Efficacy Endpoints in Clinical Trials in Actinic Keratosis

Home- vs clinic-based daylight photodynamic therapy with 5-aminolevulinic acid nanoemulsion (BF-200 ALA) for actinic keratosis: A randomized, single-blind, prospective study

BACKGROUND

Daylight photodynamic therapy (DL-PDT) has become one of the most effective treatments for the resolution of actinic keratosis (AK) of Olsen grade 1 and 2. Generally, PDT it is carried out in a clinic setting, which involves the patient's and their caregivers commuting to the hospital as well as a significant use of resources to carry it out within the clinic setting.

OBJECTIVES

To determine the efficacy and safety of a home-based treatment of AK with DL-PDT with the BF-200 ALA gel compared to a clinic-based setting.

METHODS

The study was performed as a randomized, single-center, non-inferiority clinical trial with two parallel groups. 9 patients received one clinic-based DL-PDT (group 1) and 11 patients received one session of home-based DL-PDT (group 2). The primary endpoints were the mean AK clearance per patient and the total AK lesion clearance rate 12 weeks after treatment. The secondary endpoints were the number of remaining AKs and new AKs appearing in the treatment field 12 weeks after one PDT session. The pain during and 24 h after PDT as well as the local skin reactions were also assessed.

RESULTS

The overall reduction of AK lesions per patient was similar in both groups with one PDT session. An overall AK clearance per patient of 10 ± 4.33 for group 1 versus 9.73 ± 2.9 for group 2 without statistically significant differences (p = 0.868). Regarding the clearance rate, although it was slightly higher in group 2 (71.58 ± 22.51 vs 82.1 ± 11.13), the analysis did not show statistically significant differences. The mild pain recorded during the treatment course and the mild local skin reactions were similar in both groups. Patient satisfaction was high for both groups without statistically significant differences.

CONCLUSION

Self-performed home-based DL-PDT with BF-200 ALA gel is as effective as the one performed in a clinic-based setting, with a comparable safety profile, high levels of patient satisfaction and with advantages for the patients and their caregivers that can enhance patient´s adherence to the treatment.

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.

Phase 3 Trials of Tirbanibulin Ointment for Actinic Keratosis

BACKGROUND

The tubulin polymerization and Src kinase signaling inhibitor tirbanibulin is being investigated as a topical treatment for actinic keratosis, a precursor of squamous-cell carcinoma.

METHODS

In two identically designed double-blind trials, we randomly assigned, in a 1:1 ratio, adults with actinic keratoses on the face or scalp to receive either topical tirbanibulin or vehicle (placebo) ointment. The ointment was applied by the patients to a 25-cm² contiguous area containing four to eight lesions once daily for 5 consecutive days. The primary outcome was the percentage of patients with a complete (100%) reduction in the number of lesions in the application area at day 57. The secondary outcome was the percentage of patients with a partial (≥75%) reduction in the number of lesions within the application area at day 57. The incidence of recurrence was evaluated at 1 year. Local reactions were scored with the use of 4-point scale (ranging from 0 [absent] to 3 [severe]).

RESULTS

A total of 702 patients were enrolled in the two trials (351 patients per trial). Complete clearance in trial 1 occurred in 44% of the patients (77 of 175) in the tirbanibulin group and in 5% of those (8 of 176) in the vehicle group (difference, 40 percentage points; 95% confidence interval [CI], 32 to 47; P<0.001); in trial 2, the percentages were 54% (97 of 178 patients) and 13% (22 of 173), respectively (difference, 42 percentage points; 95% CI, 33 to 51; P<0.001). The percentages of patients with partial clearance were significantly higher in the tirbanibulin groups than in the vehicle groups. At 1 year, the estimated percentage of patients with recurrent lesions was 47% among patients who had had a complete response to tirbanibulin. The most common local reactions to tirbanibulin were erythema in 91% of the patients and flaking or scaling in 82%. Adverse events with tirbanibulin were application-site pain in 10% of the patients and pruritus in 9%, all of which resolved.

CONCLUSIONS

In two identically designed trials, tirbanibulin 1% ointment applied once daily for 5 days was superior to vehicle for the treatment of actinic keratosis at 2 months but was associated with transient local reactions and recurrence of lesions at 1 year. Trials comparing tirbanibulin with conventional treatments and that have longer follow-up are needed to determine the effects of tirbanibulin therapy on actinic keratosis. (Funded by Athenex; ClinicalTrials.gov numbers, NCT03285477 and NCT03285490.).

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.

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.