Daylight photodynamic therapy with methyl aminolevulinate cream is effective and nearly painless in treating actinic keratoses: a randomised, investigator-blinded, controlled, phase III study throughout Europe

Efficacy of different photoprotection strategies in preventing actinic keratosis new lesions after photodynamic therapy. The ATHENA study: a two-center, randomized, prospective, assessor-blinded pragmatic trial

Background: Treatment of actinic keratosis (AK) and field cancerization with photodynamic therapy (PDT) is an effective therapeutic approach with a significant reduction in the number of AK lesions (-75% or more) associated with a significant cosmetic improvement of the photodamaged skin. Recently, also, the daylight PDT (DL-PDT) has proven to be as effective as the conventional PDT (C-PDT), but with a better tolerability. After C-PDT and DL-PDT it is advised to use photoprotection strategies to improve the clinical evolution and prevent the appearance of new AK lesions that usually appear 3-6 months after the last phototherapy session. However, there are no robust clinical data regarding the type of photoprotection to be used (SPF level, duration of treatment, etc.) after successful PDT.Study aim: The present study (ATHENA trial) evaluated the efficacy and tolerability of a topical product based on 0.8% piroxicam and 50+ solar filters (ACTX), applied twice a day as sequential therapy after C-PDT or DL-PDT on the evolution of AK lesions number compared to the use of very high photoprotection products commonly used in this clinical setting (SPF50+ or SPF100+ associated with photolyase) (Standard Sunscreens: SS group). Subjects and methods: This was a multicenter, randomized, two-arm, prospective controlled, assessor-masked outcome evaluation, parallel group (1:1), pragmatic study of 6 months duration in patients with multiple AK lesions suitable for photodynamic therapy. The objectives of the study were the evaluation of the evolution of the number of AK lesions during the period of treatment/application of the study products, and the Investigator global clinical assessment score (IGA score; 4: marked improvement, 3: good, 2: moderate; 1 no improvement; 0: worsening) 2, 3, and 6 months after the last PDT session. A total of 68 subjects (50 men, 18 women; mean age 70 years), 34 assigned to treatment with ACTX and 34 to treatment with SS (17 treated with a SPF50+ and 17 with a photolyase-containing SPF100+ products), were enrolled in the study.Results: The number of AK lesions present before C-PDT/DL-PDT was 11.8 ± 5.8 in the ACTX group and 12.4 ± 6.9 in the SS group. In both groups, there was a progressive reduction of AK lesions observed at baseline (-86% and -87% after 2 months and -88% and -83% at month 3 in ACTX and in the SS group, respectively). At month 6, AK mean lesion number was 1.8 ± 1.6 in the ACTX and 3.2 ± 2.3 in the SS group; this difference was statistically significant (p = 0.03). The IGA score at the end of the study was 3.2 in the ACTX and 2.7 in the SS group (p = 0.05). The percentage of subjects with an IGA score of 4/3 (very good or good) was 81% in the ACTX and 55% in the SS group (p = 0.06).Conclusion: In subjects with AK treated with C-PDT or DL-PDT, a "medicalized" photoprotection treatment is associated with a favorable clinical outcome with progressive reduction of lesions. In contrast to a very high photoprotection (SPF50+ or SPF100+/photolyase), the use of piroxicam 0.8%/SPF 50+ is associated with a significantly greater improvement in clinical evolution of AK lesions.

Current developments in pharmacotherapy for actinic keratosis

INTRODUCTION

Actinic keratosis (AK) is a superficial squamous cell carcinoma (SCC) where chronic sun exposure playing central role in its pathogenesis. UVB causes direct damage to DNA, producing pyrimidine dimers, and suppressing the protective role of p53. The stepwise progression of AK, with increased expression of anti-apoptotic Bcl-2, favors progression to SCC. Moreover, the dermal response characterized by inflammation and mediated by prostaglandins is a critical component of tumorigenesis that promotes tumor growth, tissue invasion, angiogenesis and metastasis. Other risk factors are represented by age, gender, phototype and drugs.

AREAS COVERED

In this review, the authors document the recent developments of different therapies used to treat AK and provide their perspectives on current and future treatment strategies.

EXPERT OPINION

The usefulness of long-term treatment with piroxicam and sun filters or diclofenac targeting the inflammation phases of skin tumorigenesis favors AK's healing and provides greater control of the cancerization field. Nonsteroidal anti-inflammatory drugs can be safely used in patients who use photosensitizing drugs and, therefore, are more at risk of developing skin tumors. Immunomodulatory therapies, which require shorter treatment, are characterized by more common local side effects, and need more attention by the dermatologist in the concern of patient education, resulting essential to improve adherence and outcomes.

