Photodynamic therapy of cervical intraepithelial neoplasia with hexaminolevulinate

Comparative study of photodynamic therapy (PDT) of cervical low-grade squamous intraepithelial lesion (LSIL)

BACKGROUND

Prevention of high-risk HPV (HR-HPV) infection and effective medical intervention of persistent HPV infection and precancerous lesions are critical for the prevention of cervical cancer.

AIMS

The aim of this retrospective comparative study was to evaluate the outcomes of ALA PDT and observation only in the management of low-grade squamous intraepithelial lesions (LSIL).

METHODS

In PDT Group (n = 138), ALA PDT was applied to patients with colposcopic biopsy confirmed cervical LSIL accompanied with HR-HPV infection longer than 1 year or HPV 16/18 subtype infection. Cervical LSIL only patients received 3 times of ALA PDT and those with concurrent cervical canal or vaginal lesions received 6 times ALA PDT. Control Group (n = 69) received observation only. Colposcopy, TCT and HPV typing were performed before and after treatment. Patients were followed up for up to two years.

RESULT

The observation group showed 26.1%, 34.8% and 53.6% HR-HPV negative conversion at 3-6, 12 and 24 months, respectively. LSIL regression rate of the observation group was 33.33%, 36.23% and 65.22% at 3-6, 12 and 24 months, respectively. There was 62.32%, 80.56% and 89.22% patients achieved HPV clearance at 3-6, 12 and 24 months after PDT treatment, respectively. The LSIL remission rate was 89.86%, 94.40% and 96.08% at 3-6, 12 and 24 months after ALA PDT, respectively. The abnormal TCT (≧ ASCUS) was reduced from 92% to 10.1%, 4.6% and 3.9% at 3-6, 12 and 24 months after ALA PDT, respectively. The patient age was not a factor affecting the clearance of HPV infection and the LSIL regression rate of PDT treatment.

CONCLUSIONS

This study demonstrates that the application of multiple ALA PDT treatments has added value in achieving both short-term and long-term HPV and lesion clearance.

The use of photodynamic therapy in medical practice

Cancer therapy, especially for tumors near sensitive areas, demands precise treatment. This review explores photodynamic therapy (PDT), a method leveraging photosensitizers (PS), specific wavelength light, and oxygen to target cancer effectively. Recent advancements affirm PDT's efficacy, utilizing ROS generation to induce cancer cell death. With a history spanning over decades, PDT's dynamic evolution has expanded its application across dermatology, oncology, and dentistry. This review aims to dissect PDT's principles, from its inception to contemporary medical applications, highlighting its role in modern cancer treatment strategies.

Photodynamic therapy of cervical cancer: a scoping review on the efficacy of various molecules

Background

Cervical cancer poses a considerable worldwide health issue, where infection with the human papillomavirus (HPV) plays a vital role as a risk factor. Photodynamic therapy (PDT) is a minimally invasive treatment for HPV-related cervical lesions, which uses photosensitizers and light to selectively destroy abnormal cells.

Objectives

Our objective is to present a comprehensive overview of the different types of molecules employed in PDT to reduce the occurrence and fatality rates associated with cervical cancer.

Design

Scoping review and bibliometric analysis.

Methods

The article explores clinical trials investigating the efficacy of PDT in treating low-grade squamous intraepithelial lesion and high-grade squamous intraepithelial lesion, as well as preclinical approaches utilizing various molecules for PDT in cervical cancer. Furthermore, the article sheds light on potential molecules for PDT enhancement, examining their properties through computer modeling simulations, molecular docking, and assessing their advantages and disadvantages.

Results

Our findings demonstrate that PDT holds promise as a therapeutic approach for treating cervical lesions associated with HPV and cervical cancer. Additionally, we observe that the utilization of diverse dye classes enhances the anticancer effects of PDT.

Conclusion

Among the various molecules employed in PDT, functionalized fullerene exhibits a notable inclination toward overexpressed receptors in cervical cancer cells, making it a potential candidate for intensified use in PDT. However, further research is needed to evaluate its long-term effectiveness and safety.

Recent advancement of nanomedicine-based targeted delivery for cervical cancer treatment

Cervical cancer is a huge worldwide health burden, impacting women in impoverished nations in particular. Traditional therapeutic approaches, such as surgery, radiation therapy, and chemotherapy, frequently result in systemic toxicity and ineffectiveness. Nanomedicine has emerged as a viable strategy for targeted delivery of therapeutic drugs to cancer cells while decreasing off-target effects and increasing treatment success in recent years. Nanomedicine for cervical cancer introduces several novel aspects that distinguish it from previous treatment options such as tailored delivery system, precision targeting, combination therapies, real-time monitoring and diverse nanocarriers to overcome the limitations of one another. This abstract presents recent advances in nanomedicine-based tailored delivery systems for the treatment of cervical cancer. Liposomes, polymeric nanoparticles, dendrimers, and carbon nanotubes have all been intensively studied for their ability to transport chemotherapeutic medicines, nucleic acids, and imaging agents to cervical cancer cells. Because of the way these nanocarriers are designed, they may cross biological barriers and preferentially aggregate at the tumor site, boosting medicine concentration and lowering negative effects on healthy tissues. Surface modification of nanocarriers with targeting ligands like antibodies, peptides, or aptamers improves specificity for cancer cells by identifying overexpressed receptors or antigens on the tumor surface. Furthermore, nanomedicine-based techniques have made it possible to co-deliver numerous therapeutic drugs, allowing for synergistic effects and overcoming drug resistance. In preclinical and clinical investigations, combination treatments comprising chemotherapeutic medicines, gene therapy, immunotherapy, and photodynamic therapy have showed encouraging results, opening up new avenues for individualized and multimodal treatment regimens. Furthermore, the inclusion of contrast agents and imaging probes into nanocarrier systems has enabled real-time monitoring and imaging of treatment response. This enables the assessment of therapy efficacy, the early diagnosis of recurrence, and the optimization of treatment regimens.

A Recent Advancement in Nanotechnology Approaches for the Treatment of Cervical Cancer

BACKGROUND

Cervical cancer is one of the leading causes of female death, with a mortality rate of over 200,000 per year in developing countries. Despite a decrease in cervical cancer occurrences in developed countries over the last decade, the frequency of the disease in developing nations continues to rise at an alarming rate, particularly when it is linked to the human papillomavirus (HPV). With just a few highly invasive conventional therapies available, there is a clear need for novel treatment options such as nanotechnology-based chemotherapeutic drug delivery.

METHODS

Traditional anticancer therapy is limited by poor drug potency, non-specificity, unwanted side effects, and the development of multiple drug resistance (MDR), leading to a decrease in long-term anticancer therapeutic efficacy. An ideal cancer therapy requires a personalized and specialized medication delivery method capable of eradicating even the last cancer cell responsible for disease recurrence.

