A Study to Learn How Safe ACT-777991 is and How Well it Works in Adults With Non-segmental Vitiligo

NCT07667569 | Not Yet Recruiting Phase 2 DMC FDA Drug

• 2 other identifiers: ID-089B2012025-524865-25-00
• Study Type: interventional
• Target: 30
• Locations: 0 countries
• Sites: N/A

Brief Summary

The purpose of this clinical trial is to learn how well ACT-777991 works, how safe it is and how well it is tolerated by adults with non-segmental vitiligo. The main question this clinical trial aims to answer is:

• Can ACT-777991 help return color to the skin of the face of adults with non-segmental vitiligo? Researchers will compare ACT-777991 to placebo (a look-alike inactive treatment that contains no medicine) to see if ACT-777991 works to treat non-segmental vitiligo. Trial participants will:
• Take the trial intervention (either ACT-777991 or placebo) daily for 24 weeks.
• Visit the clinic 7 times for check-up and tests.

Conditions

Non-Segmental Vitiligo

Outcome Measures

Primary Outcomes (6)

• Main primary outcome measure: Percentage change from baseline in Facial Vitiligo Area Scoring Index (F-VASI) based on Blinded Independent Central Reading (BICR) at Week 24

  The vitiligo area scoring index (VASI) is a validated clinician-reported outcome measure that scores both the extent (surface area) and degree (level of depigmentation) of vitiligo lesions over time. The F-VASI describes involvement of the face, with higher scores indicating more severe disease. Negative changes from baseline indicate improvement.

  Baseline; Week 24

• Supplementary primary outcome measure: Percentage change from baseline in F-VASI based on investigator assessment at Week 24

  Baseline; Week 24

• Supplementary primary outcome measure: Percentage change from baseline in F-VASI at Week 4, 8 and 16

  F-VASI will be assessed by the investigator and by BICR.

  Baseline; Week 4, Week 8; Week 16

• Supplementary primary outcome measure: Achievement of F-VASI50 at Week 4, 8, 16 and 24

  Proportion of patients achieving at least a 50% improvement from baseline in F-VASI.

  Baseline; Week 4; Week 8; Week 16; Week 24

• Supplementary primary outcome measure: Achievement of F-VASI75 at Week 4, 8, 16 and 24

  Proportion of patients achieving at least a 75% improvement from baseline in F-VASI.

  Baseline; Week 4; Week 8; Week 16; Week 24

• Supplementary primary outcome measure: Achievement of F-VASI90 at Week 4, 8, 16 and 24

  Proportion of patients achieving at least a 90% improvement from baseline in F-VASI.

  Baseline; Week 4; Week 8; Week 16; Week 24

Secondary Outcomes (14)

• Percentage change from baseline in Total Body Vitiligo Area Scoring Index (T-VASI) at Week 4, 8, 16 and 24

  Baseline; Week 24

• Achievement of T-VASI50 at Week 4, 8, 16 and 24

  Baseline; Week 4; Week 8; Week 16; Week 24

• Adverse events (AEs) leading to premature discontinuation of trial intervention

  From start of trial intervention to last dose of trial intervention, assessed up to Week 24

• Treatment-emergent AEs and serious AEs (SAEs)

  From start of trial intervention up to 37 days after last dose of trial intervention (Follow-up visit)

• Treatment-emergent AEs of special interest (AESI)

  From start of trial intervention up to 37 days after last dose of trial intervention (Follow-up visit)

Study Arms (2)

ACT-777991

EXPERIMENTAL

Participants will receive ACT-777991 tablets orally for 24 weeks.

Drug: ACT-777991

Placebo

PLACEBO COMPARATOR

Participants will receive placebo tablets orally for 24 weeks.

Drug: Placebo

Interventions

ACT-777991 DRUG

ACT-777991 tablets

ACT-777991

Placebo DRUG

ACT-777991-matching placebo tablets

Placebo

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Clinical diagnosis of either active or stable non segmental vitiligo for at least 3 months prior to Screening and meet all the following criteria:
• F-VASI score ≥ 0.3 based on BICR at Screening.
• T-VASI score ≥ 5 based on investigator assessment at Screening and Randomization.
• Total body surface area (BSA) involvement, including the face, ≤ 50% based on investigator assessment at Screening and Randomization.
• Participants must agree not to use therapeutic agents and procedures to treat vitiligo from Screening until Participant Last Visit.

You may not qualify if:

• Clinical diagnosis of other forms of vitiligo (e.g., segmental) or other hypo- or depigmentation disorders (e.g., piebaldism, leukoderma, Vogt-Koyanagi-Harada disease, malignancy-induced hypopigmentation).
• Any autoimmune disease, except adequately treated thyroid disease.
• History of systemic immunotherapy treatment, including JAK inhibitors, for any inflammatory disease in the 12 months prior to Randomization.
• History of topical JAK inhibitors for any inflammatory disease in the 6 weeks prior to Screening.
• Use of laser or light-based treatment (phototherapy), including tanning beds, in the 8 weeks prior to Screening.
• eGFR \< 90 mL/min/1.73 m2, defined by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation, at Screening.

Sponsors & Collaborators

• Idorsia Pharmaceuticals Ltd.: lead

Study Officials

• Clinical Trials

  Idorsia Pharmaceuticals Ltd.

  STUDY DIRECTOR

Central Study Contacts

Clinical Trial Information USA

CONTACT

+1 856 661 37 21; idorsiaclinicaltrials@idorsia.com

Clinical Trial Information Europe

CONTACT

+41 58 844 1977; idorsiaclinicaltrials@idorsia.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 11, 2026
• First Posted: June 25, 2026
• Study Start: June 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): July 1, 2027
• Last Updated: June 25, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share