Lichen Planus Mucosae at USZ, Efficacy of Oral Alitretinoin

Inclusion criteria * Aged 18 to 75 years * MLP for at least 3 months * Disease activity according to Escudier score of 10 points or greater or erosive lesion of any score * Refractory to standard topical therapy * Consensus to a 2 weeks wash-out period of topical steroids before starting study treatment Exclusion criteria * Unable to comply with the requirements of the study * Pregnant or lactating women * Female patients of childbearing potential who cannot use or will not commit to using two effective forms of contraception simultaneously under supervision of the investigator or a gynecologist * Active hepatitis and/or vaccination against hepatitis A/B during the last 4 weeks * Adequate control of the disease by standard topical therapy and standard topical corticosteroid therapy * Known hypersensitivity to other retinoids or vitamin A derivatives, or to any study medication component * Patients treated with any of the following treatments 4 weeks before the start of study treatment: 1. systemic drugs: corticosteroids, immunosuppressants, methotrexate 2. phototherapy * Treatment with any systemic or topical retinoids within 1 year or 1 month, respectively, before start of study treatment or treatment with systemic retinoids for treatment for MLP at any time * coexistence of any serious medical condition which, in the opinion of the investigator, may interfere with the safety of the patient, including 1. hepatic insufficiency (alanine aminotransferase and /or aspartate aminotransferase values \> 2.5 x ULN) 2. severe renal failure 3. uncontrolled hypertriglyceridemia (triglycerides \>150 % of the upper limit of normal), 4. uncontrolled hypercholesterolemia (cholesterol or low density lipoprotein (LDL) cholesterol values \> 1.5 x ULN 5. Patients with cardiovascular risk factors that would exclude a starting dose of 30 mg of alitretinoin 6. Uncontrolled hypothyroidism 7. Hypervitaminosis A 8. Active major psychiatric disorder including depression and suicidal ideation * Concomitant medications such as systemic tetracyclines, CYP3A4 inhibitors such as ketoconazole, Vitamin A or St. John's Wort within 1 week, or receiving systemic itraconazole within 2 weeks, before start of study treatment * Trial participation within 2 months before start of study treatment (3 months for biologics)