of newer agents such as resiquimod, betulinic acid, piroxicam, and dobesilate. The combination between therapies has presented relevant results with intention to reduce duration of therapy and side effects. All AK cases must be treated because of their propensity to transform into malignancy and further complicate treatment. In addition to medical or surgical care, education about sun exposure prevention remains the best and most cost-effective method for AK prevention. The objective of this article is to conduct a literature review of the clinical presentation of AK including advances in treatment options available.

Patient satisfaction and reported outcomes on the management of actinic keratosis

Actinic keratosis (AK) is a common dermatologic condition in which hyperplastic epidermal lesions develop in response to excessive and chronic exposure to ultraviolet (UV) radiation. If left untreated, AK can progress to squamous cell carcinomas of the skin. Incidence is rising worldwide as a result of the progressive aging of populations and an increase in lifetime cumulative exposure to UV radiation. Currently, various treatment options exist, which range from topical medications to light-based therapies and procedural modalities. In this article, we will review the treatment options for AK with a focus on assessments of patient satisfaction with treatment.

Increased number of mast cells in the dermis in actinic keratosis lesions effectively treated with imiquimod

Actinic keratosis (AK) is a cutaneous cancer in situ which develops as a result of excessive exposure to ultraviolet (UV). Toll-like receptor (TLR)7 agonist imiquimod is a topical immune response modifier and is effective for the treatment of non-melanoma skin cancers. Recently, the diagnostic role of the dermatoscope has been reported in the course of treatment of AK. In addition, mast cells are now considered to contribute to both the innate and adaptive immune systems in topical imiquimod therapy. We assessed the effect of imiquimod treatment by dermatoscopic and immunohistochemical findings in 14 patients with a total of 21 AK lesions. With the dermatoscope, though the mean erythema score was not significantly different between the cured lesions and the unresponsive lesions, the erythema/red pseudo-network ("strawberry") pattern was decreased significantly in the cured lesions. By immunohistochemistry, the number of Ki-67-positive proliferative cells in the epidermis was decreased and that of CD117-positive mast cells in the dermis was increased in the responding lesions. To the best of our knowledge, this is the first study demonstrating that the number of mast cells in the dermis was increased in AK lesions effectively treated with imiquimod. Our present result suggests that mast cells may contribute an antitumor effect in human skin treated with topical imiquimod.

Topical Imiquimod in the Treatment of Conjunctival Actinic Keratosis

Conjunctival actinic keratosis is rare and difficult to treat, as recurrences are common. Imiquimod, an immune response modulator, is currently Food and Drug Administration-approved for cutaneous actinic keratosis and superficial basal cell carcinomas. Emerging reports have shown it to be effective in treating some periocular and conjunctival lesions. The authors present a case of a 68-year-old white man with recurrent actinic keratosis involving the pretarsal conjunctiva, which was successfully treated with 5% topical imiquimod following previous failure with cryotherapy and interferon α-2b. The patient had ocular irritation that resolved on cessation of treatment. To the authors' knowledge, this is the first report of conjunctival actinic keratosis being treated with and successfully eradicated by topical imiquimod.

Current perspective on actinic keratosis: a review

Actinic keratoses (AKs) are common, with prevalence in the U.S.A. estimated at almost 40 million in 2004 and annual costs of > $1 billion (U.S.D.). However, there is no universally accepted definition of AK and thus it is difficult to identify reliably. AKs are lesions of epidermal keratinocytic dysplasia that result from chronic sun exposure and have the ability to progress to invasive squamous cell carcinoma (SCC), but clinicians disagree about whether AKs are premalignant lesions, superficial SCCin situ or epiphenomena of chronically sun-damaged skin. Yearly AK to SCC progression rates of 0·6% were reported in an elderly population with multiple prior keratinocyte carcinomas (KCs); and rates of spontaneous AK regression have been reported to be > 50%, but regressed lesions often reappear. As AKs have both cosmetic consequences and potential for malignant transformation, there are multiple reasons for treatment. There is no current agreement on the most efficacious treatment, but 5-fluorouracil has been shown to both prevent and treat AKs, and imiquimod and photodynamic therapy may have the best cosmetic outcomes. AKs may be treated to improve appearance and relieve symptoms, but the keratinocytic dysplasia that gives rise to malignancy, and sometimes appears as an AK, may be what actually threatens patient health. Thus, treatments should aim to decrease the risk of KC or facilitate KC diagnosis by reducing the potential for misidentification created when a KC appears in a field of AKs. Improved agreement among clinicians on AK definition may improve management.