RESULTS

Nanotechnology provides effective drug delivery mechanisms, allowing it to serve both therapeutic and diagnostic purposes. Nanotechnology-based formulations are widely used to accurately target the target organ, maintain drug load bioactivity, preferentially accumulate the drug at the target location, and reduce cytotoxicity.

CONCLUSION

The key benefits of this drug delivery are that it improves pharmacological activity, solubility, and bioavailability and reduces toxicity in the target tissue by targeting ligands, allowing for new innovative treatment methods in an area that is desperately required. The goal of this review is to highlight possible research on nanotechnologybased delivery systems for cancer detection and treatment.

Enhanced Intracellular Photosensitizer Uptake and Retention by Targeting Viral Oncoproteins in Human Papillomavirus Infected Cancer Cells and Cancer Stem Cells

Immunogenic proteins in cancer are relevant targets for drug delivery. In Photodynamic Therapy (PDT), surface antigens have previously been used to deliver the photosensitizer (PS) to the tumor microenvironment for specific targeting. However, can we target intracellular antigens to achieve more than surface recognition? Can we possibly increase PS intracellular localization and prevent drug efflux at the same time? In this study, these questions were addressed by using a compound that can not only specifically recognize and bind to intracellular E6 oncoproteins in Human Papillomavirus (HPV)-Transformed cancer cells, but is also capable of enhancing transmembrane uptake using the cells' own active transport mechanisms. HPV-transformed SiHa cells were cultured in vitro, and the resistant subpopulation was isolated using Magnetic Activated Cell Sorting (MACS). PDT was performed on four different cell types with varying physiognomies in terms of HPV oncoprotein expression and physiological form. Results demonstrated that tagging PSs on a carrier molecule that specifically delivers the PS inside the cells that express the target proteins enhanced both cellular uptake and retention of the PS even in the presence of drug efflux proteins on resistant subpopulations. These findings provide insight into the possibility of preventing cell-mediated resistance to PDT.

5-aminolevulinic acid photodynamic therapy combined with carbon dioxide laser therapy is a safe and effective treatment for vaginal intraepithelial neoplasia

BACKGROUND

Vaginal intraepithelial neoplasia (VaIN) is a precursor of vaginal carcinoma that is often treated with CO₂ laser therapy. However, recurrence after laser therapy is common, so new approaches are needed to enhance treatment effectiveness. The aim of this study was to investigate the efficacy and safety of combining 5- aminolevulinic acid photodynamic therapy (5-ALA-PDT) with CO₂ laser therapy for the treatment of VaIN.

METHODS

Clinical data from 40 VaIN patients who received CO2 laser therapy with or without ALA-PDT were retrospectively analyzed. Cytology, human papillomavirus (HPV) status, colposcopic images, and histopathology before and after treatment were compared, and treatment efficacy, adverse reactions, and patient prognosis were assessed.

RESULTS

There was no significant difference in the cure rate between the CO2 laser group and the CO2 laser+5-ALA-PDT group after 12 months of follow-up. The difference in HPV clearance rate between the CO₂ laser only group and the CO₂ laser + 5-ALA-PDT group was significant at 6 and 12 months after treatment but not at 3 months after treatment. 10% patients in the CO₂ laser only group experienced adverse events, while no serious adverse events were observed in the CO₂ laser + 5-ALA-PDT group.

CONCLUSIONS

5-ALA-PDT combined with CO₂ laser therapy appears to be a safe and effective treatment for VaIN that results in a high rate of HPV clearance with few side effects.

Efficacy of photodynamic therapy with 5-aminolevulinic acid for the treatment of cervical high-grade squamous intraepithelial lesions with high-risk HPV infection: A retrospective study

BACKGROUND

The current principle of clinical management of cervical high-grade squamous intraepithelial lesion(HSIL) is surgical excision. However excisional procedures of the uterine cervix may have a negative impact on fertility. Topical photodynamic therapy(PDT) is a non-invasive and selective tissue destruction. We investigated the clinical efficacy of PDT for cervical HSIL with high-risk human papilloma virus(HPV) infection.

METHODS

A retrospective study consisting of 96 patients aged 20-50 years with a histologically confirmed cervical HSIL with high-risk HPV infection from July 2018 to June 2022 was carried out. Patients were treated with six times of 20% 5-aminolevulinic acid photodynamic therapy (5-ALA PDT) at intervals of 7-14 days. Three months after treatment, the effect was evaluated through HPV typing and colposcopy directed biopsy. Six and twelve months after treatment, TCT and HPV tests were carried out.

RESULTS

Three months after 5-ALA PDT treatment, among 96 HSIL with high-risk HPV infection patients, the total lesion regression rate was 89.58%(86/96), and the HPV clearance rate was 79.17 % (76/96) at 3 months follow-up. At 6 and 12 months follow-up, the patients who was HSIL pathological regression and negative HPV at 3 months follow-up continued negative results in both TCT and HPV. All patients with ineffective 5-ALA PDT treatment had persistent HPV infections. There was no significant difference in the HSIL regression rate and HPV clearance rate among different age groups. The main side effects of PDT were abdominal pain and increased vaginal secretions. Univariate analysis showed that the different severity of cervical cytology was associated with lesion regression rate in 5-ALA PDT treatment. The HSIL regression rate of TCT<ASC-H was higher than that of TCT≧ASC-H(94.59% vs 72.72%; P<0.01).Multicentric lesions,the proportion of visible lesion size in ectocervical size≥24.59%, size of visible lesion ≥1.23cm² and maximum linear length of visible lesion ≥0.90cm were risk factors of HSIL persistence after 5-ALA PDT treatment (P<0.05).

CONCLUSION

5-ALA PDT can be a safe and efficient treatment for cervical HSIL who wish to preserve fertility. 5-ALA PDT did not appear to create cervical damage and have negligible side effects. But we need evaluate the type of transformation zone, the visible lesion size, the location of lesion,baseline status of TCT and histological results before 5-ALA PDT treatment.

Advanced techniques for performing photodynamic therapy in deep-seated tissues

Photodynamic therapy (PDT) is a promising localized cancer treatment modality. It has been used successfully to treat a range of dermatological conditions with comparable efficacy to conventional treatments. However, some drawbacks limit the clinical utility of PDT in treating deep-seated tumors. Notably, the penetration limitation of UV and visible light, commonly applied to activate photosensitizers, makes PDT incompetent in treating deep-seated tumors. Development in light delivery technologies, especially fiber optics, led to improved clinical strategies for accessing deep tissues for irradiation. However, PDT efficacy issues remained partly due to light penetration limitations. In this review, we first summarized the current PDT applications for deep-seated tumor treatment. Then, the most recent progress in advanced techniques to overcome the light penetration limitation in PDT, including using functional nanomaterials that can either self-illuminate or be activated by near-infrared (NIR) light and X-rays as transducers, and implantable light delivery devices were discussed. Finally, current challenges and future opportunities of these technologies were discussed, which we hope may inspire the development of more effective techniques to enhance PDT efficacy against deep-seated tumors.

