Time-dependent hexaminolaevulinate induced protoporphyrin IX distribution after topical application in patients with cervical intraepithelial neoplasia: A fluorescence microscopy study

Multicentre, prospective, randomised controlled trial to evaluate hexaminolevulinate photodynamic therapy (Cevira) as a novel treatment in patients with high-grade squamous intraepithelial lesion: APRICITY phase 3 study protocol

INTRODUCTION

High-risk human papilloma virus (HPV)-associated cervical cancer is the fourth most common cancer in women worldwide. Current treatments of high-grade squamous intraepithelial lesion (HSIL) of the cervix are based on invasive surgical interventions, compromising cervical competence and functionality. APRICITY is a multicentre, prospective, double-blind, randomised controlled phase 3 study further evaluating the efficacy and safety of Cevira, an integrated drug-delivery and light-delivery device for hexaminolevulinate photodynamic therapy, which shows promise as a novel, non-invasive outpatient therapy for women with HSIL.

METHODS AND ANALYSIS

Patients with biopsy-confirmed HSIL histology are invited to participate in the study planned to be conducted at 47 sites in China and 25 sites in Ukraine, Russia and the European Union. The aim is to include at least 384 patients, which will be randomised to either Cevira or placebo group (2:1). All patients will be assessed 3 months after first treatment and a second treatment will be administered in patients who are HPV positive or have at least low-grade squamous intraepithelial lesion. Primary endpoint is the proportion of the responders 6 months after first treatment. Secondary efficacy and safety endpoints will be assessed at 6 months, and data for secondary performance endpoints of the Cevira device will be collected at 3 months and 6 months, in case second treatment was administered. All patients in the Cevira group will be enrolled in an open, long-term extension study for 6 months to collect additional efficacy and safety data (study extension endpoints).

ETHICS AND DISSEMINATION

The study was approved by the ethics committee of the Peking Union Medical College Hospital and Hannover Medical University, Germany. Findings will be disseminated through peer review publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT04484415; clinicaltrials.gov.

In vivo photobleaching kinetics and epithelial biodistribution of hexylaminolevulinate-induced protoporphyrin IX in rat bladder cancer

In a previous paper, we showed that rat bladder instillations with 8 or 16 mM of hexyl aminolevulinate (hALA) result in diametrically opposed photodynamic therapy efficiency. Although the same fluorescent intensities were detected spectroscopically and by fluorescent microscopy in both conditions, while a given light dose resulted in tumor necrosis with an intact bladder wall after 8 mM hALA, bladders instilled with 16 mM showed total wall necrosis without impact on the tumor. The current study investigated the photobleaching and localization pattern of protoporphyrin IX (PpIX) after both hALA intravesical instillations in tumor-bearing rat bladders. The total PpIX content was evaluated by the extraction of postmortem whole bladders. Photobleaching was evaluated in vivo by fluorescent spectroscopy. Cryosections of bladders were subjected to fluorescent microscopy for cellular localization of the photosensitizer. PpIX extraction showed identical amounts of photosensitizer in tumor-bearing bladders at both concentrations. Photobleaching experiments revealed mono-exponential decay curves in both situations but with a two times faster decay constant in 16 mM bladders. Fluorescent microscopy showed an identical fluorescent pattern for normal bladders at both concentrations and tumor bladders at 8 mM with bright spots. Tumor bladders at 16 mM exhibited a more diffuse cytoplasmatic fluorescent distribution. The different response to photodynamic therapy with regard to the initial pro-drug concentration can thus be attributed to the different cellular localizations.

Efficacy and safety of an adsorbent and anti-oxidative vaginal gel on CIN1 and 2, on high-risk HPV, and on p16/Ki-67: a randomized controlled trial

PURPOSE

The effect of SAM vaginal gel, a medical device containing adsorptive silicon dioxide and antioxidative sodium selenite and citric acid, on histologically-proven cervical intraepithelial neoplasia type 2 (CIN2) as well as p16 positive CIN1, and on the presence of the onco-marker p16 was investigated.

METHODS

216 women aged 25-60 years were randomized to either receive an intravaginal daily dose of SAM gel for three 28-day periods, or be followed-up without intervention. The primary endpoint was efficacy, defined as a combined histological and cytological regression. At baseline and after 3 months participants had: a guided biopsy including p16 immunohistochemical (IHC) staining, only if a lesion was visible at colposcopy; a cervical smear for cytology, high-risk human papillomavirus (hr-HPV) and a p16/Ki-67 test. At 6 months a further cytology and p16/Ki-67 test was performed.

