Topical treatment of malignant and premalignant skin lesions by very low concentrations of a standard mixture (BEC) of solasodine glycosides

183

Cancer Letters, 59 (1991) 183 - 192 Elsevier Scientific Publishers Ireland Ltd.

Topical treatment of malignant and premalignant skin lesions by very low concentrations of a standard mixture (BEC) of solasodine glycosides B.E. Cham”,

B. Daunterb

and R.A. Evansc

“Department of Medicine, bDepartment of Obstetrics and Gynaecology. The University of Queensland, Clinical Sciences Building, Royal Brisbane Hospital, Queensland 4029 and ‘Acacia Arcade, Acacia Ridge, Queensland 4110 (Australia)

(Received 11 January 1991) (Revision received 25 April 1991) (Accepted 26 April 1991)

tntroduction

Summary A cream

formulation

centrations

(10 %)

solasodine glycosides to be effective in the and

benign

report

human

that

containing

of

high

a standard

Previous studies have demonstrated that a cream formulation containing 10% of a standard mixture of purified solasodine glycosides (solamargine 33%) solasonine 33% and diand monoglycosides 34%)) referred to as BEC [l], was effective clinically and histologically in the treatment of human malignant skin tumours; BCCs, SCCs and benign tumours; keratoses and keratoacanthomas. 1r1 such studies [l-4] it was shown that there was no recurrence of any of the skin tumours after a 3-6-year follow-up period [Z]. Some patients in the previous study [2] have now been followed up for up to 10 years and no recurrence of the treated lesions have been observed (unpublished results). These results compare favourably with modalities of treatment such as surgery, radiotherapy and dermatology which have certain limitations such as formation of scar tissue, lack of normal tissue regrowth, limited access to the lesion if it is deep within the skin and a high rate of recurrence [4]. BEC is cytotoxic and selectively kills cancer cells [l-6]. Specific endogenous endocytic lectins which are present on the plasma membranes of susceptible cells recognize and bind

con-

mixture

of

(BEG’) has been shown treatment skin

a preparation

of malignant

tumours.

We

(Curaderm)

now which

very low concentrations of BEC (0.005 W) is effectiue in the treatment of keratoses, basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of the skin of humans. In an open study, clinical and

contains

histological sions (56 treated placebo number adverse

observations indicated that all lekeratoses, 39 BCCs and 29 SCCs)

with Curaderm had regressed. A formulation had no effect on a smaller of treated effect

haematopoietic

lesions. on

the

Curaderm liver,

had

kidneys

no or

system.

topical treatment; solasodine Keywords: glycosides; BEC; basal cell carcinoma; squamous cell carcinoma; keratosis Correspondence to: B.E. Cham,

Department of Medicine, The University of Queensland, Clinical Sciences Building, Royal Brisbane Hospital, Queensland 4029, U.S.A.

0304.3835/91/$03.50 Published

and Printed

0

1991 Elsevier Scientific

in Ireland

Publishers

Ireland

Ltd

184

tionale for this formulation has recently been described [4]. A placebo cream was also formulated which contained no BEC but ail the other components at identical concentrations as in Curaderm. Curaderm and placebo were supplied by Cura Nominees Pty . Ltd. Brisbane, Australia.

the sugar moiety of the solasodine glycoside. The glycosides are subsequently internalized and induce cell death by lysis of the targeted tumour cells as shown by in vitro [1,4--61 and in vivo [l-4,6,7] studies. Because the mode of action of BEC in treating tumour cells is now known [4-61 and because BEC is expensive to prepare, studies were undertaken to define more precisely the dose effective cost of BEC in the treatment of human skin tumours. The results of these studies demonstrated that the optimum concentration of BEC in a cream formulation containing keratolytic agents was 0.005%. This preparation is known commercially as Curaderm [4]. Preliminary studies with Curaderm have therefore been undertaken in the treatment of human skin tumours.

