Podophyllin ( 10 % ) Ointment : A New Therapeutic Modality for Psoriasis *

Background: There are many topical therapies for the treatment of plaque psoriasis like steroid, dithranol, tar and vitamin D analogues, but none of them is ideal. Most recently, in a pilot study, podophyllin 5% ointment on every other day regimen was as effective as clobetasole 0.05% ointment twice daily. Objective: To reassess the efficacy of a higher concentration of podophyllin (10%) in the treatment of mild psoriasis in comparison with clobetasole using a different regimen. Patients and Methods: This is therapeutic, comparative, placebo-controlled study conducted at the Department of Dermatology-Baghdad Teaching Hospital, during the period of January 2011 October 2012. Eighty-seven patients with mild plaque-type psoriasis were divided into three groups: Group A (30) patients were treated with podophyllin 10% ointment; Group B (30) patients were treated with clobetasol propionate 0.05% ointment and Group C (27) patients were treated with Vaseline as a placebo control group. All patients were treated on every other day. The efficacy was evaluated every 2 weeks for 8 weeks using PASI score and the local and systemic side effects were recorded. The relapse was recorded after cessation of therapy in those patients who achieved good response during another 8 weeks follow-up period. Results: The patients were 60 (68.9%) males and 27 (31.1%) females (male: female ratio, 2.2:1). Their ages ranged from 18 62 (36.4 ± 10) years. Their disease duration ranged from 0.1 40 (7.8 ± 8.5) years. Their baseline PASI score ranged from 1.6 9.6 (4.4 ± 5.85). At the end of 8 week of therapy, Group A patients had achieved much higher reduction in PASI score (77.4 ± 14.1) than Group B patients (60.4 ± 27.8), P value = 0.004, and both of them were with statistically and significantly higher PASI reduction than patients in Group C (28 ± 23.4), P value = <0.001. The total relapse rate during 8 weeks follow-up was much lower among Group A treated patients, 20% versus 66.6% in Group B (P-value = 0.002), while the relapse rate was 100% in the Group C patients. Regarding side effects: 3 (10%) patients developed erythema, burning, pain, blistering and hypopigmentationin Group A. No side effects were reported in Groups B nor C patients with no statistically significant difference among the three groups (P = 0.052). Conclusion: Podophyllin 10% ointment was more effective than clobetasole 0.05% ointment on every other day treatment regimen at the end of 8 weeks treatment with no side effects and a much lower relapse rate in treatment of mild plaque-type psoriasis.


Introduction
Psoriasis is a common dermatological disease whose aetiology is multifactorial, but the immune theory is the most established one.Treatment of psoriasis depends on its severity which could be topical or systemic.Topical corticosteroid is commonly prescribed in psoriasis, but frequently associated with many side effects especially on long term use with high relapse rate.Dovonex and dovobet had also been used but with less encouraging results, and less side effects than topical corticosteroids [1,2].* Disclosure: This study is an independent study and not funded by any drug company.# Corresponding author.
Podophyllin, an alcoholic plant extract obtained from dried rhizomes of common plants called emodi (Indian podophyllum) or podophyllumpeltatum (May apple or Mandrake) [3].Podophyllun resin contains many active ingredients that work through multiple actions mainly by arresting mitosis and differentiation, blocking oxidation enzymes in tricaboxylic acid cycle and thus interfering with cell nutrition, inhibiting axonal transport, protein, RNA, and DNA synthesis and affecting mitochondrial activity with reducing cytochrome oxidase activity [4].Podophyllin had been used over a long time for the treatment of viral warts with possible side effects if it's used on large area [3], and also been used in treatment of genital warts in infants with no noticeable side effects [5].Recently, podophyllin 25% had been used as effective therapy for cutaneous leishmaniasis [6] and basal cell carcinoma [7,8].Most recently podophyllin 25% solution had been used in treatment of genital warts in pregnant women with no reported side effects in mothers and infants for one year follow-up [9].Those studies encouraged us to conduct a pilot study for the treatment of 62 patients with mild plaque psoriasis and the results were very promising [10].In that study, at the end of 8 weeks treatment, podophyllin 5% ointment on every other day was found to be as effective as clobetasole 0.05% ointment twice daily with no local or systemic side effects and with a much lower relapse rate.
Therefore the objective of the present work is to perform a further study to re-evaluate the efficacy and safety of a higher concentration of podophyllin (10%) in comparison with clobetasole and Vaseline with all being used on every other day based regimen.

