A Phase 3 Trial to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics of Zasocitinib in Pediatric Participants Aged 4 to Less Than 18 Years With Moderate-to-Severe Plaque Psoriasis

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Takeda Development Center Americas Inc.

Participant type

Pediatric, Patients

Age range

0-17 years

Gender

Male and Female

Therapeutic area

Diseases [C] - Skin and Connective Tissue Diseases [C17]

Trial duration

28 Apr 2026 → ongoing

Decision date (initial)

2026-04-07

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

Yes

Funding sources

Takeda Development Center Americas, Inc.

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Pharmacokinetic, Efficacy, Safety

Part A: To evaluate the efficacy of zasocitinib administered PO QD for 16 weeks at the selected dose as compared to placebo for participants in Cohort 1 and Cohort 2 with moderate-to-severe plaque psoriasis.
Part A Cohort 1: Includes adolescent participants aged 12 to <18 years.
Part A Cohort 2: Includes children participants aged 4 to <12 years.
Note: Under this protocol amendment, ONLY eligible participants who are ≥12 years of age (that is, Part A Cohort 1) at screening will be enrolled. Upon availability of the juvenile toxicity data and phase 3 safety data in adults, a future protocol amendment is planned to initiate the enrollment of participants who are <12 years of age in Part B (open-label PK trial, aged 4 to <12 years) followed by the enrollment of Part A Cohort 2 (aged 4 to <12 years). Part B participants will be separate from Part A Cohort 2 participants. Part A Cohort 2 will be initiated after adequate data becomes available from Part B to determine the dose.

Part B: To evaluate the PK of zasocitinib following multiple doses administered PO QD at the selected dose in children participants with moderate-to-severe plaque psoriasis.
Part B: Includes only children participants aged 4 to <12 years. Part B participants will be separate from Part A Cohort 2 participants

Secondary objectives 6

1. 1. Part A: To further evaluate whether zasocitinib administered PO QD for 16 weeks at the selected dose for participants in Cohort 1 and Cohort 2 with moderate-to-severe plaque psoriasis is superior in efficacy to placebo.
2. 2. Part A (Cohort 1 only): To further evaluate whether zasocitinib administered PO QD for 16 weeks at the selected dose for participants in Cohort 1 with moderate-to-severe plaque psoriasis is superior in efficacy to placebo.
3. 3. Parts A and B: To further evaluate the efficacy of zasocitinib administered PO QD at the selected dose in adolescents and children participants with moderate-to-severe plaque psoriasis over the duration of the open-label period.
4. 4. Part A (Cohort 1 only): To further evaluate the efficacy of zasocitinib administered PO QD at the selected dose for participants in Cohort 1 with moderate-to-severe plaque psoriasis over the duration of the open-label period.
5. 5. Part A: To evaluate the PK of zasocitinib administered PO QD at the selected dose for participants in Cohort 1 and Cohort 2 with moderate-to-severe plaque psoriasis.
6. 6. Part B: To evaluate the acceptability/palatability of zasocitinib in children participants.

Conditions and MedDRA coding

Plaque Psoriasis

Study design 2 periods

Regulatory references

EMA paediatric investigation plan (PIP)

EMEA-003478-PIP01-23

Plan to share IPD

Yes

IPD plan description

Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda’s data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 13

