Cabergoline in acromegaly: a renewed role for dopamine agonist treatment?

Objective and design: Eighteen active acromegalics entered a prospective open study with cabergoline (CAB), a dopaminergic drug much more potent than bromocriptine (Br). Methods: CAB was administered for 6 months at doses ranging between 0.5mg twice weekly and 0.5 mg/day. Clinical-anamnestic characteristics of the patients were: (i) sensitivity to dopamine agonist drugs (10 patients): (ii) resistance to somatostatin analogs (SAs) (8 patients); (iii) intolerance to SA (3 patients). In 2 patients marked hyperprolactinemia was present. Results: Basal GH was 6.6 mu g/l (2.2=50) (median (range)), and on treatment it was 3.5 mu g/l (1.2-34) (P=0.013). The corresponding IGF-I Values were 720 mu g/l (410-1438) and 375 mu g/l (167-1260) respectively (P=0.00001). Individual GH levels decreased below 2 mu g/l in 5 patients, and between 2 and 5 mu g/l in another 5 patients. IGF-I levels were suppressed below 50% of baseline in 8 patients and normal age-adjusted IGF-I values were reached in 5 patients (27% of the series). The retrospective comparison with previous chronic treatment with Br in the 10 suitable patients showed a greater effectiveness of CAB (IGF-I decrease on CAB treatment, 46.8%, on Br treatment, 31%, P=0.02). Adenoma shrank in the 3 patients whose pituitary imaging was repeated during CAB. Conclusions: These results envisage that CAB may represent a worthy therapeutic tool in acromegalic patients, inducing a degree of IGF-I and GH suppression comparable to SAs, administered by the oral route and much less expensive.