The study will be conducted at multiple research sites in the UK, Spain, and Czech Republic. Eligible participants will be randomly assigned to receive either setanaxib or placebo. Setanaxib dose level will depend on age and all participants will receive their standard of care in addition to setanaxib or placebo. The study consists of a Screening period of up to 4 weeks, a 24-week Treatment period and a 4- week Follow-up period. conditions: Alport Syndrome studyType: INTERVENTIONAL phases: PHASE1 phases: PHASE2 allocation: RANDOMIZED interventionModel: PARALLEL primaryPurpose: TREATMENT masking: TRIPLE whoMasked: PARTICIPANT whoMasked: CARE_PROVIDER whoMasked: INVESTIGATOR count: 18 type: ESTIMATED name: Setanaxib name: Placebo measure: Percentage of patients with Serious Adverse Events (SAEs) measure: Percentage of patients with treatment-emergent Adverse Events of Special Interest (AESIs) measure: The ratio of urine protein to creatinine ratio (UPCR) analysed in 24-hour urine sample measure: Percentage of patients with a 25% reduction in UPCR analysed in 24-hour urine sample measure: Pre-dose and post-dose plasma concentrations of setanaxib and GKT138184 measured as the area under the concentration-time curve over 24 hours at steady state (AUC0-24-ss) measure: Pre-dose and post-dose plasma concentrations of setanaxib and GKT138184 measured as the minimum plasma concentration at steady state (Cmin-ss) measure: Pre-dose and post-dose plasma concentrations of setanaxib and GKT138184 measured as the maximum plasma concentration at steady state (Cmax-ss) measure: Percentage of patients with clinically significant changes in heart rate measure: Percentage of patients with clinically significant changes blood pressure measure: Percentage of patients with clinically significant changes in 12-lead electrocardiogram (ECG) measure: Percentage of patients with clinically significant changes in physical examination measure: Percentage of patients with clinically significant changes in hematology, serum chemistry, urinalysis, and thyroid function measure: Percentage of patients with clinically significant changes in hearing audiometric testing (bone- and air-conduction) sex: ALL minimumAge: 12 Years maximumAge: 40 Years stdAges: CHILD stdAges: ADULT facility: Fakultni Nemocnice Hradec Kralove status: RECRUITING city: Hradec Králové country: Czechia name: Roman Safranek role: CONTACT lat: 50.20923 lon: 15.83277 facility: Fakultni Nemocnice Olomouc status: RECRUITING city: Olomouc country: Czechia name: Karel Krejci role: CONTACT lat: 49.59552 lon: 17.25175 facility: Institut Klinicke a Experimentalni Mediciny status: RECRUITING city: Praha country: Czechia name: Ondrej Viklicky role: CONTACT lat: 50.08804 lon: 14.42076 facility: Vseobecna Fakultni Nemocnice v Praze status: RECRUITING city: Praha country: Czechia name: Vladimir Tesar role: CONTACT lat: 50.08804 lon: 14.42076 facility: Hospital Clinic Barcelona status: RECRUITING city: Barcelona state: L'eixample zip: 08036 country: Spain name: Marc Xipell Font role: CONTACT lat: 41.38879 lon: 2.15899 facility: Hospital Universitario 12 de Octubre status: RECRUITING city: Madrid state: Usera zip: 28041 country: Spain name: Enrique Morales role: CONTACT lat: 40.4165 lon: -3.70256 facility: Hospital Universitario Vall d'Hebron status: RECRUITING city: Barcelona country: Spain name: Irene Agraz Pamplona role: CONTACT lat: 41.38879 lon: 2.15899 facility: Hospital Universitario Reina Sofia status: RECRUITING city: Córdoba zip: 14004 country: Spain name: Cristina Rabasco role: CONTACT lat: 37.89155 lon: -4.77275 facility: Hospital Universitario Virgen de las Nieves status: RECRUITING city: Granada zip: 18014 country: Spain name: Rafael Jose Esteban de la Rosa role: CONTACT lat: 37.18817 lon: -3.60667 facility: Royal Free London NHS Foundation Trust status: RECRUITING city: London zip: NW3 2QG country: United Kingdom name: Daniel Gale role: CONTACT lat: 51.50853 lon: -0.12574 facility: Great Ormond Street Hospital for Children status: NOT_YET_RECRUITING city: London zip: WC1N 3JH country: United Kingdom name: Zainab Arslan role: CONTACT lat: 51.50853 lon: -0.12574 facility: Royal Manchester Children's Hospital status: RECRUITING city: Manchester zip: M13 9WL country: United Kingdom name: Rachel Lennon role: CONTACT lat: 53.48095 lon: -2.23743 facility: Nottingham City Hospital status: RECRUITING city: Nottingham country: United Kingdom name: Matthew Hall role: CONTACT lat: 52.9536 lon: -1.15047 hasResults: False