Patients and Methods
This is therapeutic, comparative, single-blind, placebocontrolled study was carried out at the Department of Dermatology and Venereology, Baghdad Teaching Hospital, during the period from July 2011 to October 2012.
The nature and target of this study were explained for each patient.Formal consent was taken from each patient before starting the therapy, after full explanation about the nature of the disease, course, and the options of treatment, follow up, prognosis, complications and the need for pre and post treatment photographs.Also, the ethical approval was given by the scientific committee of the Scientific Council of Dermatology & Venereology-Iraqi Board for Medical Specializations.
Inclusion criteria: Mild plaque-type psoriasis which is defined as PASI score of less than 10.
Exclusion criteria: making use of history, physical examination and investigations, the following population were excluded: pregnant or lactating women, patients younger than 18 years, those with hepatic, renal, haematological or other systemic disorders, immunosuppression, diabetes mellitus, peripheral neuropathy, poor peripheral circulation, patients with lesions on the follow-ing sites: Scalp, face, acral parts, hands and feet, intertriginous and anogenital areas.Patients with pustular and guttate psoriasis were also excluded.
The diagnosis was established on clinical basis, and the patients were not taking any topical nor systemic psoriasis treatment for at least 3 months prior to starting the treatment.History was taken regarding: gender, age, and age of onset, duration of disease and presence of itching.Physical examination was done to assess the site, surface area and severity of psoriasis using PASI score.A total of 98 patients with mild plaque-type psoriasis were evaluated but only 87 patients completed the study (both the treatment and follow up period).The patients defaulted for many reasons mainly transport and security reasons.They were divided into three groups according to their treatments model: Group A: Thirty patients treated with podophyllin 10% ointment every other day.Podophyllin 10% ointment was prepared by mixing 10 g of podophyllum resin powder (purchased from Merck Company, Germany) with up to 100 grams Vaseline kept in a plastic container at room temperature in the hospital.Patients were instructed to apply a thin layer of podophyllin preparation on the psoriatic plaque, avoiding the surrounding normal skin, with the use of disposable nylon gloves and to wash off the area with water and soap after 6 hours (Figure 1).
Group B: Thirty patients treated with clobetasole propionate 0.05% ointment [manufactured by the State Company for Drug Industries and Medical Appliances Nineveh-Iraq (NDI) under licence of SDI Co.] in unlabelled tube.
Group C: Twenty seven patients treated with Vaseline only (manufactured by Anglo-Dutch Company Unilever) kept in a plastic container at room temperature in the hospital.
All patients in the three groups were treated on every other day.Patients were assessed at 5 visits during the treatment period: at week zero, week 2, week 4, week 6 and week 8 to record the clinical response, cure and any local or systemic side effects.After the cessation of treatment, all patients were followed up every 4 weeks for another 8 weeks during which relapse and any local or systemic side effects were recorded.Patients were screened to record any systemic podophyllin side effects by clinical assessment and by doing the following investigations before, during and after treatment: general urine examination, complete blood picture, erythrocyte sedimentation rate, liver and renal function tests, serum electrolytes, fasting blood sugar, and serum amylase and serum lactate dehydrogenase.

