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

Long-term follow-up of a randomized, double-blind, phase III, multi-centre study to evaluate the safety and efficacy of field-directed photodynamic therapy (PDT) of mild to moderate actinic keratosis using BF-200 ALA versus placebo and the BF-RhodoLED® lamp

BACKGROUND

In actinic keratosis (AK), field cancerization describes areas of skin where multiple visible AK lesions are surrounded by healthy looking skin containing non-visible (subclinical) lesions. As all AK lesions have a risk of progression to cutaneous squamous cell carcinoma, experts advise field-directed treatment. Photodynamic therapy (PDT) is an effective field-directed treatment option for AK; however, long-term efficacy data are still scarce.

OBJECTIVES

This publication presents follow-up data of a phase III study evaluating the efficacy and safety of field-directed PDT.

METHODS

The study was conducted in seven centres in Germany. For PDT, participants with AKs on the face and scalp (treatment area of 20 cm2) had received up to two field-directed PDTs using BF-200 ALA or placebo, and illumination with narrow-spectrum red light. Only participants or lesions with complete response 12 weeks after the last PDT were assessed for recurrences. The treatment area was evaluated 6 and 12 months after the last PDT for recurrence, cosmetic outcome and new lesions.

RESULTS

Fifty-four participants in the BF-200 ALA and 30 in the placebo group entered the follow-up. The probability of a participant to be initially completely cleared and to remain cleared for 12 months was 57.4% for BF-200 ALA versus 20.0% for placebo. The probability of a lesion to be initially cleared and remain cleared for 12 months was 85.4% for BF-200 ALA versus 31.5% for placebo. 83.3% of participants with cosmetic impairment at baseline rated the cosmetic outcome 12 months after PDT with BF-200 ALA as very good or good. All parameters of skin quality further improved during follow-up.

CONCLUSIONS

We showed that effectiveness of field-directed PDT with BF-200 ALA and narrow-spectrum red light was maintained during follow-up. Based on our results, field-directed PDT is a beneficial long-lasting treatment for AK patients.

CLINICAL TRIAL REGISTRATION NUMBERS

2013-002510-12 (EudraCT); NCT01966120 (Clinicaltrials.gov).

High efficacy of red light photodynamic therapy with 10 % aminolevulinic acid gel irrespective of the extent of keratinocyte atypia in actinic keratosis - exploratory post-hoc analysis of three pivotal phase III trials

BACKGROUND

Primary endpoints of clinical studies investigating treatments for actinic keratosis (AK) are mainly based on clinical evaluation, but a recent study showed that in AK, clinical classification according to Olsen and the extent of keratinocyte atypia do not necessarily correlate. The influence of the epidermal extent of atypia on treatment efficacy is usually not investigated and therefore remains largely unknown.

OBJECTIVE

To evaluate whether the extent of keratinocyte atypia influences efficacy of photodynamic therapy (PDT) when treating AK.

METHODS

We performed a post-hoc analysis of histological (keratinocyte intraepithelial neoplasia (KIN)), and clinical (Olsen) data of biopsied lesions of three pivotal studies evaluating PDT using 10 % aminolevulinic acid (ALA) gel or vehicle and narrow- or broad-spectrum red light lamps.

RESULTS

Overall, 514 biopsied lesions were considered. Clearance rates after red light PDT with 10 % ALA gel were comparable for KIN I-III (88.2 %, 92.0 % and 87.9 %) and Olsen I-II lesions for any given lamp type. Generally, clearance rates were higher using narrow- compared to broad-spectrum lamps. For both lamp types, the variation in clearance rates from KIN I-III was low. Clearance was lower with vehicle.

LIMITATIONS

Varying lesion numbers in the subgroups and a remaining risk of bias due to the biopsies are potential limitations.

CONCLUSION

Our results suggest that red light PDT with 10 % ALA gel is an effective treatment option for AK regardless of the extent of keratinocyte atypia.

Application of biomacromolecule-based passive penetration enhancement technique in superficial tumor therapy: A review

Transdermal drug delivery (TDD) has shown great promise in superficial tumor therapy due to its noninvasive and avoidance of the first-pass effect. Especially, passive penetration enhancement technique (PPET) provides the technical basis for TDD by temporarily altering the skin surface structure without requiring external energy. Biomacromolecules and their derived nanocarriers offer a wide range of options for PPET development, with outstanding biocompatibility and biodegradability. Furthermore, the abundant functional groups on biomacromolecule surfaces can be modified to yield functional materials capable of targeting specific sites and responding to stimuli. This enables precise drug delivery to the tumor site and controlled drug release, with the potential to replace traditional drug delivery methods and make PPET-related personalized medicine a reality. This review focuses on the mechanism of biomacromolecules and nanocarriers with skin, and the impact of nanocarriers' surface properties of nanocarriers on PPET efficiency. The applications of biomacromolecule-based PPET in superficial tumor therapy are also summarized. In addition, the advantages and limitations are discussed, and their future trends are projected based on the existing work of biomacromolecule-based PPET.