Daylight Photodynamic Therapy for Actinic Keratoses

Topical photodynamic therapy (PDT) using daylight is effective in the treatment of actinic keratoses (AKs), offering the potential for treatment of large fields such as full face and balding scalp, but with minimal therapy-associated pain. Comparison with conventional PDT indicates similar efficacy for thin and moderate-thickness AKs, but with significantly less discomfort/pain, driving a patient preference for daylight-mediated PDT (DL-PDT) compared with conventional PDT using high-intensity office/hospital-based light sources. Treatment protocol involves the application of a photosensitizing agent without occlusion and subsequent exposure to ambient daylight within 30 min, with patients exposed to daylight for 1.5-2.0 h. Pivotal randomized controlled trials in Europe and Australia have confirmed the efficacy of methyl aminolevulinic acid (MAL) DL-PDT in comparison with conventional MAL-PDT for mild and moderate-thickness lesions on the face and scalp. Initial clearance rates of 70-89% are reported. DL-PDT using a nanoemulsion aminolevulinic acid (ALA) has recently been shown to be at least as effective as MAL DL-PDT in treating mild and moderate-thickness AKs. DL-PDT may offer a better-tolerated method for treating patients with extensive AK disease. There is emerging literature on the potential for field PDT to reduce the number of new AKs developing, potentially preventing/slowing skin cancer development. Conventional PDT remains established as a therapy for Bowen's disease (squamous cell carcinoma in situ), superficial and certain thin basal cell carcinomas (BCCs), and AKs. The evidence for the use of DL-PDT beyond AK is limited, although has been reported in actinic cheilitis, superficial BCC, and acne and cutaneous leishmaniasis. There is emerging interest in combination therapy for AK, using one or more field therapies such as DL-PDT as an option to complement with localized treatment for residual lesions. We review current recommendations and consider the appropriate place for DL-PDT in our treatment armamentarium.

The safety and efficacy of daylight photodynamic therapy in the treatment of actinic keratoses: a systematic review and meta-analysis

Daylight photodynamic therapy (DLPDT) is a novel therapeutic approach for actinic keratoses (AKs). This study aimed to evaluate the safety and efficacy of DLPDT in treating patients with AKs as compared to conventional photodynamic therapy (CPDT). PubMed, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials were searched for relevant randomized controlled trials (RCTs) published before November 2017, based on the following search terms: "solar keratoses", "actinic keratoses", "photodynamic therapy", "daylight photodynamic therapy", "conventional photodynamic therapy", and "randomized". The complete response rate, patient satisfaction, and patient-reported pain after intervention with DLPDT or CPDT were primarily measured. Sensitivity analysis was conducted to determine the reliability of results. Begg's and Egger's tests were used to assess the likelihood of publication bias. Eight RCTs, comprising a total of 424 patients with AKs treated with DLPDT or CPDT, were included. No significant difference was found between the lesion response rate and the mean lesion response in a comparison of DLPDT and CPDT treatments. Generally, DLPDT was associated with higher patient satisfaction than CPDT. The patients who underwent DLPDT experienced less pain than those who underwent CPDT. Most of our results were of high stability and low sensitivity. Meanwhile, no statistical evidence of publication bias among studies was found under all comparisons. In conclusion, DLPDT is a safe and effective therapy, which could help in selecting the most appropriate therapeutic method for treating AKs and in guiding physicians to optimize treatment strategies.

A randomized, intraindividual, non-inferiority, Phase III study comparing daylight photodynamic therapy with BF-200 ALA gel and MAL cream for the treatment of actinic keratosis

Background

The most effective treatment modality for actinic keratosis (AK) is photodynamic therapy (PDT). Major obstacles of PDT are the need of a special illumination device and pain accompanying the illumination. These issues may be overcome by replacing an artificial high‐power light source with natural daylight for more extended illumination at lower light doses.

Objective

To determine whether BF‐200 ALA (a nanoemulsion gel containing 7.8% 5‐aminolaevulinic acid) is non‐inferior to MAL (a cream containing 16% methyl‐aminolaevulinate) in the treatment of mild‐to‐moderate AK with daylight PDT (dPDT). Non‐inferiority of the primary efficacy variable (total lesion clearance rate per patient's side 12 weeks after PDT) is established if the mean response for BF‐200 ALA is no worse than for MAL, within a statistical margin of Δ = −12.5%.

Methods

The study was performed as an intraindividual comparison with 52 patients in seven centres in Germany and Spain. Each patient received one dPDT. Results include clinical endpoints as well as 1‐year follow‐up results.

Results

Twelve weeks after a single dPDT, 79.8% of the AK lesions treated with BF‐200 ALA gel and 76.5% of the lesions treated with MAL cream were completely cleared. The median of differences was 0.0 with a one‐sided 97.5% CI of 0.0, establishing non‐inferiority (P < 0.0001). Results for secondary efficacy parameters were in line with the primary outcome. Recurrence rates 1 year after the treatment were 19.9% for lesions treated with BF‐200 ALA and 31.6% for lesions treated with MAL. Adverse reactions including pain were mostly mild and transient and identical to those previously described for dPDT.

Conclusion

Daylight PDT of AK with BF‐200 ALA is well‐tolerated and non‐inferior to MAL/dPDT. The study demonstrates a trend towards higher efficacies after 3 months and significantly lower recurrence rates after 1 year follow‐up.