Efficacy Evaluations
Pre, during and post treatment photographs were taken using Sony-digital, high sensitivity ISO 1600, 10.1 mega pixels, DSC-N2 optical steady shot camera, in the same place with fixed illumination and distance.
Assessment of drug efficacy was based on the reduction of PASI score.Patients were considered as good responders if the reduction in PASI score was 50% or more [11], partial responders if the reduction in PASI score was 25% -49% and poor responders if the reduction in PASI score was <25% [12].Complete clearance was considered when there was a reduction in PASI score of ≥90%.Relapses defined as loss of 50% of PASI improvement from baseline in patients who achieved at least 50% reduction in PASI score [13].

Statistical Analysis
SPSS v.18 (statistical package for social sciences version 18) used for data input and analysis.Continuous variables presented as mean ± SD (standard deviation) and discrete variables presented as numbers and percentages.Chi square test for independence is used to test the significance of association between discrete variables.For testing the significance in means between more than two samples; ANOVA test & Kruskal Wallis test are used as appropriate for independent samples and Friedman test used for related samples.For testing the significance of difference in means between two samples; Wilcoxon rank test used to test the significance of difference in means between tow related samples or in any place where the normality of distribution in question.Turkey HD test used to test the significance of difference between means of two independent samples as a complementary test after ANOVA test looking for the exact significance of difference between two means.For testing the significance of observed difference in means of two normally distributed continuous variables; t test for two independent samples was used.Findings with P value less than 0.05 were considered significant.

