Phase 2a study to assess the efficacy and safety of CD07805/47 0.5% gel in the prevention of the flush of rosacea.

The objectives of this study in rosacea patients (type I&II) are:

• to demonstrate objectively that CD07805/47 0.5% gel is able to prevent a flush induced by a specific trigger (hot water) in controlled condition;
• to demonstrate that CD07805/47 0.5% gel is able to prevent a flush whatever the trigger in everyday life condition;
• to investigate if reduction in redness is associated with a decrease in skin sensations such as heat, stinging/burning, skin tension and sweating;
• to demonstrate that such efficacy on transient redness and sensations takes place in both populations (rosacea type I and rosacea type II).

This is a single-centre, randomized, Investigator masked, placebo controlled study comprising the following periods:

A screening period of maximum 4 weeks

A one-week treatment phase (Period 1) with 3 sessions using the flush model, every other day.

This Period 1 includes a cross-over design (first and third sessions) and a split face design (second session). During this period, thirty six (36) subjects will receive on site the study drugs as follows (the order of each session being randomized):

• CD07805/47 placebo gel on both sides of the face,
• one side of the face treated with CD07805/47 0.5% gel, the other side treated with the CD07805/47 placebo gel (the allocation of treatment on each half-face will be determined according to a randomization list),
• CD07805/47 0.5% gel on both sides of the face;

A 2-days wash-out period (between Period 1 and Period 2) with no treatment on either side of the face

A 4-week treatment phase (Period 2) corresponding to a cross-over design during which the subjects will apply themselves the study drugs at home on the whole face, once daily 7 days per week.

The subjects will be divided in 2 groups of eighteen (18) subjects and will receive either the CD07805/47 0.5% gel the first 2 weeks and then the CD07805/47 placebo gel or the CD07805/47 placebo gel the first 2 weeks and then the CD07805/47 0.5% gel, according to randomization.

All the subjects taking part into the study will not be randomized separately in the two periods but to the full sequence at the beginning of the clinical trial (same randomization number during all the study), explaining the arms/groups detailed in the section "Arms and Interventions".

Only primary efficacy endpoint: total number of flushes for each 2-week period will be detailed in the outcome measures section.

The other endpoints are secondary or exploratory.

The purpose of Period 1 is to assess whether simpler and shorter designs based on flush induced by a trigger could be as efficient to detect prevention of flush than the more classical and longer design of Period 2.

Inclusion Criteria:

1. The subject is a male or female, who is at least 18 years of age or older at Screening visit.
2. The subject has a clinical diagnosis of mild to moderate erythemato-telangiectatic rosacea or mild to moderate papulo-pustular rosacea according to the National Rosacea Society grading (Wilkin et al., 2004)
3. The subject had at least five flushing episodes during the last week before Screening and Baseline visits

Exclusion Criteria:

1. The subject has particular forms of rosacea (rosacea conglobata, rosacea fulminans, isolated rhinophyma, isolated pustulosis of the chin), or other concomitant facial dermatoses that are similar to rosacea such as peri-oral dermatitis, demodicidosis facial keratosis pilaris, seborrheic dermatitis, acute lupus erythematosus or actinic telangiectasia;
2. The subject has current treatment with monoamine oxidase inhibitors, barbiturates, opiates, sedatives, systemic anesthetics, or alpha-agonists;
3. The subject has less than 3 months stable dose treatment with tricyclic anti-depressants, cardiac glycosides, beta blockers or other antihypertensive agents;