Long-Term Improvement of Different Types of Acne Vulgaris Using a Mild Photodynamic Therapy Protocol with BF-200 ALA Gel: A Series of Cases

Background: Photodynamic therapy (PDT) can be a promising alternative for patients with acne vulgaris. Our study aimed to evaluate the efficacy and safety of red light photodynamic therapy with BF-200 ALA gel in the treatment of different types of acne vulgaris. Methods: We performed a retrospective, observational study of a series of 22 cases. All patients were treated according to a mild PDT protocol. After a careful wash of the affected skin areas, BF-200 ALA gel was applied to the skin in a thin layer and incubated for 30 min, followed by illumination using narrow-spectrum red light (635 nm) at a dose of 4 J/cm2. Most patients received one (36.4%), two (27.3%), or three (22.7%) PDT sessions. About a third of the patients received concomitant acne treatment with topical retinoids. Results: Patients of 25.1 ± 8.9 years suffering from papulopustular (45.5%), nodular (27.3%), and comedonal acne (27.3%) in the face were included. Irrespective of acne type or severity, 95.5% of patients had good or excellent responses to the treatment with PDT (≥60% lesion clearance). We found no association between concomitant acne medication and the favorable results achieved by PDT. Most patients reported no adverse events (72.7%), except for six patients who experienced erythema. The good efficacy results were maintained over a follow-up period of 12.5 ± 10.8 months. Conclusions: In this study, we show that PDT with BF-200 ALA gel and low light dose is an effective and long-lasting option for the treatment of different acne types.

Acquiring of photosensitivity by Mycobacterium tuberculosis in vitro and inside infected macrophages is associated with accumulation of endogenous Zn-porphyrins

Mycobacterium tuberculosis (Mtb) is able to transition into a dormant state, causing the latent state of tuberculosis. Dormant mycobacteria acquire resistance to all known antibacterial drugs and can survive in the human body for decades before becoming active. In the dormant forms of M. tuberculosis, the synthesis of porphyrins and its Zn-complexes significantly increased when 5-aminolevulinic acid (ALA) was added to the growth medium. Transcriptome analysis revealed an activation of 8 genes involved in the metabolism of tetrapyrroles during the Mtb transition into a dormant state, which may lead to the observed accumulation of free porphyrins. Dormant Mtb viability was reduced by more than 99.99% under illumination for 30 min (300 J/cm2) with 565 nm light that correspond for Zn-porphyrin and coproporphyrin absorptions. We did not observe any PDI effect in vitro using active bacteria grown without ALA. However, after accumulation of active cells in lung macrophages and their persistence within macrophages for several days in the presence of ALA, a significant sensitivity of active Mtb cells (ca. 99.99%) to light exposure was developed. These findings create a perspective for the treatment of latent and multidrug-resistant tuberculosis by the eradication of the pathogen in order to prevent recurrence of this disease.

Treatment of acne in the aesthetic patient: A round table update

BACKGROUND

The popularity of social media appears to be increasing the acceptance of cosmetic treatments, prompting more consumers to seek cosmetic treatments. As the estimated prevalence of acne vulgaris among adult women may be as high as 54%, acne is commonly observed among patients presenting for cosmetic treatments. Concomitant treatment of acne in the aesthetic patient population will improve overall clinical outcomes.

AIMS

The goal of this work was to deliver a high-quality ethical and evidence-based educational program to physicians and adjunctive health care providers to advance patient care.

METHODS

This paper is based on a webcam presentation with roundtable discussion by several notable experts in their field.

RESULTS

A range of topical medications, injectable products, chemical peels, and energy-based devices are available for treating acne vulgaris. In most instances, these are compatible with rejuvenation procedures in the aesthetic patient.

CONCLUSION

The growth of social media is raising awareness of aesthetic procedures and appears to be increasing the number of patients seeking aesthetic treatment. Educating patients about the importance of treating acne vulgaris can improve overall treatment outcomes. In most instances, the presence of acne is not a barrier to aesthetic care.

