Use of Lesion Response Rate in Actinic Keratosis Trials

Evaluating the Efficacy and Safety of 4% 5-Fluorouracil Cream in Patients with Actinic Keratosis: An Expert Opinion

Actinic keratosis is a lesion that develops in sun-exposed areas of the skin and is considered to be a precancerous condition or an early in situ squamous cell carcinoma. Treatment of actinic keratosis is important for reducing skin cancer risk, with treatment choice based on patient-, lesion- and treatment-related considerations. Of the topical treatments used for field-directed therapy, those containing 5-fluorouracil are among the most effective and widely prescribed. The most recently developed topical 5-fluorouracil preparation (Tolak®; Pierre Fabre, France) contains 4% 5-fluorouracil in an aqueous cream. This narrative review discusses data on 4% 5-fluorouracil cream to treat actinic keratosis, and provides the authors' expert opinion on issues associated with it use. The effect of the cream has been evaluated in phase 2 and 3 trials of adult patients with actinic keratosis on the face, ears or scalp. These trials included patients with severe baseline disease, defined by high lesion counts and large-size treatment fields, which possibly affected the proportion of patients who were able to achieve complete clearance. Other efficacy parameters (e.g. percentage change in lesion count, ≥ 75% clearance of lesions or clinically significant changes in validated severity scales) should also be assessed to fully evaluate 4% 5-fluorouracil treatment efficacy in these patients. Nevertheless, 4% 5-fluorouracil is associated with high efficacy, a low level of recurrence and a satisfactory safety profile.

Intensity of Local Skin Reactions During 5-Fluorouracil Treatment Related to the Number of Actinic Keratosis Lesions: A Post Hoc, Exploratory Analysis

INTRODUCTION

Actinic keratoses (AK) are epithelial lesions caused by chronic skin exposure to ultraviolet light that can progress into squamous cell carcinoma. Although several treatments are effective, they are associated with severe skin reactions, which might be related to the extent of the disease. This study aimed to examine the relationship between the severity of local skin reactions during treatment with 5-fluorouracil 4% cream and the number of AK lesions at baseline.

METHODS

This post hoc analysis pooled data from two multicentre randomised phase III studies (HD-FUP3B-048, HD-FUP3B-049) in patients with AK treated with topical 5-fluorouracil 4% once daily (OD) or 5% twice daily (BID) for 4 weeks. First, we compared the severity, assessed using a numerical rating scale, of the local skin reactions between 5-fluorouracil 4% and 5%. Then, we investigated the relationship between the number of lesions at baseline and severe skin reactions with 5-fluorouracil 4% OD.

RESULTS

Safety data were included from 397 patients who had received 5-fluorouracil 4% (348 in study HD-FUP3B-048, 49 in study HD-FUP3B-049) OD and 342 (HD-FUP3B-048) who had received 5-fluorouracil 5% BID. For most skin reactions, severe ones were more common in patients treated with 5-fluorouracil 5% cream BID than in those treated with 5-fluorouracil 4% cream OD (P < 0.05). With 5-fluorouracil 4% OD, the incidence of severe erythema was significantly higher in patients with at least 10 lesions (46%) than in patients with 5-10 lesions (28%; P < 0.001). Similar results were observed for the other local skin reactions.

CONCLUSION

Treatment with 5-fluorouracil 4% cream OD was associated with less severe local skin reactions than 5-fluorouracil 5% BID. The number of AK lesions at baseline seems to have predictive value regarding the severity of local skin reactions that appear during treatment.

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 Endpoints in Clinical Trials in Actinic Keratosis

Introduction

Actinic keratosis is regarded as a chronic disease of the skin and, although fluctuating, is chronically progressive. Approval of new products for the treatment of actinic keratosis requires the use of a standard methodology in clinical trials which emphasize complete clearance of all actinic keratoses in a treatment field in a defined time span and the evaluation of long-term efficacy in terms of recurrence rate among completely cleared patients.

Methods

Analysis of data from six previously published clinical trials in patients with actinic keratosis.

Results

There was poor agreement over a period of 1 month in the complete clearance endpoint. This variation in assessment renders recurrence in cleared patients invalid as the estimate of long-term efficacy. Furthermore, complete clearance was shown to depend heavily on the number of baseline actinic keratoses.

Conclusion

The main endpoints presently in use for the assessment of short- and long-term efficacy of actinic keratosis field-directed therapy, namely, complete clearance and recurrence rate, are obsolete and should be replaced by the percentage reduction in actinic keratosis count or the absolute actinic keratosis count.

Funding

LEO Pharma A/S.

Patient and physician satisfaction in an observational study with methyl aminolevulinate daylight photodynamic therapy in the treatment of multiple actinic keratoses of the face and scalp in six European countries

BACKGROUND

Guidelines recommend treating actinic keratoses (AKs) as they are recognized as precursors of invasive squamous cell carcinoma.

OBJECTIVE

The objective of this study was to collect real-world clinical data on the use of methyl aminolevulinate daylight photodynamic therapy (MAL DL-PDT) for the treatment of face and scalp AK in Europe.

METHODS

A prospective, multicenter, non-interventional study was conducted in six European countries in patients receiving a single treatment of MAL DL-PDT for face and/or scalp AK. Patient-reported outcomes were assessed by patient questionnaires at baseline and at 3 months after treatment, efficacy was assessed at 3 months using a 6-point global improvement scale, and adverse events (AE) were recorded at each visit.

RESULTS

Overall, 325 patients were enrolled from 52 investigational centres, 314 of whom attended the 3-month visit. Most patients had multiple lesions (58.4% had >10 lesions) with lesions mainly located on the scalp (60.0%) and/or forehead (54.2%). AKs were predominantly grade I (39.4%) or grade II (33.2%), and 10.5% of patients had grade III lesions. The proportions of patients and physicians that were overall satisfied to very satisfied with the MAL DL-PDT treatment were 80.4% and 90.3%, respectively. The vast majority of patients (90.0%) would consider using MAL DL-PDT again if needed. Physician-assessed efficacy at 3 months was at least much improved in 83.5% of patients, with 45.9% of patients requiring no retreatment. Related AEs were reported in 15% of patients.

CONCLUSION

Use of MAL DL-PDT for multiple face and/or scalp AKs resulted in high levels of patient and physician satisfaction in clinical practice in Europe, reflecting the good efficacy and high tolerability of this convenient procedure.