Understanding efficacy end-points in studies of field-directed therapy for actinic keratosis

Actinic keratosis: Current challenges and unanswered questions

Actinic keratoses (AK) are common skin lesions associated with chronic exposure to sun. They are believed to be precursors of malignancy as they potentially may progress to invasive squamous cell carcinomas. The goal of current therapies is to reduce the number of AK and to prevent future cancer development. This review aims at providing an overview of the hallmarks of AK and skin field cancerization. We discuss epidemiology trends, risk factors and the state of the art and evidence of the current treatments. We review key figures of AK prevalence from different countries with regard to skin cancer risk and the associated economic burden of AK. We discuss the mutational status in AK lesions and the difficulties encountered by clinicians in evaluating AK visible and invisible lesions, referring to the concept of field cancerization. Based on a systematic literature review, we further evaluate the available treatment options. The presence of subclinical skin alterations in the periphery of visible AK lesions has gained a particular attention as those non-visible lesions are known to contain the same genetic changes as those found in the AK lesions themselves, prompting the concept of 'field cancerization'. Therefore, AK treatment guidelines now recognize the importance of treating the field in patients with AK. A recent systematic literature review and network meta-analysis showed that 5-FU interventions were associated with the best efficacy and a satisfactory acceptability profile compared with other field-directed therapies used in the treatment of AK. Although AK are considered quite common, they lack an accurate descriptive definition and conclusive epidemiologic data. Limited public awareness is a barrier to early and effective treatment, including prevention strategies. While different treatment options are available, there is still a limited understanding of long-term outcomes of treatment as measured by recurrence of cancer prevention.

Early clinical response to 5-fluorouracil 0.5% and salicylic acid 10% topical solution in the treatment of actinic keratoses of the head: an observational study

BACKGROUND

Actinic keratosis is one of the most common dermatological disorders. A new topical solution, constituted by 0.5% 5-fluorouracil and 10% salicylic acid (Actikerall, Almirall) has been introduced in the treatment pipeline of non-hyperkeratotic actinic keratoses of the head and neck.

PATIENTS AND METHODS

We analyzed in an observational prospective clinical study the short-term treatment effectiveness of 5-fluorouracil and salicylic acid on face and scalp actinic keratoses of grade 1 and 2 of forty patients. Efficacy assessment was performed by clinical dermatological examination, collecting color photographs, calculating AKASI score, and by means of dermoscopy for each target lesion at every visit.

RESULTS

AKASI score decreased from an initial score of 3.3 to a final score of 0.9. At week 4, we were able to record a complete clearance of 50% of the treated lesions and a partial clearance of 28%. At the end of 12 weeks, 84% of the total lesions showed complete clearance, while 8% had partial clearance.

CONCLUSIONS

5-fluorouracil and salicylic acid topical solution is effective in the treatment of mild to moderate actinic keratoses. In the future, further studies are needed to evaluate the chance of adjusting drug dosage according to patients' and actinic keratoses features.

Use of complete clearance for assessing treatment efficacy for 5-fluorouracil interventions in actinic keratoses: how baseline lesion count can impact this outcome

Background: Many trials in actinic keratoses (AK) use complete clearance rate (100% reduction in number of lesions) as the primary endpoint. We explore limitations (predominantly baseline factors) associated with this outcome. Objective: This analysis assessed the effect of baseline lesion count on complete clearance rate using randomized controlled trials (RCTs) that evaluated 5-fluorouracil (5-FU) formulations, alone or with 10% salicylic acid solution, in patients with AK. Methodology: Correlation between baseline lesion count and complete clearance rate at week 8 was assessed using Pearson's coefficient. Results: Five RCTs assessing 5-FU (4%, 5%, or 0.5% in 10% salicylic acid solution) in 1,080 patients with AK were included. Mean lesion count at baseline ranged from 8.1 to 21.2 lesions per patient. Complete clearance rate was negatively associated with number of lesions at baseline. Correlation between mean number of lesions at baseline and complete clearance rate was strong (r² = 0.94) and statistically significant (p < 0.001). Conclusion: This analysis showed that, in a homogenous set of trials, complete clearance rates achieved with 5-FU interventions are inversely related to number of lesions at baseline. These findings highlight the limits of restricting treatment evaluation to complete clearance rate and the relevance of alternative measures.

Efficacy and safety of ingenol mebutate gel in field treatment of actinic keratosis on full face, balding scalp, or approximately 250 cm2 on the chest: A phase 3 randomized controlled trial

BACKGROUND

Ingenol mebutate (IngMeb) 0.015% or 0.05% is approved for actinic keratosis (AK) areas of 25 cm² or less; some patients require treatment of larger fields.

OBJECTIVE

To determine efficacy and safety of IngMeb 0.027% in areas of AK of up to 250 cm² during an 8-week initial assessment period and extended 12-month follow-up.