Field Cancerization Therapies for Management of Actinic Keratosis: A Narrative Review

Actinic keratoses (AKs) are atypical, precancerous proliferations of keratinocytes that develop because of chronic exposure to ultraviolet (UV) radiation. Treatment of AK can be lesion-directed or field-directed. Field cancerization theory postulates that the skin surrounding AK is also at increased risk for possible malignant transformation since it has been exposed to the same chronic UV light. Field-directed therapies thus have the potential to address subclinical damage, reduce AK recurrence rates, and potentially reduce the risk of squamous cell carcinoma (SCC) development. Published clinical studies have found lesion clearance rates ranging from 81 to 91% for photodynamic therapy (PDT) with either aminolevulinic acid (ALA) or methylaminolevulinate (MAL). Clinical studies have also been published on various topical treatments. Complete clinical clearance (CCC) was significantly higher in patients treated with a combination of 5-fluorouracil and salicylic acid (5-FU-SA) than in the vehicle group across multiple studies, and CCC ranged between 46 and 48% following treatment with imiquimod. Additionally, treatment with diclofenac sodium (DFS) found reduction in lesion sizes to range from 67 to 75%. Reported results have been similar for another non-steroidal anti-inflammatory drug (NSAID), piroxicam, which has more cyclooxygenase (COX)-1 activity than DFS. Active treatments with ingenol mebutate were also significantly more effective than vehicle at clearing AK lesions. All treatments resulted in mild, localized skin reactions. PDT using conventional light sources was associated with increased severity of pain and/or discomfort, while PDT using daylight as the light source was associated with less pain and occasionally no pain at all. Though no widely accepted algorithm for the treatment of AKs exists, field-directed therapy can be particularly useful for treating photo-exposed areas containing multiple AKs. Additional research with more direct comparisons between these field-directed therapies will help clinicians determine the best therapeutic approach. Here, we provide a balanced and comprehensive narrative review of the literature, considering both light-based and topical therapies with a focus on their field-therapy aspects, and propose a therapeutic algorithm for selecting an appropriate treatment in the clinical setting.

A novel light source with tuneable uniformity of light distribution for artificial daylight photodynamic therapy

OBJECTIVES

Implementation of daylight photodynamic therapy (dPDT) is somewhat limited by variable weather conditions. Light sources have been employed to provide artificial dPDT indoors, with low irradiances and comparable treatment times to dPDT. Uniform light distribution across the target area is desirable in effective treatment planning, particularly for large areas. A novel light source is developed with tuneable direction of light emission in order to meet this challenge.

METHODS

Wavelength composition of the novel light source is controlled such that the protoporphyrin-IX (PpIX) weighted spectra of both the light source and daylight match. The uniformity of the light distribution is characterised on a flat surface, a model head and a model leg. For context, a typical conventional PDT light source is also characterised. Additionally, the wavelength uniformity across the treatment site is characterised.

RESULTS

The PpIX-weighted spectrum of the novel light source matches the PpIX-weighted daylight spectrum, with irradiance values within the bounds for effective dPDT. By tuning the direction of light emission, improvements are seen in the uniformity across large anatomical surfaces. Wavelength uniformity is discussed.

CONCLUSIONS

We have developed a light source that addresses the challenges in uniform, multiwavelength light distribution for large area artificial dPDT across curved anatomical surfaces.

Long-term efficacy data for daylight-PDT

INTRODUCTION

Conventional photodynamic therapy (c-PDT) is an established successful treatment for non-melanoma skin cancers (NMSC). Daylight PDT (DL-PDT) was introduced to overcome the main inconveniencies associated with c-PDT such as pain during illumination and long clinic visits. DL-PDT was shown to have similar short-term efficacy to c-PDT for the treatment of mild/moderate actinic keratosis (AKs) but it is associated with better tolerability. Since AKs tend to regress and reoccur over time, data on long-term efficacy of DL-PDT become crucial.

EVIDENCE ACQUISITION

We performed a systematic review search up to February 2018 of available studies on DL-PDT long-term efficacy using the MEDLINE database and made a manual search of selected references.

EVIDENCE SYNTHESIS

Most current studies on DL-PDT have limited follow-up periods of 3 to 6 months. Only 2 randomized, intra-individual studies provided efficacy data on AK treatment at 12 month-follow-up and supported the long-term efficacy of this novel treatment modality showing a low recurrence rate, varying from 8.7% to 13%. Current evidences for other NMSCs are limited and efficacy seems to be not as good as for AK.

CONCLUSIONS

DL-PDT is a very promising treatment for mild to moderate AKs of the face and scalp. Efficacy outcomes of DL-PDT are similar to those of c-PDT in the short-term. Additional studies are required to increase our knowledge on DL-PDT long-term efficacy, as limited data are currently available.

