Effectiveness and tolerability of slow release lanreotide treatment in active acromegaly

This single-center open sequential study aimed at comparing the efficacy of a 6-month treatment with lanreotide (LAN) (60-90 mg/month im), to that of octreotide (OCT) (0.3-0.6 mg/day sc) in 45 patients with active acromegaly (GH, 63.2+/-12.1 ng/ml, IGF-I, 757+/-67.1 ng/ml). After 6 months of OCT tre atment, safe GH (fasting <2.5, glucose suppressed <1 ng/ml) and IGF-I (norm alized for age) levels were achieved in 23 patients. After treatment withdr awal, GH levels significantly increased in all patients, though remaining s lightly lower than pre-OCT therapy (39.2+/-5.8 ng/ml) while plasma IGF-I le vels were unchanged (654+/-59.4 ng/ml). After 6 months of LAN treatment, sa fe GH and IGF-I levels were achieved in 26 patients (57.7%). After OCT or L AN treatments, no significant difference was found between nadir GH (6+/-1 vs 5.9+/-1.1 ng/ml) and IGF-I levels (281+/-23.3 vs 262+/-20.6 ng/ml). Four out of the 20 patients poorly responsive to OCT achieved safe GH and IGF-I levels after LAN treatment. Among the 20 non-operated patients, a signific ant tumor shrinkage was documented by CT and/or MRI in 5 patients after OCT and in 1 patient after LAN treatment. All patients referred a notable impr ovement of soft tissue swelling, arthralgia, headache and weakness, both af ter OCT and LAN treatments. During the first days of OCT treatment, abdomin al discomfort was referred by 12 patients and steatorrhea by 5 patients: si de effects disappeared spontaneously in 6 cases while during treatment with pancreatic enzymes in the remaining ones. After the first injections of LA N, abdominal discomfort was referred by 10 patients and steatorrhea by 2 of them. No difference in the prevalence of both early and late side effects was noted after treatment with OCT and LAN (chi(2), 0.49). The majority of these poorly tolerant patients had side effects with both compounds. During LAN treatment, side effects were mild and spontaneously disappeared but re curred after the injection of the drug in six patients. Gallstones were det ected in one patient during OCT and in another during LAN, sludge was noted in 6 patients after OCT and in 2 after LAN treatment. In conclusion, the t reatment with LAN allowed to achieve safe GH and IGF-I levels in 57.7% of a cromegalics with an excellent patients' compliance. LAN treatment possessed similar efficacy and caused side effects with a similar incidence of OCT t reatment. The recurrence of side effects after LAN injection suggests the n ecessity of a careful monitoring of adverse reactions. (J. Endocrinol. Inve st. 22: 40-47, 1999) (C)1999, Editrice Kurtis.