Comparison of pegvisomant and long-acting octreotide in patients with acromegaly naïve to radiation and medical therapy.
BACKGROUND
Normalization of IGF-I in patients with acromegaly is associated with a decrease in mortality. Pegvisomant may be more effective in lowering IGF-I than octreotide.


METHODS
The efficacy and safety of pegvisomant and octreotide long-acting release (LAR) were compared in 118 patients with acromegaly in this 52-week, multicenter, open-label, randomized study. The primary endpoint was IGF-I normalization at week 52. Secondary endpoints included mean changes from baseline in IGF-I, IGF binding protein 3, acromegaly signs and symptom scores, ring size, acromegaly quality of life questionnaire scores, and safety.


RESULTS
Fifty-six patients received pegvisomant and 57 received octreotide LAR. IGF-I normalized in 51% of pegvisomant patients and 34% treated with octreotide LAR (p=0.09, ns). Patients with baseline IGF-I > or = 2x upper limit of normal had a higher rate of IGF-I normalization with pegvisomant vs octreotide LAR (p=0.05). Among the patients who did not achieve a normalized IGF-I, pegvisomant-treated patients were more likely to be receiving < 30 mg of study drug (71% vs 16%). Treatment-related adverse events were mild-to-moderate in both groups. Mean fasting glucose decreased in diabetic and non-diabetic patients on pegvisomant whereas octreotide LAR was associated with an increase at week 52 (p=0.005 and p=0.003 between groups, respectively). Mean change in tumor volume during treatment was similar between groups.


CONCLUSIONS
Pegvisomant and octreotide LAR were equally effective in normalizing IGF-I in the overall population, and pegvisomant was more effective in patients with higher baseline IGF-I levels. Pegvisomant had a more favorable effect on parameters of glycemic control.
Ghigo
E
E
Division of Endocrinology and Metabolism, University of Turin, Molinette Hospital, Corso Dogliotti 14, 10126 Torino, Italy. ezio.ghigo@unito.it
Biller
B M K
BM
Colao
A
A
Kourides
I A
IA
Rajicic
N
N
Hutson
R K
RK
De Marinis
L
L
Klibanski
A
A
D000172:Acromegaly / Q000188:drug therapy*; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003692:Delayed-Action Preparations / Q000627:therapeutic use; D005260:Female; D005704:Gallbladder / Q000000981:diagnostic imaging; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000008:administration & dosage / Q000627:therapeutic use*; D014463:Ultrasonography
D001786:Blood Glucose; D003692:Delayed-Action Preparations; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; C406545:pegvisomant; D015282:Octreotide