All enrolled participants will be randomized to 3 cohorts with 8 participants each and will receive BAP5191 and placebo topically on a square of 121 cm2 each in the left and right scapula region daily for 28 days, with a 28-d safety follow-up.

The squares will be covered with a semi-occlusive patch. The doses will escalate from Cohort 1 to Cohort 2 to Cohort 3.

Key Inclusion Criteria:

• Healthy adult participants,18 to 65 years of age.
• Women of childbearing potential (WOCBP) must agree to use a highly effective form of contraception, from at least 7 days prior to first administration to 28 days after last administration.
• Male participants with WOCBP partner must be willing to use condoms from first IMP application to 90 days after last application.
• Body Mass Index (BMI) between 18 and 29.9 kg/m2. Body weight must be greater than 50 kg.
• Clinical laboratory parameters, vital signs, pulse oximetry, and ECG within the reference range from population studies, or showing no clinically relevant deviations.

Key Exclusion Criteria:

• Chronic use of immunosuppressants within 3 years prior to the first administration of the study drug.
• History of prior leishmaniasis or extensive travel to endemic regions within 1 year prior to the first administration of the study drug.
• Presence or history of severe adverse reaction to any drug, or sensitivity to components of the study medication or to adhesive bandages or tape.
• Skin diseases, excessive hair, tattoos, pigmentation, scars or moles that could interfere with patch application and skin assessment at the site of application.