Patients and skin tumours Before entering the study, patients were informed verbally and gave their consent. Fortytwo females, aged 42-71 years, weight 51-75 kg with a total number of 72 lesions and 44 males, aged 38-74 years, weight 63-91 kg with a total number of 66 lesions, were studied. The diagnostic categories of the treated lesions are presented in Table I. All lesions including those with placebo treatment were at least 5 mm in diameter and were on faces, limbs or trunks of the subjects. The subjects attended a special outpatient clinic once a week. Diagnoses of all lesions before commencement of treatment and 3 months after completion of treatment were confirmed by of standard biopsy histological studies specimens (2 mm punch biopsy for lesions smaller than 10 mm and 4 mm punch biopsy for lesions larger than 10 mm). The progress of some cases was photographically documented at different stages of treatment and during the follow-up period. No local anaesthesia was used during the treatment.

Materialsand Methods Solasodine glycosides The solasodine glycosides (BEC) , consisted of a standard mixture of triglycosides solasonine, solamargine and their corresponding diand monoglycosides [l--8]. Formulations Curaderm contained BEC (0.005 %) , salicylic acid (lo%), urea (5%), meialeuca oil (0.1%) and linolenic acid (0.05%) in an oil-inwater cetomacrogol-based cream. The ra-

Table 1. Diagnostic No. of patients

category

and effect of Curaderm

Type of lesion

and placebo

No. of lesions

therapy Complete regression %

on human

skin tumors.

Treatment (weeks) Mean

28 20 24

Basal cell carcinoma Squamous cell carcinoma Keratosis

2 12

Basal cell carcinoma Keratosis

Curaderm therapy 39 100 29 100 56 100 Placebo therapy 2 0 12 0

f

period

S.D.

5.2 + 2.1 5.6 f 1.9 2.9 f 0.8 14 14

*o

l o

Range

3-13 3-11 l-4 14 14

185

Clinical, biochemical and haematological studies At each visit, routine clinical observations were made. Biochemical profiles (SMAC profiles I and II), full blood count and differential were performed on blood samples obtained from an antecubital vein before and on cessation of the therapy. Therapy - Curaderm treatment The application of Curaderm was according to the manufacturer’s instructions. These were explained verbally to each subject and, in addition, the patient received printed instructions. Curaderm was applied twice a day and the area was covered with a plastic dressing-strip. Treatment was continued until clinical regression was observed (l- 13 weeks).

Placebo treatment BCC is usually controlled by local means and is rarely metastatic. Nevertheless the potential risk of metastasis, though small, is real. In the case of SCC there is a much higher probability of metastases in patients with SCC of the skin. Because of these facts it was regarded unethical and unacceptable to perform a balanced placebo-control prospective preliminary trial in patients with these tumours. Therefore in these initial studies it seemed prudent to carry out placebo studies on only 2 patients with BCC and no patient with SCC. The patients were randomly selected and were able to apply Curaderm to the lesions. The treatment procedure with the placebo was identical to that of Curaderm; however, in the placebo group, treatment period was for 14 weeks, which was 1 week more than the longest treatment period with Curaderm (Table I). Compliance Compliance with study medication was assessed by requesting all patients to return Curaderm and placebo cream bottles, whether empty or not, at their weekly visits, and recording the weight of the bottles.

Basal cell carcinomas With Curaderm therapy the BCCs responded by initial swelling of the lesion with erythema of surrounding tissue. The area of erythema varied from lesion to lesion (approximately 5-20 mm around the lesion). The lesion ulcerated in about 2 days and this continued until neoplastic cells were destroyed (3-13 weeks) (Table I). Ulceration was followed by normal new non-malignant cell growth. In the 28 patients treated with Curaderm, all 39 lesions regressed clinically and histologically (Table I). Photographic documentation of two examples of Curaderm therapy for BCCs are presented. The first case (Fig. 1) is a BCC of the nose. This BCC was present for at least 12 months before treatment started. Independent prognoses for this patient were plastic surgery of limited effect and/or complete loss of the nose which was to be replaced with a prosthesis. Figure 1A illustrates several lesions on the nose before treatment started. Fig. 1B shows the lesion 3 weeks after commencement of Curaderm treatment. The lesions ulcerated over a wide area giving appearance of one large single lesion. During this period the ulceration progressed to the extent that the soft tissue (cartilage) of the nose was visible. Fig. 1C iltustrates where the BCC was. The patient was treated with Curaderm for 13 weeks. Although true comparison between the photographs in this case is difficult in view of the different exposures, it can be seen that the nose resumed its originat shape. A biopsy taken at the conclusion of the treatment indicated histologically that BCC was no longer present. No clinical recurrence was seen 3 years after compIetion of therapy. The second case is a BCC close to the eye (Fig. 2). This lesion was present for 4 months and was growing rapidly (Fig. 2A). Fig, 2B illustrates the lesion 2 weeks after commencement of Curaderm treatment. There was a distinct area of ulceration which was larger in area than the clinically