1. 01. In the opinion of the investigator, the participant (as age appropriate) and/or LAR or adult caregiver is capable of understanding and complying with protocol requirements.
2. 02. Before the initiation of any trial assessments or procedures: • The participant, participant’s LAR, or adult caregiver signs and dates a written ICF; and • Pediatric assent is obtained (where appropriate); and • Any required privacy authorization is also obtained, as required per local regulations.
3. 03. Participant has a diagnosis of chronic plaque psoriasis for ≥6 months prior to the screening visit.
4. 04. Participant has stable plaque psoriasis defined as no significant flare or change in morphology (as assessed by the investigator) in psoriasis for ≥6 months before screening.
5. 05. Participant has moderate-to-severe plaque psoriasis as defined by a PASI score ≥12 and an sPGA score ≥3 at screening and Day 1.
6. 06. Participant has plaque psoriasis covering ≥10% of total BSA at screening and Day 1.
7. 07. Participant must be a candidate for phototherapy or systemic therapy.
8. 08. Inclusion Criteria for Part A Cohort 1: The participant is male or female and aged 12 to <18 years, at the time of screening and informed consent. – Note: Under this protocol amendment, ONLY eligible participants who are ≥12 years of age (that is, Part A Cohort 1) at screening will be enrolled. Upon availability of the juvenile toxicity data and phase 3 safety data in adults, a future protocol amendment is planned to initiate the enrollment of participants who are <12 years of age in Part B (open-label PK trial, aged 4 to <12 years) followed by the enrollment of Part A Cohort 2 (aged 4 to <12 years). Part B participants will be separate from Part A Cohort 2 participants. Part A Cohort 2 will be initiated after adequate data becomes available from Part B to determine the dose.
9. 9. In the EU/EEA, for participants currently smoking or using chewing tobacco, the investigator must document a favorable benefit-risk assessment to justify the participants’ inclusion in the trial.
10. 10. A WOCBP (as defined in Section 13.1.1.1) who is sexually active with a male partner agrees to use a highly effective method of contraception (as listed in Section 13.1.2.1.1) from signing of participant/parental informed consent and pediatric assent (if applicable) throughout the duration of the trial and for 10 days after the last dose of trial intervention. The use of effective contraception is not required for participants assigned male sex at birth during the duration of the trial. Pregnancy reporting responsibilities are defined in Section 8.5.1.1. • In the EU/EEA, for participants who elect to use hormonal contraception as a form of highly effective contraception, the investigator must document a favorable benefit-risk assessment at screening and every 3 months during the trial, to justify the participant's inclusion in the trial. Note: Oral hormonal contraception may be susceptible to interaction with zasocitinib, which may reduce the efficacy of the contraceptive method. Therefore, if the participant chooses oral hormonal contraception as the primary highly effective method of contraception, a second highly effective or an acceptable method of contraception should also be used during the treatment period and for at least 10 days after the last dose of trial intervention, if the participant is sexually active with a partner with whom the participant could become pregnant. A barrier method is recommended, preferably a male condom.
11. 11. For participants in the EU/EEA, the investigator must have no reason to believe that the participant would be placed at risk by participating in the trial with regard to the European Commission Decision as of 10 March 2023 on measures to minimize risk of serious side effects with JAKi (EMA/142279/2023 guideline on JAKi): new measures to reduce risks of major cardiovascular events, malignancy, venous thromboembolism, serious infections and increased mortality as of 26 April 2023 (Drug Safety Update volume 16, issue 9).
12. 12. Inclusion Criteria for Part A Cohort 1: The participant must weigh ≥40 kg at the time of screening in order to be enrolled in the trial.
13. 13. Inclusion Criteria for Part A Cohort 1: The participant, participant’s LAR, or adult caregiver should be confident that the participant will be able to swallow.