Microneedle-assisted transdermal delivery of perfluorotripropylamine-based oxygenated emulsion gel loaded with 5-aminolevulinic acid for enhanced photodynamic therapy of cutaneous squamous cell carcinoma

Topical photodynamic therapy (TPDT) is a clinical treatment for cutaneous squamous cell carcinoma (CSCC). However, the therapeutic efficacy of TPDT for CSCC is significantly weakened by hypoxia, which is caused by the oxygen-poor environment of the skin and CSCC and by the high oxygen consumption of TPDT itself. To overcome these problems, we developed a topically applied perfluorotripropylamine-based oxygenated emulsion gel loaded with the photosensitizer 5-ALA (5-ALA-PBOEG) by a simple ultrasound-assisted emulsion method. With the aid of the microneedle roller, 5-ALA-PBOEG dramatically increased the accumulation of 5-ALA in the epidermis and the dermis, as well as throughout the dermis; a total of 67.6% ± 9.97% of the applied dose penetrated into and through the dermis, which is 19.1±3.2-fold that of the 5-ALA-PBOEG without microneedle treatment group, and 16.9±0.3-fold that of the aminolevulinic acid hydrochloride topical powder treatment group (p<0.001). Meanwhile, PBOEG enhanced the singlet oxygen yield of 5-ALA-induced protoporphyrin IX. The results of in vivo antitumor activity in human epidermoid carcinoma (A431) bearing mice showed that by increasing the oxygen content in tumor tissues, the developed 5-ALA-PBOEG plus microneedle treatment and laser irradiation showed better tumor growth inhibition than the respective control formulations. In addition, the results of safety studies, including the multiple-dose skin irritation study, allergy tests, and skin H&E staining, demonstrated the safety of 5-ALA-PBOEG plus microneedle treatment. In conclusion, the 5-ALA-PBOEG plus microneedle treatment shows great potential in the fight against CSCC and other skin cancers.

5-Aminolevulinic Acid as a Theranostic Agent for Tumor Fluorescence Imaging and Photodynamic Therapy

5-Aminolevulinic acid (ALA) is a naturally occurring amino acid synthesized in all nucleated mammalian cells. As a porphyrin precursor, ALA is metabolized in the heme biosynthetic pathway to produce protoporphyrin IX (PpIX), a fluorophore and photosensitizing agent. ALA administered exogenously bypasses the rate-limit step in the pathway, resulting in PpIX accumulation in tumor tissues. Such tumor-selective PpIX disposition following ALA administration has been exploited for tumor fluorescence diagnosis and photodynamic therapy (PDT) with much success. Five ALA-based drugs have now received worldwide approval and are being used for managing very common human (pre)cancerous diseases such as actinic keratosis and basal cell carcinoma or guiding the surgery of bladder cancer and high-grade gliomas, making it the most successful drug discovery and development endeavor in PDT and photodiagnosis. The potential of ALA-induced PpIX as a fluorescent theranostic agent is, however, yet to be fully fulfilled. In this review, we would like to describe the heme biosynthesis pathway in which PpIX is produced from ALA and its derivatives, summarize current clinical applications of ALA-based drugs, and discuss strategies for enhancing ALA-induced PpIX fluorescence and PDT response. Our goal is two-fold: to highlight the successes of ALA-based drugs in clinical practice, and to stimulate the multidisciplinary collaboration that has brought the current success and will continue to usher in more landmark advances.

5-aminolevulinic acid-loaded dissolving microneedle array for photodynamic therapy of rheumatoid arthritis on rats

Photodynamic therapy (PDT) is a noninvasive technique that can be used to treat rheumatoid arthritis (RA) by irradiating photosensitizers with specific wavelengths of light to generate reactive oxygen species (ROS), thus leading to targeted cell necrosis. However, efficient delivery of photosensitizers with low side effects is a key issue. We developed a 5-aminolevulinic acid-loaded dissolving microneedle array (5-ALA@DMNA) that can locally and efficiently deliver photosensitizers for RA treatment by PDT. 5-ALA@DMNA was fabricated through a two-step molding process, which was characterized. The effects of 5-ALA-mediated PDT on RA fibroblast-like synoviocytes (RA-FLs) were investigated via in vitro experiments. Adjuvant arthritis rat models were established to evaluate the therapeutic effect of 5-ALA@DMNA-mediated PDT on RA. The results showed that 5-ALA@DMNA could penetrate the skin barrier and efficiently deliver photosensitizers. 5-ALA-mediated PDT can significantly inhibit the migration ability and selectively induce apoptosis of RA-FLs. Moreover, 5-ALA-mediated PDT had a significant therapeutic effect on rats with adjuvant arthritis, which may be related to the upregulation of interleukin (IL)- 4 and IL-10 and downregulation of TNF-α, IL-6, and IL-17. Thus, 5-ALA@DMNA-mediated PDT may be a potential therapy for RA.

