Pharmacotherapy of actinic keratosis

Pharmacokinetics, Safety, and Tolerability of a Single 5-Day Treatment of Tirbanibulin Ointment 1% in 100 cm2 : A Phase 1 Maximal-Use Trial in Patients with Actinic Keratosis

Tirbanibulin ointment 1% is approved in the United States and Europe for the treatment of actinic keratosis with demonstrated efficacy, safety, and tolerability when applied over a field up to 25 cm2 . This Phase 1 maximal-use trial determines the plasma pharmacokinetics, safety, and tolerability of tirbanibulin ointment 1% applied to 100 cm2 of the face or balding scalp in adults with actinic keratosis. Twenty-eight patients self-applied tirbanibulin once daily for a single 5-day treatment course. On Day 5, the mean maximum plasma concentration was 1.06 ng/mL and area under the plasma concentration-time curve during a dosing interval was 16.2 ng • h/mL. Systemic exposure was approximately 4-fold higher than in a previous pharmacokinetic study with a 25 cm2 field, consistent with the increase in the treated area. Tirbanibulin applied to a 100-cm2 treatment field showed favorable safety and tolerability. The most common treatment-emergent adverse events were application site reactions (in 35.7% of patients). All treatment-emergent adverse events and most of the tolerability signs were mild/moderate and resolved or returned to baseline by Day 29. In summary, under maximal-use conditions, tirbanibulin ointment 1% was safe and well tolerated supporting its potential use over a field up to 100 cm2 .

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.

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.

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

BACKGROUND

Imiquimod 5% is licensed for the treatment of external genital warts, superficial basal cell carcinoma, and actinic keratosis (AK) and is being used experimentally in various other dermato-oncological conditions.

OBJECTIVE

This observational study shall show that nonmelanoma skin cancer can be detected at its earliest subclinical stage by its reaction with imiquimod and can be cleared by finishing the course of treatment.

MATERIAL AND METHODS

In this single arm trial 15 patients with chronically sun-exposed skin who had no clinical evidence of AK were treated with 5% imiquimod cream on the face or scalp for 4 weeks three times per week.

RESULTS

During treatment, all patients developed multiple areas with mild to moderate inflammatory skin reactions, such as erythema, induration, and scaling. Biopsies obtained from 12 patients prior to treatment revealed no malignancies. However, in cases with more pronounced inflammation during treatment, targeted biopsies indicated very early malignant alterations.

CONCLUSION

Topical imiquimod treatment of chronically sun-exposed skin without overt clinical signs of AK is able to detect subclinical actinic keratoses (SAK) and to completely clear the lesions, even before they can be clinically diagnosed as AK. In such patients, imiquimod might be able to prevent the evolution of SCC.

Perillyl Alcohol (Monoterpene Alcohol), Limonene

Natural products have a long history of use in traditional medicines and their activities against different diseases have been the focus of many basic and clinical researches in past few decades. The essential oils, volatile liquid containing aroma compound from plants, are known as active ingredients in the herbal medicine. Perillyl alcohol (POH) is usually available through dietary sources and is being explored for its cancer chemoprevention, tumor growth suppression, and regression. Citrus peels are the waste product of juice manufacturing industries and have been considered as a critical problem for environmental green ecology policies for years. One of the most well-known approaches to overcome this problem is transformation of these monoterpene by the use of specific strains of bacteria or yeasts. Limonene (1-methyl-4-isopropyl-cyclohexene) is a monoterpene, as other monoterpenes consists of two isoprene units, that comprises more than 90% of citrus essential oil and it exists in many fruits and vegetables. Although, the anticancer activity of d-limonene has identified nearly two decades ago, it has recently attracted much more attention in translational medicine. In this chapter, we will overview the anticancer effects of POH and d-limonene. Later, we will address the pharmacokinetics of these compounds, highlight the signaling pathways which are targeted by these proteins, review the clinical trials which have been done for these compounds in different cancer models, and finally discuss the future directions of the research in this field that might be more applicable in future cancer therapy strategies.

Low-dose 5-fluorouracil in combination with salicylic acid as a new lesion-directed option to treat topically actinic keratoses: histological and clinical study results

BACKGROUND

Actinic keratoses (AKs) arise after chronic sun exposure. Because long-term ultraviolet (UV) damage may induce proliferation of atypical keratinocytes, treatment of AKs is recommended.

OBJECTIVES

To compare 5-fluorouracil 0·5%/salicylic acid 10·0% [low-dose 5-FU/SA (Actikerall®)] with diclofenac 3% in hyaluronic acid (diclofenac HA) and vehicle for the treatment of AKs.