The influence of different illumination parameters on protoporphyrin IX induced cell death in squamous cell carcinoma cells

BACKGROUND

Topical photodynamic therapy (PDT) is a highly effective therapy especially for extended cancerized fields of the skin. Whenever extended fields are treated pain management is advisable. Light source mediated pain management can be performed by reducing fluence rates, as long as this does not compromise efficacy.

METHODS

Two squamous cell carcinoma cell lines (A431 and SCC-13) were subjected to in vitro PDT using two different ALA concentrations and synthesis intervals and protoporphyrin IX (PpIX) synthesis was assessed. Two total light doses (6 J/cm² and 37 J/cm²) were applied at three different fluence rates and cell viability was measured using the MTS-test.

RESULTS

Both cell lines synthetized PpIX at different kinetics. A431 cells produced a maximum 28.6 nmol/l PpIX, while SCC-13 reached only a production of 8.7 nmol/l. Illumination reduced cell viability depending on PpIX content and light dose. When a lower light dose (6 J/cm²) was applied, only the combination with the highest PpIX content was effective in A431 cells and no effect could be detected in SCC-13 cells. With a light dose of 37 J/cm², lower PpIX amounts became effective in A431 and cell death could be induced in SCC-13 cells. Light fluence rate had no differential effect in this setup.

CONCLUSIONS

In both, A431 and SCC-13 cells, total light dose is a key factor for photodynamic efficacy. Additionally, our results hint towards a threshold concentration of PpIX upon which a drastic loss of viability occurs. Light fluence rate in the analyzed range is not a limiting factor of photodynamic cytotoxicity. This may allow for the clinical implementation of low fluence rate protocols for pain management without compromising efficacy.

Quantifying the radiant exposure and effective dose in patients treated for actinic keratoses with topical photodynamic therapy using daylight and LED white light

Daylight photodynamic therapy (dl-PDT) is as effective as conventional PDT (c-PDT) for treating actinic keratoses but has the advantage of reducing patient discomfort significantly. Topical dl-PDT and white light-PDT (wl-PDT) differ from c-PDT by way of light sources and methodology. We measured the variables associated with light dose delivery to skin surface and influence of geometry using a radiometer, a spectral radiometer and an illuminance meter. The associated errors of the measurement methods were assessed. The spectral and spatial distribution of the radiant energy from the LED white light source was evaluated in order to define the maximum treatment area, setup and treatment protocol for wl-PDT. We compared the data with two red LED light sources we use for c-PDT. The calculated effective light dose is the product of the normalised absorption spectrum of the photosensitizer, protoporphyrin IX (PpIX), the irradiance spectrum and the treatment time. The effective light dose from daylight ranged from 3  ±  0.4 to 44  ±  6 J cm^-2due to varying weather conditions. The effective light dose for wl-PDT was reproducible for treatments but it varied across the treatment area between 4  ±  0.1 J cm^-2 at the edge and 9  ±  0.1 J cm^-2 centrally. The effective light dose for the red waveband (615-645 nm) was 0.42  ±  0.05 J cm^-2 on a clear day, 0.05  ±  0.01 J cm^-2 on an overcast day and 0.9  ±  0.01 J cm^-2 using the white light. This compares with 0.95  ±  0.01 and 0.84  ±  0.01 J cm^-2 for c-PDT devices. Estimated errors associated with indirect determination of daylight effective light dose were very significant, particularly for effective light doses less than 5 J cm^-2 (up to 83% for irradiance calculations). The primary source of error is in establishment of the relationship between irradiance or illuminance and effective dose. Use of the O'Mahoney model is recommended using a calibrated logging illuminance meter with the detector in the plane of the treatment area.

Daylight Photodynamic Therapy Versus 5-Fluorouracil for the Treatment of Actinic Keratosis: A Case Series

Introduction

The incidence of actinic keratosis (AK) continues to increase worldwide. Currently available options for the treatment of AK include topical 5-fluorouracil (5-FU) and daylight-mediated photodynamic therapy (DL-PDT). This split-face pilot study compared DL-PDT using 16% methyl aminolevulinate (MAL) cream versus 5-FU cream in patients with AK on the face/scalp.

Methods

Five male subjects (mean age 70 years) with grade I–III AK on the face/scalp were enrolled. Subjects received a single session of DL-PDT with 16% MAL on one side and topical 5% 5-FU for 21 days on the other side. Evaluations of efficacy, safety, and subject satisfaction were conducted 48 h, 7 days, 14 days, 1 month, and 3 months after treatment.

Results

At 3 months, the lesion complete response rate was 80% and 93% for DL-PDT and 5-FU, respectively. Lesion partial response was 20% and 7%, respectively. Fewer treatment-related adverse events (AEs) were reported with DL-PDT than with 5-FU, and they resolved spontaneously in 5–7 and 27–30 days, respectively. Subjects preferred DL-PDT because of the lower incidence of AEs and rapid recovery compared with 5-FU.

Conclusion

DL-PDT is a convenient alternative to 5-FU with good efficacy and a favorable safety profile, allowing patients to effectively treat their AK without compromising their social life.

Funding

Galderma.

