Pasireotide LAR and Pegvisomant Study in Acromegaly

Inclusion Criteria: * written informed consent male or female aged ≥ 18 years * documentation supporting the diagnosis of acromegaly based on elevated GH and/or IGF-I levels due to a pituitary tumor * the patient is treated with lanreotide Autogel or octreotide LAR and PEGV (twice) weekly for at least 6 months and has a serum IGF-I level within 120 % of the age adjusted normal limits. These patients were previously not controlled by somatostatin analogs alone. * female of no childbearing potential or male. No childbearing potential is defined as being postmenopausal for at least 1 year, or women with documented infertility (natural or acquired) or using two acceptable contraceptive measures, except for oral contraceptives. * 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. use a condom) for the duration of the study * 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: Patients will not be included in the study if he or she: * has undergone pituitary surgery or radiotherapy within 6 months prior to study entry. * it is anticipated that the patient will receive pituitary surgery or radiotherapy during the study. * has a history of hypersensitivity to lanreotide, octreotide or pegvisomant or drugs with a similar chemical structure * has been treated with any unlicensed drug within the last 30 days before study entry. * has abnormal hepatic function at study entry (defined as AST, ALT, gGT, alkaline phosphatase, or total bilirubin above 3 ULN) * is at risk of pregnancy or is lactating. Females of childbearing potential must provide a negative pregnancy test within 5 days before the start of the study and must be using contraception. Non-childbearing potential is defined as post-menopause for at least one year, surgical sterilization or hysterectomy at least three months before the start of the study. * has a history of, or known current problems with alcohol or drug abuse. * has a mental condition rendering the subject unable to understand the nature, scope and possible consequences of the study, and/or evidence of an uncooperative attitude. * has abnormal baseline findings, any other medical condition(s) or laboratory findings that, in the opinion of the investigator, might jeopardize the subject's safety or decrease the chance of obtaining satisfactory data needed to achieve the objective(s) of the study. * renal insufficiency, clearance \< 50ml/min * poorly controlled diabetes mellitus with an HbA1c \> 9.0% * patients with a QTc \> 500 ms on the EKG * participation in a clinical trial in the last 6 months