Long-term treatment of acromegaly with the somatostatin analogue SR-lanreotide

Objective: To assess the efficacy and tolerability of SR-lanreotide in the treatment of active acromegaly. Patients and design: 30 patients (17 men and 13 women) were treated in whom active acromegaly was confirmed by clinical features, a mean GH level of >5 mlU/l and failure to suppress GH to <2 mIU/l after a 75 g glucose load. Patients were treated for a median period of 60 weeks (range 12-168) with im injections of SR-lanreotide 30 mg given every 7-14 days. Measurements: Mean GH and IGF-I levels were measured at baseline and every 12-weeks together with symptom score assessment. MRI of the pituitary gland was performed at baseline and if an adenoma was identified at yearly intervals. Gall bladder ultrasound scans were performed at baseline and then every 24-weeks. Results: Twenty-three patients were treated for at least 48-weeks and, in these, GH levels fell from 10.5 mlU/l (7.6-17.6) (median and interquartile range) at baseline to 3.2 mIU/l (2.4-3.9) (p<0.0001) and IGF-I levels ftom 88.9 nmol/L (71.4-137.1) to 56.8 nmol/l (39.3-75.4) (p=0.0002). GH response to treatment was better in elderly patients (age≥65 years) compared to younger patients but neither sex, pre-treatment GH levels, previous surgery nor previous radiotherapy influenced the response. Treatment resulted in a significant improvement in the symptoms of active acromegaly in the majority of patients. A significant reduction in the size of the pituitary adenoma was documented in 6 of 10 patients who had a repeat MRI scan after one year. Treatment was well-tolerated by the majority of patients; side effects were mainly transient gastrointestinal symptoms. These were severe in only 2 patients necessitating discontinuation of the drug. Two patients developed new gall stones and 4 female patients had temporal hair loss necessitating stopping treatment in one of them. There were minor effects on glucose tolerance which were not of clinical importance. Conclusion: Long-term treatment of acromegaly with SR-lanreotide is effective in controlling GH and IGF-l levels and symptoms and is well tolerated in the majority of patients.