The trial medicine (LEO 152020) is being developed to treat people with eczema.

The aims of this trial are to find out about:

• How the trial medicine affects participant's heart rhythm.
• How much of the trial medicine is absorbed into the bloodstream, and how quickly the body gets rid of it.
• The safety of the trial medicine and any side effects that might be related to it.

The trial will last up to 45 days, and there will be up to 6 visits.

Four treatment periods are planned for this trial. In each treatment period, participant will receive a single dose of the trial medicine at dose A, trial medicine at dose B, dummy tablet, or an approved medication named moxifloxacin (used for the treatment of bacterial infections). The order of these 4 treatment periods is chosen at random. Participant will receive all 4 treatments; it is only the order of the treatments that is random.

There will be 6 trial visits and they will include 1 screening visit, 4 treatment period visits and 1 final, follow-up visit at the clinic. The 4 treatment period visits will last for 3 days, from Day -1 (check-in to the clinic) to Day 2 (check-out of the clinic). There will be a period of at least 3 days between the 4 dosing occasions.

Inclusion Criteria:

• Men or women between 18 and 55 years of age, inclusive, at screening.
• Body mass index between 18.0 and 30.0 kg/m2, inclusive.
• In good health at screening and check-in (as applicable) for Treatment Period 1, as assessed by the investigator (or designee) based on medical history, physical examination, 12-lead ECG, vital signs measurements, and clinical laboratory evaluations (congenital nonhemolytic hyperbilirubinemia [e.g. suspicion of Gilbert's syndrome based on total and direct bilirubin] is not acceptable).
• Female subjects of childbearing potential must be willing to comply with the contraception requirements.

Exclusion Criteria:

• ECG with any clinically relevant abnormality, such as QTcF >450 ms (males) or >460 ms (females), QRS duration >110 ms, or PR interval >220 ms.

• Subjects at risk for Torsades de pointes based on any of the following:

  1. Uncorrected hypokalaemia or hypomagnesaemia at screening or check-in for Treatment Period 1, history of cardiac failure, history of clinically significant/symptomatic bradycardia.
  2. (Congenital) long QT syndrome or family history of idiopathic sudden death.

• Known history of ventricular arrhythmias.

• Second- or third-degree atrioventricular block.

• Use or intend to use any medications or products known to alter drug absorption, metabolism, or elimination processes, including St. John's wort, within 30 days prior to check-in for Treatment Period 1, considered to potentially impact subject safety or the objectives of the trial, as determined by the investigator (or designee).

• Use of tobacco- or nicotine-containing products within 3 months prior to check-in for Treatment Period 1, or positive cotinine at screening or check-in for Treatment Period 1.

Other protocol defined criteria may apply.

Data sharing is subject to approved scientifically sound research proposal and signed data agreement