Exclusion criteria 33

1. 01. Participant has evidence of nonplaque psoriasis (erythrodermic, pustular, predominantly guttate psoriasis, predominantly inverse, or drug-induced psoriasis). If a participant meets criteria for inclusion based on typical plaque psoriasis presentation, a limited amount of inverse psoriasis is not exclusionary.
2. 02. Participant requires systemic treatment, other than NSAIDs, during the trial period for an immune-related disease (for example, inflammatory bowel disease).
3. 03. Participant has a history of excessive sun exposure, has used tanning booths within 4 weeks prior to Day 1, or is not willing to minimize natural and artificial sunlight exposure during the trial period. Use of sunscreen products and protective apparel is recommended when sun exposure cannot be avoided.
4. 04. Participant has concomitant comorbid skin condition that, in the opinion of the investigator, would interfere with the trial assessments.
5. 05. TB: a) Participant has history of active TB infection, regardless of treatment status. b) Participant has signs or symptoms of active TB (including, but not limited to, chronic fever, chronic productive cough, night sweats, or weight loss) as judged by the investigator. c) Participant has evidence of LTBI as evidenced by a positive QFT result OR 2 indeterminate QFT results and participant does not have documentation of appropriate LTBI prophylaxis or is not able or not willing to initiate appropriate LTBI prophylaxis. Participant remains eligible if there are no signs/symptoms of active TB AND participant can provide documentation of no history of active TB AND either: (1) participant can provide documentation of prior and complete treatment for LTBI (appropriate in duration and type per current local country guidelines) OR (2) participant has initiated prophylaxis (appropriate in duration and type per current local guidelines) a minimum of 2 weeks prior to Day 1. In the EU/EEA, participants with evidence of LTBI, regardless of prophylaxis treatment status, must receive approval to participate in the trial from an infectious disease or other TB specialist (for example, pulmonologist). – Note: TB prophylaxis regimens should be administered according to local guidelines; however, because of potential interactions with zasocitinib, rifampin should not be used. Additional excluded medications are provided in Table 6.b and Table 13.d, and the investigator should consult with the medical monitor to discuss any LTBI treatment medication not listed if treatment will occur during the trial. – Note: TB testing should be conducted using QFT submitted to the central laboratory. Additional tests may be performed as required per local guidelines. – Note: For participants who have documentation of LTBI and who have completed a course of prophylaxis (appropriate in duration and type per current local country guidelines and documented in the medical record), QFT does not need to be performed. d) Participant has had any imaging during or 6 months prior to screening, including chest X-ray, chest CT, MRI of the chest, or other chest imaging suggesting evidence of current active or a history of active TB. Chest X-ray is required for all participants regardless of QFT results as allowed per country-specific guidelines and regulations unless the participant has had normal chest imaging within 6 months prior to screening.
6. 06. Herpes infections: a) Participant has active herpes virus infection, including herpes zoster or herpes simplex 1 and 2 (demonstrated on physical examination and/or medical history) at screening or Day 1. b) Participant has history of serious herpetic infection that includes any episode of disseminated disease; multidermatomal herpes zoster, herpes encephalitis, or ophthalmic herpes; or a history of recurrent herpes zoster (defined as 2 episodes within 2 years).
7. 07. Nonherpetic viral diseases: a) HCV: • Participant has presence of HCV Ab and a positive confirmatory test result for HCV RNA (nucleic acid test or PCR). – In the EU/EEA, if the participant has positive total HCV Ab at screening but is confirmed to have no detectable HCV RNA by PCR testing, HCV RNA PCR testing will be performed per the SoA (Section 1.3). b) HBV: • Participant has presence of positive or indeterminate HBsAg; or • Participant has presence of HBV DNA (regardless of serology); or • Participant has presence of positive HBcAb without concurrent positive HBsAb (HBcAb+ and HBsAb-). – In the EU/EEA: o If the participant has positive total HBcAb at screening (HBcAb+; note that HBcAb+ without concurrent HBsAb+ is exclusionary) and is confirmed to have no detectable HBV DNA by PCR testing, the HBV DNA PCR testing will be performed per the SoA (Section 1.3); or o If a participant has isolated positive HBsAb at screening but is without documentation of prior vaccination as proven by medical records and is confirmed to have no detectable HBV DNA by PCR testing, the participant will repeat HBV DNA PCR testing per the SoA (Section 1.3). c) HIV: • Participant has positive results for HIV by serology, regardless of viral load.