Pharmacological Agents Used in the Prevention and Treatment of Actinic Keratosis: A Review

Actinic keratosis (AK) is among the most commonly diagnosed skin diseases with potentially life-threatening repercussions if left untreated. Usage of pharmacologic agents represents one of many therapeutic strategies that can be used to help manage these lesions. Ongoing research into these compounds continues to change our clinical understanding as to which agents most benefit particular patient populations. Indeed, factors such as past personal medical history, lesion location and tolerability of therapy only represent a few considerations that clinicians must account for when prescribing appropriate treatment. This review focuses on specific drugs used in either the prevention or treatment of AKs. Nicotinamide, acitretin and topical 5-fluorouracil (5-FU) continue to be used with fidelity in the chemoprevention of actinic keratosis, although some uncertainty persists in regard to which agents should be used in immunocompetent vs. immunodeficient/immunosuppressed patients. Topical 5-FU, including combination formulations with either calcipotriol or salicylic acid, as well as imiquimod, diclofenac and photodynamic light therapy are all accepted treatment strategies employed to target and eliminate AKs. Five percent of 5-FU is regarded as the most effective therapy in the condition, although the literature has conflictingly shown that lower concentrations of the drug might also be as effective. Topical diclofenac (3%) appears to be less efficacious than 5% 5-FU, 3.75-5% imiquimod and photodynamic light therapy despite its favorable side effect profile. Finally, traditional photodynamic light therapy, while painful, appears to be of higher efficacy in comparison to its more tolerable counterpart, daylight phototherapy.

Sandpaper curettage: A simple method to improve PDT outcomes for actinic keratosis

INTRODUCTION

Photodynamic therapy (PDT) is a non-scarring, repeatable, and safe treatment for actinic keratosis (AK), but improvements in efficacy are still needed.

BACKGROUND

Devices such as steel blades, needle rollers, and lasers are currently used to remove hypertrophic stratum corneum on AKs to improve PDT outcomes. However, curettage with fine sandpaper could be a gentler, effective alternative.

METHODS

A retrospective study was designed to compare PDT with or without sandpaper curettage. Patients were selected from a database registry of patients with face and scalp AKs (ClinicalTrials.gov NCT03319251). Patients in Group 1 underwent PDT alone (20% ALA, 15 min; blue light 417 nm, 30 min). Patients in Group 2 were pretreated with gentle sandpaper curettage prior to ALA and illumination. The two groups were compared using multivariate matching, normalizing for age, sex, initial AK counts, and time to follow-up.

RESULTS

Sixty-six patients were selected for matching analysis (n=38, PDT only; n=28, PDT+curettage). Demographics between the groups were similar (mean ± SD), including age (71.0 ± 8.3 vs. 71.0 ± 8.0 years), baseline AK count (53 ± 39 vs. 44± 32), and time to post-PDT follow-up (111 ± 28 vs. 113 ± 32 days). At follow-up, patients who received curettage showed an overall 55% improvement in scalp AK clearance compared to patients who did not receive curettage, adjusting for sex, age, time to follow-up, and baseline AK count (p = 0.0322, multivariable linear regression).

DISCUSSION

Sandpaper curettage before PDT treatment is an easy and inexpensive method to significantly improve AK clearance rates.

Long-term follow up of ALA 10% gel and red-light photodynamic therapy for the treatment of squamous cell carcinoma in situ

Photodynamic Therapy (PDT) with 10% aminolevulinic acid (ALA) gel and narrow-band red light has been previously shown to be safe and effective for the treatment of squamous cell carcinoma in situ (SCCis) on the trunk and extremities. However, there is a paucity of data in the literature evaluating long-term disease recurrence after PDT. Hence, we performed a follow-up study in which nine of the original twelve patients from our pilot study returned 29-40 months after their last PDT treatment. All patients were clinically clear of disease and only one of seven patients biopsied had residual disease, indicating a long-term clearance rate of 88%. Cosmetic outcomes and patient satisfaction were favorable. Our data supports that red-light PDT with 10% ALA gel can achieve long-term clinical and histopathologic disease clearance and is a viable alternative to surgery for select SCCis.

Nanoemulsion applications in photodynamic therapy

Nanoemulsion, or nanoscaled-size emulsions, is a thermodynamically stable system formed by blending two immiscible liquids, blended with an emulsifying agent to produce a single phase. Nanoemulsion science has advanced rapidly in recent years, and it has opened up new opportunities in a variety of fields, including pharmaceuticals, biotechnology, food, and cosmetics. Nanoemulsion has been recognized as a potential drug delivery technology for various drugs, such as photosensitizing agents (PS). In photodynamic therapy (PDT), PSs produce cytotoxic reactive oxygen species under specific light irradiation, which oxidize the surrounding tissues. Over the past decades, the idea of PS-loaded nanoemulsions has received researchers' attention due to their ability to overcome several limitations of common PSs, such as limited permeability, non-specific phototoxicity, hydrophobicity, low bioavailability, and self-aggregation tendency. This review aims to provide fundamental knowledge of nanoemulsion formulations and the principles of PDT. It also discusses nanoemulsion-based PDT strategies and examines nanoemulsion advantages for PDT, highlighting future possibilities for nanoemulsion use.

