Brief Summary

The main aim of this study is to see how well the medicine zasocitinib works, how safe it is, and how children and teenagers aged 4 to under 18 with moderate-to-severe plaque psoriasis respond to it.

The study will be done in 2 parts: Part A will include both children and teenagers, while part B will only include children.

At first, only teenagers who meet the study rules can participate in this study. Children may only start to participate once enough information has been collected from other studies with zasocitinib.

Participants in Part A will initially be assigned to receive either zasocitinib or placebo for the first 16 weeks of treatment, then all participants will receive zasocitinib through the end of the study. All participants in Part B will be assigned to receive treatment with zasocitinib throughout the study.

Participants will be in the study for up to 4 years and 2 months (217 weeks), including up to 35 days for the screening period, 208 weeks of treatment (Part A and Part B) and a 4-week safety follow-up period. During the study, participants will visit their study site multiple times.

Conditions

• Plaque Psoriasis

Intervention / Treatment

• Drug: Zasocitinib
• Drug: Placebo

Primary Outcome Measures

• Part A: Percentage of Participants Achieving a Static Physician's Global Assessment (sPGA) of Clear (0) or Almost Clear (1) With a Greater than or Equal to (>=) 2-Point Decrease From Baseline at Week 16 (At Week 16)
  The sPGA is an assessment by the investigator of the overall disease severity at the time of evaluation. Erythema (E), induration (I), and desquamation (D) are scored on a 5-point scale ranging from 0 (none) to 4 (severe). The sPGA composite score ranges from 0 to 4 and is calculated as Clear (0) = 0 for all three; Almost clear (1) = mean greater than (\>) 0, less than (\<) 1.5; Mild (2) = mean \>= 1.5, \<2.5; Moderate (3) = mean \>=2.5, \<3.5; and Severe (4) = mean \>=3.5. The percentage of participants achieving an sPGA of Clear (0) or Almost Clear (1) with a \>= 2-point decrease from baseline at Week 16 will be reported.
• Part A: Percentage of Participants Achieving >= 75 Percent (%) Improvement From Baseline in Psoriasis Area and Severity Index (PASI) Score at Week 16 (At Week 16)
  The PASI is a measure of the average redness, thickness and scaliness of psoriatic skin lesions (each graded on a 0 to 4 scale; 0 = none to 4 = very severe), weighted by the area of involvement (head, upper extremities, trunk, and lower extremities). The PASI score ranges from 0 to 72, with higher PASI scores denoting more severe disease activity (less than or equal to \[\<=\] 3 representing mild disease, \>= 3 to 15 representing moderate disease, and \>= 15 indicating severe disease). The PASI-75 is defined as 75% improvement from baseline in PASI score. The percentage of participants achieving \>= 75% improvement from baseline in PASI score at Week 16 will be reported.
• Part B: Maximum Observed Plasma Concentration (Cmax) of Zasocitinib (Pre-dose and Post-dose on Day 7)
  Cmax of zasocitinib in plasma will be assessed.
• Part B: Time to Maximum Concentration (Tmax) of Zasocitinib (Pre-dose and Post-dose on Day 7)
  Tmax of zasocitinib in plasma will be assessed.
• Part B: Area Under the Concentration-Time Curve From Time 0 to the Time of Last Quantifiable Concentration (AUC0-Last) of Zasocitinib (Pre-dose and Post-dose on Day 7)
  AUC0-Last of zasocitinib in plasma will be assessed.