Long-term outcomes of photodynamic therapy for a positive resection margin after conization for cervical intraepithelial neoplasia grade 3

BACKGROUND

Positive resection margins after conization or loop electrosurgical excision procedure (conization/LEEP) are associated with increased risks of recurrence or residual cervical intraepithelial neoplasia (CIN). Herein, we investigated the long-term outcomes of photodynamic therapy (PDT) for incomplete excision of CIN3.

METHODS

We retrospectively reviewed the medical charts of 73 patients treated with PDT between 2000 and 2011. Patients who underwent conization/LEEP before PDT within 6 months were included. The primary outcomes were the complete response (CR) rate after 1 year and human papillomavirus (HPV) eradication rate at 6 months after PDT.

RESULTS

A total of 34 patients with positive resection margins were finally enrolled. The median patient age was 33 years. Carcinoma in situ was diagnosed in 25 patients and CIN3 in 7 patients. The CR rate was 97.1% after 1 year. Except for one case of a persistent disease, there was no recurrence or newly developed disease during the median follow-up of 84 months (range, 12-224 months). The HPV eradication rate of PDT following conization/LEEP after 6 months was 96.9% (31/32). Photosensitivity was identified in five patients and cervical stenosis in one patient.

CONCLUSIONS

In conclusion, PDT could be an effective therapeutic option for patients with a positive resection margin after conization/LEEP for CIN3. It could reduce the residual or recurrence rate of CIN lesions with tolerable adverse events.

The effect of 5-Aminolaevulinic Acid Photodynamic Therapy versus CO2 laser in the Treatment of Cervical Low-grade Squamous Intraepithelial Lesions with High-Risk HPV Infection: A non-randomized, controlled pilot study

BACKGROUND

There are insufficient studies comparing the efficacy of 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) against CO₂ laser therapy in the treatment of cervical low-grade squamous intraepithelial lesion (LSIL) with high-risk human papillomavirus (HR-HPV), especially for long-term efficacy.

METHODS

Patients with cervical LSIL and HR-HPV infection were divided into two treatment groups based on their own choice. All patients had a follow-up test including HPV testing, cytology and colposcopy at 4-6 months and 12 months after the treatment.

RESULTS

(1) Among 277 patients, 176 patients received 5-ALA PDT and 101 patients received CO₂ laser therapy. (2) 4-6 months after treatment, there was no significant difference between two groups in the complete remission (CR) rates of cervical LSIL and the clearance rate of HR-HPV infection. (3) 12 months after treatment, compared with the CO₂ laser group, the CR rates of cervical LSIL in the 5-ALA PDT group was significantly higher than the CO₂ laser group. There was no statistical difference in the clearance rate of HR-HPV infection between the two groups. (4) 12 months after treatment, the recurrence rate of cervical lesions and the reinfection rate of HR-HPV infection in 5-ALA PDT group were significantly lower than those in CO₂ laser group.

CONCLUSION

The effect of 5-ALA PDT is similar to CO₂ laser at 4-6 months. The long-term efficacy of 5-ALA PDT appears better than CO₂ laser. As a non-invasive treatment, 5-ALA PDT is a highly effective therapeutic procedure for cervical LSIL with HR-HPV infection.

Efficacy of photodynamic therapy in women with HSIL, LSIL and early stage squamous cervical cancer: a systematic review and meta-analysis

BACKGROUND

We sought to conduct a systematic review and meta-analysis of randomized and non-randomized clinical trials to assess the efficacy of photodynamic therapy (PDT) in cervical epithelial neoplasia (CIN) and early-stage cervical cancer. Additionally, according to the results, we tried to consider which stage of CIN is more sensitive to PDT.

METHODS

A systematic search was conducted using electronic databases including PubMed, ClinicalTrials.gov, the Cochrane Library, and Google Scholar.

INCLUSION CRITERIA

all patients had confirmed low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL), or an early-stage cervical cancer - the cancer is less than 3 mm deep into the cervix -IA; type of photosensitizer and any type of wavelength.

EXCLUSION CRITERIA

women who were previously treated with PDT; Risk of bias assessment was carried out for each study included in the systematic review using the Cochrane Handbook for Systematic Reviews of Interventions: RoB-2 was used to assess the risk of bias in randomized studies, while ROBINS-I - in non-randomized ones.

RESULTS

We identified 2213 publications, but only 6 met the inclusion criteria and were included in the synthesis. PDT is most effective when patients have CIN 2 or photosensitizer is administered intravenously.

CONCLUSION

Based on our systematic review and meta-analysis, it could be concluded that photodynamic therapy may be a practical approach in CIN (LSIL) regression compared with placebo. Nevertheless, we need more evidence and long-term follow-up to answer all questions thoroughly.

A Warp-Knitted Light-Emitting Fabric-Based Device for In Vitro Photodynamic Therapy: Description, Characterization, and Application on Human Cancer Cell Lines

Simple Summary

While photodynamic therapy appears to be a promising approach to treating cancers, the complexity of its parameters prevents wide acceptance. Accurate light dose measurement is one of the keys to photodynamic effect assessment, but it remains challenging when comparing different technologies. This work provides a complete demonstration of the technical performance of a homemade optical device, based on knitted light-emitting fabrics, called CELL-LEF. Thermal and optical distributions and related safeties are investigated. The results are discussed in relation to the requirements of photodynamic therapy. The usability of CELL-LEF is investigated on human cancer cell lines as a proof of concept. This study highlights that new light-emitting fabric-based technologies can be relevant light sources for in vitro photodynamic therapy studies of tomorrow.

Abstract

Photodynamic therapy (PDT) appears to be a promising strategy in biomedical applications. However, the complexity of its parameters prevents wide acceptance. This work presents and characterizes a novel optical device based on knitted light-emitting fabrics and dedicated to in vitro PDT involving low irradiance over a long illumination period. Technical characterization of this device, called CELL-LEF, is performed. A cytotoxic study of 5-ALA-mediated PDT on human cancer cell lines is provided as a proof of concept. The target of delivering an irradiance of 1 mW/cm² over 750 cm² is achieved (mean: 0.99 mW/cm²; standard deviation: 0.13 mW/cm²). The device can maintain a stable temperature with the mean thermal distribution of 35.1 °C (min: 30.7 °C; max: 38.4 °C). In vitro outcomes show that 5-ALA PDT using CELL-LEF consistently and effectively induced a decrease in tumor cell viability: Almost all the HepG2 cells died after 80 min of illumination, while less than 60% of U87 cell viability remained. CELL-LEF is suitable for in vitro PDT involving low irradiance over a long illumination period.

Efficacy and safety of photodynamic therapy mediated by 5-aminolevulinic acid for the treatment of cervical intraepithelial neoplasia 2: A single-center, prospective, cohort study

BACKGROUND

Photodynamic therapy (PDT) mediated by 5-aminolevulinic acid (5-ALA) is a minimally-invasive treatment for cervical intraepithelial neoplasia (CIN). The present study was carried out to investigate the effect of 5-ALA-PDT on CIN2 and the factors influencing outcome of 5-ALA-PDT.