Identification and pharmacological modification of resistance mechanisms to protoporphyrin-mediated photodynamic therapy in human cutaneous squamous cell carcinoma cell lines

BACKGROUND

Photodynamic therapy (PDT) is clinically approved to treat neoplastic skin diseases such as precursors of cutaneous squamous cell carcinoma (cSCC). In PDT, 5-aminolevulinic acid (5-ALA) drives the selective formation of the endogenous photosensitizer protoporphyrin IX (PpIX). Although 5-ALA PDT is clinically highly effective, resistance might occur due to decreased accumulation of PpIX in certain tumors. Such resistance may be caused by any fundamental step of PpIX accumulation: 5-ALA uptake, PpIX synthesis and PpIX efflux.

METHODS

We investigated PpIX accumulation and photodynamically induced cell death in PDT refractory SCC-13, PDT susceptible A431, and normal human epidermal keratinocytes (NHEK). Expression of genes associated with cellular PpIX kinetics was investigated on mRNA and protein level. PpIX accumulation and cell death upon illumination were pharmacologically manipulated using drugs targeting 5-ALA uptake, PpIX synthesis or efflux.

RESULTS

The experiments indicate that taurine transporter (SLC6A6) is the major pathway for 5-ALA uptake in cSCC cells, while being less important in NHEK. Downregulation of PpIX synthesis enzymes in SCC-13 was counteracted by methotrexate (MTX) treatment, which restored PpIX formation and cell death. PpIX efflux inhibitors targeting ABC transporters led to significantly increased PpIX accumulation in SCC-13, thereby fully overcoming resistance.

CONCLUSIONS

The results indicate a conserved threshold for PpIX accumulation with respect to PDT-resistance. Cells showed increased viability after PDT at PpIX concentrations below 1.5 nM. Selective uptake of 5-ALA via taurine transporter SLC6A6 in cutaneous tumor cells is novel but unrelated to resistance. MTX can partially abrogate resistance by PpIX synthesis enzyme induction, while efflux mechanisms via ABC transporters seem the main driving force and promising drug targets.

No room for pain: A prospective study showing effective and nearly pain-free treatment of actinic keratosis with simulated daylight photodynamic therapy (SDL-PDT) using the IndoorLux® System in combination with BF-200 ALA (Ameluz®)

BACKGROUND

Photodynamic therapy (PDT) with natural daylight is effective and less painful than conventional PDT when treating actinic keratosis (AK), however its weather dependency is restrictive. This prospective open-label observational single-arm study examined efficacy and safety of simulated daylight (SDL)-PDT using the IndoorLux® system in combination with 5-aminolevulinic acid gel (BF-200 ALA).

METHODS

12 patients with mild/moderate AK on the face or scalp received two SDL-PDTs. BF-200 ALA was applied prior to a 2 h illumination with the IndoorLux® System. Patients evaluated pain during and after SDL-PDT on visual analogue scales (VAS). Primary endpoint was lesion count reduction three months after the second SDL-PDT. Secondary endpoint was pain during and after illumination.

RESULTS

Median individual clearance rate was 83.75% (66.7-100.0%); 33.3% of the patients and 84.9% of the lesions were completely cleared. Median size of the remaining partially cleared lesions decreased by 42.9%. The first SDL-PDT was pain-free for 7 patients (58.3%, VAS=0). Median VAS during and after the first treatment was 0 (0.0-0.3). For the second SDL-PDT, median VAS was 0.1 (0.0-5.5, during) and 0 (0.0-4.5, after). Both SDL-PDTs were pain-free for 6 patients.

CONCLUSION

SDL-PDT was effective and nearly pain-free, emphasizing its advantages and potential for common practice.

Dermoscopy and ultrosound monitoring actinic keratosis with cutaneous squamous cell carcinoma: A case report and literature review

Actinic keratosis(AK) is a common premalignant skin lesion that can progress to invasive squamous cell carcinoma(iSCC). Clinically, AK presents as reddish or brownish macules, papules, or hyperkeratotic plaques. AK cannot be reliably predicted whether it will transform into invasive carcinomas, so skin biopsy is currently a gold standard for identifying suspicious malignancy. Currently, there are non-invasive methods to help diagnose and determine the difference between AKs and iSCC. For example, dermoscopy and ultrasound can be very useful in diagnosing and monitoring skin diseases non-invasively. Therefore, we report a case of multiple facial AKs with poorly differentiated skin squamous cell carcinoma, which was diagnosed early through dermoscopy and ultrasound, and confirmed by histopathology.