RESULTS

Regression of CIN lesions was observed in 78 out of 108 patients (72.2%) in the SAM gel arm and in 27 out of 108 patients (25.0%) in the control arm. Similarly, the change in the p16/Ki-67 cytological test status was significantly in favor of the treatment arm. The prevalence of hr-HPV decreased significantly (p < 0.001) in the treatment arm, from 87.0% to 39.8%, while it slightly increased in the control arm, from 78.7% to 83.3%. At 6 months the cytological regression in the treatment group and the highly significant effect on p16/Ki-67 was still present.

CONCLUSION

SAM vaginal gel enhances the regression of cervical lesions and clears hr-HPV and p16/Ki-67 in smears significantly, thus offering an active non-destructive management to prevent cervical cancer.

TRIAL REGISTRATION NUMBER

ISRCTN11009040, date of registration: 10/12/2019; https://doi.org/10.1186/ISRCTN11009040 ; retrospectively registered.

5-Aminolevulinic Acid-Squalene Nanoassemblies for Tumor Photodetection and Therapy: In Vitro Studies

Protoporphyrin IX (PpIX) as natural photosensitizer derived from administration of 5-aminolevulinic acid (5-ALA) has found clinical use for photodiagnosis and photodynamic therapy of several cancers. However, broader use of 5-ALA in oncology is hampered by its charge and polarity that result in its reduced capacity for passing biological barriers and reaching the tumor tissue. Advanced drug delivery platforms are needed to improve the biodistribution of 5-ALA. Here, we report a new approach for the delivery of 5-ALA. Squalenoylation strategy was used to covalently conjugate 5-ALA to squalene, a natural precursor of cholesterol. 5-ALA-SQ nanoassemblies were formed by self-assembly in water. The nanoassemblies were monodisperse with average size of 70 nm, polydispersity index of 0.12, and ζ-potential of + 36 mV. They showed good stability over several weeks. The drug loading of 5-ALA was very high at 26%. In human prostate cancer cells PC3 and human glioblastoma cells U87MG, PpIX production was monitored in vitro upon the incubation with nanoassemblies. They were more efficient in generating PpIX-induced fluorescence in cancer cells compared to 5-ALA-Hex at 1.0 to 3.3 mM at short and long incubation times. Compared to 5-ALA, they showed superior fluorescence performance at 4 h which was diminished at 24 h. 5-ALA-SQ presents a novel nano-delivery platform with great potential for the systemic administration of 5-ALA.

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.

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.

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.

Photodynamic therapy for gynecological diseases and breast cancer

Photodynamic therapy (PDT) is a minimally invasive and promising new method in cancer treatment. Cytotoxic reactive oxygen species (ROS) are generated by the tissue-localized non-toxic sensitizer upon illumination and in the presence of oxygen. Thus, selective destruction of a targeted tumor may be achieved. Compared with traditional cancer treatment, PDI has advantages including higher selectivity and lower rate of toxicity. The high degree of selectivity of the proposed method was applied to cancer diagnosis using fluorescence. This article reviews previous studies done on PDT treatment and photodetection of cervical intraepithelial neoplasia, vulvar intraepithelial neoplasia, ovarian and breast cancer, and PDT application in treating non-cancer lesions. The article also highlights the clinical responses to PDT, and discusses the possibility of enhancing treatment efficacy by combination with immunotherapy and targeted therapy.

Photodynamic therapy based on 5-aminolevulinic acid and its use as an antimicrobial agent

Exogenous 5-aminolevulinic acid (ALA) is taken up directly by bacteria, yeasts, fungi, and some parasites, which then induces the accumulation of protoporphyrin IX (PPIX). Subsequent light irradiation of PPIX leads to the inactivation of these organisms via photodamage to their cellular structures. ALA uptake and light irradiation of PPIX produced by host cells leads to the inactivation of other parasites, along with some viruses, via the induction of an immune response. ALA-mediated PPIX production by host cells and light irradiation result in the inactivation of other viruses via either the induction of a host cell response or direct photodynamic attack on viral particles. This ALA-mediated production of light-activated PPIX has been extensively used as a form of photodynamic therapy (PDT) and has shown varying levels of efficacy in treating conditions that are associated with microbial infection, ranging from acne and verrucae to leishmaniasis and onychomycosis. However, for the treatment of some of these conditions by ALA-based PDT, the role of an antimicrobial effect has been disputed and in general, the mechanisms by which the technique inactivates microbes are not well understood. In this study, we review current understanding of the antimicrobial mechanisms used by ALA-based PDT and its role in the treatment of microbial infections along with its potential medical and nonmedical applications.

