The primary purpose of this trial is to evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of NDI-5001 administered as a capsule following daily oral dosing in adult males with X-linked congenital nephrogenic diabetes insipidus (NDI) due to vasopressin receptor Type 2 (V2R) mutations.
X-linked congenital NDI with a genotype-confirmed arginine vasopressin receptor 2 (gene) (AVPR2) mutation and no mutation in aquaporin-2 (AQP2).
Urine osmolality of ≤ 200 milliosmoles per kilogram of water (mOsm/kg) in a spot urine sample obtained from a first morning void upon awakening (at screening, check-in [Day -4], and Day -1) before consuming any food or drink after awakening.
Participant who is not willing to follow a low-sodium (<=1 gram/day) diet during the in-clinic portion of the trial.
A positive drug screen for substances of abuse (including THC, cannabidiol) at screening or check-in.
Estimated glomerular filtration rate <60 milliliters per minute per 1.73-kilogram square meters by serum creatinine and cystatin C at screening.
Participants who have taken an investigational drug within 30 days prior to screening.