This study is designed to assess the effect of the different continuous s.c. infusion treatments on the human growth hormone (hGH) levels in untreated acromegalic patients in comparison to a standard dose of octreotide. In addition, the pharmacokinetic profile and the safety and tolerability of DG3173 after continuous s.c. infusion will be evaluated.

Inclusion Criteria:

• Men, women of non child-bearing potential, or women of child-bearing potential who either abstain from sexual intercourse, have a sterile partner or practice two medically approved, non-hormonal methods of contraception
• Diagnosis of acromegaly of pituitary origin
• Have an age-adjusted insulin-like growth factor type 1 (IGF-1) concentration ≥1.2 times the upper limit of normal range on at least one measurement in the 12 months prior to screening (Visit 1) AND a second raised value screening
• Have at least one random hGH level of ≥5 μg/L in the 12 months prior to screening AND a second raised value at screening
• Have given written informed consent
• Ability to comply with the requirements of the protocol for the study

Exclusion Criteria:

• Previous specific treatment for acromegaly in the 12 months prior to screening, including somatostatin analogues (SSAs); surgery; radiotherapy and pegvisomant
• Treatment with dopamine agonists in the 3 months prior to screening
• Uncontrolled hypertension
• Type I diabetes mellitus, poorly-controlled type II diabetes mellitus (glycosylated haemoglobin [HbA1c] ≥7.5%) and patients requiring insulin treatment
• Gallstones or gravel that could cause biliary obstruction
• Hyperprolactinaemia
• Participation in a clinical study within 60 days prior to screening
• Receipt of blood, blood products or plasma derivatives 60 days prior to screening
• Body mass index (BMI) below 22 or above 37 kg/m2
• Pregnancy, lactation or use of any hormonal based contraceptives
• Concomitant intake of corticosteroids or levodopa
• A history of active alcohol abuse or drug addiction
• Positive viral serology screening result for hepatitis B surface antigen, antibodies to hepatitis C virus, or human immunodeficiency virus type 1 and 2
• Evidence or suspicion of tumour expansion
• Clinically significant abnormality in screening ECG in the opinion of the Investigator
• Any clinically significant abnormal in screening laboratory safety test (biochemistry, haematology and dipstick urinalysis) in the opinion of the Investigator
• Any disease which in the Investigator's opinion would exclude the patient from the study