METHODS

Patients diagnosed as CIN2 who met the inclusion criteria were enrolled in this study sequentially from January 2019 to April 2020. Patients were treated by PDT or cryotherapy according to their intentions. The primary endpoint was pathological regression. The secondary endpoint was HPV clearance. Affecting factors of the efficacy of PDT and adverse events were also assessed during treatment.

RESULTS

A total of 210 patients were enrolled, including 97 patients in PDT group and 101 patients in cryotherapy group, with 12 patients excluded. There was no statistical difference in population characteristics. The pathological regression rate in PDT group was 92.0% (80/87), compared with 81.4% (79/97) in cryotherapy group (P < 0.05). The HPV clearance rate was 64.4% (56/87) in PDT group and 57.8% (56/97) in cryotherapy group (P = 0.36). The main side effects of PDT were abdominal pain (24.1%, 21/87) and increased vaginal secretions (23.0%, 20/87). On univariate analysis, the risk for lesions persisting at 6 months after PDT was increased by recurrent genital tract inflammation (P = 0.004), smoking or passive smoking (P = 0.020), and multicentric lesions (P = 0.020).

CONCLUSION

PDT can be a safe and efficient treatment for CIN2. Risk factors for persisting HSIL after PDT include recurrent genital tract inflammation, smoking or passive smoking, and multicentric lesions.

Alternative methods of photodynamic therapy and oxygen consumption measurements-A review

Photooxidation generates reactive oxygen species (ROS) through the interaction of dyes or surfaces with light radiation of appropriate wavelength. The reaction is of wide utility and is highly effective in photodynamic therapy (PDT) of various types of cancer and skin disease. Understanding generation of singlet oxygen has contributed to the development of PDT and its subsequent use in vivo. However, this therapy has some limitations that prevent its use in the treatment of cancers located deep within the body. The limited depth of light penetration through biological tissue limits initiation of PDT action in deep tissue. Measurement of oxygen photo consumption is critical due to tumor hypoxia, and use of magnetic resonance imaging (MRI) is particularly attractive since it is non-invasive. This article presents bioluminescence (BL) and chemiluminescence (CL) phenomena based on publications from the last 20 years, and preliminary results from our lab in the use of MRI to measure oxygen concentration in water. Current work is aimed at improving the effectiveness of singlet oxygen delivery to deep tissue cancer.

Laser technologies in treatment of cervical intraepithelial neoplasia (review)

This review article discusses the key aspects of the use of laser technologies, namely, laser vaporization (LV) and photodynamic therapy (PDT), in the treatment of patients with cervical intraepithelial neoplasia (CIN). The authors analyzed and systematized the foreign experience of these methods of treatment, their indications and contraindications, as well as the advantages over traditional approaches to the treatment of this pathology. The main advantages of the LV are the possibility of complete evaporation of the pathological focus, visual control over the depth of tissue destruction, the absence of prolonged edema and cicatricial deformities, which allows maintaining the integrity of the cervix and its reproductive function. Despite the low trauma and low frequency of adverse reactions, the data on the effectiveness of LV are quite contradictory and, according to various authors, vary from 50% to 98%. To date, there is a significant amount of accumulated experience in the use of PDT with various photosensitizing agents (5-aminolevulinic acid (5-ALA), hematoporphyrin and chlorin and their derivatives) in the treatment of patients with CIN. The main advantages of the PDT are minimal toxicity to the surrounding normal tissues due to the selective accumulation of photosensitizer in pathological tissues, a low risk of severe pain syndrome, the absence of mechanisms of primary and acquired resistance, the possibility of an outpatient treatment session, the possibility of combining with other methods of therapeutic action, the absence of limiting cumulative doses of photosensitizers and light exposure, the possibility of multiple repetitions of the session, good cosmetic results and the possibility of implementing an organ-preserving method of treatment. The obtained results indicate good tolerability of the method (no severe adverse reactions) and a fairly high efficiency of PDT: the frequency of complete regressions varies from 30% to 67% - for application forms of 5-ALA and from 90% to 98.1% - for hematoporifirin and chlorin photosensitizers. Thus, LV and PDT can be considered safe and effective treatment options for patients with CIN.

Efficacy of 5-aminolevulinic acid and LED photodynamic therapy in cervical intraepithelial neoplasia: A clinical trial

BACKGROUND

5-Aminolaevulinic acid (5ALA) is a precursor of the strong sensitizer protoporphyrin IX (PpIX) in the heme synthesis pathway. We conducted aclinical trial designed to evaluate the efficacy and safety of 5ALA photodynamic therapy (PDT) using a light-emitting diode (LED) in patients with cervical intraepithelial neoplasia (CIN).

METHODS

Data for 51 CIN patients who underwent 5ALA-PDT between 2012 and 2017 were prospectively analysed. After a 20 % 5ALA jelly formulation was topically applied to the cervix, the region was irradiated with red light at approximately 633 nm to excite PpIX for treatment. We estimated outcomes by cytology, pathology, and human papilloma virus (HPV) testing after PDT.

RESULTS

Patients underwent two PDT sessions at one-week intervals during outpatient treatment and achieved favourable results without photosensitivity and severe adverse events. Over a long follow-up period, 96.1 % of all patients showed some positive effects, including approximately 70 % with a complete response (CR), 10 % with a partial response, and 15 % with downgrades. The HPV clearance rate in patients with CR was 79.4 %. Recurrence occurred in five patients who mostly remained HPV-positive after PDT.

CONCLUSIONS

Based on our study, topical 5ALA-PDT using an LED light source potentially represents a safe treatment for CIN on an outpatient basis.

Light Sources and Dosimetry Techniques for Photodynamic Therapy

Effective treatment delivery in photodynamic therapy (PDT) requires coordination of the light source, the photosensitizer, and the delivery device appropriate to the target tissue. Lasers, light-emitting diodes (LEDs), and lamps are the main types of light sources utilized for PDT applications. The choice of light source depends on the target location, photosensitizer used, and light dose to be delivered. Geometry of minimally accessible areas also plays a role in deciding light applicator type. Typically, optical fiber-based devices are used to deliver the treatment light close to the target. The optical properties of tissue also affect the distribution of the treatment light. Treatment light undergoes scattering and absorption in tissue. Most tissue will scatter light, but highly pigmented areas will absorb light, especially at short wavelengths. This review will summarize the basic physics of light sources, and describe methods for determining the dose delivered to the patient.

A New Optical Method for Online Monitoring of the Light Dose and Dose Profile in Photodynamic Therapy

BACKGROUND AND OBJECTIVES

Photodynamic therapy (PDT) has gained widespread popularity in the last decades because of its distinctive advantages over the other commonly used cancer treatments. PDT dosimetry is a crucial factor in achieving a good optimization of PDT treatment planning. PDT dosimetry is a complex task since light dose as well as photosensitizer and oxygen concentrations in tissue need to be measured (ideally continuously) to be able to fully characterize the biological response. Light dose in PDT is routinely measured by the optical fibers that provide dose data at a limited number of discrete points and are not able to capture spatial dose profiles. The objective of this study is to propose and develop a new optical method for online monitoring of the dose profile data for PDT.

