Comparison of cabergoline versus raloxifene add-on therapy to long-acting somatostatin analogue in patients with inadequately controlled acromegaly: A randomized open label clinical trial

Abstract

Objective: The present study aimed to evaluate the efficacy of add-on therapy of cabergoline versus raloxifene to long-acting somatostatin analogues (SAs) in patients with inadequately controlled acromegaly. Methods: This was a prospective, randomized open label clinical trial. Forty-four patients (22 per group) completed the study; where participants received either cabergoline (3 mg/week) or raloxifene (60 mg twice daily) add-on therapy for 12 weeks in a parallel manner. The primary outcome was the rate of reduction in serum insulin-like growth factor 1 (IGF-1) from baseline. Secondary outcomes comprised normalization of serum IGF-1 for age and sex. Results: Serum IGF-1 was significantly decreased in both the cabergoline (40.3 ± 25.6%, P .05). Normalization in serum IGF-1 values occurred in 40.9% of patients who were on cabergoline compared to 45.5% of those receiving raloxi- fene (P = .76). The subsequent logistic regression analysis highlighted baseline IGF-1 as a significant predictor of IGF-1 normalization (odds ratio, 0.995; 95% confidence interval, 0.990-0.999; P = .02). Using the receiver operating characteristic (ROC) curve analysis for the entire group, the baseline IGF-1 value of 1.47 the upper limit of normal (ULN) was the best cut-off point to identify patients with normal IGF-1 at the end of the study (sensitivity: 52.6%, specificity: 84.0%, Yoden's index: 0.366). Full biochemical control of acromegaly was achieved in 22.7% of patients in the cabergoline group compared to 13.6% of those in the raloxifene group (P = .43). Conclusion: Cabergoline and raloxifene add-on therapy could effectively decrease serum IGF-1 level in patients with inadequately controlled acromegaly. The efficacy profiles of both drugs are comparable.