Clinical Pharmacokinetics and Safety of a 10% Aminolevulinic Acid Hydrochloride Nanoemulsion Gel (BF-200 ALA) in Photodynamic Therapy of Patients Extensively Affected With Actinic Keratosis: Results of 2 Maximal Usage Pharmacokinetic Trials

The nanoemulsion‐based 10% aminolevulinic acid (ALA) hydrochloride gel BF‐200 ALA optimizes epidermal penetration of its active ingredient and is approved for topical photodynamic therapy (PDT) for the treatment of actinic keratosis in the United States and Europe. To characterize systemic absorption from dermal application during PDT, ALA and its key active metabolite protoporphyrin IX (PpIX) were analyzed in 2 maximal usage pharmacokinetic trials (MUsT) in patients severely affected with actinic keratosis. The primary objective of both MUsTs was to assess baseline‐adjusted plasma concentration–time curves for ALA and PpIX after a single PDT treatment applying either 2 g (1 tube) of BF‐200 ALA on the face (MUsT‐1) or applying 6 g (3 tubes) of BF‐200 ALA on the face/scalp or body periphery (MUsT‐2), to 20 or 60 cm², respectively. All PDTs were performed using red light at around 635 nm wavelength. Safety and tolerability were documented along with pharmacokinetics. In both MUsTs, ALA plasma concentrations were transiently increased to a maximum concentration at about 2.5 to 3.3 times above endogenous baseline with time to maximum concentration at ≈3 hours after dosing. Plasma levels subsequently returned to baseline within 10 hours after dosing. Overall baseline‐adjusted mean area under the baseline‐adjusted plasma concentration‐time curve from time zero to the last sampling time point at which the concentration was at or above the lower limit of quantification ranged from 142.8 to 146.2, indicating that a similar, minor fraction of topical ALA is systemically absorbed under both dosing regimens. Systemic PpIX exposure after administration of either dose of BF‐200 ALA was equally minimal. Application site skin reactions were treatment area size‐related, albeit transient and consistent with the known safety profile of BF‐200 ALA.

Micro- and Nano-Based Transdermal Delivery Systems of Photosensitizing Drugs for the Treatment of Cutaneous Malignancies

Photodynamic therapy is one of the more unique cancer treatment options available in today’s arsenal against this devastating disease. It has historically been explored in cutaneous lesions due to the possibility of focal/specific effects and minimization of adverse events. Advances in drug delivery have mostly been based on biomaterials, such as liposomal and hybrid lipoidal vesicles, nanoemulsions, microneedling, and laser-assisted photosensitizer delivery systems. This review summarizes the most promising approaches to enhancing the photosensitizers’ transdermal delivery efficacy for the photodynamic treatment for cutaneous pre-cancerous lesions and skin cancers. Additionally, discussions on strategies and advantages in these approaches, as well as summarized challenges, perspectives, and translational potential for future applications, will be discussed.

Medical and aesthetic improvement of photodamaged skin by the combination of intense pulsed light and photodynamic therapy with 10% aminolevulinic acid hydrochloride gel

OBJECTIVE

To evaluate the efficacy and safety of photodynamic therapy (PDT) with the novel 10% aminolevulinic acid (ALA) hydrochloride gel (10% ALA gel) and BF-RhodoLED® light (635 nm; 37 J/cm² ) in combination with intense pulsed light (IPL) to augment the medical and aesthetic improvement of photodamaged skin of the décolleté.

METHODS

This was a single-site prospective, randomized, intraindividual split chest pilot study with 20 female subjects with moderate to severe photodamage of the décolleté. Subjects were randomized to ALA-PDT + IPL to one split-side of the chest and ALA-PDT only to the contralateral side. Three blinded raters assessed aesthetic improvement using the global aesthetic improvement scale (GAIS).

RESULTS

Eighteen subjects completed the study. Superior GAIS results were achieved on the ALA-PDT + IPL treatment side than on the ALA-PDT only treatment side (p < 0.001) after 24 weeks of follow-up.

CONCLUSIONS

ALA-PDT using 10% ALA hydrochloride gel and BF-RhodoLED® light had superior rejuvenation effects on the décolleté when combined with IPL compared to ALA-PDT alone.

Photodynamic therapy utilizing 10% ALA nano-emulsion gel and red-light for the treatment of squamous cell carcinoma in-situ on the trunk and extremities: Pilot study and literature update

BACKGROUND

Data evaluating the effectiveness of photodynamic therapy (PDT) with aminolevulinic acid (ALA) 10% nanoemulsion gel and red-light LED lamp for the treatment of squamous cell carcinoma in situ (SCCis) on the trunk and extremities is limited. Our study sought to investigate the safety and efficacy of utilizing ALA 10% gel with red-light lamp for the treatment of SCCis on the trunk and extremities.

METHODS

A single center prospective study of 12 patients with biopsy proven SCCis underwent one or two cycles of red-light PDT with ALA 10 % gel and 3 hours incubation period. Each cycle consisted of two treatments approximately 10 days apart. All participants had a biopsy for histologic evaluation 4 weeks following the last treatment.