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.

Daylight photodynamic therapy versus cryosurgery for the treatment and prophylaxis of actinic keratoses of the face - protocol of a multicenter, prospective, randomized, controlled, two-armed study

BACKGROUND

Photodynamic therapy with daylight (DL-PDT) is efficacious in treating actinic keratosis (AK), but the efficacy of field-directed, repetitive DL-PDT for the treatment and prophylaxis of AK in photodamaged facial skin has not yet been investigated.

METHODS/DESIGN

In this multicenter, prospective, randomized, controlled, two-armed, observer-blinded trial, patients with a minimum of 5 mild-to-moderate AK lesions on photodamaged facial skin are randomly allocated to two treatment groups: DL-PDT with methyl aminolevulinate (MAL) and cryosurgery. In the DL-PDT group (experimental group), 5 treatments of the entire face are conducted over the course of 18 months. After preparation of the lesion and within 30 min after MAL application, patients expose themselves to daylight for 2 h. In the control group, lesion-directed cryosurgery is conducted at the first visit and, in the case of uncleared or new AK lesions, also at visits 2 to 5. The efficacy of the treatment is evaluated at visits 2 to 6 by documenting all existing and new AK lesions in the face. Cosmetic results and improvement of photoaging parameters are evaluated by means of a modified Dover scale. Primary outcome parameter is the cumulative number of AK lesions observed between visits 2 and 6. Secondary outcome parameters are complete clearance of AK, new AK lesions since the previous visit, cosmetic results independently evaluated by both patient and physician, patient-reported pain (visual analogue scale), patient and physician satisfaction scores with cosmetic results, and patient-reported quality of life (Dermatology Life Quality Index). Safety parameters are also documented (adverse events and serious adverse events).

DISCUSSION

This clinical trial will assess the efficacy of repetitive DL-PDT in preventing AK and investigate possible rejuvenating effects of this treatment. (Trial registration: ClinicalTrials.gov Identifier: NCT02736760).

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02736760 . Study Code Daylight_01. EudraCT 2014-005121-13.

High Patient Satisfaction with Daylight-Activated Methyl Aminolevulinate Cream in the Treatment of Multiple Actinic Keratoses: Results of an Observational Study in Australia

Introduction

Actinic keratoses (AK) are treated to reduce the risk of progression to squamous cell carcinoma and for symptomatic and cosmetic benefits. The objective of this observational study was to generate real-life data on the use of daylight photodynamic therapy with methyl aminolevulinate cream (MAL DL-PDT) in treating mild to moderate facial/scalp AK.

Methods

A multicenter, prospective, observational study was conducted in Australia in patients receiving a single treatment of MAL DL-PDT for mild to moderate AK. Efficacy was assessed 3 months after treatment by investigator-assessed improvement and patient- and physician-completed satisfaction questionnaires. Adverse events were recorded throughout the study.

Results

Overall, 81 patients were enrolled of mean age 62.7 years, mostly men (76.5%) with skin phototype I (64.2%) or II (35.8%) and a long history of AK (mean duration 16.8 years). Most had multiple lesions (82.7% had >10 lesions) of predominantly grade I (75.3%). At 3 months after treatment, almost half the patients (46.8%) required no further treatment. The proportions of patients and physicians satisfied to very satisfied with the MAL DL-PDT treatment were 79.7% and 83.3%, respectively. After receiving the treatment, 74.1% of patients indicated via the questionnaire that they were not bothered at all by the pain. Related AEs were reported in 48.1% of patients, mainly mild erythema (44.4%).

Conclusions

In clinical practice in Australia, the use of MAL DL-PDT in treating multiple mild to moderate non-hyperkeratotic AK of the face and/or scalp results in high levels of patient and physician satisfaction reflecting the good efficacy and tolerability of this almost painless, convenient procedure.

Trial Registration

ClinicalTrials.gov identifier, NCT02674048.

Funding

Galderma R&D.

PDT: What's Past Is Prologue

Despite descriptions of light-mediated therapy in ancient texts and the discovery of photodynamic therapy (PDT) in the early 1900s, the landmark article in 1978 in Cancer Research by Dougherty and his colleagues at the Roswell Park Cancer Institute remains rightly viewed as the starting point for clinical PDT in modern medicine. As a large clinical series that explored many of the factors now viewed as critical determinates of PDT dose, efficacy, and toxicity, that study showed remarkable foresight, yet it also served to raise as many questions as it answered. Since its publication, PDT has been increasingly utilized in clinical practice for the treatment of both benign and malignant conditions, and many of their questions have yielded new technologies and areas of investigation, thus remaining highly relevant nearly 40 years after their initial asking. Moreover, continuing advances in our ability to measure physical properties such as absorbed light dose, photosensitizer concentration, tissue oxygen concentration, and singlet oxygen production in real-time may allow for adaptive modification of light delivery during PDT on a fine scale to optimize treatment response. Finally, combining molecularly targeted drugs and novel photosensitizers has the potential to improve further the therapeutic index and extend the spectrum of clinical PDT far beyond what was imagined when that sentinel manuscript was written. Cancer Res; 76(9); 2497-9. ©2016 AACRSee related article by Dougherty et al., Cancer Res 1978;38:2628-35Visit the Cancer Research 75(th) Anniversary timeline.