8. 08. Other infectious diseases: a) Participant has a history of active infection or febrile illness within 7 days prior to Day 1, as assessed by the investigator. b) Participant has history of symptoms suggestive of systemic or invasive infection within 30 days prior to Day 1, as assessed by the investigator. c) Participant has history of bacterial, viral, or fungal infection that required hospitalization or treatment with intravenous antimicrobial therapy within 8 weeks prior to Day 1 or oral antimicrobial therapy within 30 days prior to Day 1. d) Participant has a history of chronic or recurrent bacterial disease, including but not limited to chronic pyelonephritis or cystitis, chronic bronchitis/pneumonitis, osteomyelitis, or chronic skin ulcerations/infections or fungal infections (except superficial onychomycosis). e) Participant has a history of an infected joint prosthesis, unless that prosthesis has been removed or replaced at least 60 days prior to Day 1. f) Participant has a history of opportunistic infections (for example, Pneumocystis jirovecii pneumonia, histoplasmosis, coccidiomycosis). g) Participant had a confirmed bacterial infection requiring antibiotic treatment within 60 days prior to Day 1, as assessed by the investigator, for which he or she did not receive treatment.
9. 09. Participant has any clinically significant medical condition, evidence of an unstable clinical condition (for example, cardiovascular, renal, hepatic, hematologic, gastrointestinal, endocrine, pulmonary, or immunologic), or vital signs/physical examination/laboratory/ECG abnormality that would, in the opinion of the investigator, put the participant at undue risk or interfere with interpretation of trial results. These include but are not limited to: a) Participant has a history of known or suspected condition/illness that is consistent with compromised immunity, including but not limited to any identified congenital or acquired immunodeficiency or history of splenectomy. b) Participant had a major surgery within 60 days prior to Day 1 or has a major surgery planned during the trial. c) Participant has unstable, poorly controlled, or severe hypertension (defined as BP exceeding the 95th percentile for age, sex, and height) at screening, confirmed by 2 repeat assessments. d) Participant has a history of Class III or IV congestive heart failure as defined by NYHA criteria. e) Participant has a history of malignancy or lymphoproliferative disease, with the exception of successfully treated nonmetastatic cutaneous squamous cell or basal cell carcinoma and/or localized carcinoma in situ of the cervix; in the EU/EEA, investigators must specifically document a favorable benefit-risk assessment. f) For participants with asthma, chronic obstructive pulmonary disease, or other pulmonary illnesses, participant has been hospitalized in the past 3 months, has ever required intubation for treatment, currently requires oral corticosteroids, or has required more than 1 course of oral corticosteroids within 6 months prior to Day 1. g) Participant has any of the following cardiovascular disease history: • A new diagnosis of atrial fibrillation or an episode of atrial fibrillation with rapid ventricular response or other dysrhythmia, nonacute cardiac hospitalization (for example, pacemaker implantation), pulmonary embolism, or deep venous thrombosis within the past 6 months prior to screening. • Any history of cerebrovascular event, myocardial infarction, coronary stenting, or aorto-coronary bypass surgery. If, however, the investigator determines there are no suitable treatment alternatives available for the participant and it has been at least 6 months since the occurrence of any such event, the participant may enroll; in the EU/EEA, investigators must specifically document a favorable benefit-risk assessment. h) Participant has ECG abnormalities that are considered clinically significant and would pose an unacceptable risk to the participant if he or she participated in the trial, in the opinion of the investigator. i) Participant has significant/uncontrolled psychiatric illness, in the opinion of the investigator. j) Participant has a history of clinically significant drug or alcohol abuse within 12 months prior to Day 1.
10. For the below prohibited psoriasis treatment, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer, regardless of whether they are prescribed for psoriasis or another condition: Note: If the participant is currently receiving an approved therapy for psoriasis that is not permitted in the trial, but the approved therapy is well-tolerated and effective for moderate-to-severe psoriasis in the opinion of the participant and the investigator, the participant should not discontinue this therapy solely to enter the clinical trial. 10. Participant has received any of the following biologics or biosimilar versions within the time frame indicated: a) Antibodies to IL-12/-23, IL-17, or IL-23 (for example, ustekinumab, secukinumab, bimekizumab, risankizumab, tildrakizumab, ixekizumab, guselkumab, brodalumab, or biosimilar versions) within 6 months prior to Day 1. b) TNF inhibitor(s) (for example, etanercept, adalimumab, infliximab, certolizumab, or biosimilar versions) within 2 months prior to Day 1. c) Agents that modulate integrin pathways to impact lymphocyte trafficking (for example, natalizumab) or agents that modulate B cells or T cells (for example, alemtuzumab, abatacept, or visilizumab) within 3 months prior to Day 1. d) Rituximab or other immune cell–depleting therapy within 6 months prior to Day 1.