RESULTS

All patients achieved clinical and histologic clearance following either one or two cycles at the 4-week post treatment follow up period. The majority of lesions were located on the extremities (n=10) with the remainder located on the trunk (n=2). The mean diameter of the lesions was 1.83 cm. Mild pain was noted in patients, with no interruption of treatment.

CONCLUSIONS

Our study indicates that ALA 10% gel with a red-light lamp is a safe and effective treatment option for SCCis on the trunk and extremities.

The Role of Porphyrinoid Photosensitizers for Skin Wound Healing

Microorganisms, usually bacteria and fungi, grow and spread in skin wounds, causing infections. These infections trigger the immune system and cause inflammation and tissue damage within the skin or wound, slowing down the healing process. The use of photodynamic therapy (PDT) to eradicate microorganisms has been regarded as a promising alternative to anti-infective therapies, such as those based on antibiotics, and more recently, is being considered for skin wound-healing, namely for infected wounds. Among the several molecules exploited as photosensitizers (PS), porphyrinoids exhibit suitable features for achieving those goals efficiently. The capability that these macrocycles display to generate reactive oxygen species (ROS) gives a significant contribution to the regenerative process. ROS are responsible for avoiding the development of infections by inactivating microorganisms such as bacteria but also by promoting cell proliferation through the activation of stem cells which regulates inflammatory factors and collagen remodeling. The PS can act solo or combined with several materials, such as polymers, hydrogels, nanotubes, or metal-organic frameworks (MOF), keeping both the microbial photoinactivation and healing/regenerative processes' effectiveness. This review highlights the developments on the combination of PDT approach and skin wound healing using natural and synthetic porphyrinoids, such as porphyrins, chlorins and phthalocyanines, as PS, as well as the prodrug 5-aminolevulinic acid (5-ALA), the natural precursor of protoporphyrin-IX (PP-IX).

Red light photodynamic therapy with BF-200 ALA showed superior efficacy in the treatment of actinic keratosis on the extremities, trunk, and neck in a vehicle-controlled phase III study

BACKGROUND

Actinic keratoses (AK) may occur in all sun-exposed skin areas. Those occurring outside the head area are generally more resistant to treatment than those on the face.

OBJECTIVE

To determine efficacy and safety of BF-200 ALA versus vehicle in the treatment of mild-to-severe AK located on extremities, trunk, and neck with red light photodynamic therapy (PDT).

METHODS

This phase III study had an intra-individual design with 50 patients in 6 centers in Germany. Each patient received a maximum of 2 field-directed PDTs. Clinical end points and 1-year follow-up results were recorded.

RESULTS

BF-200 ALA was superior to the vehicle with respect to total lesion clearance rates (86.0% vs 32.9%; P < .0001) and patient complete clearance per patient's side (67.3% vs 12.2%, P < .0001). One-year overall lesion recurrence rate was 14.1% versus 27.4% (BF-200 ALA vs vehicle; P = .0068). Patients were more satisfied by the cosmetic outcome of BF-200 ALA/PDT than the vehicle/PDT. Adverse events were consistent with the known safety profile of BF-200 ALA/PDT.

LIMITATIONS

Small number of severe lesions; limited sample size; unbalanced but representative distribution of AK.

CONCLUSION

BF-200 ALA showed significantly higher AK clearance rates on extremities, trunk, and neck than the vehicle and was well tolerated.

Daylight Photodynamic Therapy: An Update

Daylight photodynamic therapy (dPDT) uses sunlight as a light source to treat superficial skin cancer. Using sunlight as a therapeutic device has been present for centuries, forming the basis of photodynamic therapy in the 20th century. Compared to conventional PDT, dPDT can be a less painful, more convenient and an effective alternative. The first clinical uses of dPDT on skin cancers began in Copenhagen in 2008. Currently, aminolevulinic acid-mediated dPDT has been approved to treat actinic keratosis patients in Europe. In this review article, we introduce the history and mechanism of dPDT and focus on the pros and cons of dPDT in treating superficial skin cancers. The future applications of dPDT on other skin diseases are expected to expand as conventional PDT evolves.

Actinic keratosis: where do we stand and where is the future going to take us?

Introduction: Actinic keratosis (AK) is a chronic disease which is mainly located across areas of sun-exposed skin. Clinical and subclinical lesions coexist across a large area resulting in a field cancerization. As these lesions have the potential to transform into invasive squamous cell carcinoma (iSCC), treatment is crucial. With global prevalence increasing, AK is expected to be the most common in situ carcinoma of the skin.Areas covered: In this article, we cover the established algorithm of treating AK and give an insight into the drugs under development. There are six compounds under development covering different treatment angles, from Sinecatechin a Polyphenon E which targets the link between HPV infection and development of AK, over Tirbanibulin which targets the SRC proto-oncogene and fast proliferating cells, to Tuvatexib a small-molecule dual VDAC/HK2 modulator that has shown that it can compete with the established therapies.Expert opinion: These new treatment options are moving us further toward a more individually tailored treatment for each patient considering his abilities, the size and location of his lesions but also the genetic bases as well as individual risk of transforming into a iSCC and possibly other factors contributing to each patients individual AK lesions.