Fig. 1. Clinical diagnosis of a BCC on the nose of a patient before treatment with Curaderm (a), during therapy (b) and site of treated BCC after completion of therapy (c) Fig. 2. Clinical progress of a BCC close to the eye of the patient before treatment (a). during therapy (b) and site of treated BCC after completion of therapy with Curaderm (c).

187

Fig. 3. Histological diagnosis of a BCC of a patient before treatment (A) and site of treated BC:C(B) after c of therapy with Curaderm. Orig. mag. x 250, haematoxylin and eosin stain.

Jetion

188

189

Fig. 4.

Clinical progress of an SCC on the back of a hand of a patient before treatment site of treated SCC after completion of therapy with Curaderm (C).

distinguishable BCC prior to the Curaderm treatment. Fig. 2C shows where the BCC was after treatment with Curaderm. The treatment period in this case was 5 weeks. A biopsy taken at the conclusion of the treatment indicated histologically that BCC was no longer present. Figure 3A shows a typical histologically diagnosed BCC of a biopsy, whereas, Fig. 3B illustrates histologically that the BCC was no longer present after treatment with Curaderm. Squamous cell carcinomas The SCCs responded to Curaderm treatment by rapid softening and sloughing of their crusts, surrounding inflammation and ulceration. Twenty patients with a total number of 29 lesions were treated. All lesions responded to

(A), during therapy

(B) and

treatment by regressing clinically and histologically (Table I). As an example, the response of a large SCC towards Curaderm therapy is presented. Figures 4 and 5 illustrate clinical and histological progress, respectively, of an SCC on the back of a hand of a patient. The SCC was present for at least 6 months before treatment started. Before treatment, the SCC was 20 mm in diameter and protruded approximately 10 mm from the patient’s hand (Fig. 4A). Figure 4B shows the lesion 3 weeks after commencement of Curaderm treatment. There was a definite reduction in height of the lesion. The observable treated area appeared larger, indicating that the cancer cells had spread beyond the visible cancer on the skin before treatment commenced. Figure 4C shows the

Fig. 5. Histological diagnosis of an SCC of a patient before treatment (A) and site of treated SCC (B) after completion of therapy with Curaderm. Orig. mag. x250, haematoxylin and eosin stain.

191

situation after 5 weeks of treatment. Histological examination before (Fig. 5A) and after (Fig. 5B) treatment confirmed that the SCC was ablated by treatment with Curaderm. Keratoses The solar keratoses gradually decreased in size with Curaderm therapy until complete regression had occurred. Twenty-four patients with a total number of 56 keratoses were treated. All 56 lesions regressed clinically and histologically (Table I). Placebo treatment The clinical reaction of the placebo to the BCCs and keratoses was manifested by mild erythema of the lesions. Keratolysis was observed with some of the keratoses. However, on microscopic examination, there was still evidence of BCCs and keratoses in all cases after 14 weeks of treatment with the placebo. Thus, the placebo had no lasting therapeutic efficacy on these lesions. Duration of therapy The time required for complete removal of the tumours by Curaderm therapy varied between subjects and types of tumours (Table I). Toxicity Haematological, biochemical and urinalytical parameters obtained from each subject prior to, and after Curaderm treatment indicated that the parameters remained within the population normal range. There were no major adverse side-effects during Curaderm therapy except that itching and a burning sensation surrounding the treated lesions occurred in most cases. Discussion This study shows that BEC at low concentrations in the cream formulation Curaderm is a well-tolerated and effective treatment of large BCCs, SCCs and keratoses. An outstanding observation of the use of Curaderm was the cosmetic result. Other treatments such as