STUDY DESIGN/MATERIALS AND METHODS

Using the digital holography technique, first, the general sketch of an experimental setup for PDT light dosimetry is provided. The theory behind the proposed method for using the experimental setup in PDT light dosimetry is fully described, and its limits of validity are determined. In a proof of principle study, the ability of the method for online monitoring of the absorbed light dose profile in PDT is evaluated by a simple experimental setup.

RESULTS

The experimental results confirm the usefulness of the proposed method in providing continuous online dose profiles. The absorbed light dose profiles from an infrared light source in a quartz cell containing water are measured and shown. The depth-dose curves are extracted and it is shown that how these dosimetric data can be used for assisting the physicians in determining the appropriate spatiotemporal characteristics for treating the infected tissues and solid tumors with the required light dose amounts. A conversion relation is also derived for transforming the measured light dose with the proposed method to the most frequently used dose values by PDT practitioners, in terms of light power per square area.

CONCLUSIONS

There is no restriction in using the method with other commonly used light sources in PDT, like light-emitting diodes and filtered lamps, with different wavelengths in visible or infrared regions of the spectrum. More complex experimental setups can be used in future studies to study the role of accumulated photosensitizers in malignant tissues. The proposed method in this study can also be used for light dose monitoring in other biomedical applications, where light is used for treating special diseases, and patients must receive sufficient amounts of light dose. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Trends and targets in antiviral phototherapy

Photodynamic therapy (PDT) is a well-established treatment option in the treatment of certain cancerous and pre-cancerous lesions. Though best-known for its application in tumor therapy, historically the photodynamic effect was first demonstrated against bacteria at the beginning of the 20^th century. Today, in light of spreading antibiotic resistance and the rise of new infections, this photodynamic inactivation (PDI) of microbes, such as bacteria, fungi, and viruses, is gaining considerable attention. This review focuses on the PDI of viruses as an alternative treatment in antiviral therapy, but also as a means of viral decontamination, covering mainly the literature of the last decade. The PDI of viruses shares the general action mechanism of photodynamic applications: the irradiation of a dye with light and the subsequent generation of reactive oxygen species (ROS) which are the effective phototoxic agents damaging virus targets by reacting with viral nucleic acids, lipids and proteins. Interestingly, a light-independent antiviral activity has also been found for some of these dyes. This review covers the compound classes employed in the PDI of viruses and their various areas of use. In the medical area, currently two fields stand out in which the PDI of viruses has found broader application: the purification of blood products and the treatment of human papilloma virus manifestations. However, the PDI of viruses has also found interest in such diverse areas as water and surface decontamination, and biosafety.

5-aminolevulinic acid photodynamic therapy reduces HPV viral load via autophagy and apoptosis by modulating Ras/Raf/MEK/ERK and PI3K/AKT pathways in HeLa cells

Human papillomavirus (HPV) infection is linked to several diseases, the most prominent of which are cervical cancer and genital condyloma acuminatum. Previous studies have suggested an effective role for 5-aminolevulinic acid photodynamic therapy (ALA-PDT) against various cancers by the induction of autophagy and apoptosis. However, few reports have focused on the effectiveness of ALA-PDT on HPV related disorders. To identify the role of ALA-PDT in the context of HPV infection, we initially investigated 111 patients suffering from genital condyloma acuminatum. HPV viral load detected before and after ALA-PDT treatment was compared during this procedure; a significant difference was noted. HeLa (HPV18) cells were exposed to ALA-PDT in vitro to further explore the underlying mechanisms. Western blot analysis showed that ALA-PDT induces LC3II and p62 expression, along with the up regulation of caspase-3 and cleaved caspase-3. Our study also demonstrated that ALA-PDT treatment inhibits the proliferation of HeLa cells in a dose dependent manner and effectively reduces HPV viral load via autophagy and apoptosis by regulating the Ras/Raf/MEK/ERK and PI3K/AKT/mTOR pathways. Hydroxychloroquine (HCQ), although it inhibited autophagy degradation, functioned to activate reactive oxygen species (ROS) levels of ALA-PDT to enhance the observed effect. These findings suggest strategies for the improvement of PDT efficacy in patients.

Advances in Designing and Developing Vaccines, Drugs and Therapeutic Approaches to Counter Human Papilloma Virus

Human papillomavirus (HPV) is a viral infection with skin-to-skin based transmission mode. HPV annually caused over 500,000 cancer cases including cervical, anogenital and oropharyngeal cancer among others. HPV vaccination has become a public-health concern, worldwide, to prevent the cases of HPV infections including precancerous lesions, cervical cancers, and genital warts especially in adolescent female and male population by launching national programs with international alliances. Currently, available prophylactic and therapeutic vaccines are expensive to be used in developing countries for vaccination programs. The recent progress in immunotherapy, biotechnology, recombinant DNA technology and molecular biology along with alternative and complementary medicinal systems have paved novel ways and valuable opportunities to design and develop effective prophylactic and therapeutic vaccines, drugs and treatment approach to counter HPV effectively. Exploration and more researches on such advances could result in the gradual reduction in the incidences of HPV cases across the world. The present review presents a current global scenario and futuristic prospects of the advanced prophylactic and therapeutic approaches against HPV along with recent patents coverage of the progress and advances in drugs, vaccines and therapeutic regimens to effectively combat HPV infections and its cancerous conditions.

Efficacy and safety of photodynamic therapy for cervical intraepithelial neoplasia and human papilloma virus infection: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

We sought to conduct a systemic review and meta-analysis of randomized clinical trials to assess the efficacy and safety of photodynamic therapy (PDT) in cervical intraepithelial neoplasia (CIN) and cervical human papilloma virus (HPV) infection.

METHODS

The Medline, EMBASE, and Cochrane Central Register databases were searched using relevant keywords for entries up to May 1, 2017, irrespective of year of publication. The language was restricted to English. Randomized clinical trials and qualitative studies comparing PDT and placebo for CIN or HPV-positive patients were included. We assessed the evidence quality using a risk of bias graph in RevMan V5.3 and the Grading of Recommendations Assessment, Development, and Evaluation scoring system.

RESULTS

Of the 168 studies identified, only 4 RCTs met the inclusion criteria for meta-analysis. In all, 292 and 141 patients received PDT or placebo, respectively. PDT significantly increased the complete remission rate (CRR) among those with CIN (odds ratio [OR]: 2.51 [1.23-5.12]; P = .01) and HPV infection (OR: 3.82 [1.91-7.65]; P = .0002). The adverse events rate (AER) for PDT was greater than that for placebo (OR: 13.32 [4.44, 40.02]; P < .00001). The overall evidence quality was very low. Similarly, in a systematic review including 21 qualitative records, the CRRs for CIN patients with PDT and cervical HPV infection patients with PDT were 82.0% and 77.5%, respectively. The AER for PDT was 31.6%, which was lower than that observed in our meta-analysis (74.6%).

