Study to Determine the Maximum Tolerated Dose, Safety and Tolerability of a Single Dose of Lanreotide Prolonged Release Formulation (PRF) in Subjects With Acromegaly

Inclusion Criteria: * Documented diagnosis of acromegaly. * Provided written informed consent prior to any study related procedures. * Between 18 and 75 years of age inclusive. * Female of non-childbearing potential or male. Non-childbearing potential is defined as being postmenopausal for at least 1 year, or women with documented infertility (natural or acquired). * Male subjects must agree that, if their partner is at risk of becoming pregnant, they will use a medically accepted, effective method of contraception (i.e. condom) for the duration of the study (maximum of 7.5 months). * Treatment with a stable dose of either octreotide LAR or lanreotide Autogel for at least 3 months immediately prior to study entry, with confirmation of disease control during this treatment period (documentation of age adjusted IGF 1 \<1.3 x upper limit of normal (ULN), based on local laboratory results, during screening period). * If the subject is receiving treatment for hypertension, the dose has been stable for at least 1 month prior to study entry. * Subjects must be willing and able to comply with study restrictions and to remain at the clinic for the required duration during the study period and willing to return to the clinic for the follow up evaluation as specified in the protocol. Exclusion Criteria: * Has undergone radiotherapy within 2 years prior to study entry. * Has been treated with a dopamine agonist and/or GH receptor antagonist or has undergone pituitary surgery within 3 months prior to study entry. * Is anticipated to require pituitary surgery or radiotherapy during the study. * Has clinically significant hepatic abnormalities and/or alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) ≥3 x ULN and/or alkaline phosphatase (AP) ≥2.5 x ULN and/or total bilirubin ≥1.5 x ULN and/or gamma-glutamyl transpeptidase (GGT) ≥2.5 x ULN during the Screening period (central laboratory results) or a history of these findings when on somatostatin analogue (SSTa) treatment. * Has clinically significant pancreatic abnormalities and/or amylase and/or lipase ≥1.5 x ULN during the Screening period (central laboratory results). * Has any significant renal abnormalities and/or creatinine ≥1.5 x ULN during the screening period (central laboratory results). * Has uncontrolled diabetes (glycosylated haemoglobin (HbA1c) ≥9%, centrally assessed during the Screening period), or has diabetes treated with insulin for less than 6 months prior to study entry. * Has any known uncontrolled cardiovascular disease or had any of the following within 6 months of Screening: ventricular or atrial dysrhythmia ≥grade 2, bradycardia ≥grade 2, electrocardiogram (ECG) QT interval corrected (QTc) prolonged ≥grade 2, myocardial infarction, severe/unstable angina, symptomatic congestive heart failure, cerebrovascular accident or transient ischemic attack, pulmonary embolism, hypertension not adequately controlled by current medications. * Use of any hormone replacement therapy (HRT) with oestrogens. * Has symptomatic gallstones/ sludge at the Screening Visit echography (local assessment) OR is asymptomatic but has echography showing clear evidence of impending inflammation such as localised mucosal thickening suggesting the subject is at high risk of developing acute disease. Subjects with asymptomatic gallstones/ sludge and otherwise normal echography may be entered at the discretion of the investigator. * Has abnormal findings during the Screening period, any other medical condition(s) or laboratory findings that, in the opinion of the investigator, might jeopardise the subject's safety. * Has been treated with any other investigational medicinal product (IMP) prior to the first study visit without undergoing a washout period of seven times the elimination half-life of the investigational compound. * Has a known hypersensitivity to any of the test materials or related compounds. * Is likely to require treatment during the study with drugs that are not permitted by the study protocol. * Has a history of, or known current, problems with alcohol or drug abuse. * Has any mental condition rendering him/her unable to understand the nature, scope and possible consequences of the study, and/or evidence of an uncooperative attitude.