METHODS

This phase 3, randomized, double-blind, vehicle-controlled trial (NCT02361216) enrolled adult patients with 5 to 20 AK lesions on the face/scalp (25-250 cm²) or chest (approximately 250 cm²). Patients received once-daily IngMeb or vehicle for 3 consecutive days on the full face, full balding scalp, or approximately 250 cm² on the chest. The primary endpoint was complete AK clearance (AKCLEAR 100; week 8). Additional endpoints included partial AK clearance (AKCLEAR 75), recurrence, patient satisfaction, cosmetic outcome, and safety.

RESULTS

IngMeb was superior to vehicle for complete AK clearance (21.4% vs 3.4%, P < .001) and AK clearance of 75% or greater (59.4% vs 8.9%, P < .001) at week 8. Probability of sustained clearance during the 12-month follow-up was 22.9% for patients treated with IngMeb. Increased treatment satisfaction and cosmetic outcomes were observed with IngMeb versus vehicle. No unexpected safety signals were identified.

LIMITATIONS

Localized skin responses hindered maintenance of double-blinding.

CONCLUSIONS

IngMeb 0.027% was superior to vehicle for treatment of AK areas of up to 250 cm². The safety profile of IngMeb was as expected.

Diclofenac Sodium 3% in Hyaluronic Acid 2.5% Gel Significantly Diminishes the Actinic Keratosis Area and Severity Index

BACKGROUND/AIMS

Actinic keratosis area and severity index (AKASI) is a new assessment tool to quantify the severity of actinic damage on the head. Thus far, it has not been evaluated in monitoring the efficacy of field-directed topical treatments in actinic keratosis (AK) in routine clinical practice. Thus, the aim of this study was to determine treatment outcomes by using AKASI 3 months after the initiation of topical application of diclofenac sodium 3% in hyaluronic acid 2.5% gel (DFS) in patients with AKs on the head.

METHODS

We performed a retrospective analysis of patients with AKs who had AKASI scores prior to and after treatment with DFS.

RESULTS

Of the 24 patients included, 20 (83.3%) showed an improvement in AKASI, 2 (8.3%) a stable AKASI, and 2 (8.3%) a worsening of AKASI after a median (interquartile range) follow-up period of 91.5 days (89.8-104.3). The median AKASI reduction was 31.4% (16.7-59.1). The Wilcoxon test showed significant differences (p = 0.0008) between baseline and posttreatment AKASI values.

CONCLUSIONS

AKASI is an easy-to-use quantitative tool for assessing the treatment outcome of field-directed therapies. Field-directed therapies of AK should no longer be monitored by assessments based on lesion counts alone.

Phase IV head-to-head randomized controlled trial comparing ingenol mebutate 0·015% gel with diclofenac sodium 3% gel for the treatment of actinic keratosis on the face or scalp

BACKGROUND

Ingenol mebutate (IngMeb) and diclofenac sodium (DS) are approved treatments for actinic keratosis (AK).

OBJECTIVES

To compare the efficacy and safety of IngMeb 0·015% gel with DS 3% gel (NCT02406014).

METHODS

Patients with 4-8 visible, discrete AK lesions on the face/scalp in a 25 cm² contiguous area of skin were randomized 1:1 to IngMeb once-daily for three consecutive days or DS twice-daily for 90 days. Patients with AK lesions at Week 8 following IngMeb were offered a second IngMeb course. Primary end point was complete clearance of AK lesions (AKCLEAR 100) at end of first treatment course (Week 8, IngMeb; Week 17, DS). Secondary end points included AKCLEAR 100 at end of last treatment course and Week 17; adverse events (AEs) were assessed at these time points. Patients completed treatment satisfaction questionnaires for medication (TSQM; Week 17).

RESULTS

AKCLEAR 100 at end of first treatment course was higher with IngMeb (34%) vs. DS (23%; P = 0·006). AKCLEAR 100 at end of last IngMeb course (53%) and Week 17 (45%) was higher than DS (both P < 0·001). The most frequent AE was application-site erythema (IngMeb 19%; DS 12%). Treatment-related AE (TRAE) duration was shorter with IngMeb. TRAE withdrawals were lower for IngMeb (2%) vs. DS (6%). TSQM scores for global satisfaction (P < 0·001) and effectiveness (P = 0·002) were higher with IngMeb, as was dosing instruction adherence (≥ 90% vs. 70%).

CONCLUSIONS

AKCLEAR 100, patient treatment satisfaction and effectiveness were significantly higher with IngMeb compared with DS, demonstrating superiority of IngMeb for AK treatment on face/scalp.