Effects of photodynamic therapy using topical applied hexylaminolevulinate and methylaminolevulinate upon the integrity of cervical epithelium

BACKGROUND AND OBJECTIVE

Cervical intraepithelial neoplasia (CIN) is associated with genital human papillomavirus (HPV) infection and represents the precursor of cervical cancer. Established ablative treatment methods may cause substantial complications in following pregnancies including premature delivery and the birth of low-weight babies. Photodynamic therapy (PDT) of CIN using esters of 5-aminolevulinic acid (5-ALA) represents a promising alternative. However, it has not been analyzed yet if the PDT itself leads to sustained damage of the cervical tissue. This study aims at evaluating the effect of hexylaminolevulinate (HAL) and methylaminolevulinate (MAL) PDT on cervical tissue.

STUDY DESIGN/MATERIALS AND METHODS

Twenty-five patients underwent 1-2 PDT cycles for CIN 1-3 applying topical HAL and MAL. Before and 6 months after PDT, biopsies were obtained from the cervix. Macroscopic changes of the cervix were evaluated. We assessed H&E slides for signs of sustained tissue damage. Furthermore, expression profiles of p16(INK4a), Ki67, Bcl-2, Bax, and CD31 were evaluated.

RESULTS

PDT was performed satisfactory in all patients. No macroscopic changes of the cervix were encountered and histological evaluation revealed no signs of apoptosis, necrosis, irritation, vascular changes and fibroses 6 months after PDT. Ki67 and p16(INK4a) were useful for the prediction of response to PDT. Bcl-2 and Bax showed no significant expression profile changes after PDT and the micro-vessel pattern was not altered.

CONCLUSIONS

HAL and MAL PDT do not leave any sustained damage in normal cervical tissue. This is of paramount importance as cervical insufficiency or stenosis may have implications on pregnancy and cervical cancer screening.

Photodynamic therapy for intraepithelial neoplasia of the lower genital tract

Photodynamic Diagnosis (PDD) and Therapy (PDT) are modern methods which are evaluated in different fields in gynaecology. PDT has been successfully evaluated in human papillomavirus-related (HPV) genital dysplasia like CIN and VIN. The aim of this review is to give an overview about current applications.

Successful photodynamic therapy with topical 5-aminolevulinic acid for five cases of cervical intraepithelial neoplasia

OBJECTIVES

Photodynamic therapy (PDT) is a minimally invasive treatment for cervical intraepithelial neoplasia. The purpose of this study was to assess the feasibility and effectiveness of PDT in patients with CIN and high-risk HPV infection.

METHODS

Five patients diagnosed CIN 2 or CIN 3 with human papillomavirus (HPV) infection were included. Each patient had gynecologic examination including cervical cytology, HPV DNA testing, colposcopy and biopsy. Two grams of 5-aminolevulinic acid (ALA) gel (118 mg/g) was topically applied to the cervix and covered with a special plastic cap for 3-4 h, followed by 20 min illumination of both ecto- and endo-cervical canal with red coherent light (wavelength 633 nm) using a PDT laser and a special light catheter. The PDT therapy was repeated with an interval of 1 week. Follow-up examination including biopsy and histology, colposcopy, HPV DNA testing were carried out after 3, 6 and 9 months.

RESULTS

Treatment could be accomplished in all cases and no severe side effect was encountered. All the CIN2 patients had a complete response for 9 months and one CIN3 HPV remained positive for 6 months after three or four treatments.

CONCLUSION

PDT seems to be a non-invasive, repeatable procedure for CIN and cervical HPV infection with minimal side effects and can be easily performed on outpatient basis.

[Diagnosis of cervical squamous intraepithelial lesions by fluorescence imaging: clinical feasibility study]

OBJECTIVE

Fluorescence diagnosis is still undeveloped in gynaecology. In order to diagnose and localize squamous intraepithelial lesion (SIL) of the cervix, a new method improving the low specificity of colposcopy would be useful. The goal of this study was to assess the feasibility and safety of colposcopic fluorescence diagnosis of SIL after topically application of methyl aminolevulinate (MAL).