CONCLUSIONS

PDT that targets CIN or cervical HPV infection improves the CRR, but slightly compromises safety. Further studies are necessary to identify the most effective and least toxic photosensitizer.

Modulating mitochondrial morphology enhances antitumor effect of 5-ALA-mediated photodynamic therapy both in vitro and in vivo

5-aminolevulinic acid mediated PDT (5-ALA-PDT) is an approved therapeutic procedure for treating carcinomas of the cervix. However, when employed as a monotherapy, 5-ALA-PDT could not produce satisfactory results toward large and deep tumors. Therefore, developing a method to improve the efficacy of 5-ALA-PDT becomes important. In this study, we demonstrate an enhanced antitumor effect of 5-ALA-PDT by the modulation of mitochondrial morphology. The mitochondria in the cells were regulated into tubular mitochondria or fragmented mitochondria through over expression of Drp1 or Mfn2. Then these cells were treated with identical dose of 5-ALA-PDT. Our results suggest that HeLa cells predominantly containing fragmented mitochondria were more sensitive to 5-ALA-PDT than the cells predominantly containing tubular mitochondria. The morphology of mitochondria changed as the cell cycle progressed, with tubular mitochondria predominantly exhibited in the S phase and uniformly fragmented mitochondria predominantly displayed in the M phase. Paclitaxel significantly increased the population of M-phase cells, while 5-fluorouracil significantly increased the population of S-phase cells in xenograft tumors. Furthermore, low-dose paclitaxel significantly increased the antitumor effects of PDT. However, 5-fluorouracil didn't improve the antitumor effects of PDT. These results demonstrated an enhanced antitumor effect of 5-ALA-PDT from the modulation of mitochondrial morphology. We anticipate that our results will provide an insight for selecting potential chemotherapeutic agents to combine with PDT for tumor treatment.

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.

A Surgical View of Photodynamic Therapy in Oncology: A Review

Clinical photodynamic therapy (PDT) has existed for over 30 years, and its scientific basis has been known and investigated for well over 100 years. The scientific foundation of PDT is solid and its application to cancer treatment for many common neoplastic lesions has been the subject of a huge number of clinical trials and observational studies. Yet its acceptance by many clinicians has suffered from its absence from the undergraduate and/or postgraduate education curricula of surgeons, physicians, and oncologists. Surgeons in a variety of specialties many with years of experience who are familiar with PDT bear witness in many thousands of publications to its safety and efficacy as well as to the unique role that it can play in the treatment of cancer with its targeting precision, its lack of collateral damage to healthy structures surrounding the treated lesions, and its usage within minimal access therapy. PDT is closely related to the fluorescence phenomenon used in photodiagnosis. This review aspires both to inform and to present the clinical aspect of PDT as seen by a surgeon.

Vulvovaginal photodynamic therapy vs. topical corticosteroids in genital erosive lichen planus: a randomized controlled trial

BACKGROUND

Genital erosive lichen planus (GELP) in women is a chronic inflammatory disease characterized by painful vulval and vaginal erosions. Topical photodynamic therapy (PDT) is increasingly used in premalignant and malignant diseases and may have an effect in inflammatory diseases.

OBJECTIVES

To assess the feasibility, efficacy and safety of hexyl 5-aminolevulinate-hydrocloride (HAL)-PDT in GELP.

METHODS

Forty women, diagnosed with GELP at a specialized vulva clinic, were randomized to one session HAL-PDT in vulva and/or vagina (n = 20) or daily applications of clobetasol propionate 0·05% ointment in vulva and optional hydrocortisone acetate 1·0% foam in vagina for 6 weeks (n = 20). After 6 weeks, all patients were allowed to use topical corticosteroids as needed. Clinical examinations were performed at weeks 0, 6 and 24, using a clinical score developed for the study. All patients wrote a weekly log on pain, topical corticosteroid use and adverse events.

RESULTS

Three patients, all in the corticosteroid group, withdrew from the study after 1-3 weeks. The mean reduction in clinical scores was similar in the PDT group and the corticosteroid group; 25% vs. 22% after 6 weeks (P = 0·787) and 35% vs. 38% after 24 weeks (P = 0·801). The mean reduction in pain visual analogue scale scores was 38% vs. 55% after 6 weeks (P = 0·286) and 39% vs. 12% after 24 weeks (P = 0·452). Patients in the PDT group reported significantly less topical corticosteroid use during weeks 7-24 than those in the corticosteroid group. No major adverse events were reported.

CONCLUSIONS

Vulvovaginal HAL-PDT seems to be an effective and safe treatment for GELP.

A randomized study of hexaminolevulinate photodynamic therapy in patients with cervical intraepithelial neoplasia 1/2

OBJECTIVE

The objective of the study was to investigate the efficacy and safety of hexaminolevulinate (HAL) photodynamic therapy (PDT), a novel therapy for women with cervical intraepithelial neoplasia (CIN)1/2, to define the appropriate population and endpoints for a phase 3 program.

STUDY DESIGN

This was a double-blind, randomized, placebo-controlled, dose-finding study that included a total of 262 women with biopsy-confirmed CIN 1/2 based on local pathology. Patients received 1 or 2 topical treatments of HAL hydrochloride 0.2%, 1%, 5%, and placebo ointment and were evaluated for response after 3-6 months based on biopsy, Papanicolaou test, and oncogenic human papillomavirus (HPV) test. All efficacy analyses were performed on blinded central histology review to avoid interreader variability. Adverse events, blood biochemistry, and vital signs were assessed after 3 months.

RESULTS

There were no statistically significant differences between placebo and either the CIN 1 or combined CIN 1/2 populations. A clear dose effect with a statistically significant response in the HAL 5% group of 95% (18/19 patients) compared to 57% (12/21 patients) in the placebo group (P < .001) was observed at 3 months in women with CIN 2, including an encouraging 83% (5/6 patients) clearance of HPV 16/18 compared to 33% (2/6 patients) in the placebo group at 6 months. The treatment was easy to use and well accepted by patients and gynecologists. Only local self-limiting adverse reactions including discharge, discomfort, and spotting were reported.

CONCLUSION

HAL PDT is a novel therapy that shows promise in the treatment of CIN 2 including clearance of oncogenic HPV, but not of CIN 1. The positive risk/benefit balance makes HAL PDT a tissue-preserving alternative in women of childbearing age who wish to preserve the cervix. Confirmatory studies are planned.

Topical hexaminolevulinate photodynamic therapy for the treatment of persistent human papilloma virus infections and cervical intraepithelial neoplasia

INTRODUCTION

Current treatments for high-grade cervical intraepithelial neoplasia (CIN2/3) are mainly excisional procedures, which are associated with significant side effects and pose risks for future pregnancies. An effective and safe therapy is needed to reduce the requirement for surgical interventions in women of reproductive age.

