A dose-finding trial with a novel ingenol derivative (ingenol disoxate: LEO 43204) for field treatment of actinic keratosis on full face or 250 cm2 on the chest

Accelerating patient recruitment using social media: Early adopter experience from a good clinical practice-monitored randomized controlled phase I/IIa clinical trial on actinic keratosis

Background

Patient recruitment is a major cause of delays in randomized controlled trials (RCT). Online recruitment is evolving into an alternative to conventional in-clinic recruitment for RCT. The objective of this study was to test the effectiveness of online patient recruitment for an RCT on actinic keratosis (AK).

Methods

In this proof-of-concept study, adults with AK were recruited for a Phase I/IIa RCT (NCT05164393) via social media using targeted advertising Interested users were directed to a landing page to learn about the study, respond to questionnaires, and upload self-obtained smartphone pictures of potential AK. Facebook Analytics was used to track the number of advertisement views, individual users exposed to the advertisement, and advertisement clicks. Following eligibility-review by remote dermatologists, candidates were contacted for an in-clinic visit. A review of pertinent RCTs on AK (2012-2022) was conducted to compare recruitment metrics.

Results

The online campaign served 886,670 views, reached 309,000 users, and generated 27,814 clicks. A total of 556 users underwent eligibility review, leading to 140 pre-evaluated potential study subjects. The RCT's enrollment target of 60 patients (68.8 ± 7.1 years, 43.3 % female) was reached in 53 days after screening 90 participants in-clinic, corresponding to a screen failure rate of 33.3 %. The total cost of this online recruitment campaign was 14,285 USD i.e. 238 USD per randomized patient. Compared to the existing literature (44 RCTs), our online approach resulted in 9 times more time-efficient recruitment per site.

Conclusion

Using targeted advertisements, 60 patients with AK were recruited for a single-center Phase I/IIa RCT in 53 days. Social media appears to be an efficient platform for online recruitment of patients with low-grade AK for RCT.

Systematic characterization of metabolic profiles of ingenol in rats by UPLC-Q/TOF-MS and NMR in combination with microbial biotransformation

Ingenol, as the precursor of the marketed drug ingenol mebutate, has been proven to have a variety of bioactivities. The purpose of this study was to identify the metabolites of ingenol using ultra-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UPLC-Q/TOF-MS) combined with UNIFI software. Plasma, urine and fecal samples of rats were obtained and analyzed. A total of 18 metabolites were detected and identified in rat, including five phase II metabolites (M14-M18). Moreover, as microbial biotransformation is helpful to obtain sufficient reference standards of metabolites, the co-culture of ingenol with the fungus Cunninghamella elegans bio-110930 was also studied and yielded 4 phase I metabolites, in which reference standards of three metabolites were further obtained by preparative scale biotransformation. By matching their retention times, accurate masses, and fragment ions with metabolites in rat, the structures of three metabolites (M2, M3 and M4) were unambiguously confirmed by NMR technology. The results revealed that C. elegans bio-110930 functioned as an appropriate model to mimic and prepare phase I metabolism of ingenol in vivo to a certain extent. It also revealed that hydroxylation, oxygenation, sulfonation, and glucuronidation were the major metabolic pathways of ingenol. Furthermore, the first systematic metabolic study of ingenol is of great significance to elucidate the metabolites and metabolic pathways in vivo, which is helpful to predict metabolites of ingenol in humans, understand the elimination mechanism of ingenol, and clarify its effectiveness and toxicity.

Safety of topical interventions for the treatment of actinic keratosis

Introduction: Actinic keratosis (AK) are proliferations of atypical keratinocytes that may eventually progress to cutaneous squamous cell carcinoma. Therefore, AK requires consequent and early treatment. Areas covered: A variety of effective approaches is currently available for the clearance of AK. These interventions may be applied either in a lesion-directed or field-directed mode as AK can occur as single or multiple lesions. Field-directed approaches typically comprise topical drug-mediated interventions which aim at eliminating all visible lesions and also at clearing subclinical changes of the actinically damaged field. However, most treatment options are associated with local adverse events such as erythema, scaling, pain, and rarely with systemic symptoms. This expert review provides a comprehensive and up-to-date overview of the safety considerations of the commonly prescribed topical treatment agents cyclooxygenase inhibitors, 5-fluorouracil, imiquimod, ingenol mebutate, and photodynamic therapy. All these therapies have been proven efficient, yet they differ considerably regarding their safety profile. Expert opinion: In the future, safety concerns will relate to long-term and irreversible adverse drug events instead of application site reactions. In particular, the rate of treatment-associated non-melanoma skin cancers will increasingly come into focus and warrant investigation in postmarketing surveillance trials with a long-term follow-up.

Updates on Treatment Approaches for Cutaneous Field Cancerization

Purpose of Review

Field cancerization describes the phenomenon that multiple heterogenous mutations may arise in an area exposed to chronic carcinogenic stimuli. Advances in the understanding of cutaneous field cancerization have led to novel therapeutic approaches to the management of actinic keratoses (AKs). Herein, we review the literature on the pathophysiology and emerging research of field cancerization in dermatology.

Recent Findings

The classification systems for grading AK lesions are being refined with investigations focusing on their clinical utility. There is a growing shift towards field-directed treatment for AKs as the importance of field cancerization becomes clearer. Current field-directed therapies are being optimized and novel therapeutic modalities are being studied.

Summary

Field cancerization underlies the transformation of photodamaged skin into AKs and potentially cutaneous SCC (cSCC). Clinically meaningful classification systems for AKs are needed to better inform decisions regarding treatment. As we learn more about the role of field characterization in photodamage, AKs and cSCCs, therapeutic strategies are becoming more field-directed rather than lesion-directed.

Pharmacokinetics and Safety of Ingenol Disoxate Gel Administered Under Maximum-Use Conditions to Patients With Actinic Keratosis

BACKGROUND AND OBJECTIVES

Ingenol disoxate (LEO 43204) is a field therapy in development for the treatment of actinic keratosis (AK) on areas between 25 and 250 cm². We evaluated the systemic exposure and safety of ingenol disoxate under maximum-use conditions.

METHODS

This was a phase I, open-label, non-randomized, multicenter trial. Patients ≥ 18 years of age with ≥ 15 clinically typical, visible, discrete AK lesions in a treatment area on the full face or approximately 250 cm² on the arm or scalp were treated once-daily for 3 consecutive days with ingenol disoxate 0.018, 0.1, or 0.037% gel, respectively.

RESULTS

The trial included 58 patients. Median age (range) of patients was 68 years (42-89) [face, N = 18], 66 years (43-88) [arm, N = 21], and 67 years (37-83) [scalp, N = 19]. The highest quantifiable ingenol disoxate level was observed in the arm group (0.33 nM, area under the concentration-time curve from time zero to the last data point [AUC_tlast] 3.12 nM·h). Mean composite local skin response scores peaked at Day 4 and declined towards baseline by Day 15 in all treatment groups. Most adverse events (AEs) were of mild or moderate intensity; the most common treatment-related AEs were application-site pain (face, 88.9%; arm, 57.1%; scalp, 100.0%) and application-site pruritus (face, 50.0%; arm, 52.4%; scalp, 42.1%).

CONCLUSION

Very low systemic exposure to ingenol disoxate was observed when applied to the face, arm, or scalp in patients with AK under maximum-use conditions. No new safety signals were identified.

TRIAL REGISTRATION

NCT02424305.