PATIENTS AND METHODS

Patients with histologic proved cervical intraepithelial neoplasia (CIN) and planned for loop electrosurgical excision procedure (LEEP) under general anesthesia were included in a prospective study. Before general anesthesia, a thick layer of MAL (Metvix-160 mg/mL cream) was applied on the cervix for 35-150 min. Fluorescent colposcopic inspection of the cervix was performed using a rigid 10-mm laparoscope inserted in the vaginal cavity and connected to D-light AF system (Karl Storz Endoskope, Tuttlingen Germany). In order to confirm neoplasic status, fluorescent foci underwent directed punch biopsy(ies).

RESULTS

Fourteen patients were included in the study. Colposcopic fluorescence imaging revealed red fluorescent foci in 71.4% of cases (10/14) (neoplasic status of fluorescent foci was confirmed in 80%). Concerning MAL, the mean of application time was 73 min (35-150). Two cases presented a false-positive fluorescence and four cases of false-negative fluorescence. For all cases of false-negative fluorescence, application time of MAL was less than 60 min. We observed no systemic or local toxicity of MAL application in any group.

DISCUSSION AND CONCLUSION

Using topical application of MAL to the cervix, we demonstrated that fluorescence diagnosis of SIL is feasible. This study justifies the further development of fluorescence imaging that combines classical white light colposcopy with the use of a photosensitizer.

Photodynamic therapy of cervical intraepithelial neoplasia with hexaminolevulinate

BACKGROUND AND OBJECTIVE

CIN is a disease of women in their reproductive years, and treatment includes excisional techniques with increased risk of preterm deliveries. Photodynamic therapy (PDT) using topical precursor of photoactive porphyrins may be a non-invasive alternative with minimal side effects. This study assessed the feasibility and response rate of PDT with hexaminolevulinate (HAL) in cervical intraepithelial neoplasia (CIN) and human papillomavirus (HPV) infection.

STUDY DESIGN/MATERIALS AND METHODS

Twenty four patients with a CIN 2 or 3 or a persistent CIN 1 and a positive high-risk HPV-DNA test were included. Each patient had gynaecologic examination including cervical cytology, HPV DNA testing, colposcopy and biopsy. Ten milliliters of HAL-thermogel (10 mM) were topically applied to the cervix for 3-5 hours, followed by 1,000 seconds of illumination of both ecto- and endocervical canal with red coherent light (wave length 633 nm) using a PDT laser and a special light catheter. Follow-up examinations were carried out after 3 (cytology, colposcopy, HPV DNA testing, and if needed re-PDT) and 6 months.

RESULTS

Seven, 10, and 7 patients had a CIN 1, 2, or 3, respectively. Treatment could be accomplished in all cases and no severe side effects were encountered. Fifteen out of the 24 patients had a complete response (15/24 = 63%) and a HPV remission 6 months after 1-3 treatments. The remission rates were 71%, 50%, and 71% for CIN 1, 2 and 3.

CONCLUSION

HAL PDT seems to be a non-invasive, repeatable procedure for CIN and cervical HPV infection with minimal side effects which can be easily performed on outpatient basis.

Thermosetting Gel for the Delivery of 5-Aminolevulinic Acid Esters to the Cervix

5-Aminolevulinic acid (5-ALA)-mediated photodynamic therapy has been proposed as an alternative, cervix-sparing treatment for cervical intraepithelial neoplasia (CIN). In this context, topical application of 5-ALA to the cervix is beneficial due to the small necessary dose and its minimal side effects. Therefore, lipophilic 5-ALA esters, such as hexylaminolevulinate (HAL), have led to improved local bioavailability and therapeutic efficacy. Hydrogels have shown to be more appropriate for the local delivery of these derivatives, but due to the limited long-term stability of such formulations at 25 degrees C, the development of an extemporaneously prepared hydrogel targeting CIN can be advantageous. Therefore, a poloxamer 407 thermosetting gel, which is liquid at room temperature and becomes a semi-solid when in contact with the female genital tract, has been evaluated in vitro and in vivo. Rheological evaluation has shown that a 17.0% poloxamer 407 hydrogel with a sol-gel transition at 24.8 +/- 0.6 degrees C was the best formulation for easy application and optimal residence time. Furthermore, similarly to other hydrogels previously tested, such a formulation shows a more complete HAL release in vitro than conventional cream vehicles, and tends to increase porphyrin accumulation in nude mice skin. Finally, in vitro release profiles were correlated to the in vivo results.