AREAS COVERED

This review looks at the pharmacokinetic and clinical data for topical hexaminolevulinate (HAL) photodynamic therapy (PDT), which is currently entering late phase clinical trials for high-grade CIN. The authors include published studies in patients and volunteers but laboratory and animal studies have been excluded as have studies on other porphyrins such as Photofrin, 5-aminolevulinic acid, methyl aminolevulinate and studies reporting other clinical applications for HAL.

EXPERT OPINION

Topical HAL PDT has potential as a non-surgical tissue-preserving treatment for CIN and persistent oncogenic human papilloma virus infections. HAL PDT selectively treats the entire epithelial sheet, without the tissue destruction seen in excisional procedures. The authors believe that this treatment could replace surgery in a large proportion of patients. It would be of particular value to the high percentage of women who are interested in future child-bearing. If the treatment is approved, it is very likely that physicians will want to use this treatment, as many patients will be keen to consider a non-surgical option.

Bioadhesive mini-tablets for vaginal drug delivery

Different non-ionic cellulose ethers (methyl cellulose, MC; hydroxyethyl cellulose, HEC; hydroxypropyl cellulose, HPC; hydroxypropylmethyl cellulose, HPMC) and microcrystalline cellulose (MCC) were investigated as matrix formers for preparation of mini-tablets targeting vaginal drug delivery. Hexyl aminolevulinat hydrochloridum (HAL) was used as a model drug. The mini-tablets were characterized with respect to their mechanical strength, bioadhesion towards cow vaginal tissue in two independent tests (rotating cylinder test, detachment test using texture analyzer), and dissolution rate in two media mimicking the pH levels of fertile, healthy and post-menopausal women (vaginal fluid simulant pH 4.5, phosphate buffer pH 6.8). Mini-tablets with a matrix of either HPMC or HPC were found to possess adequate mechanical strength, superior bioadhesive behavior towards vaginal tissue, and pH independent controlled release of the model drug, suggesting that both systems would be suited for the treatment of women regardless of age, i.e., respective of their vaginal pH levels. Bioadhesive mini-tablets offer a potential for improved residence time in the vaginal cavity targeting contact with mucosal tissue and prolonged release of the drug.

Efficacy and safety of hexaminolevulinate photodynamic therapy in patients with low-grade cervical intraepithelial neoplasia

OBJECTIVE

Non-surgical therapies are needed to reduce the rate of progression of low-grade cervical intraepithelial neoplasia (CIN 1) to high grade CIN (CIN 2/3). The aim of this study was to assess the efficacy and safety of hexaminolevulinate (HAL) photodynamic therapy (PDT) in the treatment of patients with CIN 1.

STUDY DESIGN

This phase IIa prospective double-blind study randomized patients with CIN 1 into three groups: HAL vaginal suppository, placebo vaginal suppository or follow-up only. Patients in the first two groups received HAL or placebo suppositories 5 hours before illumination with 50 J/cm(2) red coherent light (633 nm) using a special light catheter. All patients had a follow up including colposcopy, cytology and human papilloma virus (HPV) testing 3 and 6 months and additional biopsy 6 months after PDT. The main outcome measure was efficacy, defined as complete histologic remission 6 months after PDT. Secondary outcomes were histologic remission 3 months and HPV eradication 6 months after first PDT.

RESULTS

Seventy patients were randomized: 47 to HAL, 12 to placebo, 11 to follow up only. After 6 months CIN lesions had cleared in 57% of patients in the HAL-PDT group compared to 25% in the combined control group (per protocol population, P = 0.04). Twenty-six patients (37%) reported 44 adverse events (AEs), of which 40 were mild or moderate. Nineteen treatment-related AEs were reported by 15 patients (32%) in the HAL PDT group, one in the placebo PDT group (8%), and none in the follow-up group. The most common adverse events were local discomfort including mild pain/cramping (11) and leucorrhoea (2).

CONCLUSION

HAL PDT shows a favorable efficacy and safety profile and represents a promising alternative to observation and surgical procedures in patients with CIN 1.

Topical photodynamic therapy using different porphyrin precursors leads to differences in vascular photosensitization and vascular damage in normal mouse skin

Different distributions of hexyl aminolevulinate (HAL), aminolevulinic acid (ALA) and methyl aminolevulinate (MAL) in the superficial vasculature are not well studied but they are hypothesized to play an important role in topical photodynamic therapy (PDT). The colocalization of fluorescent CD31 and protoporphyrin IX (PpIX) was calculated using confocal microscopy of mouse skin sections to investigate the vascular distribution after topical application. Vascular damage leads to disruption of the normal endothelial adherens junction complex, of which CD144 is an integral component. Therefore, normal CD31 combined with loss of normal fluorescent CD144 staining was visually scored to assess vascular damage. Both the vascular PpIX concentration and the vascular damage were highest for HAL, then ALA and then MAL. Vascular damage in MAL was not different from normal contralateral control skin. This pattern is consistent with literature data on vasoconstriction after PDT, and with the hypothesis that the vasculature plays a role in light fractionation that increases efficacy for HAL and ALA-PDT but not for MAL. These findings indicate that endothelial cells of superficial blood vessels synthesize biologically relevant PpIX concentrations, leading to vascular damage. Such vascular effects are expected to influence the oxygenation of tissue after PDT which can be important for treatment efficacy.

Efficacy and safety of photodynamic therapy for cervical intraepithelial neoplasia: a systemic review

BACKGROUND

The current treatment of cervical intraepithelial neoplasia (CIN) is primarily based on surgical excision using laser, a loop electrosurgical procedure, or a cold knife technique. Unfortunately, these treatments often lead to obstetrical problems during the subsequent pregnancy, particularly in young women. Photodynamic therapy (PDT), which uses a topical or intravenous photosensitizer (PS) activated by a light source to ablate abnormal tissue, offers a minimally invasive alternative. The purpose of this study was to comprehensively assess the effectiveness and safety of PDT in the treatment of CIN.

METHODS

Following Cochrane guidelines, a comprehensive systematic review of all clinical studies and reports examining the use of PDT for CIN was conducted. Study quality was assessed using the Oxford Levels of Evidence Scale.

RESULTS

The 14 studies included two randomized control trials (RCTs), one case-control study, and 11 case series. Among the 506 patients studied, 472 were included to study the effectiveness of PDT on CIN and 10 were lost to follow-up. An assessment of clinical effectiveness included the response of the lesion to treatment (may include lesion recurrence) reported by all 14 studies. The complete response rate (CRR) of PDT on CIN ranged from 0% to 100%. HPV eradication rate (HER) was reported in seven studies, with rates ranging from 53.4% to 80.0%.

CONCLUSIONS

PDT is a safe and tolerable treatment for CIN. Evidence regarding the efficacy of PDT for CIN is conflicting, which may, in part, be explained by the limited number of controlled comparative clinical trials.

