Randomized, double-blind, placebo-controlled, parallel group clinical study with 3 active dose arms (Rivelin®-CLO patches) and one placebo arm (Rivelin® plain patch). Up to 6 Rivelin® patches will be applied to symptomatic ulcerative and symptomatic erythematous OLP lesions.
After screening (visit 1, day -14 to day -7), patients who have signed the informed consent form and who are fulfilling the inclusion criteria and none of the exclusion criteria will be randomized at baseline (visit 2, day 1) to one of the four treatment arms in a double-blinded fashion.
* Arm A: Rivelin® plain patch (Placebo)
* Arm B: Rivelin®-CLO 1 μg/patch
* Arm C: Rivelin®-CLO 5 μg/patch
* Arm D: Rivelin®-CLO 20 μg/patch Randomization will be 1:1:1:1 and patients will be stratified according to number of patches needed (1-3 and 4-6).
The screening phase ranges between 7 and 14 days, i.e. that the screening visit (visit 1) needs to be performed 7 days prior to baseline at latest. For visits 3 (day 8), 4 (day 15), 5 (day 22), and 6 (day 29) a visit window of +/- 2 days will be allowed. Visit 7 will be defined as visit 6 + 14 days, with a visit window of +/- 3 days.
Randomized patients will enter a 28-days (4-weeks) treatment period. Dosing is two times per day (morning and evening) with patches applied directly on OLP lesions as instructed by a clinician or delegated site staff. Patients will record symptoms and adhesion time in daily diaries by using an electronic diary (eDiary).
During the treatment period, the treating physician or dentist will perform an assessment of the disease status on a weekly basis. A final examination of disease status will be performed at the follow-up visit (visit 7), 14 days after the end of treatment.
Other treatments of symptomatic OLP lesions during the study are prohibited. Only rescue analgesics determined by the investigator at study entry on a patient specific basis are allowed to be taken, in case that OLP associated symptoms like pain cannot be managed by the sole use of the patches. All doses of rescue analgesics will be recorded by the patient in the eDiary.
If the patients' condition is worsening (at the discretion of the investigator) and if associated symptoms cannot longer be managed acceptably by the additional use of rescue analgesics, i.e. if there is the need to start any other OLP treatment, IMP treatment for that patient should be discontinued prematurely and patient should be withdrawn from the study.
At visit 3 (day 8), a blood sample will be drawn to measure the blood plasma concentration of clobetasol and to determine the morning serum cortisol level (between 7 and 9 AM).
All patients will have a follow-up visit that will be performed 2 weeks after the EoT/ET visit (visit 6).
Safety data (by means of AE documentation including fungal infections and SAE reporting) will be closely monitored by an independent Data and Safety Monitoring Board (DSMB). DSMB will advise the Sponsor of any potential risk for the safeguard of patients.
