A Phase 2, Multicenter, Randomized, Placebo-Controlled, Double-Blind, Dose-Ranging Trial to Evaluate the Efficacy and Safety of Zasocitinib in Participants with Nonsegmental Vitiligo.
- Trial ID
- 2025-522309-40-00
- Protocol
- TAK-279-VT-2001
Trial statistics
Diseases & Conditions
Objectives
The primary objective of this trial is to evaluate the efficacy of zasocitinib compared to placebo at Week 24 in adult participants with nonsegmental vitiligo. This assessment is clinically relevant for determining whether zasocitinib demonstrates therapeutic benefit in achieving repigmentation in patients with this chronic depigmentation disorder.
The secondary objective is to further evaluate the efficacy of zasocitinib in adult participants with nonsegmental vitiligo.
Participants
The clinical trial enrolled a total of **56 participants** diagnosed with **non-segmental vitiligo**. The study population consisted of adult individuals aged **18 to 75 years**, including both **male and female participants**. Participants were selected based on a clinical diagnosis of non-segmental vitiligo with specific disease severity criteria, requiring a Facial Vitiligo Area Scoring Index (F-VASI) of at least 0.5 and a Total Vitiligo Area Scoring Index (T-VASI) ranging from 5 to 50 at screening and baseline. Individuals with potential for pregnancy were required to use highly effective contraception methods throughout the trial duration if sexually active with partners capable of reproduction. For participants in the European Union, European Economic Area, and the United Kingdom, investigators assessed individual benefit-risk profiles in relation to regulatory guidance on Janus kinase inhibitor safety, including considerations of cardiovascular events, malignancy, venous thromboembolism, serious infections, and mortality risks. Participants were required to demonstrate willingness and ability to comply with all trial procedures, including the use of digital tools and applications, and to provide written informed consent prior to any trial-related activities.
Plans and Procedures
This is a Phase 2, multicenter, randomized, placebo-controlled, double-blind, dose-ranging clinical trial designed to evaluate the efficacy and safety of zasocitinib in participants with nonsegmental vitiligo. The investigational medicinal product, zasocitinib (TAK-279), is a small molecule administered orally in capsule form. The trial includes an active treatment arm and a placebo arm, with placebo consisting of white opaque, hard hypromellose capsules containing the same excipients as the active capsules. The maximum treatment period is 52 weeks.
The primary objective is to evaluate the efficacy of zasocitinib compared to placebo at Week 24 in adult participants with nonsegmental vitiligo. The primary endpoint is the proportion of participants achieving ≥75% improvement from baseline in Facial Vitiligo Area Scoring Index (F-VASI) at Week 24. Secondary endpoints include percent change from baseline in F-VASI at Week 24, percent change from baseline in Total Vitiligo Area Scoring Index (T-VASI) at Week 24, proportion of participants achieving ≥50% improvement from baseline in F-VASI at Week 24, and proportion of participants achieving ≥50% improvement from baseline in T-VASI at Week 24.
Eligible participants must have a clinical diagnosis of nonsegmental vitiligo with F-VASI ≥0.5 and 5≤ T-VASI ≤50 at screening and Day 1. Participants must be aged ≥18 years to ≤75 years old at the time of consent. Individuals with potential for pregnancy who are sexually active with a nonsterilized individual who produces sperm must agree to use a highly effective method of contraception from the signing of informed consent throughout the duration of the trial. For participants in the EU/EEA and the UK, the investigator must document a favorable benefit-risk assessment to justify the participant's inclusion in the trial at screening and every 3 months during the trial if hormonal contraception is elected. Additionally, for participants in the EU/EEA or UK, 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 JAK inhibitors and the UK MHRA guideline on JAK inhibitors regarding risks of major cardiovascular events, malignancy, venous thromboembolism, serious infections and increased mortality. Participants must be willing and able to understand and fully comply with trial procedures and requirements, including digital tools and applications, and must provide written informed consent and any required privacy authorization before the initiation of any trial procedures.
The estimated recruitment start date is January 5, 2026, and the estimated end date is November 9, 2027. The expected length of participant involvement extends up to the maximum treatment period of 52 weeks, with key assessments conducted at Week 24.
Treatment
The experimental medication **zasocitinib** (sponsor product code **TAK-279**) is administered as an **oral capsule**. The active substance is zasocitinib, a **small molecule** of chemical origin. The pharmaceutical form consists of capsules in two formulations, both administered via the **oral route**. The maximum treatment period is **52 weeks**. Specific dosage amounts and frequency of administration are evaluated as part of the dose-ranging design of this **phase 2 trial**.
