Role of Topical Treatments in the Modulation of Skin Microbiome in Psoriatic Skin

Study Overview
=================
Brief Summary
-----------------
Changes in microbiome have been reported recently in psoriasis lesions compared to healthy surround skin. Preliminary data showed that systemic treatments of psoriasis induce modification of the skin microbiome that becomes similar to healthy individuals after successful treatment. The causative role of microbiome in psoriasis remains in debate. The modification of skin microbiome is suspected to be able to activate the innate immune response, namely natural killers (NKs) and immune lymphoid cells (ILCs). Three types of ILCs have been reported. ILC1 (immune lymphoid cells1) that trigger a Th1 response, ILC2 (immune lymphoid cells 2) that stimulate Th2 response and ILC3 (immune lymphoid cells 3) that induce Th17 response. Interestingly, ILC2 have been reported to be increased in atopic dermatitis while ILC3 are increased in psoriasis.

Detailed Description
-----------------
To date, there is no data on the impact of topical treatments in skin microbiome and in innate cells in psoriasis lesions. However, topical treatments remain in most cases the first and the more widely used option for mild psoriasis which represent the more prevalent form of psoriasis. Thus, it appears of great interest to assess the effect of topical psoriasis treatments on skin microbiome. To this respect, topical steroids by their action both on the inflammation but also potentially on bacteria are suspected to induce potent changes in the microbiome in treated psoriasis lesions. calcipotriol has been demonstrated to have a beneficial effect on psoriasis thanks to its action on keratinocyte differentiation and its combination with topical steroids has been shown to be superior in treating psoriasis as compared to topical steroids alone. It could be hypothesized that calcipotriol could also modify the skin microbiome. The main objective of this study intra individual prospective study is to compare the respective effect of betamethasone associated with calcipotriol foam and placebo foam in one hand and betamethasone with calcipotriol foam to betamethasone ointment on the other hand, on skin microbiome after 4 weeks of treatments on knee or elbow lesions. Secondary objectives are to study the impact of the treatments on ILCs (numbers and relative proportion in the 3 types) and NK in the lesions and their potential correlation with the modification of the microbiome (of note ILC can be detected and characterized in situ in skin.) To compare the relative effectiveness of the two products on targets psoriasis lesions. Tolerance and potential side effects will be also studied. Main endpoint: quantitative and qualitative assessment of microbes on psoriasis lesions before and after the treatments compared to surrounding healthy skin control. Secondary endpoints: Presence and types of ILCs and NK in the lesional psoriatic skin before and after treatment compared with control healthy skin assessed using immunohistofluorescence. Targeted PASI or PGA (physician Global Assessment) for the efficacy. Potential side effects. Patients: 30 with mild psoriasis (PASI <10) affecting elbows and knees in a symmetrical manner aged of at least 18.

Official Title
-----------------
Study Role of the Local Treatments on the Microbiome Modulation in the Psoriatic Skin. Study Monocentric, Interventional, Randomized and Single-blind

Conditions
-----------------
Psoriasis Vulgaris

Intervention / Treatment
-----------------
* Drug: Betamethasone-Calcipotriene Topical
* Drug: Betamethasone-Calcipotriene Topical
* Drug: Betamethasone-Calcipotriene Topical


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: 18 years of age who have signed and dated an informed information and consent form, Subject presenting psoriasis vulgaris with lesions symmetrical in size and severity, localized on the elbows and the knees and having a severity score (PASI) <=10. The lesions must have an area of at least 4 cm², Exclusion Criteria: Psoriasis in gout, erythrodermic, exfoliative or pustular Subject who has received systemic treatment and has a potential action on psoriasis vulgaris Subject who received topical treatments or neutral emollients within 4 weeks Subject who received antibiotic treatment in the three months preceding the randomization visit Subject with known or suspected hypersensitivity to any of the constituents of the products in the study

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: patients apply different treatment to two areas with psoriasis
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: betamethasone-calcipotriol versus placebo<br>In this arm we will compared the application association of betamethasone-calcipotriol foam in an area versus a placebo foam in an other area during 4 weeks. | Drug: Betamethasone-Calcipotriene Topical<br>* Comparison between betamethasone-calcipotriol and placebo<br>|
| Experimental: betamethasone-calcipotriol versus betamethasone<br>In this arm we will compared the application association of betamethasone-calcipotriol foam in an area versus a betamethasone pomade in an other area during 4 weeks. | Drug: Betamethasone-Calcipotriene Topical<br>* Comparison between betamethasone-calcipotriol and betamethasone<br>|
| Experimental: betamethasone-calcipotriol versus propionate of clobetasol<br>In this arm we will compared the application association of betamethasone-calcipotriol foam in an area versus a propionate of clobetasol pomade in an other area during 4 weeks. | Drug: Betamethasone-Calcipotriene Topical<br>* Comparison between betamethasone-calcipotriol and propionate de clobetasol<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quantitative evaluation of bacterial microbiota on psoriasis lesions and surrounding healthy skin by 16S rRNA (ribosomal ribonucleic acid 16S) amplification coupled with high throughput sequencing |  | after 4 weeks of treatment | 
| Qualitative evaluation of bacterial microbiota on psoriasis lesions and surrounding healthy skin by 16S rRNA (ribosomal ribonucleic acid 16S) amplification coupled with high throughput sequencing |  | after 4 weeks of treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Targetted Psoriasis Area and Severity Index for the effectiveness of the products tested. | Evaluated by PASI score (PASI= Psoriasis Area Severity Index) minimum = 0 = Absence of psoriasis maximum = 4 = very severe psoriasis | after 4 weeks of treatment | 
| Number of ILCs and NKs on skin biopsies using immunohistochemistry |  | after 4 weeks of treatment | 
| Types of ILCs and NKs on skin biopsies using immunohistochemistry |  | after 4 weeks of treatment | 
| Score of overall evaluation of the investigator's treatment | Evaluated by physician global assessment (PGA) score PGA = physician global assessment minimum = 0 = healing maximum = 5 = very severe psoriasis | after 4 weeks of treatment | 
| Evaluation of tolerance | evaluated numbers of serious adverse events | after 4 weeks of treatment | 
| Occurrence of possible adverse effects |  | after 4 weeks of treatment |