11. For the below prohibited psoriasis treatment, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer, regardless of whether they are prescribed for psoriasis or another condition. 11. Participant has used medicated shampoo and/or body wash, including formulations containing but not limited to salicylic acid, corticosteroids, coal tar, vitamin D3 analogues, or other compounds used for the management of psoriasis, within 2 weeks prior to Day 1.
12. For the below prohibited psoriasis treatment, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer, regardless of whether they are prescribed for psoriasis or another condition. 12. Participant has used any topical medication that could affect psoriasis presentation (including but not limited to corticosteroids, salicylic acid, urea, alpha- or beta-hydroxy acids, anthralin, retinoids, vitamin D analogues [such as calcipotriol], methoxsalen, trimethylpsoralen, calcineurin inhibitors [for example, tacrolimus or pimecrolimus], tapinarof, roflumilast, JAK inhibitors, or tar) within 2 weeks prior to Day 1. • Note: Low-potency topical corticosteroids (WHO Class VI and VII or equivalent) are permitted for use on the palms, soles, face, and/or intertriginous areas, but should not be used within 24 hours before any trial visit. Low-potency topical corticosteroids may be used to treat acute nonpsoriatic conditions (for example, contact dermatitis) on all body regions for no more than 2 weeks but should not be used within 24 hours before any trial visit. Low-potency topical corticosteroids co-formulated with other topical medication(s) that may affect the presentation of psoriasis are not permitted. Bland emollients (defined as emollients containing only ingredients that are pharmacologically inactive) are allowed on all body regions but should not be used within 24 hours before any trial visit. • Note: Intranasal corticosteroids, inhaled corticosteroids, and ophthalmic and otic drops containing corticosteroids are permitted.
13. For the below prohibited psoriasis treatment, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer, regardless of whether they are prescribed for psoriasis or another condition. 13. Participant has used any systemic nonbiologic treatment that could affect psoriasis presentation (including oral, intravenous, intramuscular, intra-articular, intrathecal, or intralesional corticosteroids; oral retinoids; immunosuppressive/immunomodulating medication; apremilast; methotrexate; azathioprine; 6-thioguanidine; mercaptopurine; mycophenolate mofetil; hydroxyurea; cyclosporine; 1,25-dihydroxyvitamin D3 analogues; psoralens; sulfasalazine; fumaric acid derivatives; JAK inhibitors) within 4 weeks prior to Day 1, or 5 half-lives, whichever is longer.
14. For the below prohibited psoriasis treatment, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer, regardless of whether they are prescribed for psoriasis or another condition. 14. Participant has used leflunomide within 6 months prior to Day 1.
15. For the below prohibited psoriasis treatment, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer, regardless of whether they are prescribed for psoriasis or another condition. 15. Participant has received phototherapy (including UVB, PUVA, tanning beds, therapeutic sunbathing) or excimer laser within 4 weeks prior to Day 1.
16. For the below prohibited psoriasis treatment, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer, regardless of whether they are prescribed for psoriasis or another condition. 16. Participant has used oral or topical botanical preparations (for example, herbal supplements or traditional medicines, including traditional Chinese medicines, derived from plants, minerals, or animals) intended to treat psoriasis or other immunological diseases within 4 weeks prior to Day 1.
17. For the below prohibited psoriasis treatment, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer, regardless of whether they are prescribed for psoriasis or another condition. 17. Participant has any previous exposure to zasocitinib (also known as TAK-279 or NDI-034858) or other TYK2 inhibitors (including deucravacitinib), or participated in any trial that included a TYK2 inhibitor (for example, deucravacitinib, VTX958, GLPG3667, and so forth), unless participant has documentation of posttrial unblinding that confirms the participant did not receive a TYK2 inhibitor.
