Study Investigating the Impact Burden of Nocturia Using the Nocturia Impact Diary (IMPACT)

• Correlation coefficients will be estimated between change from Baseline to Month 1 in nocturnal voids and NI total score [ Time Frame: 1 month ] [ Designated as safety issue: No ]
• Difference in mean change in NI total score in 33% responders [ Time Frame: 1 month ] [ Designated as safety issue: No ]
• Effect size/NI diary responsiveness [ Time Frame: 1 month ] [ Designated as safety issue: No ]
  Responsiveness of the NI diary, measured with Cohen´s D.
• Internal Consistency and Intra-and-Inter-subject Reliability [ Time Frame: 1 month ] [ Designated as safety issue: No ]
  Internal consistency reliability, assessed by the Cronbach´s alpha for the NI total score: A repeated measures ANOVA will be applied to estimate between-and within-subject variability of the total NI score and the Overall Impact score.
• Construct Validity [ Time Frame: 1 month ] [ Designated as safety issue: No ]
  T-tests will be applied to explore the construct validity of the NI diary.

The purpose of this study is to assess psychometric properties (reliability and validity) of the Nocturia Impact (NI) diary.

To assess the association between reduction of number of nocturnal voids and the mean changes in NI scores(sensitivity of the NI total score to change in nocturia).

To assess which NI diary items account for the main difference in change in total NI score in treatment versus placebo.

• Experimental: A - II Female - Desmopressin
  Intervention: Drug: Desmopressin
• No Intervention: B. - III Female - Placebo
• Experimental: C. - II Male - Desmopressin
  Intervention: Drug: Desmopressin
• No Intervention: D. - III Male - Placebo

Inclusion Criteria:

1. Written informed consent prior to performance of any study-related activity
2. 18 years of age (at the time of written consent) or older
3. Previous participation in FE992026 CS40 or FE992026 CS41 with a completion ≥ 30 days prior to Screening. The subject should have responded to active treatment during FE992026 CS40 or FE992026 CS41 or if he/she received placebo during these two studies he/she should have been a non-responder.
4. At least two nocturnal voids every night in two consecutive 3-day periods during the screening period (as determined by the two night-time voiding diaries dispensed at Visit 1 and collected at Visit 2)

Exclusion Criteria:

1. Chronic prostatitis (males)/chronic pelvic pain syndrome (CPPS)
2. Suspicion of bladder outlet obstruction (BOO) or a urine flow of < 5 mL/s as confirmed by uroflowmetry performed after suspicion of BOO
3. Surgical treatment, including transurethral resection, for BOO or benign prostatic hyperplasia (males) within the past six months
4. Urinary retention or a post void residual volume > 150 mL for females and > 250 mL for males as confirmed by bladder ultrasound performed after suspicion of urinary retention
5. Central or nephrogenic diabetes insipidus
6. Syndrome of inappropriate antidiuretic hormone
7. Current or a history of urologic malignancies e.g. bladder cancer
8. Genito-urinary tract pathology e.g. infection or stone in the bladder and urethra causing symptoms
9. Neurogenic detrusor activity (detrusor overactivity)
10. Suspicion or evidence of cardiac failure
11. Chronic prostatitis (males)/chronic pelvic pain syndrome (CPPS)
12. Uncontrolled hypertension
13. Uncontrolled diabetes mellitus
14. Hyponatraemia: serum sodium level must be within normal limits
15. Renal insufficiency: Serum creatinine must be within normal limits and estimated glomerular filtration rate must be ≥ 50 mL/min
16. Hepatic and/or biliary diseases: Aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) levels must not be more than twice the upper limit of normal range. Total bilirubin level must not be > 1.5 mg/dL
17. History of obstructive sleep apnea
18. Treatment with another investigational product (except desmopressin) within three months prior to screening and throughout the study
19. Concomitant treatment with loop diuretics (furosemide, torsemide, ethacrynic acid)
20. Pregnancy, breastfeeding, or an intention of becoming pregnant during the period of the clinical study. Female subjects of reproductive age must have documentation of a reliable method of contraception. All pre-and perimenopausal female subjects have to perform pregnancy tests. Amenorrhea of > 12 months duration based on the reported date of the last menstrual period is sufficient documentation of post-menopausal status and does not require a pregnancy test
21. Known alcohol or substance abuse
22. Work or lifestyle that may interfere with regular night-time sleep e.g. shiftworkers 23. Any other medical condition, laboratory abnormality, psychiatric condition, mental incapacity, or language barrier which, in the judgment of the Investigator, would impair participation in the study