Comparison of octreotide acetate LAR and lanreotide SR in patients with acromegaly

BACKGROUND AND OBJECTIVE The most effective option for the medical treatmen t of patients with acromegaly is the use of somatostatin analogues. Long-ac ting depot formulations for intramuscular injection of two somatostatin ana logues have recently become available: octreotide acetate LAR (Sandostatin( R) LAR(R), Novartis Pharma AG) and lanreotide SR (Somatuline(R), Ipsen Biot ech). We wished to compare efficacy of octreotide LAR and lanreotide SR in acromegalic patients. PATIENTS AND METHODS A group of 125 patients with acromegaly (67 females; m ean age, 47 years; 59 patients had previous pituitary irradiation) from 26 medical centres in France, Spain and Germany were studied. Before the study , all patients had been treated with intramuscular injections of lanreotide SR (mean duration, 26 months) at a dose of 30 mg which was injected every 10 days in 64 and every 14 days in 61 patients, respectively. All patients were switched from lanreotide SR to intramuscular injections of 20 mg of oc treotide LAR once monthly for three months. In order to obtain efficacy and safety data of lanreotide SR under study conditions, it was decided to ran domly assign at day 1, in a 3 : 1 ratio, the time point of the treatment sw itch; 27 of the patients were randomly assigned to continue the lanreotide SR treatment for the first 3 months of the study (group A); they were on oc treotide LAR 20 mg from month 4-6. The other 98 patients were assigned to b e switched to treatment with octreotide LAR 20 mg at day 1 (group B). In gr oup B patients, octreotide LAR treatment was continued until month 6, with an adjustment of the dose based on GH levels obtained at month 3. RESULTS The mean GH concentration decreased from 9.6 +/- 1.3 mU/l at the la st evaluation on lanreotide SR to 6.8 +/- 1.0 mU/l after three injections o f octreotide LAR (P < 0.001). The percentages of patients with mean GH valu es less than or equal to 6.5 mU/l (2.5 mug/l) and less than or equal to 2.6 mU/l (1.0 mug/l) at the last evaluation on lanreotide SR were 54% and 14%, and these values increased after 3 months treatment with octreotide LAR to 68% and 35% (P < 0.001), respectively. IGF-I levels were normal in 48% at the last evaluation on lanreotide SR and in 65% after 3 months on octreotid e LAR (P < 0.001). Patients with pre-study pituitary irradiation had lower mean GH and IGF-I concentrations. But the effects of the treatment change d id not differ between the irradiated and the nonirradiated patients. In gen eral both drugs were well tolerated. CONCLUSION Octreotide LAR 20 mg administered once monthly was more effectiv e than lanreotide SR 30 mg administered 2 or 3 times monthly in reducing GH and IGF-I in patients with acromegaly.