A review of BF-200 ALA for the photodynamic treatment of mild-to-moderate actinic keratosis

BF-200 ALA is a combination of a nanoscale-lipid vesicle formulation and the prodrug 5-aminolevulinic acid (5-ALA). The nanoemulsion stabilizes the prodrug and enhances its penetration through the stratum corneum. It has shown excellent therapeutic results in both lesion and field-directed photodynamic therapy of actinic keratosis (AK). AK is an early form of epidermal neoplasia and a precursor of invasive cutaneous squamous cell carcinoma. It is characterized by the combination of visible neoplastic lesions and surrounding tissue also harboring tumorigenic UV-induced mutations: a concept called field cancerization. A selective, field-directed treatment is ideal to meet the requirements of field change. Here, we review the clinical data on BF-200 ALA for AK along with a summary of molecular mechanisms and future perspectives.

A proposed scoring system for assessing the severity of actinic keratosis on the head: actinic keratosis area and severity index

BACKGROUND

Actinic keratosis (AK) severity is currently evaluated by subjective assessment of patients.

OBJECTIVES

To develop and perform an initial pilot validation of a new easy-to-use quantitative tool for assessing AK severity on the head.

METHODS

The actinic keratosis area and severity index (AKASI) for the head was developed based on a review of other severity scoring systems in dermatology, in particular the psoriasis area and severity index (PASI). Initial validation was performed by 13 physicians assessing AK severity in 18 AK patients and two controls using a physician global assessment (PGA) and AKASI. To determine an AKASI score, the head was divided into four regions (scalp, forehead, left/right cheek ear, chin and nose). In each region, the percentage of the area affected by AKs was estimated, and the severities of three clinical signs of AK were assessed: distribution, erythema and thickness.

RESULTS

There was a strong correlation between AKASI and PGA scores (Pearson correlation coefficient: 0.86). AKASI was able to discriminate between different PGA categories: mean (SD) AKASI increased from 2.88 (1.18) for 'light' to 5.33 (1.48) for 'moderate', 8.28 (1.89) for 'severe', and 8.73 (3.03) for 'very severe' PGA classification. The coefficient of variation for AKASI scores was low and relatively constant across all PGA categories.

CONCLUSIONS

Actinic keratosis area and severity index is proposed as a new quantitative tool for assessing AK severity on the head. It may be useful in the future evaluation of new AK treatments in clinical studies and the management of AK in daily practice.

Use of Lesion Response Rate in Actinic Keratosis Trials

Complete patient clearance is often required by regulatory agencies for the approval of treatments for actinic keratosis (AK). However, an increasing number of clinicians have challenged the use of this measure in clinical practice and its interpretation. It has been argued that complete patient clearance often underestimates the clinical benefit of a drug and is influenced by a number of key confounding factors, such as number and distribution of lesions, at baseline. Lesions response rate is one alternative which has been suggested as more relevant due to its applicability to clinical practice and closer reflection of the clinical value of the drug. This paper provides an updated perspective on the topic and details the current thinking on the role of complete clearance and lesion response rate in the context of AK.

Funding: Galderma.

End points in dermatologic clinical trials: A review for clinicians

Clinical trials are critical for the development of new therapies in dermatology, and their results help determine US Food and Drug Administration (FDA) approval and guide care. Of special relevance is the clinical trial efficacy end point, the metric from which statistically significant outcome is derived. Clinicians' understanding of a clinical trial's end point is necessary for critical analysis of the trial results and for applying those results to daily practice. This review provides practical knowledge and critical evaluation of end points used in treatment approvals by the FDA. The end points for actinic keratosis, acne vulgaris, atopic dermatitis, onychomycosis, and cutaneous ulcer serve as examples.

Primary care review of actinic keratosis and its therapeutic options: a global perspective

Actinic keratosis (AK) is a common skin condition caused by long-term sun exposure that has the potential to progress to non-melanoma skin cancers. The objective of this review is to examine the therapeutic options and management of AK globally, particularly in Australia, Canada, and the United Kingdom. Despite its potentially malignant nature, general awareness of AK is low, both in the general population and in the primary health care setting, especially in countries with low incidence. There is no standard therapeutic strategy for AK; it is treated through a variety of lesion-directed or field-directed therapies or a combination of both. A variety of treatment options are used depending on the experience of the primary care physician, the pathology of the lesion, and patient factors. Studies have shown that the physicians do not always use the optimal treatment option because of a lack of knowledge. The higher incidence of AK in fair-skinned people in Australia has resulted in well-established management strategies and guidelines for its treatment, compared with countries with lower incidence. It is essential to raise the awareness of AK because of its potential to progress to invasive squamous cell carcinoma. Primary care physicians are often the first to see this condition in their patients and are perfectly placed to educate the public and raise awareness. It is therefore desirable that their education and knowledge about AK and its treatment are up to date.