The **placebo** comparator is formulated as a white opaque, hard **hypromellose capsule**, size 3, containing the same excipients as the TAK-279 active capsule but without the active substance. This matching placebo is designed to maintain blinding in this **double-blind, placebo-controlled trial**. The placebo is administered via the same oral route as the active treatment to ensure consistency in the study design.
The trial employs a **randomized, double-blind, placebo-controlled** design to evaluate multiple dose levels of zasocitinib compared to placebo in participants with **nonsegmental vitiligo**. The dose-ranging approach allows for the assessment of efficacy and safety across different dosing regimens over the treatment period.
Efficacy
Efficacy will be assessed using the Facial Vitiligo Area Scoring Index (F-VASI) and the Total Vitiligo Area Scoring Index (T-VASI) as the primary and secondary endpoints. The primary efficacy endpoint is the proportion of participants achieving at least 75% improvement from baseline in F-VASI at Week 24. Secondary efficacy endpoints include the percent change from baseline in F-VASI at Week 24, the percent change from baseline in T-VASI at Week 24, the proportion of participants achieving at least 50% improvement from baseline in F-VASI at Week 24, and the proportion of participants achieving at least 50% improvement from baseline in T-VASI at Week 24. Baseline F-VASI and T-VASI values will be established at screening and Day 1, with participants required to have F-VASI of at least 0.5 and T-VASI between 5 and 50 at these timepoints.
Inclusion and Exclusion Criteria
Inclusion Criteria
- 1.Participants must have a clinical diagnosis of nonsegmental vitiligo: F-VASI ≥0.5 and 5≤ T-VASI ≤50 at screening and Day 1.
- 2.Participant is aged ≥18 years to ≤75 years old at the time of consent.
- 3.Participant meets the following birth control requirement: An individual with potential for pregnancy who is now of nonchildbearing potential with laboratory confirmation of postmenopausal status; or, if sexually active with a nonsterilized individual who produces sperm, an individual with potential for pregnancy who agrees to use a highly effective method of contraception from the signing of informed consent throughout the duration of the trial. The use of effective contraception will be required for assigned male sex at birth participants. In the EU/EEA and the UK, for participants who elect to use hormonal contraception as a form of highly effective contraception, the investigator must document a favorable benefit-risk assessment to justify the participant’s inclusion in the trial at screening and every 3 months during the trial.
- 4.For participants in the EU/EEA or UK, 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) and the UK MHRA 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).
- 5.Participant is willing and able to understand and fully comply with trial procedures and requirements (including digital tools and applications), in the opinion of the investigator.
- 6.Participant has provided written informed consent and any required privacy authorization before the initiation of any trial procedures.
Exclusion Criteria
- 1.Participant has segmental vitiligo (including mixed vitiligo) or any other congenital or acquired cause of hypopigmentation or depigmentation that could interfere with the diagnosis of nonsegmental vitiligo
- 10.Non-herpetic viral diseases: a) Participant has presence of HCV antibody and a positive confirmatory test result for HCV RNA (nucleic acid test or polymerase chain reaction). In the EU/EEA and the UK, if the participant has total anti-HCV antibody positivity at screening but is confirmed to have no detectable HCV RNA by PCR testing, HCV RNA PCR testing will be assessed at additional visits per SoA. b) Participant has presence of positive HBsAg, or indeterminate HBsAg, presence of HBV DNA (regardless of serology), or positive anti-HBcAb without concurrent positive HBsAb. In the EU/EEA and the UK, if the participant has total anti-HBc antibody positivity at screening but is confirmed to have no detectable HBV DNA by PCR testing, the participant will repeat HBV DNA PCR testing at additional visits per SoA; if a participant has anti-HBsAb positivity at screening but is confirmed to have no detectable HBV DNA by PCR testing, unless the participant has documented completion of the HBV vaccination series by medical records, the participant will repeat HBV DNA PCR testing at additional visits per SoA. Note: For other countries in which there are hepatitis B screening guidelines, these can be done per local regulations or site’s standard of care. c) Participant has positive results for HIV by serology, regardless of viral load.
- 11.Other infectious diseases: a) Participant has a history of active infection or febrile illness (with or without other symptoms) within 7 days prior to Day 1, as assessed by the investigator. b) Participant has a history of serious or severe invasive infection within 30 days prior to Day 1, as assessed by the Investigator. c) Participant has a 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 bacterial infection within 60 days prior to Day 1 for which he or she did not receive treatment.
