The efficacy of combined treatment in active
acromegaly with both long-acting
somatostatin analogs (SRIF) and
pegvisomant (PEG-V) has been well established. The aim was to describe the PEG-V
dose reductions after the conversion from daily PEG-V to combination treatment. To clarify the individual beneficial and adverse effects, in two
acromegaly patients, who only normalized their
insulin like growth factor (
IGF-I) levels with high-dose
pegvisomant therapy. We present two cases of a 31 and 44 years old male with
gigantism and
acromegaly that were controlled subsequently by surgery,
radiotherapy, SRIF analogs and daily PEG-V treatment. They were converted to combined treatment of monthly SSA and (twice) weekly PEG-V. High dose SSA treatment was added while the PEG-V dose was decreased during carful monitoring of the
IGF-I. After switching from PEG-V monotherapy to SRIF analogs plus
pegvisomant combination
therapy IGF-I remained normal. However, the necessary PEG-V dose, to normalize
IGF-I differed significantly between these two patients. One patient needed twice weekly 100 mg, the second needed 60 mg once weekly on top of their monthly
lanreotide Autosolution
injections of 120 mg. The weekly
dose reduction was 80 and 150 mg. After the introducing of
lanreotide, fasting
glucose and glycosylated haemoglobin concentrations increased. Diabetic medication had to be introduced or increased. No changes in liver tests or in
pituitary adenoma size were observed. In these two patients, PEG-V in combination with long-acting SRIF analogs was as effective as PEG-V monotherapy in normalizing
IGF-I levels, although significant
dose-reductions in PEG-V could be achieved. However, there seems to be a wide variation in the reduction of PEG-V dose, which can be obtained after conversion to combined treatment.