Results
A total of 87patients with mild plaque-type psoriasis who completed the study were evaluated during both the treatment and follow up period.They were 60 (68.9%) males and 27 (31.1%)females, with: male: female ratio 2.2:1.Their ages ranged from 18 -62 years with a mean ± SD of 36.4 ± 10 years.The newly diagnosed cases were 27 (31%) patients.The disease duration ranged from 0.1 -40 years with a mean ±SD of 7.8 ± 8.5 years and their age at onset ranged from 5 -55 years with a mean ± SD of 28.5 ± 12.9 years.Itching was positive in 42 (67.7%)cases.The family history was positive in 35 (40.2%) cases.
Their baseline PASI score ranged from 1.6 -9.6 with a mean ± SD of 4.4 ± 5.85.There was no statistically significant difference in the demographic features among the three groups.The location of treated psoriatic plaques in the three groups was shown in Table 1.
1. Group A: they were 21 (70%) males and 9 (30%) females with a male to female ratio of 2.3:1, their ages ranged from 18 -62 years with a mean ± SD of 35 ± 12.6 years.The newly diagnosed cases were 10 (33.3%) patients.Their disease duration ranged from 0.3 -31 years with a mean ± SD of 7.5 ± 9.1 years and their age at onset ranged from 6 -52 years with a mean ± SD of 27.4 ± 11.2 years.Itching was positive in 19 (63.3%) cases.The family history was positive in 10 (33.3%) cases.Their baseline PASI score ranged from 1.6 -9.4 with a mean ± SD of 5.1 ± 2.8 was reduced to a range of 0 -7.1 with a mean ± SD of 1.2 ± 0.9 after 8 weeks of treatment, this reduction in PASI score was statistically highly significant with P-value= <0.001.
2. Group B: they were 21 (70%) males and 9 (30%) females with a male to female ratio of 2.3:1, their ages ranged from 20 -60 years with a mean ± SD of 37.2 ± 11.4 years.The newly diagnosed cases were 9 (30%) patients.Their disease duration ranged from 0.1 -40 years with a mean ± SD of 8.3 ± 8.8 years, their age at onset ranged from 5 -55 years with a mean ± SD of 28.8 ± 13.9 years.Itching was positive in 18 (60%) cases.The family history was positive in 13 (43.3%)patients.Their baseline PASI score ranged from 1.7 -9.6 with a mean ± SD of 4.9 ± 2.7 was reduced to a range of 0 -9.6 with a mean ± SD of 2.5 ± 3 after 8 weeks of treatment, this reduction in PASI score was statistically highly signifi- cant with P-value= <0.001.
3. Group C: they were 18 (66.7%)males and 9 (33.3%)females with a male to female ratio of 2:1, their ages ranged from 20 -61 years with a mean ± SD of 37 ± 12.1 years.The newly diagnosed cases were 8 (29.6%) patients.Their disease duration ranged from 0.2 -30 years with a mean ± SD of 7.5 ± 7.8 years, their age at onset ranged from 6 -55 years with a mean ± SD of 29.4 ± 13.9 years.Itching was positive in 9 (33.3%)cases.The family history was positive in 12 (44.4%)cases.Their baseline PASI score ranged from 2 -9.6 with a mean ± SD of 4.9 ± 2 was reduced to a range of 0.3 -8.8 with a mean ± SD of 3.5 ± 1.9 after 8 weeks of treatment, this reduction in PASI score was statistically significant with P-value= <0.001.
In each group the patients were subdivided into 3 groups according to their response to treatments as follow (Tables 2 and 3): Group A, All patients, 30 (100%), achieved good response.Group B, patients who achieved good response were 21 (70%) patients, patients with partial response were 6 (20%) patients and patients who achieved poor response were 3 (10%) patients.Group C, patients who achieved good response were 3 (11.2%)patients, with partial response were 12 (44.4%)tients while those with poor response were 12 (44.4%)patients.
At the end of 8 weeks of treatment, Group A achieved a good response (≥50% PASI reduction) in all of cases 30 (100%) and the patients start to notice improvement after 4 weeks of treatment (Table 4).On the other hand, Group B achieved a good response in about 21 (70%) of cases, but the onset of action seemed to be slow as the improvement becomes clinically evident at 6 weeks of treatment.This difference was statistically significant, 100% versus 70% (P-value < 0.004), Table 3, and both of them achieved a statistically significantly higher percentage of patients with good response than Group C, 11.2%, P value = <0.001(Tables 2 and 3).
The difference in the percentage of patients who achieved complete clearance (PASI reduction ≥ 90%) between Group A and Group B treated patients was statistically not significant, 16.7% and 20% respectively (P-value = 1.000),Table 2, while no complete clearance was recorded in Group C.
The mean PASI reduction (mean ± SD) at different weeks of treatment for different groups ( When the speed of recovery was compared between Group A and Group B, the study showed no statistically significant difference at 2 weeks of therapy (P-value = 0.123), but with much quicker action in Group A at 4, 6 and 8 weeks of treatment with P-values of 0.047, 0.004, 0.004 respectively (Table 4).However, the difference in the mean PASI reduction between Group A (77.4 ± 14.1) and group C (28 ± 23.4) after 8 weeks of treatment was statistically significant with P-value = <0.001(Table 4).At the end of 8 th week of therapy, Group A was found to achieve much higher reduction in in PASI score (mean ± SD, 77.4 ± 14.1) than Group B (60.4 ± 27.8) treated patients and this difference was statistically significant (P value = 0.004) (Table 5) and both of them were with statistically significantly higher PASI reduction (mean ± SD) than patients with Group C, 77.4 ± 14.1 and 60.4 ± 27.8 versus 28.0 ± 23.4,P value = <0.001(Table 4).
The relapse rate in patients with good response was as follow: Group A, six (20%) patients relapsed after 8 weeks of stopping treatment.Group B, seven (33.3%) patients relapsed during the first 4 weeks after cessation of treatment and 7 (33.3%)patients relapsed after 8 weeks of stopping treatment.The total relapse rate was found in 14 (66.6%) of cases.
Group C, three (100%) patients relapsed during the first 4 weeks after cessation of treatment.
The total relapse rate during 8 weeks follow up was much lower among Group A, 20% versus 66.6% in Group B, which was statistically significant P-value= .002.On the other hand Group C had a relapse rate of 0   100%.The difference in relapse rate between the three modalities of treatments was statistically significant with p-value < 0.001.
The following local side effects were recorded: three (10%) patients developed erythema 3 (10%), burning 2 (6.7%), pain2 (6.7%) and blistering 2 (6.7%),where only the latter side effect necessitate temporary discontinuation of application for few days, and hypopigmentation1 (3.3%) in Group A. No side effects were reported in Groups B or C with no statistically significant difference among the three groups (P = 0.052).
Neither staining, unpleasant odour nor systemic side effects were reported.No systemic side effects were reported.

