Several recent studies have reported beneficial effects of
pegvisomant monotherapy on
glucose homeostasis for acromegalic patients resistant to
somatostatin analogs (SSA). The aim of our longitudinal study was to test whether these beneficial effects on
glucose homeostasis would also occur during combined
pegvisomant + SSA treatment amongst partially SSA-resistant acromegalic patients. Ten non-diabetic, partially SSA-resistant acromegalic patients underwent a 12-month SSA+pegvisomant treatment after SSA-only
therapy.
Glucose homeostasis was evaluated at disease diagnosis, at the end of the SSA treatment and after 6 and 12 months of combined SSA+pegvisomant treatment. The addition of
pegvisomant treatment was accompanied by a significant improvement in
insulin and glycemic responses to the oral
glucose tolerance test, without any significant changes in fasting plasma
glucose, glycosylated haemoglobin, homeostatic model assessment-derived
insulin resistance index and homeostatic model assessment-derived beta-cell function. Moreover, the number of patients with
glucose intolerance did not significantly change during the 12-month combined treatment, notwithstanding the significant decrease in serum
IGF-1 values. Therefore, our findings suggest that the combined
pegvisomant and SSA treatment may not be able to restore normal clinical and biochemical glycometabolic features occurring in acromegalic patients resistant to SSA, while a slight but significant improvement in some biochemical features may be expected.