Nanoparticles for topical drug delivery: Potential for skin cancer treatment

Nanoparticles offer new opportunities for the treatment of skin diseases. The barrier function of the skin poses a significant challenge for nanoparticles to permeate into the tissue, although the barrier is partially compromised in case of injury or inflammation, as in the case of skin cancer. This may facilitate the penetration of nanoparticles. Extensive research has gone into developing nanoparticles for topical delivery; however, relatively little progress has been made in translating them to the clinic for treating skin cancers. We summarize the types of skin cancers and practices in current clinical management. The review provides a comprehensive outlook of the various nanoparticle technologies tested for topical therapy of skin cancers and summarizes the obstacles that impede its progress from the bench-to-bedside. The review also aims to provide an understanding of the pathways that govern nanoparticle penetration into the skin and a critical analysis of the approaches used to study nanoparticle interactions within the tissue.

5-Aminolevulinic Acid-Loaded Hyaluronic Acid Dissolving Microneedles for Effective Photodynamic Therapy of Superficial Tumors with Enhanced Long-Term Stability

5-Aminolevulinic acid (5-ALA) is one of the most widely used prodrug in clinical photodynamic therapy of dermatological diseases and cancers; yet, its clinical application is still limited by the shallow skin penetration and unsatisfied stability in any existed formulations. Here, 5-ALA-loaded hyaluronic acid dissolving microneedles (5-ALA@HAMNs) are prepared for photodynamic therapy of superficial tumors. The HAMNs can not only assist the loaded 5-ALA to effectively penetrate the stratum corneum but also provide 5-ALA with an acidic and oxygen-free environment to reduce the dimerization of 5-ALA molecules via Schiff-base bonds and formation of inactive pyrazine derivatives, thus maintaining its chemical structure and biological activity. The chemical stability of 5-ALA in HAMNs is confirmed by UV-vis spectra and mass spectra measurements. The 5-ALA@HAMNs display remarkable tumor elimination both in vitro and in vivo, even after storage at room temperature for nine months, making it a highly potential device for effective delivery of 5-ALA in cancer photodynamic therapy.

Investigational drugs currently in phase II clinical trials for actinic keratosis

INTRODUCTION

Actinic keratoses (AKs) are limited areas of irregular epidermal growth on a background of excessive solar exposure. The entire sun-damaged skin is considered a field of cancerization with multiple visible and subclinical lesions. AK management requires field-directed therapies to block lesion relapse and prevent squamous cell carcinoma (SCC).

AREAS COVERED

In this review, we focused on phase II clinical trials for AKs, involving well-known agents and newer molecules such as proapoptotic drugs (VDA-1102, SR-T100, oleogel-S10, ICVT, eflornithine), immunomodulants (isotretinoin, tretinoin) and chemopreventive agents (nicotinamide, perillyl alcohol, liposomal T4N5). We used the website 'ClinicalTrials.Gov' as main reference. We selected and discussed completed and ongoing trials and analysed chemical structure and mechanism of action of the investigated molecules.

EXPERT OPINION

AK therapy should be tailored on the patient's profile considering first of all the age and site of the AKs, which are relevant parameters for local immune response. The new molecules could be combined to obtain a synergic effect blocking the different steps of skin tumorigenesis. Phase II trials highlight a new therapeutic opportunity to block selectively cell proliferation regulators and work both on the field of cancerization and on the AKs currently present.

Photodynamic therapy with the use of superluminescent diodes (sLED) in the treatment of actinic keratosis

BACKGROUND

Superluminescent diodes (sLED) appear to be an innovative and promising light source in photodynamic therapy (PDT), especially in actinic keratosis (AK) lesions treatment.

AIM

Assessment of tolerability and efficacy of sLED in topical 5-aminolevulinic acid (ALA) PDT of AK lesions.

METHODS

27 patients received ALA PDT with the use of sLED with "soft starter".

RESULTS

Tolerability of sLED lamp depended on the treated lesions field (extension) rather than on their thickness. In contrast sLED lamp efficacy depended on AK lesions thickness.

CONCLUSION

sLED PDT is highly effective in the treatment of grade I and II AK lesions. Grade III AK lesions require further treatment.

Chemical approaches for the enhancement of 5-aminolevulinic acid-based photodynamic therapy and photodiagnosis

The development of photodynamic therapy and photodiagnosis with 5-aminolevulinic acid presents a number of challenges that can be addressed by applying chemical insight and a range of novel prodrug strategies.