18. For the below prohibited concomitant medication, where applicable, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer. 18. Participant has received lithium, antimalarials, or intramuscular gold therapy within 4 weeks prior to Day 1.
19. For the below prohibited concomitant medication, where applicable, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer. 19. Participant is currently being treated with strong or moderate CYP3A4 inhibitors (such as itraconazole) or strong or moderate CYP3A4 inducers (such as rifampin, carbamazepine, or phenytoin), or has received strong or moderate CYP3A4 inhibitors or strong or moderate CYP3A4 inducers within 4 weeks or 5 half-lives of the inducer or inhibitor, whichever is longer, prior to Day 1, or is anticipated to require treatment with strong or moderate CYP3A4 inducers or inhibitors during the trial period (see Table 13.d). • Note: This includes consumption of food or beverages containing grapefruit and/or Seville oranges within 1 week of Day 1. Participants must be counseled to avoid food or beverages containing grapefruit and/or Seville oranges for the duration of the trial.
20. For the below prohibited concomitant medication, where applicable, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer. 20. Participant has received any live-attenuated vaccine within 60 days prior to Day 1 or plans to receive a live-attenuated vaccine during the trial and for up to 4 weeks after the last trial intervention administration. • Note: Non–live-attenuated vaccines for COVID-19 and/or influenza are permitted during the trial.
21. For the below prohibited concomitant medication, where applicable, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer. 21. Participant received an investigational Ab or biologic therapy within 6 months prior to Day 1.
22. For the below prohibited concomitant medication, where applicable, the washout period prior to Day 1 is within the time frame indicated or 5 half-lives, whichever is longer. 22. Participant received or is receiving the following: a) Participant received an investigational oral therapy within 3 months prior to Day 1; or b) Participant is currently receiving a nonbiological trial intervention or device or has received one within 4 weeks prior to Day 1; or c) Participant is currently enrolled in another clinical trial or anticipates enrollment in another clinical trial during the course of the trial.
23. 23. Participant has any of the following laboratory values at the screening visit: a) AST or ALT values >3×ULN. b) Tbili (unconjugated and/or conjugated) >1.5×ULN. c) ALP >1.5×ULN. d) Hgb <10.0 g/dL (<100.0 g/L). e) Absolute WBC count <4.0×109/L (<4000/mm3). f) ANC of <1.0×109/L (<1000/mm3). g) ALC of <1.0×109/L (<14000/mm3). h) Platelet count <100×109/L (<100,000/mm3). i) Estimated GFR <30 mL/min based on the pediatric bedside Schwartz equation (as referenced in Section 8.3.4.1). j) CPK >ULN. CPK may be repeated once; if repeat value is NCI CTCAE v5.0 Grade 1 or lower (or ≤2.5×ULN) and no higher than the initial value, participant remains eligible. Investigators should assess the participant for modulating factors, including concomitant medications or vigorous exercise, that may affect CPK levels.
24. 24. Participant has any other significant laboratory abnormalities that, in the opinion of the investigator, might place the participant at unacceptable risk for participation in this trial.
25. 25. Participant does not tolerate venipuncture or inability to be venipunctured.
26. 26. Participant has a history of significant drug allergy (such as anaphylaxis).
27. 27. Participant has a known or suspected allergy to zasocitinib or any of its components.
28. 28. Participant has a positive pregnancy test result or plans to become pregnant during the trial period, or participant is pregnant or lactating/nursing.
29. 29. Participants who have given greater than 500 mL of blood or plasma within 30 days of screening (during a clinical trial or at a blood bank donation) or plan to donate blood during the course of the trial.
30. 30. Participant is compulsorily detained for treatment of either a psychiatric or physical (for example, infectious disease) illness, or is committed to an institution (for example, prison) by virtue of an order issued either by judicial or administrative authorities.
31. 31. Participant is a trial site employee, an immediate family member (for example, spouse, parent, child, sibling) of a trial site employee, or is in a dependent relationship with a trial site employee who is involved in the conduct of this trial or may consent under duress.
32. 32. Participant is not up to date on all required vaccinations according to current immunization guidelines as noted by country-specific pediatric authorities.
33. 33. In Germany, the participant is incapable of giving consent or otherwise meets criteria in Sections 136 or 137 of the Verordnung zum Schutz vor der schädlichen Wirkung ionisierender Strahlung – Strahlenschutzverordnung.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 2