Comparison of the Effect of Skin Preparation Pads on Transepidermal Water Loss in Ex Vivo Human Skin

Introduction

Pre-treatment of the skin to remove scales and crusts prior to photodynamic therapy (PDT) is essential to enhance the uptake of topically applied methyl aminolevulinate (MAL) and to improve treatment efficacy. This study compared the effect of two different skin preparation pads on skin integrity in ex vivo human skin.

Methods

Ex vivo human skin samples from three donors were pre-treated in triplicates with PREPSTER™ (PR) skin preparation pad (6, 8, and 10 passages) or Ambu Unilect™ (A-UN) skin preparation pad (6, 8, and 10 passages). In addition, skin samples were pre-treated with tape strippings (10 adhesive tape strips) as a reference method for comparison. Transepidermal water loss (TEWL) was measured on intact skin and following skin barrier impairment using skin preparation pads and tape stripping. Histological analysis was performed to verify the impairment of the stratum corneum (SC) barrier function in samples from intact skin (control), 10 tape strippings (reference method), 10 passages of PR, and 10 passages of A-UN.

Results

TEWL increased with the increasing number of passages of skin preparation pads, with 2.4- and 3.3-fold increases following 10 passages of A-UN and PR, respectively, versus a 2.2-fold increase with 10 tape strippings (reference). Histological analysis showed only partial removal of the SC, with no damage observed on the epidermis, regardless of the procedure used.

Conclusion

Pre-treatment of skin using PR and A-UN skin preparation pads markedly increases TEWL, indicating slight impairment of the SC barrier function. Comparison of both skin preparation pads showed that PR pad consistently induced significantly higher TEWL than A-UN pad (p < 0.05), regardless of the number of passages. Both skin preparation pads are thought to increase the uptake of MAL and can therefore be used for the preparation of skin prior to PDT.

Funding

Nestlé Skin Health – Galderma R&D.

Photodynamic therapy in dermatology beyond non-melanoma cancer: An update

Photodynamic therapy (PDT) employs a photosensitizer (PS) and visible light in the presence of oxygen, leading to production of cytotoxic reactive oxygen species, which can damage the cellular organelles and cause cell death. In dermatology, PDT has usually taken the form of topical application of a precursor in the heme biosynthesis pathway, called 5-aminolevulinic acid (or its methyl ester), so that an active PS, protoporphyrin IX accumulates in the skin. As PDT enhances dermal remodeling and resolves chronic inflamation, it has been used to treat cutaneous disorders include actinic keratoses, acne, viral warts, skin rejuvenation, psoriasis, localized scleroderma, some non-melanoma skin cancers and port-wine stains. Efforts are still needed to mitigate the side effects (principally pain) and improve the overall procedure.

Protoporphyrin IX fluorescence as potential indicator of psoriasis severity and progression

BACKGROUND AND OBJECTIVES

In psoriatic lesions, fluorescence diagnosis with blue light can detect protoporphyrin IX accumulation, especially after topical 5-aminolaevulinic acid (ALA) application. However, variable fluorescence distributions, interpersonal variations and long incubation time limit its wide application in clinic. This study is aimed to identify a consistent and convenient method to facilitate diagnosis and evaluation of psoriatic lesions.

METHODS

104 psoriatic lesions from 30 patients were evaluated. Single lesion PSI scoring and fluorescence by macrospectrofluorometry were recorded on each lesion before and after treatment with narrow-band UVB.

RESULTS

Punctate red fluorescence, emitted mainly by protoporphyrin IX, is observed in some psoriatic lesions. According to psoriasis severity index, fluorescence-positive lesions are more severe than lesions without fluorescence. We found a significant positive correlation between psoriasis severity and fluorescence intensity from protoporphyrin IX.

CONCLUSIONS

Protoporphyrin IX-induced red fluorescence can be used as a novel and convenient approach for psoriasis diagnosis and progression evaluation.

Patient satisfaction and reported outcomes on the management of actinic keratosis

Actinic keratosis (AK) is a common dermatologic condition in which hyperplastic epidermal lesions develop in response to excessive and chronic exposure to ultraviolet (UV) radiation. If left untreated, AK can progress to squamous cell carcinomas of the skin. Incidence is rising worldwide as a result of the progressive aging of populations and an increase in lifetime cumulative exposure to UV radiation. Currently, various treatment options exist, which range from topical medications to light-based therapies and procedural modalities. In this article, we will review the treatment options for AK with a focus on assessments of patient satisfaction with treatment.