Pharmacokinetics and selectivity of porphyrin synthesis after topical application of hexaminolevulinate in patients with cervical intraepithelial neoplasia

OBJECTIVE

Photodynamic therapy has the potential of a minimal invasive outpatient procedure for CIN patients at reproductive ages. The purpose of this study was to examine the pharmacokinetics and selectivity of porphyrin synthesis after topical application of hexaminolevulinate (HAL) in patients with cervical intraepithelial neoplasia (CIN).

STUDY DESIGN

Twenty-four women with CIN 1-3 received 4 mmol/L or 10 mmol/L HAL dissolved in thermolabile pluronic F 127 gel topically 5-720 minutes before surgical conization. The microscopic fluorescence pattern was quantified by ex vivo fluorescence spectroscopy at a wavelength of 635 nm and semiquantitatively by digital image analysis from cryosections.

RESULTS

With 4 and 10 mmol/L HAL, porphyrin fluorescence intensity increased over time, reaching a peak after 180-540 minutes application intervals in CIN and normal epithelium. However, the peak was much more pronounced in CIN than in normal tissues. The fluorescence intensity with 10 mmol/L was significantly higher than that with 4 mmol/L in CIN tissues (P < .05). Maximum intensity could generally be detected in the lower layer of the epithelium.

CONCLUSION

HAL seems to be a promising molecule for fluorescence diagnosis. For further treatment studies, we recommend application of 10 mmol/L HAL 300-540 minutes before photodynamic therapy in CIN.

Fluorescence staining of human ovarian cancer tissue following application of 5-aminolevulinic acid: fluorescence microscopy studies

BACKGROUND AND OBJECTIVES

Application of 5-aminolevulinic acid (ALA) for fluorescence-guided second-look laparoscopy has been shown to be a promising new procedure in the early diagnosis of ovarian carcinoma metastases. However, for assessing the reliability of this method, information on the microscopic distribution of protoporphyrin IX (PP IX) in the tissue is needed. Additionally, the selectivity of PP IX uptake is essential for a potential photodynamic therapy (PDT) of ovarian cancer metastases.

STUDY DESIGN/MATERIALS AND METHODS

Thirty-six patients with epithelial ovarian cancer and two patients suffering from fallopian tube carcinoma underwent a laparoscopic second-look procedure 5 hours after the application of ALA. In 17 patients 36 fluorescence-guided biopsies were taken from fluorescing and non-fluorescing tissues for further evaluation. Fluorescence microscopy and digital image processing were utilized to determine the presence of PP IX fluorescence.

RESULTS

A specificity of 88% and a sensitivity of 100% with a negative predictive value of 100% and a positive predictive value of 91% were calculated for PP IX fluorescence on a microscopic level as marker for ovarian cancer metastases.

CONCLUSIONS

On a microscopic scale, ALA-induced PP IX fluorescence is confined to ovarian cancer tumor tissue sparing stromal tissues.

5-Aminolevulinic Acid Derivatives in Photomedicine: Characteristics, Application and Perspectives

The introduction of lipophilic derivatives of the naturally occurring heme precursor 5-aminolevulinic acid (5-ALA) into photomedicine has led to a true revival of this research area. 5-ALA-mediated photodynamic therapy (PDT) and fluorescence photodetection (FD) of neoplastic disease is probably one of the most selective cancer treatments currently known in oncology. To date, this method has been assessed experimentally for the treatment of various medical indications. However, the limited local bioavailability of 5-ALA has widely prevented its use in daily clinical practice. Although researchers were already aware of this drawback early during the development of 5-ALA-mediated PDT, only recently have well-established concepts in pharmaceutical science been adapted to investigate ways to overcome this drawback. Recently, two derivatives of 5-ALA, methylaminolevulinate (MAL) and hexylaminolevulinate (HAL), gained marketing authorization from the regulatory offices in Europe and Australia. MAL is marketed under the trade name Metvix for the treatment of actinic keratosis and difficult-to-treat basal cell carcinoma. HAL has recently been launched under the trade name Hexvix to improve the detection of superficial bladder cancer in Europe. This review will first present the fundamental concepts underlying the use of 5-ALA derivatives in PDT and FD from a chemical, biochemical and pharmaceutical point of view. Experimental evidences from preclinical data on the improvements and limits observed with 5-ALA derivatives will then be introduced. The state-of-the-art from clinical studies with 5-ALA esters will be discussed, with special emphasis placed on the process that led to the development of MAL in dermatology and to HAL in urology. Finally, we will discuss promising medical fields in which use of 5-ALA derivatives might potentially lead to further use of this methodology in photomedicine.