This study will look at two different oral formulations and compare them. The medicine in the study is called NDec and it is a combination of two medicines (decitabine and tetrahydrouridine). Both medicines are new for the treatment of sickle cell disease, a rare blood disease. The purpose of the study is to compare the absorption of two different NDec versions (a tablet and a capsule). Participant will either get first the tablet and then the capsule, or the other way around. The order in which participant get them is decided by chance. The study will last for about 12 to 45 days depending on the wash-out period between the two stays in the clinic and from recruitment to the first study day.

Inclusion Criteria:

• Informed consent obtained before any study-related activities. Study-related activities are any procedures that are carried out as part of the study, including activities to determine suitability for the study.
• Male or female.
• Age 18 64 years (both inclusive) at the time of signing the informed consent.
• Body weight between 60.0 and 100.0 kilogram (kg) (both inclusive) at screening.
• Body mass index between 18.5-29.9 kilograms per square meter (kg/m^2) (both inclusive).
• Considered to be generally healthy based on the medical history, physical examination, and the results of vital signs, electrocardiogram and clinical laboratory tests performed during the screening visit, as judged by the investigator.

Exclusion Criteria:

• Platelet count greater than (>) 400*10^9/ Liter (L) at visit 1

• Absolute neutrophil count less than or equal to (≤) 1.5*10^9/L at visit 1

• Female who is:

  1. pregnant, breast-feeding or intends to become pregnant during the trial or within 6 months after the last dose of trial product or
  2. of childbearing potential and not using highly effective contraceptive method and whose male partner is not using effective contraception, from screening until 6 months after the last dose of trial product

• Male of reproductive age with female partner of childbearing potential who does not agree to use condoms and whose female partner of childbearing potential is not using a highly effective contraceptive measure (or adequate contraceptive measure as required by local regulation or practice) from signing the informed consent form (ICF) until 6 months after the last dose.

According to the Novo Nordisk disclosure commitment on novonordisk-trials.com