Countries

China, Germany, Italy, Japan, Poland, Spain, United States

Locations and Investigators

• Exalt Clinical Research, Chula Vista, United States (Recruiting)
  • Site Contact
  • Jaqueline McKesey (Principal Investigator)
• First OC Dermatology Research Inc., Fountain Valley, United States (Recruiting)
  • Site contact
  • Vivian Laquer (Principal Investigator)
• Direct Helpers Medical Center, Hialeah, United States (Recruiting)
  • Site Contact
  • Frank Don (Principal Investigator)
• Arlington Dermatology, Rolling Meadows, United States (Recruiting)
  • Site Contact
  • Michael Bukhalo (Principal Investigator)
• Apex Clinical Research Center, LLC, Canton, United States (Recruiting)
  • Site contact
  • Jorge Garcia-Zuazaga (Principal Investigator)
• Wright State Physicians, Fairborn, United States (Recruiting)
  • Site contact
  • Craig Rohan (Principal Investigator)
• Apex Clinical Research Center, LLC, Mayfield Heights, United States (Recruiting)
  • Site contact
  • Jorge Garcia-Zuazaga (Principal Investigator)
• Medical University of South Carolina, Charleston, United States (Recruiting)
  • Site contact
  • Lara Wine Lee (Principal Investigator)
• UT Physicians Dermatology - Bellaire Station, Bellaire, United States (Recruiting)
  • Site contact
  • Adelaide Hebert (Principal Investigator)
• Texas Dermatology and Laser Specialists-San Antonio, San Antonio, United States (Recruiting)
  • Site contact
  • John Browning (Principal Investigator)
• Medical College of Wisconsin, Milwaukee, United States (Recruiting)
  • Site contact
  • Kristen Holland (Principal Investigator)
• Beijing Children Hospital, Capital Medical University, Beijing, China (Recruiting)
  • Site Contact
  • Zigang Xu (Principal Investigator)
• Dermatology Hospital of Southern Medical University, Guangzhou, China (Recruiting)
  • Site Contact
  • Xiaohua Wang (Principal Investigator)
• Hunan Children's Hospital, Changsha, China (Recruiting)
  • Site contact
  • Zhu Wei (Principal Investigator)
• Hangzhou First People's Hospital, Hangzhou, China (Recruiting)
  • Site Contact
  • Liming Wu (Principal Investigator)
• Peking University Third Hospital, Beijing, China (Recruiting)
  • Site Contact
  • Wenhui Wang (Principal Investigator)
• Huashan Hospital Fudan University, Shanghai, China (Recruiting)
  • Site Contact
  • Jinhua Xu (Principal Investigator)
• Fachklinik Bad Bentheim, Bad Bentheim, Germany (Recruiting)
  • Site contact
  • Athanasios Tsianakas (Principal Investigator)
• Uniklinik Koln, Klinik fur Dermatologie und Venerologie, Cologne, Germany (Recruiting)
  • Site contact
  • Daniela Neumayer (Principal Investigator)
• University Hospital of Muenster, Münster, Germany (Recruiting)
  • Site contact
  • Nina Magnolo (Principal Investigator)
• Universitätsklinikum Bonn, Bonn, Germany (Recruiting)
  • Site contact
  • Dagmar Wilsmann-Theis (Principal Investigator)
• Universitaetsmedizin der Johannes - Gutenberg Universitaet Mainz, Mainz, Germany (Not yet recruiting)
  • Site contact
  • Petra Staubach-Renz (Principal Investigator)
• Presidio Ospedaliero Gaspare Rodolico, Catania, Italy (Recruiting)
  • Site contact
  • Giuseppe Micali (Principal Investigator)
• Universita Degli Studi Di Padova, Padova, Italy (Not yet recruiting)
  • Site contact
  • Anna Belloni Fortina (Principal Investigator)
• Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy (Recruiting)
  • Site contact
  • Ketty Peris (Principal Investigator)
• Nagoya City University Hospital, Nagoya, Japan (Recruiting)
  • Site contact
  • Akimichi Morita (Principal Investigator)
• Hospital of the University of Occupational and Environmental Health, Japan, Kitakyushu-shi, Japan (Recruiting)
  • Site contact
  • Yuu Sawada (Principal Investigator)
• Mie University Hospital, Tsu, Mie, Japan (Recruiting)
  • Site contact
  • Keiichi Yamanaka (Principal Investigator)
• Nippon Life Hospital, Osaka, Japan (Recruiting)
  • Site contact
  • Mari Higashiyama (Principal Investigator)
• Teikyo University Hospital, Itabashi-Ku, Japan (Recruiting)
  • Site contact
  • Yayoi Tada (Principal Investigator)
• Cityclinic Przychodnia lekarsko psychologiczna Matusiak sp.p, Wroclaw, Poland (Recruiting)
  • Site contact
  • Jacek Szepietowski (Principal Investigator)
• Luxderm Specjalistyczny Gabinet Dermatologiczny Dorota Krasowska, Lublin, Poland (Recruiting)
  • Site contact
  • Dorota Krasowska (Principal Investigator)
• Uniwersytecki Szpital Kliniczny im. Fryderyka Chopina w Rzeszowie, Rzeszów, Poland (Recruiting)
  • Site contact
  • Adam Reich (Principal Investigator)
• Centrum Badan Klinicznych Pi-house Sp. Z O. O., Gdansk, Poland (Recruiting)
  • Site contact
  • Aleksandra Okuniewska (Principal Investigator)
• "DERMED" Centrum Medyczne Sp. z o. o., Lodz, Poland (Recruiting)
  • Site contact
  • Andrzej Kaszuba (Principal Investigator)
• Dermoklinika-Centrum Medyczne s.c, Lodz, Poland (Recruiting)
  • Site contact
  • Joanna Narbutt (Principal Investigator)
• Complejo Hospitalario Universitario de Santiago de Compostela, Santiago de Compostela, Spain (Recruiting)
  • Site contact
  • Maria Isabel Rodriguez Blanco (Principal Investigator)
• Hospital de La Santa Creu i Sant Pau - Dermatologia, Barcelona, Spain (Recruiting)
  • Site contact
  • Anna Lopez Ferrer (Principal Investigator)
• Hospital Universitario 12 de Octubre, Madrid, Spain (Recruiting)
  • Site contact
  • Raquel Rivera-Diaz (Principal Investigator)

Study Officials

• Study Director (Study Director) — Takeda