Effisayil™ ON: A Study to Test Long-term Treatment With Spesolimab in People With Generalized Pustular Psoriasis Who Took Part in a Previous Study

Inclusion Criteria: * Male or female patients who have completed the treatment period without premature discontinuation in the previous spesolimab trial and are willing and able to continue treatment in the current trial * Women of childbearing potential must be ready and able to use highly effective methods of birth control per ICH M3 (R2) that result in a low failure rate of less than 1% per year when used consistently and correctly. A list of contraception methods meeting these criteria is provided in Section 4.2.2.3 as well as in the patient information. Note: A woman is considered of childbearing potential, i.e. fertile, following menarche and until becoming postmenopausal unless permanently sterile. Permanent sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral oophorectomy. Tubal ligation is not a method of permanent sterilization. A postmenopausal state is defined as no menses for 12 months without an alternative medical cause. * Signed and dated written informed consent and assent for the current trial 1368-0025, in accordance with ICH-GCP and local legislation prior to admission to the current trial Exclusion Criteria: * Evidence of flare symptoms of moderate/severe intensity at screening. * Treatment with any restricted medication as specified in the protocol, or any drugs considered by the investigator likely to interfere with the safe conduct of the study since the last visit of the previous spesolimab trial and during the screening period for the current trial, with the exception of methotrexate, cyclosporine, or retinoids started following rescue treatment for GPP flare in trial 1368-0027. * Severe, progressive, or uncontrolled hepatic disease, defined as \>3- fold Upper Limit of Normal (ULN) elevation in Aspartate Transaminase (AST) or Alanine Aminotransferase (ALT) or alkaline phosphatase, or \>2- fold ULN elevation in total bilirubin. * Patients with congestive heart disease, as assessed by the investigator. * Relevant chronic or acute infections including human immunodeficiency virus (HIV) or viral hepatitis. A patient can be re-screened if the patient was treated and is cured from acute infection. * Active or Latent tuberculosis (TB): * Patients with active tuberculosis should be excluded * Patients will be screened with Interferon Gamma Release Assay (IGRA) such as QuantiFERON®-TB-Gold Plus or T-spot®. Patients with positive IGRA (indicating active or latent tuberculosis) are excluded unless they have completed treatment for active or latent tuberculosis per investigator discretion, at the time of screening. * Patients with indeterminate QuantiFERON®-TB-Gold Plus or invalid/borderline T-spot® may be retested with IGRA (once) or Tuberculin Skin test (TST). * TST or any alternative test/procedure (as per local standards) to rule out TB can be performed if IGRA is not available or indeterminate. A TST reaction ≥10mm (≥5mm if receiving ≥15mg/d prednisone or other immunosuppressant) is considered positive. Patients with a positive TST are excluded unless they have completed treatment as above. * History of allergy/hypersensitivity to a systemically administered trial medication agent or its excipients. * Any documented active or suspected malignancy at screening, except appropriately treated basal cell carcinoma of the skin, squamous cell carcinoma of the skin or in situ carcinoma of uterine cervix. Further exclusion criteria apply.