Discussion
Podophyllum resin contains several cytotoxic compounds in unpredictable ratio, [14] at least 16 active physiological compounds, including podophyllotoxin, picropodophyllin, α and β pellatins, podophyllotoxone and 6methoxy podophyllotoxin, kampherol and quercetin.[3] Of these podophyllotoxin is the major active constituent that is a lipid soluble compound which easily crosses cell membrane [15].
The current work showed that podophyllin 10% ointment was more effective than clobetasole 0.05% oint-ment on every other day use.All the results of the present work were much better than the results of the pilot study [10].So this study highly encourages every other day regimen probably to save time and money and insure better patient compliance (Table 5).
The speculated mechanism of action of podophyllin in psoriasis could include the antimitotic effect, arrest of cell differentiation and blocking of oxidizing enzymes.
Of interest podophyllin ointment had been showed no change in color, odors nor texture when it was kept in at room temperature after 8 weeks of preparation and use.This could probably be attributed to the occlusive properties of Vaseline providing beneficial expanded longer shelf life to podophyllin.
Podophyllin and dithranol had some features in common as both are plant derived crude compounds, acting through inhibiting cell proliferation and affecting oxidizing enzymes involved in mitochondrial function and cell nutrition [4,20].In a thrice weekly trial of short contact dithranol treatment, the mean PASI reduction was 82.3% which is very close to the present work results of 77.4% with podophyllin.Although in that study 6 out of 8 patients achieved a clearance of 90% or more with dithranol in comparison to 16.7% with podophyllin in the present work, but the drawback was using only 8 patients treated with dithranol [21].In a previous Iraqi study, dithranol on daily treatment, had resulted in a relapse of 29% at 12 weeks which was close to that of podophyllin (20%) at 8 weeks follow up in the present study [22].In addition, staining of skin, clothes, hair and nails is common with dithranol (100%) and the relative impracticality of dithranol had led to a decline in its use particularly for outpatients [1].
Five percent liquor carbonis detergens (LCD) in an emollient base resulted in a mean improvement of 48.7% by 4 weeks of daily based treatment [23] versus 77.4% mean PASI reduction by 8 weeks with alternate day podophyllin in the present work.While podophyllin achieved higher mean PASI reduction (77.4% vs. 66.6%)than crude coal tar with a lower relapse rate 20% versus 61% [22].Staining, folliculitis, unwelcome smell and appearance are well known common side effects of tar [2].
In comparison with 10% and 5% zinc sulphate cream, podophyllin achieved a higher good response in 100% of patients after 8 weeks treatment versus.60% and 53.8% after 12 weeks of treatment respectively with the onset of action seemed to be quicker with podophyllin as with zinc the patients started to notice improvement after 8 weeks of treatment with each concentration of cream versus 4 weeks in podophyllin.The relapse rate in podophyllin treated patients was much lower (20%) than that of 10% and 5% zinc sulphate creams 77.8% and 85.7% respectively.Also the side effects were much lower (10%) vs. 30.76%and 40% respectively [24].
In comparison with tazarotene, 0.05% or 0.1% gel applied once daily for 3 months showed 50% or greater improvement in 65% of patients [25], podophyllin was better with good response achieved in 100% of patients.In other study using tazarotene gel 0.05%, the percentage of patients with PASI reduction of ≥75 after 6 weeks of treatment was 45% [26] versus 87.6% after 8 weeks treatment with podophyllin in the present study.

Conclusion
In conclusion, this study has confirmed that podophyllin ointment is a new effective therapy for mild plaque-type psoriasis, and is more effective than other therapies including clobetasole with a lower relapse rate and without side effects.

Figure 1 .
Figure 1.Forty years old female patient treated with podophyllin: (a) Before treatment; (b) After 5 weeks treatment.