surgery or cryotherapy would have resulted in loss of massive amount of tissue with the resultant cosmetic limitations. Biopsies of all lesions were taken following therapy; however, in the majority of cases, the lesions were too large to allow excision of the total area of the previous tumour site. Therefore one cannot rule out absolutely residual tumour despite histological regression of the biopsy. No clinical recurrences have been observed over a 1-3-year follow-up period. In view of the original studies with high concentrations of BEC, where similar clinical and histological responses were observed over a lo-year follow-up period with no recurrences [2], it is likely that in the current studies complete regressions of these tumours were achieved. The duration of treatment is dependent on the size, mass and type of lesion being treated. Generally, redness and swelling are observed during treatment. Some pain was experienced by the patients for 15-60 min after each application of Curaderm. The treatment period is similar whether BEC 02 (10% BEC) [2] or Curaderm (0.005% BEC) is used to treat these lesions. All lesions treated with Curaderm responded virtually on application of the cream. Healing of the skin occurred simultaneously with Curaderm therapy. Regrowth of skin to the treatment sites was the endpoint of therapy. Further evidence of the efficacy of BEC in Curaderm was shown when the results of Curaderm were compared with placebo treatment. Placebo treatment had no lasting therapeutic effect on the lesions. For ethical reasons, only 2 BCCs and no SCCs were treated with the placebo. The reason for this was the risk that such lesions could metastasize with non-effective treatment. Compliance of all patients was good. These studies show that, BEC at a concentration of 0.005% in the formulation Curaderm, is as effective as the previously reported formulation BEC 02 which contained 10% BEC [2] for the treatment of skin lesions. In the previous study with the BEC 02 formulation, it was reported that complete regression was ob-

192

tained in 83% of patients with BCCs and SCCs. The remaining patients ‘dropped out’ of the study [2]. For the current trial, all patients completed the study regimen and thus it could be shown that complete regression of the treated lesions had occurred in all patients. It was previously shown that 10% BEC in the cream formulation BEC 02 had no effect on normal skin [2] indicating specificity of BEC towards malignant cells. Furthermore, more recently it was also shown in cell culture studies with various malignant and non-malignant human cells [ 1,4,5], and in animal studies with sarcoma 180 [6,7] that BEC is more specific towards cancer cells relative to normal cells. These observations are in agreement with the current studies in which it could be seen that when all malignant cells were killed, normal cells regrew during Curaderm treatment. Finally, as shown in Figs. 1 and 2, with appropriate medical supervision Curaderm can be used effectively on lesions at sites on the body where treatment is difficult by other procedures. The results of these preliminary studies warrant further investigation. Currently, balanced placebo-controlled prospective multicentre trials of Curaderm in selected patients with BCCs not known to be rapidly-growing and open sequential trials of Curaderm on patients with SCCs are underway. Such studies will

ultimately determine whether Curaderm will be advocated universally as a first fine treatment for carcinomas of the skin. Acknowledgements We wish to thank Cura Nominees Proprietary Ltd. for supplying Curaderm and the placebo for these studies. References Cham, B.E. (1988) Fut,ure, 13, 714-716.

Monograph

on BEC.

Drugs

of the

Cham. B.E. and Meares, H.M. (1987) Glycoalkaloids from Solanum sodomaeum are effective in the treatment of skin cancers in man. Cancer Lett., 36, 111-118. Cham, B.E and Daunter. B. (1989) Curaderm (anti- neoplastic) launched in Australia. Drug News Perspect., 2, ,

112. Cham, B.E. and Daunter. B. (1990) Topical treatment of pre-malignant and malignant skin cancers with Curaderm. Drugs of Today, 26, 55-58. Daunter, B. and Cham, B.E. (1990) Solasodine glycosides. In vitro preferential cytotoxicity for human cancer cells. Cancer Lett., 55. 209-220. Cham, B.E. and Daunter, B. (1990) Solasodine glycosides. Selective cytotoxicity for cancer cells and inhibition of cytotoxicity by rhamnose in mice with Sarcoma 180 activity. Cancer Lett., 55, 221-225. Cham, B.E.. Gilliver, M. and Wilson, L. (1987) Antitumour effects of glycoalkaloids isolated from Solanum sodomaeum. Planta Med., 53, 34-36. Cham, B.E. and Wilson, L. (1987) HPLC of glycoalkaloids from Solanum

sodomaeum.

Planta

Med., 53, 59-62.