The effect of light fractionation with a 2-h dark interval on the efficacy of topical hexyl-aminolevulinate photodynamic therapy in normal mouse skin

BACKGROUND

Light fractionation with a 2-h dark interval increases the efficacy of topical aminolevulinic acid (ALA) photodynamic therapy (PDT). Hexyl-aminolevulinate (HAL) is the hexyl ester of ALA. Both HAL and ALA lead to protoporphyrin IX (PpIX) accumulation in endothelial cells and to vascular effects, which are important for light fractionation. We investigated light fractionation for HAL-PDT in a mouse skin model and compared this with ALA.

METHODS

Three illumination schemes were studied: (a) 100 J cm(-2) in a single illumination; (b) 50+50 J cm(-2) in a twofold illumination; (c) a small first light fraction until 50% of PpIX was photobleached (ca. 3 J cm(-2)), followed by 97 J cm(-2) 2h later. PpIX fluorescence was measured continuously during illumination. Efficacy was evaluated by daily visual skin damage scoring up to 7 days after PDT.

RESULTS

Light fractionation showed a trend towards increased efficacy for HAL-PDT. Both the initial PpIX synthesis and the PpIX resynthesis during the dark interval were higher for ALA, but these were not correlated with efficacy. Single HAL-PDT was more effective than single ALA-PDT. Photobleaching rates of HAL and ALA were similar indicating similar biodistributions at depth.

CONCLUSION

Our results provide evidence to support that light fractionation may be beneficial for HAL-PDT. We are cautious because we found only a non-significant increase in response. However, combining our results with literature data suggest that the illumination scheme may be further optimized for HAL-PDT to potentially enhance the effect of light fractionation.

Aminolevulinic acid (ALA): photodynamic detection and potential therapeutic applications

Aminolevulinic acid (ALA) is a heme precursor that may have potential applications for photodynamic detection and photodynamic therapy-based treatment of solid tumors in a variety of malignancies. ALA may have a role in other applications in surgical oncology based on its ability to discriminate neoplastic tissue from adjacent normal tissue. In this review, we provide a comprehensive summary of the published studies of ALA in noncutaneous solid malignancies.

Formulation of bioadhesive hexylaminolevulinate pellets intended for photodynamic therapy in the treatment of cervical cancer

Photodynamic therapy has a great potential in the treatment of cervical cancer. The aim of this study was to develop bioadhesive pellets containing hexylaminolevulinate (HAL), a precursor of the photoactive substance PpIX, with a fast release for vaginal drug delivery. Pellets were produced by extrusion/spheronization, and Carbopol(®) 934 was used to obtain bioadhesive properties. A 2(2)-factorial design with center point investigating the HAL content (1 and 10%, w/w) and Carbopol(®) 934 content (1 and 8%, w/w) was set up. The most suitable formulations were mechanically stable and showed bioadhesive properties toward vaginal tissue. The drug load was released within 20 min in phosphate buffer pH 4 and 6.8 in the in vitro dissolution test. The stability of HAL in the pellet formulations varied, but the most stable formulation showed 96-97% HAL remaining in the formulation after 6-7 weeks of storage at accelerated temperature conditions (40 °C). The investigated formulations seem promising for vaginal delivery of HAL.

Vitamin D Combined with Aminolevulinate (ALA)-Mediated Photodynamic Therapy (PDT) for Human Psoriasis: A Proof-of-Principle Study

We previously showed that select agents (methotrexate or Vitamin D), when administered as a preconditioning regimen, are capable of promoting cellular differentiation of epithelial cancer cells while simultaneously enhancing the efficacy of 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT). In solid tumors, pretreatment with Vitamin D simultaneously promotes cellular differentiation and leads to selective accumulation of target porphyrins (mainly protoporphyrin IX, PpIX) within diseased tissue. However, questions of whether or not the effects upon cellular differentiation are inexorably linked to PpIX accumulation, and whether these effects might occur in hyperproliferative noncancerous tissues, have remained unanswered. In this paper, we reasoned that psoriasis, a human skin disease in which abnormal cellular proliferation and differentiation plays a major role, could serve as a useful model to test the effects of pro-differentiating agents upon PpIX levels in a non-neoplastic setting. In particular, Vitamin D, a treatment for psoriasis that restores (increases) differentiation, might increase PpIX levels in psoriatic lesions and facilitate their responsiveness to ALA-PDT. This concept was tested in a pilot study of 7 patients with bilaterally-matched psoriatic plaques. A regimen in which calcipotriol 0.005% ointment was applied for 3 days prior to ALA-PDT with blue light, led to preferential increases in PpIX (~130%), and reductions in thickness, redness, scaling, and itching in the pretreated plaques. The results suggest that a larger clinical trial is warranted to confirm a role for combination treatments with Vitamin D and ALA-PDT for psoriasis.

Matrix mediated fluorescence enhancement — why nanoparticles and PPIX make a friendly couple

The hexyl ester of 5-aminolevulinic acid (HAL) is an efficient inducer of the endogenous photosensitizer protoporphyrin IX (PPIX) in neoplastic tissue and approved for the fluorescence photodetection of bladder cancer. It is, however, limited to topical application due to unsuitable pharmacokinetic and pharmacodynamic properties following systemic administration. In this study we sought to prepare HAL laden polymeric nanoparticles made from polylactic acid (PLA) as possible means to improve the systemic bioavailability of HAL. Nanoparticles were prepared by nanoprecipitation. Particle size and morphology of freshly prepared and dehydrated nanoparticles were assessed and the ability to generate PPIX fluorescence was tested on a T24 human bladder carcinoma cell line. Fluorescence intensities of cells incubated with nanoencapsulated HAL were significantly higher than in presence of free HAL. Interestingly, the effect was — at least partly — provoked by the direct interaction of exogenously induced PPIX with the nanoparticles.

Photodynamic therapy of cervical intraepithelial neoplasia 1-3 and human papilloma virus (HMV) infection with methylaminolevulinate and hexaminolevulinate--a double-blind, dose-finding study

INTRODUCTION

Cervical intraepithelial neoplasia (CIN) 1-3 is the precursor of invasive cervical cancer and associated with human papillomavirus infection. Standard treatment is surgical and may be associated with subsequent pregnancy complications. Photodynamic therapy (PDT) of CIN may be an interesting alternative.

MATERIAL AND METHODS

Patients were treated by PDT using hexaminolevulinate (HAL) and methylaminolevulinate in six dose and light groups and two incubation periods in a double-blind setting. Follow-up examinations were performed after 3, 6, and 12 months with histology, cytology, and HPV testing.

RESULTS

We included eight patients with CIN1, 23 with CIN2, and 36 with CIN3. Treatment was well tolerated. HAL 40 mM with 3-hour application turned out to be the most-effective group with 67% (10/15) complete response rate. The combined complete and partial response for patients with CIN2 was 83% (20/24).

CONCLUSION

PDT with CIN may be a safe and effective procedure for CIN treatment.