Photodynamic therapy (PDT) was the selective destruction of abnormal cells through light activation of a photosensitiser in the presence of oxygen. These cells accumulated more photosensitiser than normal cells. The photosensitiser generated reactive oxygen species upon illumination. For skin diseases, there had been an increasing interest in using precursors of the endogenous photosensitiser protoporphyrin IX (PpIX). The most commonly used precursors had been 5-aminolevulinic acid (ALA) and its derivatives. The present test drug, Metvix®, contained the methyl ester of ALA, which penetrated the lesions well and shows high lesion selectivity . In vitro studies of animal and human tissues had shown significant intracellular formation of photoactive porphyrins after addition of Metvix®. The increased levels of photoactive porphyrins induced cytotoxic effects in tumour cells after photoactivation. The primary objective was to compare PDT with Metvix® cream to PDT with placebo cream in terms of participant complete response rates based on histologically verified disappearance of the lesions at 6 months after last treatment cycle. Secondary objectives were to compare the two treatments in terms of histological and clinical mean participant response weighted by the number of lesions within a participant, lesion response rates across participants, clinical complete participant response, cosmetic outcome and adverse events.
A participant was randomised to PDT with Metvix® cream or PDT with placebo cream. All eligible Basal cell carcinoma (BCC) lesions within a participant had got the same treatment. All participants got two consecutive treatments one week apart. At the 3-months follow-up visit, lesions with no clinical response or progression had been surgically excised. Lesions with partial response (50% or greater reduction on lesion area) had been re-treated, if they do not show complete response three months later they would have been be surgically excised. Lesions with complete response had been surgically excised 6 months after the first or second PDT cycle. All excised tissue specimens had been histologically examined.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
66
Dept. of Dermatology, Royal Prince Alfred Hospital
Camperdown, New South Wales, Australia
Dermatology Dept., St. George Hospital
Kogarah, New South Wales, Australia
Dermatology Centre
Liverpool, New South Wales, Australia
Dr. Michael Freeman
Benowa, Queensland, Australia
Dermatology Dept., Princess Alexandra Hospital
Woolloongabba, Queensland, Australia
Department of Dermatology, St. Vincent's Hospital Melbourne
Fitzroy, Victoria, Australia
Fremantle Dermatology
Fremantle, Western Australia, Australia
Percentage of Participants With Histologically Confirmed Complete Response (CR)
Complete Response (CR) was defined as 100 percentage of the lesions within the participant having negative findings for nodular basal cell carcinoma (BCC) in the histological examination. Histological examination included evaluation of all the microscopical slides from the excised tissue for presence of malignant basal cells. Complete response was defined as complete disappearance of lesion. Percentage of participants with histologically confirmed complete response were reported.
Time frame: up to 6 months
Percentage of Lesions Per Participant: Histologically Confirmed Participant Weighted Response
Histological response weight means no signs of malignant basal cells in all microscopical slides containing excised tissue. The histologically confirmed participant weighted response, weighted by percentage of lesions per participant are reported in this outcome measure. Number of lesions per participant with-in treatment group were calculated in following way: ni = number of lesions within 1 participant, ci= number of lesions in complete response within 1 participant, xi= 100%. ci/ni= response rate within one participant, Nt= number of participant within one treatment, nt=number of lesions with-in one treatment, wi=ni/nt= weight for one participant with Nt Σ wi (i=1) = 1 for each treatment.
Time frame: Up to 3 months
Histological Lesion Response
Histological examination included from the excised tissue were examined for presence of malignant basal cells, where complete response (CR) was no signs of malignant basal cells and non-CR was evidence of malignant basal cells
Time frame: Up to 3 months
Percentage of Participants With Clinically Confirmed Participant Complete Response (CR)
A CR to treatment was documented clinically by visual evaluation and palpation. The on-site investigator evaluated the lesion response by comparing with the lesion size before treatment using the following definitions: CR - complete disappearance of a lesion. Partial response (PR) -the longest diameter of the lesion is reduced by 50% or more. No response (NR) - the longest diameter of the lesion is less than 50% reduced. Progression - the longest diameter is increased by 20% or more.
Time frame: Up to 9 months
Cosmetic Outcomes for Lesions Assessed by Investigator
Cosmetic outcome for those lesions with complete histological response was assessed by both the investigator and by the participant. Cosmetic outcome was assessed with regards to occurrence of the following signs or symptoms like scarring, atrophy, induration, redness, and change in pigmentation. The cosmetic outcome was graded as excellent: no scarring, atrophy or induration, and no or slight occurrence of redness or change in pigmentation compared to adjacent skin; good: no scarring, atrophy or induration but moderate redness or change in pigmentation compared to adjacent skin; fair: slight to moderate occurrence of scarring, atrophy or induration; poor: extensive occurrence of scarring, atrophy or induration.
Time frame: Up to 3 months
Number of Participants With Serious Adverse Events (SAEs) and AEs Leading to Discontinuation
An AE was any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and which does not necessarily had a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory value), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. A SAE was any untoward medical occurrence that at any dose: results in death, was life-threatening, required hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, or was a congenital anomaly/birth defect.
Time frame: Up to 6 months
Cosmetic Outcomes for Lesions Assessed by Participants
Cosmetic outcome for those lesions with complete histological response was assessed by both the investigator and by the participant. Cosmetic outcome was assessed with regards to occurrence of the following signs or symptoms like scarring, atrophy, induration, redness, and change in pigmentation. The cosmetic outcome was graded as excellent: no scarring, atrophy or induration, and no or slight occurrence of redness or change in pigmentation compared to adjacent skin; good: no scarring, atrophy or induration but moderate redness or change in pigmentation compared to adjacent skin; fair: slight to moderate occurrence of scarring, atrophy or induration; poor: extensive occurrence of scarring, atrophy or induration.
Time frame: Up to 3 months
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