IGF1 and acromegaly: Indeed, results from a prospective, long-term study (up to 9 years) in 67 patients with de novo acromegaly showed that 68.7% and 70.1% of patients treated with octreotide LAR as first-line therapy achieved GH levels <2.5 μg/L and normal IGF-1 levels, respectively, and tumor volume decreased by >25% in 82% of patients [104].