In the present study, remarkably, within a month of switching medical treatment from octreotide to pasireotide, there was not only a notable reduction in IGF1 levels to 14.12 nmol/L (108 ug/L)(normal range, 12.94-31.25 nmol/L [99-239 μg/L]) but a complete resolution of headache, suggesting that for a certain patient subset, pasireotide can provide rapid biochemical and symptomatic improvement, in this case freeing the patient from this debilitating clinical manifestation of acromegaly and dramatically improving his quality of life. Here, IGF1 is linked to acromegaly.