Trial to Compare the Efficacy and Safety of NNC0195-0092 (Somapacitan) With Placebo and Norditropin® FlexPro® (Somatropin) in Adults With Growth Hormone Deficiency.

Inclusion Criteria: * Male or female of at least 23 years of age and not more than 79 years of age at the time of signing informed consent * Human growth hormone (hGH) treatment naïve or no exposure to hGH or growth hormone (GH) secretagogues for at least 180 days prior to randomisation with any registered or investigational hGH or GH secretagogue product (if only used in connection with stimulation tests for diagnosis of growth hormone deficiency (GHD), subjects can be included) * If applicable, hormone replacement therapies for any other hormone deficiencies, adequate and stable for at least 90 days prior to randomisation as judged by the investigator * FOR ALL COUNTRIES EXCEPT JAPAN: Confirmed diagnosis of adult growth hormone deficiency (Subjects must satisfy one of the following criterion and documentation of test results must be available before randomisation (either from subjects' file or new test): 1. Insulin tolerance test (ITT) or glucagon test: a peak GH response of less than 3 ng/mL (3 mcg/L) 2. Growth hormone releasing hormone (GHRH) + arginine test according to body mass index (BMI): i) BMI less than 25 kg/m\^2, a peak GH less than 11 ng/mL (11 mcg/L), ii) BMI 25-30 kg/m\^2, a peak GH less than 8 ng/mL (8 mcg/L), iii) BMI greater than 30 kg/m\^2, a peak GH less than 4 ng/mL (4 mcg/L) 3. Three or more pituitary hormone deficiencies and insulin like growth factor - I standard deviation score (IGF-I SDS) less than -2.0 - FOR JAPAN ONLY: Confirmed diagnosis of adult growth hormone deficiency (subjects with adult onset adult growth hormone deficiency (AGHD) need to satisfy at least one of the following criteria, subjects with a history of childhood GHD need to satisfy at least 2 of the following criteria): a. ITT test: a peak GH of less than or equal to 1.8 ng/mL (assay using recombinant GH standard) b. glucagon test: a peak GH of less than or equal to 1.8 ng/mL (assay using recombinant GH standard) c. growth hormone releasing peptide 2 (GHRP-2) tolerance test: a peak GH of less than or equal to 9 ng/mL (assay using recombinant GH standard) Exclusion Criteria: * Active malignant disease or history of malignancy. Exceptions to this exclusion criterion: - Resection in situ carcinoma of the cervix uteri. Complete eradication of squamous cell or basal cell carcinoma of the skin * Subjects with GHD attributed to treatment of intracranial malignant tumours or leukaemia, provided that a recurrence-free survival period of at least 5 years is documented in the subject's file