- 12.Exclusion Criteria 12 excludes participants with recent or chronic infection history that may present a safety risk. This includes acute or recent infections (e.g., any infection or febrile illness within 7 days, systemic illness within 30 days, or serious infections within 8 weeks of Day 1), as well as any history of chronic or opportunistic infections. See protocol for the full list and detailed definitions of infection-related exclusions.
- 13.Participant has any of the following laboratory values at the screening visit, in addition to others listed in the protocol: a) AST or ALT values ≥3 times the ULN. b) Total bilirubin (unconjugated and/or conjugated) ˃1.5 times the ULN. c) Hgb <9.0 g/dL (<90.0 g/L). d) Absolute white blood cell count <3.0 × 109/L (<3000/mm3). e) Absolute neutrophil count of <1.0 × 109/L (<1000/mm3). f) Absolute lymphocyte count of <0.5 × 109/L (<500/mm3). g) Platelet count <100 × 109/L (<100,000/mm3). h) TSH outside the normal reference range AND free T4 or T3 outside the normal reference range. i) Estimated creatinine clearance <45 mL/min based on the Cockcroft-Gault calculation. j) CPK > ULN. CPK may be repeated once; if repeat value is CTCAE Grade 1 or lower (or ≤2.5 × ULN) and no higher than the initial value, participant remains eligible. Investigators should assess the participant for symptoms of rhabdomyolysis and for modulating factors including concomitant medications or vigorous exercise that may affect CPK levels.
- 14.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.
- 15.Participant does not tolerate venipuncture or inability to be venipunctured.
- 16.Participant has a history of significant drug allergy (such as anaphylaxis).
- 17.Participant has a known or suspected allergy to zasocitinib or any of its components.
- 18.Participant has a positive pregnancy test result or plans to become pregnant during the trial period, including plans to undergo in vitro fertilization, donate ova (eggs), or sperm, or participant is lactating/nursing.
- 19.Participant has 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 plans to donate blood during the course of the trial.
- 2.Participant has >50% leukotrichia on the face or >50% leukotrichia of the body (includes the face), within the skin affected by vitiligo
- 20.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.
- 21.Participant is a trial site employee, an immediate family member (for example, spouse, parent, child, sibling), or is in a dependent relationship with trial site employee who is involved in the conduct of this trial, or may consent under duress.
- 3.Participant has a history of phototherapy within 8 weeks before Day 1 including, but not limited to, broadband UV-B, narrowband UV-B, psoralen and UV-A, excimer or other laser therapy, or tanning booth use) within 8 weeks before Day 1.
- 4.Participant has concomitant comorbid skin condition that, in the opinion of the investigator, would interfere with the trial assessments.
- 5.History of any depigmenting or bleaching treatment for vitiligo or other skin disorder (for example, monobenzone or phenol).
- 6.History of any surgical treatments for vitiligo.
- 7.History of recent or progressive undiagnosed hearing loss.
- 8.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 documentation of no history of active TB can be provided AND (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 a positive QFT result or 2 indeterminate QFT results but 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 and the UK, 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. For isoniazid monotherapy, a minimum of 6 months should be used. TB testing should be conducted using QuantiFERON-TB Gold submitted to central laboratory unless alternate or additional tests are required per local guidelines. See Appendix 13.4 for country specific requirements. d) Participant has had any imaging trial during or 6 months prior to screening, including x-ray, chest CT, magnetic resonance imaging, or other chest imaging suggesting evidence of current active or a history of active TB. X-ray is required for all participants regardless of QuantiFERON-TB Gold results unless the participant has had normal chest imaging in the 6 months prior to screening. CT imaging is allowed per local sites requirements.
- 9.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, ophthalmic herpes, or recurrent herpes zoster (defined as 2 episodes within 2 years).
- 22.History of rhabdomyolysis
Trial Status by Country
| Country | Status | Start of Recruitment | Planned Patients |
|---|---|---|---|
 France | Recruiting | 05 Jan 2026 | 39 |
 Italy | Recruiting | 05 Jan 2026 | 26 |
 Poland | Recruiting | 05 Jan 2026 | 58 |
 Spain | Recruiting | 05 Jan 2026 | 28 |
Sites & Investigators
Investigational Products
Details about the medicinal products being studied in this clinical trial.
| Product Name | Role in Trial | Formulation | Administration | Max Daily Dose | Treatment Duration | EU MP Number |
|---|---|---|---|---|---|---|
ZASOCITINIB | Test | CAPSULE | ORAL | 0 | 52 | PRD10260443 |
ZASOCITINIB | Test | CAPSULE | ORAL | 0 | 52 | PRD10260444 |
White opaque, hard hypromellose capsule, size 3 containing same excipients as TAK-279 active capsule | Placebo | N/A | — | — | — | N/A |