Pioglitazone in acromegaly - an open-label, prospective study.

ABSTRACT

OBJECTIVE: Preclinical studies demonstrate that thiazolidinediones (TZDs) decrease growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels, suggesting that they might be effective treatments for acromegaly. This study investigated the effect of pioglitazone on biochemical indices of disease activity in acromegaly. DESIGN AND PARTICIPANTS: This was a 4-month open-label prospective study in 16 patients with active acromegaly who were attending public hospital endocrinology clinics. METHODS: The intervention was pioglitazone 45 mg/day. The primary outcome was change in serum IGF-1; the secondary outcome was change in area under the curve of glucose-suppressed GH. RESULTS: Serum IGF-1 did not change during treatment with pioglitazone (P = 0·95). After 4 months, the mean (95% CI) change from baseline was -1 µg/l (-51, 49). GH levels following oral glucose loading were unchanged during pioglitazone therapy. After 4 months, the mean (95% CI) change from baseline in area under curve for glucose-suppressed GH was 31 µg/l (-75, 138, P = 0·54). CONCLUSIONS: Short-term treatment with conventional doses of pioglitazone did not improve biochemical measures of disease activity in acromegaly.