A Study to Test How Effective and Safe Different Doses of BI 655130 Are in Patients With a Moderate to Severe Form of the Skin Disease Palmoplantar Pustulosis

Inclusion Criteria: * 18 to 75 years of legal age (according to local legislation) at screening. * Diagnosis of Palmoplantar Pustulosis defined as presence of primary, persistent (\>3 months duration), sterile, macroscopically visible pustules on the palms and/or soles, without or with plaque psoriasis elsewhere on the body. * PPP PGA of at least moderate severity (≥3) at screening and baseline. * A minimum PPP ASI score of 12 at screening and baseline. * Male or female patients. Women of childbearing potential (WOCBP) must be ready and able to use highly effective methods of birth control per ICH M3 (R2). * Signed and dated written informed consent in accordance with ICH GCP and local legislation prior to admission to the trial. * Further criteria apply. Exclusion Criteria: * Women who are pregnant, nursing, or who plan to become pregnant while in the trial. * Severe, progressive, or uncontrolled condition such as renal, hepatic, haematological, endocrine, pulmonary, cardiac, neurologic, cerebral, or psychiatric disease, or signs and symptoms thereof. * Presence or known history of anti-TNF-induced PPP-like disease. * Patient with a transplanted organ (with exception of a corneal transplant \>12 weeks Prior to screening) or who have ever received stem cell therapy (e.g., Prochymal). * Known history of lymphoproliferative disease, including lymphoma, or signs and symptoms suggestive of possible lymphoproliferative disease, such as lymphadenopathy and/or splenomegaly. * Fur…