The study compares two medicines for children with a low level of hormone to grow: somapacitan (a new medicine) given once a week and Norditropin® (a medicine doctors can already prescribe) given once a day. Researchers will test somapacitan to see how well it works, compared to the standard treatment with Norditropin®. The participants will either get Norditropin® once every day or somapacitan once every week - which treatment the participant gets is decided by chance. The participant and the study doctor will know which treatment the participant gets. The study includes a 52 week treatment period and a minimum of 30 days follow up period.

Inclusion Criteria:

• Informed consent of parent or legally acceptable representative of participant and child assent, as age-appropriate must be obtained before any trial related activities
• The parent or legally acceptable representative of the child must sign and date the Informed consent form (according to local requirements)
• The child must sign and date child assent form or provide oral assent (if required according to local requirements)
• Prepubertal children: a) Boys: Age more than or equal to 2 years and 26 weeks and less than or equal to 11.0 years at the time of signing informed consent.
• Testis volume less than 4 ml. b) Girls: Age more than or equal to 2 years and 26 weeks and less than or equal to 10.0 years at the time of signing informed consent. Tanner stage 1 for breast development (no palpable glandular breast tissue)
• Confirmed diagnosis of growth hormone deficiency determined by two different growth hormone stimulation tests performed within 12 months prior to randomisation, defined as a peak growth hormone level of less than or equal to 10.0 ng/ml using the WHO International Somatropin 98/574 standard
• If only one growth hormone stimulation test is available before screening, then confirmation of growth hormone deficiency by second and different growth hormone stimulation test must be done
• For children with at least 2 additional pituitary hormone deficiencies (other than growth hormone deficiency) only one growth hormone stimulation test is needed
• Impaired height defined as at least 2.0 standard deviations below the mean height for chronological age and gender according to Chinese general population standards at screening
• Impaired height velocity defined as annualised height velocity at screening less than 7cm/year for subjects between 2.5 and 3 years old and less than 5 cm/year for subjects from 3 years and above calculated over a time span of minimum 3 months and maximum 18 months prior to screening according to Chinese guideline and expert consensus on children with short stature and GH therapy
• No prior exposure to growth hormone therapy or IGF-I treatment
• Bone age less than chronological age at screening
• Body Mass Index more than 5th and less than 95th percentile, Body Mass Index-for-age growth charts according to Chinese general population standards.
• IGF-I < -1.0 SDS at screening, compared to age and gender normalized range measured at central laboratory
• No intracranial tumour confirmed by magnetic resonance imaging or computer tomography scan. An image or scan taken within 9 months prior to screening can be used as screening data if the medical evaluation and conclusion is available

Exclusion Criteria:

• Known or suspected hypersensitivity to trial product(s) or related products.

• Previous participation in this trial. Participation is defined as randomisation.

• Receipt of any investigational medicinal product within 3 months before screening or participation in another clinical trial before randomisation

• Any known or suspected clinically significant abnormality likely to affect growth or the ability to evaluate growth with standing height measurements:

• Turner Syndrome (including mosaicisms)

• Chromosomal aneuploidy and significant gene mutations causing medical "syndromes" with short stature, including but not limited to Laron syndrome, Noonan syndrome, Prader-Willi Syndrome, abnormal SHOX-1 gene analysis or absence of GH receptors

• Significant spinal abnormalities including but not limited to scoliosis, kyphosis and spina bifida variants

• Congenital abnormalities (causing skeletal abnormalities), including but not limited to Russell-Silver Syndrome or skeletal dysplasias

• Family history of skeletal dysplasia

• Children born small for gestational age (birth weight 10th percentile of the recommended gender-specific birth weight for gestational age according to national standards in China5

• Children diagnosed with diabetes mellitus or screening values from central laboratory of

  1. fasting plasma glucose more than or equal to 126 mg/dl (7.0 mmol/L) or
  2. HbA1c more than or equal to 6.5 %

• Current inflammatory diseases requiring systemic corticosteroid treatment for longer than 2 consecutive weeks within the last 3 months prior to screening

• Children requiring inhaled glucocorticoid therapy at a dose greater than 400 µg/day of inhaled budesonide or equivalents for longer than 4 consecutive weeks within the last 12 months prior to screening

• Concomitant administration of other treatments that may have an effect on growth, e.g. but not limited to methylphenidate for treatment of attention deficit hyperactivity disorder (ADHD)

• Diagnosis of attention deficit hyperactivity disorder

• Prior history or presence of malignancy including intracranial tumours

• Prior history or known presence of active Hepatitis B or Hepatitis C (exceptions to this exclusion criterion is the presence of antibodies due to vaccination against Hepatitis B)

• Any clinically significant abnormal laboratory screening tests, as judged by the study doctor

• Any disorder which, in the opinion of the study doctor, might jeopardise Participant's safety or compliance with the protocol

• The participant or the parent/legally acceptable representative is likely to be non-compliant in respect to trial conduct, as judged by the study doctor

• Children with hypothyroidism and/or adrenal insufficiency not on adequate and stable replacement therapy for at least 90 days prior to randomisation.

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