Effects of Lanreotide Autogel on Growth Hormone, Insulinlike Growth Factor 1, and Tumor Size in Acromegaly : A 1-Year Prospective Multicenter Study

Objective: To evaluate the safety and effectiveness of lanreotide Autogel on growth hormone and insulinlike growth factor 1 (IGF-1) concentrations and tumor size in patients with acromegaly. Methods: Between September 2004 and March 2006, patients with active acromegaly who had not previously been treated with somatostatin analogues or received irradiation were enrolled in a 1-year, prospective, open, multicenter study. Lanreotide Autogel was injected subcutaneously starting with 90 mg every 4 weeks for 2 cycles and then individually titrated, aiming for safe growth hormone concentrations (<2.5 ng/mL) and normal age-matched IGF-1 concentrations. Tumor shrinkage, clinical score, pituitary function, and safety parameters were evaluated. Results: Twenty-seven patients (15 women, 12 men) were enrolled. One patient withdrew because of treatment intolerance, and 5 proceeded to neurosurgery 6 months into the study. Lanreotide Autogel was the primary treatment in 19 patients (4 with microadenoma, 15 with macroadenoma) and the adjuvant treatment in 8 patients in whom it followed a previous unsuccessful neurosurgery. In the 26 patients, safe growth hormone values were achieved in 11 (42%), normal IGF-1 values in 14 (54%), and both targets were achieved in 10 (38%). Tumors shrank in 16 of the 22 patients (73%) in whom tumor shrinkage could be evaluated. The maximal vertical diameter of the tumor decreased by a mean of 24% (range, 0% to 50%), from 14.4 ± 8.4 mm to 10.4 ± 7 mm, and tumor volume decreased by a mean of 44% (range, 0% to 76%), from 2536 mm3 (range, 115-7737 mm3) to 1461 mm3 (range, 63-6217 mm3) (both P<.015). Symptom scores and lipid levels significantly improved. In the 26 patients, glucose metabolism deteriorated in 3 (12%) and improved in 4 (15%). New biliary alterations appeared in 26%. Pituitary function and safety parameters did not change. Conclusions: Lanreotide Autogel treatment, titrated for optimal hormonal control, effectively controls IGF-1 and growth hormone levels, shrinks tumors, reduces acromegalic symptoms, and is well tolerated.