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Taking people in United StatesPhase 2

ACT-777991 for adults with non-segmental vitiligo

Tests ACT-777991 against placebo for skin color return in adults with non-segmental vitiligo.

Key facts

Who runs it
Idorsia Pharmaceuticals Ltd.
Where
Los Angeles, United StatesSee the siteAlso in 2 other countries, 7 sites
Registry title
A Study to Learn How Safe ACT-777991 is and How Well it Works in Adults With Non-segmental Vitiligo
Status
Recruiting
Phase
Phase 2
People taking part
30 people, planned
Started
6 Oct 2026
Expected to end
31 Jul 2027
Type of study
Interventional, 2 groupsOne group gets a placebo (a dummy treatment), for comparison.
Treatments tested
  • ACT-777991
  • Placebo
Record updated
2 November 2026

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for adults with non-segmental vitiligo, including on the face. It compares ACT-777991 tablets with placebo tablets taken daily for 24 weeks.

Age
18 Years to 65 Years
Sex
All sexes can join
Disease stage
Active or stable non-segmental vitiligo, diagnosed at least 3 months before Screening. F-VASI score ≥ 0.3 and T-VASI score ≥ 5. Vitiligo covers ≤ 50% of the body surface, including the face.
Earlier treatment
No systemic immunotherapy, including JAK inhibitors, for any inflammatory disease in the 12 months before Randomization. No JAK inhibitor creams in the 6 weeks before Screening. No laser or light treatment, including tanning beds, in the 8 weeks before Screening. You must agree to use no other vitiligo treatments during the trial. In the EU, you cannot have stopped or changed a vitiligo treatment just to join this trial.

Main reasons for not taking part

  • Segmental vitiligo or other disorders that cause loss of skin color
  • Any autoimmune disease, except thyroid disease that is well treated
  • Kidney function (eGFR) < 90 mL/min/1.73 m^2 at Screening
  • Recent immunotherapy, JAK inhibitors, or light-based treatment

The registry criteria, word for word

Show all 8 criteriaShow less

Who can take part

  • 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; Applicable only to EU: In addition to the above, participants must not have discontinued, reduced, or modified a vitiligo treatment/ procedure for the purpose of meeting trial eligibility criteria or a wash out requirement

Who cannot take part

  • 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
  • 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
  • eGFR < 90 mL/min/1.73 m\^2, defined by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation, at Screening

Check if you might fit

Answer for yourself. This is not a decision: only the study team can say whether you can take part.

  • Are you between 18 and 65 years old?

Where in United States

Also in 2 other countries, 7 sites

  • Vitiligo & Pigmentation Institute of Southern CaliforniaLos Angeles, United StatesTaking people

About the trial

What the trial wants to find out

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.

Read full original descriptionShow less

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.

The 2 groups in the trial

  • ACT-777991Treatment being tested

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

  • PlaceboPlacebo, for comparison

    Participants will receive placebo tablets orally for 24 weeks.

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Data and sources

Registry record
Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
Official title
A Phase 2a, Proof of Concept, Multicenter, Double Blind, Randomized, Placebo Controlled, Parallel Group Trial to Assess the Efficacy and Safety of ACT-777991 in Adults With Non-segmental Vitiligo
Plain-language title
ACT-777991 for adults with non-segmental vitiligoGenerated from the registry record. The registry title is the official one.
AI summary
From the trial's eligibility criteria. Read by machine on 14 November 2026.
Fit questions
Built from NCT07667569, who can take part
Record updated
2 November 2026