Daylight photodynamic therapy in Scotland

Chronic sun-induced dysplastic skin changes (actinic keratoses) are extremely common in fair-skinned people in Scotland. These changes are a major cause of morbidity and may develop into skin cancer. Actinic keratoses are often extensive and pose a therapeutic challenge as field-directed treatment is required for chronic disease management. One such treatment approach is hospital-based photodynamic therapy, which is a well-established treatment in Scotland for actinic keratoses, using a photosensitiser pro-drug and red LED light irradiation. However, photodynamic therapy using daylight as the activating light source is increasingly and effectively used in continental Europe, but had not been explored in Scotland until we initiated this in 2013. We report our experience of daylight photodynamic therapy in 64 patient-treatment courses and demonstrate that this can be an effective, well-tolerated treatment, which is liked by patients. Our most recent data show that most patients (73%) achieved clearance or at least a good response to treatment and had high levels of satisfaction with daylight photodynamic therapy. Daylight exposure measurements indicated that treatment is feasible in Scotland between April to September. Daylight photodynamic therapy is an important advancement in treatment options for Scottish patients with extensive pre-cancerous field changes and provides opportunities for home-based treatment and increased efficiency of photodynamic therapy services.

Oncologic Photodynamic Therapy: Basic Principles, Current Clinical Status and Future Directions

Photodynamic therapy (PDT) is a clinically approved cancer therapy, based on a photochemical reaction between a light activatable molecule or photosensitizer, light, and molecular oxygen. When these three harmless components are present together, reactive oxygen species are formed. These can directly damage cells and/or vasculature, and induce inflammatory and immune responses. PDT is a two-stage procedure, which starts with photosensitizer administration followed by a locally directed light exposure, with the aim of confined tumor destruction. Since its regulatory approval, over 30 years ago, PDT has been the subject of numerous studies and has proven to be an effective form of cancer therapy. This review provides an overview of the clinical trials conducted over the last 10 years, illustrating how PDT is applied in the clinic today. Furthermore, examples from ongoing clinical trials and the most recent preclinical studies are presented, to show the directions, in which PDT is headed, in the near and distant future. Despite the clinical success reported, PDT is still currently underutilized in the clinic. We also discuss the factors that hamper the exploration of this effective therapy and what should be changed to render it a more effective and more widely available option for patients.

Cyclooxygenase in Cancer Prevention and Treatments for Actinic Keratosis

Non-steroidal anti-inflammatory drugs (NSAIDs) are a chemically diverse class of drugs that target the cyclooxygenase (COX) pathway and have anti-inflammatory, analgesic, and antipyretic properties. Elevated expression of COX-2 has been associated with tumor progression in skin cancer through multiple mechanisms. We present evidence for a chemoprotective effect of NSAIDs and discuss potential mechanisms of action of COX-2 in cancer. We also discuss the challenges associated with the treatment of actinic keratosis and the factors that should be taken into consideration when selecting a treatment regimen. A range of treatments are reviewed, with an emphasis on combination therapies.

Switching From Conventional Photodynamic Therapy to Daylight Photodynamic Therapy For Actinic Keratoses: Systematic Review and Meta-analysis

Actinic keratosis is a precursor lesion to the most common nonmelanoma skin cancer. Conventional photodynamic therapy (PDT) has been shown to be effective, but the procedure is time-consuming, can be very painful, and requires infrastructure. These shortcomings led to the emergence of daylight PDT. To obtain a global estimate of efficacy, we undertook a systematic literature review and performed a meta-analysis of the available evidence on the efficacy and safety of daylight PDT as compared to conventional PDT in the treatment of actinic keratosis and/or field cancerization. The conclusion is that the difference in efficacy is clinically negligible (global estimate of the mean response rate difference, -3.69%; 95% CI, -6.54% to -0.84%). The adverse effects of daylight PDT are mild and localized (79% of patients report no discomfort), and patients report less pain (P<.001). Daylight PDT gives good to excellent cosmetic results in more than 90% of patients, and patient satisfaction is greater (P<.001).

Photodynamic Therapy and Non-Melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common malignancy among the Caucasian population. Photodynamic therapy (PDT) is gaining popularity for the treatment of basal cell carcinoma (BCC), Bowen's disease (BD) and actinic keratosis (AK). A topical or systemic exogenous photosensitiser, results in selective uptake by malignant cells. Protoporphyrin IX (PpIX) is produced then activated by the introduction of a light source. Daylight-mediated MAL (methyl aminolaevulinate) PDT for AKs has the advantage of decreased pain and better patient tolerance. PDT is an effective treatment for superficial BCC, BD and both individual and field treatment of AKs. Excellent cosmesis can be achieved with high patient satisfaction. Variable results have been reported for nodular BCC, with improved outcomes following pretreatment and repeated PDT cycles. The more aggressive basisquamous, morphoeic infiltrating subtypes of BCC and invasive squamous cell carcinoma (SCC) are not suitable for PDT. Prevention of "field cancerization" in organ transplant recipients on long-term immunosuppression and patients with Gorlin syndrome (naevoid basal cell carcinoma syndrome) is a promising development. The optimisation of PDT techniques with improved photosensitiser delivery to target tissues, new generation photosensitisers and novel light sources may expand the future role of PDT in NMSC management.

