A Long-Term Study of Zasocitinib in Children and Teenagers With Plaque Psoriasis

Condition(s) studied

Investigational drug(s) / intervention(s)

Zasocitinib: Zasocitinib.

Placebo: Zasocitinib matching placebo.

Zasocitinib: Zasocitinib.

Study 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.

Eligibility

Primary outcome measure(s)

• 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.

Trial sites (39)

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