METHODS

This was a randomized, placebo-controlled, double-blind, parallel-group, multicentre trial. Patients received topical low-dose 5-FU/SA once daily, its vehicle or diclofenac HA twice daily for a maximum of 12 weeks. The final evaluation was at week 20. The primary objectives were to demonstrate the histological clearance rate of one predefined lesion. The secondary objectives were the improvement of treated lesions, tolerability and safety.

RESULTS

There were 470 patients with 4-10 AK lesions each (grade I or II) on the face/forehead or bald scalp included in the study. Low-dose 5-FU/SA was superior to diclofenac HA (P < 0·01) and vehicle (P < 0·0001) for histological clearance of one representative lesion 8 weeks post-treatment. In 72·0%, 59·1% and 44·8% of patients in the low-dose 5-FU/SA, diclofenac HA and vehicle groups, respectively, the week-20 biopsy revealed no AKs. Significantly more lesions were cleared with low-dose 5-FU/SA (74·5%) compared with diclofenac HA (54·6%; P < 0·001) or vehicle (35·5%; P< 0·001). Low-dose 5-FU/SA was superior in terms of complete clinical clearance: 55·4%, vs. diclofenac HA (32·0%, P < 0·001) and vehicle (15·1%P < 0·001). Application-site disorders (mainly burning and inflammation) were more frequent with low-dose 5-FU/SA but mainly of mild to moderate intensity.

CONCLUSIONS

Topical low-dose 5-FU/SA demonstrated higher histological and clinical clearance rates vs. diclofenac HA or vehicle. Low-dose 5-FU/SA is an effective lesion-directed treatment for AKs.

Imiquimod 3.75% cream (Zyclara) for the treatment of actinic keratoses

INTRODUCTION

actinic keratosis is a premalignant disease with a high incidence and is a strong predictor for the development of squamous cell carcinoma. Various treatment options have been established over recent years, including topical treatment with imiquimod, 5-fluorouracil, diclofenac or photodynamic therapy, cryotherapy and surgical procedures.

AREAS COVERED

this review covers basic and clinical experiences with imiquimod 3.75% for topical treatment of actinic keratosis of the face and balding scalp and its comparators with special focus on imiquimod 5%. It also covers pharmacology of imiquimod 3.5% and its contribution to the current treatment options of actinic keratoses.

EXPERT OPINION

imiquimod 3.75% is an interesting, safe and well-tolerated treatment option for actinic keratoses of the face or balding scalp especially in respect of compliance, as it is indicated for daily use for a shorter time period (2 times, 2-week cycles) and approved for use on larger areas compared with imiquimod 5%. Data from current trials indicate lower efficacy compared with imiquimod 5% cream when applied three times a week for 16 weeks or for two 4-week cycles with a 4-week no-treatment interval, but indicate similar efficacy when compared with a twice-weekly schedule for 16 weeks. An additive effect was observed when combining cryosurgery followed by imiquimod 3.75%.

Laser-assisted topical drug delivery by using a low-fluence fractional laser: imiquimod and macromolecules

The aim of this study was to evaluate the ability of a low-fluence fractional erbium:yttrim-aluminum-garnet (Er:YAG) laser, with a wavelength of 2940 nm, for enhancing and controlling the skin permeation of imiquimod and macromolecules such as polypeptides and fluorescein isothiocyanate (FITC)-labeled dextran (FD). The in vitro permeation has been determined using a Franz diffusion cell, with porcine skin and nude mouse skin as the barriers. Hyperproliferative and ultraviolet (UV)-irradiated skins were also used as barrier models to mimic the clinical therapeutic conditions. Confocal laser scanning microscopy (CLSM) was used to examine the in vivo nude mouse skin uptake of peptide, FITC, and FD. Both in vitro and in vivo results indicated an improvement in permeant skin delivery by the laser. The laser fluence and number of passes were found to play important roles in controlling drug transport. Increases of 46- and 127-fold in imiquimod flux were detected using the respective fluences of 2 and 3 J/cm(2) with 4 pulses. An imiquimod concentration of 0.4% from aqueous vehicle with laser treatment was sufficient to approximate the flux from the commercial cream with an imiquimod dose of 5% without laser treatment, indicating a reduction of the drug dose by 125-fold. The enhancement of peptide permeation was size and sequence dependent, with the smaller molecular weight (MW) and more-hydrophilic entities showing greater enhancing effect. Skin permeation of FD with an MW of at least 150 kDa could be achieved with fractional laser irradiation. CLSM images revealed intense green fluorescence from the permeants after exposure of the skin to the laser. The follicular pathway was significant in laser-assisted permeation.