A comparison between octreotide-LAR and lanreotide-SR in the chronic treatment of acromegaly.
BACKGROUND
At present long-acting somatostatin analogs represent the first-line medical treatment of acromegaly. These drugs produce stable suppression of GH in most sensitive patients and IGF-I normalization in many; they also increase the compliance of acromegalic patients. The recent availability of octreotide (OC)-LAR, a somatostatin analog to be administered at 28-day intervals, has prompted us to compare, in the same group of patients, its effects and those of another somatostatin analog already available, lanreotide-SR (LSR, to be administered at 14-day intervals).


METHODS
Twelve somatostatin analog-sensitive acromegalic patients with active disease were enrolled in a prospective open sequential study after giving their informed consent. After chronic treatment with LSR (6-24 months), the patients were changed to treatment with OC-LAR, without wash-out. LSR had been administered at individually tailored dosages (30 mg i.m. at 7-21-day intervals, median 10 days - every 7 days in seven patients, 10 days in two patients, 14 days in two patients and 21 days in one patient) according to GH and IGF-I responses. Disease stability was obtained, as shown by maximal GH/IGF-I suppression without any significant hormonal change between the last two control measurements. OC-LAR was administered i.m. at 28-day intervals six times at the dosage of 20 mg for the first three times and 10 or 30 mg for the last three times (according to individual GH/IGF-I responses). GH (mean of three, hourly samples) and IGF-I concentrations were evaluated on the same day as each administration of the drug, before its injection.


RESULTS
GH and IGF-I values were significantly decreased by LSR treatment. GH decreased from 41.6 +/- 14.6 microg/l (mean +/- s.e.) to 7.2 +/- 1.5 microg/l (P < 0.02), whereas IGF-I values declined from 959 +/- 95 microg/l to 460 +/- 61 microg/l (P < 0.00001), expressed as absolute values, and from 287 +/- 30% to 137 +/- 19% expressed as percentage of the upper limit of normal range (% ULNR). At the end of the last cycle, OC-LAR treatment achieved a significant further suppression both in GH (to 5.1 +/- 1.1 microg/l, P < 0.05 compared with LSR) and in IGF-I concentrations (to 374 +/- 60 microg/l, P<0.05 compared with LSR, and to 112 +/- 19% as % ULNR). LSR decreased GH concentrations to less than 2.5 microg/l in one patient and normalized IGF-I concentrations in four patients. OC-LAR decreased GH concentrations to less than 2.5 microg/l in four patients and normalized or near-normalized IGF-I concentrations (i.e. to < 110% ULNR) in eight patients.


CONCLUSIONS
These preliminary results show that the once-monthly OC-LAR administration schedule proved more efficacious than LSR given every 7-21 days, in a greater number of acromegalic patients.
Cozzi
R
R
Division of Endocrinology, Niguarda Hospital, Milan, Italy. endonig@rdn.it
Dallabonzana
D
D
Attanasio
R
R
Barausse
M
M
Oppizzi
G
G
D000172:Acromegaly / Q000188:drug therapy* / Q000503:physiopathology; D000328:Adult; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000627:therapeutic use*; D001786:Blood Glucose / Q000032:analysis; D018592:Cross-Over Studies; D005260:Female; D005704:Gallbladder / Q000000981:diagnostic imaging; D006442:Glycated Hemoglobin / Q000032:analysis; D006728:Hormones / Q000008:administration & dosage / Q000627:therapeutic use*; D019382:Human Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000008:administration & dosage / Q000627:therapeutic use*; D010456:Peptides, Cyclic / Q000008:administration & dosage / Q000627:therapeutic use*; D011446:Prospective Studies; D011863:Radioimmunoassay; D013004:Somatostatin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D014463:Ultrasonography
D000894:Anti-Inflammatory Agents, Non-Steroidal; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D006728:Hormones; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D015282:Octreotide; D010456:Peptides, Cyclic; D013004:Somatostatin; C060347:lanreotide