A randomized split-face clinical trial analyzing daylight photodynamic therapy with methyl aminolaevulinate vs ingenol mebutate gel for the treatment of multiple actinic keratoses of the face and the scalp

INTRODUCTION

Daylight photodynamic therapy with methyl aminolaevulinate (dlPDT) and ingenol mebutate gel (IMB) are approved therapeutic options for multiple actinic keratoses (AKs). The aim of this comparative, intra-patient, split-face, randomized clinical trial was to compare treatment outcomes of dlPDT and IMB.

METHODS

Two symmetrical contralateral areas of 25cm², harboring a similar (5-10) number of AKs, were selected and randomly assigned either to a 3days' IMB treatment cycle or to a single session of dlPDT. The day after the local skin reaction (LSR) score was registered. Patients' scored pain (assessed through VAS method) after the treatment, and time needed for wound closure, were subsequently registered. After 90days, the complete remission (CR) rate recorded for both single lesions and patients, the cosmetic outcome and the patients' preference, were assessed.

RESULTS

22 patients with a total of 311 AKs were enrolled. The mean pain VAS score was 3.55±1.82 with IMB and 2.05±0.72 with dlPDT (p<0.01). The mean LSR score was 9.91±4.24 and 4.59±4.03 (p<0.01), respectively. The mean days necessary for wound closure were 9.45±3.51 and 4.36±1.18days (p<0.01), respectively. After 3 months, 119 lesions with IMB and 120 lesions with dlPDT were healed and the CR rate with IMB (75.8%) was non-inferior to the CR rate with dlPDT (77.9%). The comparisons of CR rates of grade I and II AKs did not show any inferiority for one treatment compared to the other. Eight patients (36.4%) had all lesions cleared with IMB and 7 (31.8%) with dlPDT (p=NS). The cosmetic outcome was better with dlPDT and 17 patients evaluated dlPDT as their preferred treatment.

CONCLUSIONS

A 3days' treatment cycle with IMB and a single session of dlPDT had a similar efficacy for both grade I AKs and grade II AKs but dl PDT showed lower pain and inflammation scores, quicker wound closure, better cosmetic outcome and higher patients' preference.

[Procedure for daylight methyl aminolevulinate photodynamic therapy to treat actinic keratoses]

Actinic keratosis (AK), also known as solar keratosis or pre-cancerous keratosis, is frequently observed in areas of skin exposed to sunlight, particularly in light-skinned patients. In France, photodynamic therapy using red light (conventional PDT) and methylamino 5-levulinate (MAL) is indicated in the treatment of thin or non-hyperkeratotic and non-pigmented multiple AK lesions or large zones covered with AK lesions. It is well-known for its efficacy but also for its side effects, especially pain during illumination, which can limit its use. An alternative to PDT using natural daylight has recently been proposed to treat actinic keratosis lesions, and results in greater flexibility as well as significant reduction in pain. The lesions are prepared as for conventional PDT, with MAL cream being applied by the physician or the patient, after which they are exposed to natural daylight for 2hours. The lesions are then gently cleansed and protected from natural light for 24hours. This paper seeks to provide a precise description of the daylight PDT procedure for the treatment of AK.

Spanish-Portuguese consensus statement on use of daylight-mediated photodynamic therapy with methyl aminolevulinate in the treatment of actinic keratosis

INTRODUCTION

Daylight-mediated photodynamic therapy (PDT) is a new type of PDT that is as effective as conventional PDT in grade 1 and 2 actinic keratosis but with fewer adverse effects, resulting in greater efficiency. The climatic conditions in the Iberian Peninsula require an appropriately adapted consensus protocol.

OBJECTIVE

We describe a protocol for the treatment of grade 1 and 2 actinic keratosis with daylight-mediated PDT and methyl aminolevulinate (MAL) adapted to the epidemiological and clinical characteristics of Spanish and Portuguese patients and the climatic conditions of both countries.

METHODS

Twelve dermatologists from different parts of Spain and Portugal with experience in the treatment of actinic keratosis with PDT convened to draft a consensus statement for daylight-mediated PDT with MAL in these countries. Based on a literature review and their own clinical experience, the group developed a recommended protocol.

RESULTS

According to the recommendations adopted, patients with multiple grade 1 and 2 lesions, particularly those at risk of developing cancer, are candidates for this type of therapy. Daylight-mediated PDT can be administered throughout the year, although it is not indicated at temperatures below 10°C or at excessively high temperatures. Likewise, therapy should not be administered when it is raining, snowing, or foggy. The procedure is simple, requiring application of a sunscreen with a protection factor of at least 30 based exclusively on organic filters, appropriate preparation of the lesions, application of MAL without occlusion, and activation in daylight for 2hours.

CONCLUSION

This consensus statement represents a practical and detailed guideline to achieve maximum effectiveness of daylight-mediated PDT with MAL in Spain and Portugal with minimal adverse effects.