Resistance of Nonmelanoma Skin Cancer to Nonsurgical Treatments. Part I: Topical Treatments

A wide range of treatments is now available for nonmelanoma skin cancer (NMSC), including 5-fluorouracil, ingenol mebutate, imiquimod, diclofenac, photodynamic therapy, methotrexate, cetuximab, vismodegib, and radiotherapy. All are associated with high clinical and histologic response rates. However, some tumors do not respond due to resistance, which may be primary or acquired. Study of the resistance processes is a broad area of research that aims to increase our understanding of the nature of each tumor and the biologic features that make it resistant, as well as to facilitate the design of new therapies directed against these tumors. In this article we review resistance to the authorized topical treatments for NMSC.

Pharmacoeconomy of drugs used in the treatment of actinic keratoses

Actinic keratosis (AK) represents an emerging issue in the area of skin diseases which undergo high risk for developing squamous cell carcinoma (SCC). Recently, evidence has been accumulated that 3% diclofenac sodium and ingenol mubetate may efficiently counteract the development of progressive AK even if the pharmacoeconomic impact of such a treatment remains poorly defined. With the objective of assessing the efficacy of 3% diclofenac sodium versus ingenol mebutate, a comparative cost-efficacy analysis was performed between both pharmacological treatments. In the present analysis, data of efficacy of clinical studies were combined with information on the quality of life associated with AK lesions based on available literature data. Furthermore, the cost associated with the management of these lesions in Italy has been taken into account. To this purpose, we carried out a literature survey on the clinical and economic data among clinical reports available in Italy based on the assessment of related expenditure of public resources and their relationship with the subsequent health benefits.

Quality of life and side effects in patients with actinic keratosis treated with ingenol mebutate: a pilot study

INTRODUCTION

Actinic keratosis (AK) lesions are in situ squamous cell carcinoma. These lesions have a low risk of progressing to invasive disease but significant impact on patients' quality of life (QoL). The aim of this study was to assess QoL and side effects in patients with AK receiving treatment with ingenol mebutate.

MATERIAL AND METHODS

This was a prospective, non-randomized pilot study carried out in Spain. The target population was adults with a clinical diagnosis of AK affecting any part of the body. Outcomes were assessed on the basis of a QoL questionnaire (Skindex-29), local skin response, the Treatment Satisfaction Questionnaire for Medication (TSQM 1.4), and clinical response.

RESULTS

A total of 19 patients were studied. Most of the participants were men (89.5%) and mean age was 76.2 years. After treatment with ingenol mebutate, significant improvement was observed in the Skindex-29 subscales relating to symptom severity (P=.041), the patients' emotional state (P=.026), and in the overall score (P=.014). Erythema, crusting, and flaking or scaling were the local skin responses with highest median score (2.0 in all 3 cases). Imiquimod 5% and ingenol mebutate achieved higher median scores for effectiveness and global satisfaction than any other previous treatments (as measured by TSQM 1.4). In the patients' assessment of convenience, ingenol mebutate had a higher median score than previous treatments. Over half of the patients (52.6%) had an improvement of at least 75% at month 3.

CONCLUSIONS

QoL in patients with AK improves after treatment with ingenol mebutate. The presence of side effects did not affect QoL or patient satisfaction with treatment.

Efficacy of imiquimod 3.75% from Lmax according to the number of actinic keratosis lesions

BACKGROUND

Imiquimod 3.75% reduces 92.2% of all actinic keratosis (AK) lesions, assumed to include both subclinical and clinical lesions, across a large sun-exposed field such as the full face or balding scalp.

OBJECTIVE

To evaluate the efficacy of imiquimod 3.75% using the reduction in lesions from Lmax (the maximum lesion count during treatment) in subgroups of patients with low and high AK lesion counts.

METHODS

Patients from two 14-week, placebo-controlled, double-blind studies were subgrouped according to whether they had ≤ 10 or >10 AK lesions at baseline. Treatment was applied to the full face or balding scalp during two 2-week treatment cycles separated by a 2-week treatment-free interval.

RESULTS

Overall, 167 patients had ≤ 10 lesions and 152 patients had >10 AK lesions at baseline. With imiquimod 3.75%, the median percentage reduction in AK lesions from Lmax to end of study was similar in patients with ≤ 10 and >10 baseline lesions (91.5% and 93.0% respectively). The median absolute reduction in AK lesions from Lmax to end of study was 24.0 for patients with >10 baseline lesions and 10.0 for those with ≤ 10 baseline lesions. The median percentage and absolute reductions in lesions from Lmax were significantly greater with imiquimod 3.75% vs. placebo (P < 0.0001).

CONCLUSIONS

Imiquimod 3.75% is effective regardless of disease severity as shown in this study by the reduction of over 90% of lesions from Lmax in patients with low or high AK lesion counts.