A Clinical Study of MK-6194 for the Treatment of Vitiligo (MK-6194-007)

Researchers are looking for a new way to treat people with non-segmental vitiligo (NSV). The goal of this study is to learn about the safety of MK-6194 and how well people tolerate it. Researchers also want to learn if people who take MK-6194 have more of a decrease in the amount of vitiligo on their face compared to people who take placebo.

Inclusion Criteria: * Has a clinical diagnosis of non-segmental vitiligo * Has non-segmental vitiligo with disease duration of at least 6 months * Has depigmentation contributing to Facial Vitiligo Area Scoring Index (F-VASI) ≥ 0.3 at screening and baseline * Has depigmented facial body surface area (BSA) ≥0.3% at screening and baseline * Has Total Vitiligo Area Scoring Index (T-VASI) ≥4 at screening and baseline * Has total body vitiligo area ≥4% at screening and baseline excluding hands and feet involvement Exclusion Criteria: * Has segmental vitiligo * Has ≥50% leukotrichia on face or body * Has any other dermatological diseases that would interfere with vitiligo assessments * Has history of or current inflammatory condition other than vitiligo that, in the opinion of the investigator, could interfere with the evaluation of vitiligo * Has a known systemic hypersensitivity to interleukin 2 (IL-2), or modified IL-2 including MK-6194, or its inactive ingredients * Has an active or clinically significant infection requiring hospitalization or treatment with IV anti-infectives within 4 weeks prior to Randomization, or oral/intramuscular anti-infective therapy within 2 weeks prior to Randomization * Has symptomatic heart failure (New York Heart Association class III or IV) or myocardial infarction or unstable angina pectoris within 6 months prior to Screening * Has a severe chronic pulmonary disease requiring oxygen therapy * Has a transplanted organ, which requires continued immunosuppression * Has a history of any malignancy, except for successfully treated non-melanoma skin cancer or localized carcinoma in situ of the cervix * Has evidence of active tuberculosis (TB), latent TB, or inadequately treated TB * Has confirmed or suspected COVID-19 infection * Has history of drug or alcohol abuse within 6 months prior to Screening * Has had major surgery within 3 months prior to Screening OR has a major surgery planned during the study * Has had an inadequate response (as evaluated by a dermatologist or local physician specialist equivalent) to previous treatment with a Janus kinase inhibitor (JAKi) after an appropriate treatment duration (eg, ≥12 weeks) * Has received prohibited medications within protocol-specified timeframes prior to Randomization * Has participated in another investigational clinical study within 4 weeks prior to Randomization * Has donated or lost ≥1 unit of blood (approximately 500 mL) within 4 weeks prior to the Screening Visit * Has received cosmetic or other procedures that could interfere with evaluation of vitiligo during the study