1. Part A: Coprimary Endpoints (vs Placebo) at Week 16 • sPGA 0/1 response: Proportion of participants achieving an sPGA of clear (0) or almost clear (1) with a ≥2-point decrease from baseline. • PASI-75 response: Proportion of participants achieving ≥75% improvement from baseline in PASI score. Part A Cohort 1: Includes adolescent participants aged 12 to <18 years. Part A Cohort 2: Includes children participants aged 4 to <12 years.
2. Part B: PK Primary Endpoints • PK parameters (that is Cmax, Tmax, AUC0-Last) of zasocitinib on Day 7. Part B: Includes only children participants aged 4 to <12 years. Part B participants will be separate from Part A Cohort 2 participants.

Secondary endpoints 12

1. Part A: Key Secondary Efficacy Endpoints (vs Placebo) at Week 16 • PASI-90 response: Proportion of participants achieving PASI-90. • Enhanced sPGA response: Proportion of participants achieving an sPGA of clear (0). • PASI-100 response: Proportion of participants achieving PASI-100.
2. Part A: Additional Secondary Efficacy Endpoints (vs Placebo) at Week 16 • ssPGA response: Proportion of participants achieving an ssPGA of clear (0) or almost clear (1) with a ≥2-point decrease from baseline for participants with a baseline ssPGA ≥3. • Change and percent change from baseline in BSA affected by psoriasis.
3. • DLQI response: Proportion of participants with a DLQI score of 0/1 (for participants with a baseline DLQI score ≥2). • CDLQI response: Proportion of participants with a CDLQI score of 0/1 (for participants with a baseline CDLQI score ≥2). • Change from baseline in DLQI. • Change from baseline in CDLQI.
4. Part A (Cohort 1 only): Additional Secondary Efficacy Endpoints (vs Placebo) at Week 16 • Itch NRS response: Proportions of participants achieving a ≥4-point improvement in Itch NRS for participants in Cohort 1 who had an itch NRS ≥4 at baseline. • Change and percent change from baseline in Itch NRS for participants in Cohort 1.
5. Parts A and B: Additional Secondary Efficacy Endpoints at Each Scheduled Visit Over the Duration of the Open-Label Period • PASI-75 response: Proportion of participants achieving PASI-75. • PASI-90 response: Proportion of participants achieving PASI-90. • PASI-100 response: Proportion of participants achieving PASI-100.
6. • sPGA 0/1 response: Proportion of participants achieving an sPGA of clear (0) or almost clear (1) with a ≥2-point decrease from baseline. • Enhanced sPGA response: Proportion of participants achieving an sPGA of clear (0).
7. • ssPGA response: Proportion of participants achieving an ssPGA of clear (0) or almost clear (1) with a ≥2-point decrease from baseline for participants with a baseline ssPGA ≥3. • Change and percent change from baseline in BSA affected by psoriasis.
8. • DLQI response: Proportion of participants with a DLQI score of 0/1 (for participants with a baseline DLQI score ≥2). • CDLQI response: Proportion of participants with a CDLQI score of 0/1 (for participants with a baseline CDLQI score ≥2).
9. • Change from baseline in DLQI. • Change from baseline in CDLQI.
10. Part A (Cohort 1 only): Additional Secondary Efficacy Endpoints at Each Scheduled Visit Over the Duration of the Open- Label Period • Itch NRS responses: Proportions of participants achieving a ≥4-point improvement in Itch NRS for participants in Cohort 1 who had an itch NRS ≥4 at baseline. • Change and percent change from baseline in Itch NRS for participants in Cohort 1.
11. Part A: Additional Secondary PK Endpoint • Plasma concentrations of zasocitinib in participants receiving active treatment.
12. Part B: Additional Secondary Endpoint • Acceptability/palatability assessment scores.

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Placebo 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Takeda Development Center Americas Inc.

Sponsor organisation

Takeda Development Center Americas Inc.

Address

500 Kendall Street

City

Cambridge

Postcode

02142-1108

Country

United States

Scientific contact point

Organisation

Takeda Development Center Americas Inc.

Contact name

Takeda

Public contact point

Organisation

Takeda Development Center Americas Inc.

Contact name

Takeda

Third parties 15

Locations

4 EU/EEA countries · 19 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 98 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

1 submissions — initial application plus substantial / non-substantial modifications