Optimizing medical therapy of acromegaly: beneficial effects of cabergoline in patients uncontrolled with long-acting release octreotide.
BACKGROUND
Previous data indicate a beneficial effect of cabergoline (CAB) association to somatostatin analogs (SA) in acromegalics resistant to SA monotherapy.


OBJECTIVE
To assess the efficacy of CAB association on acromegalics with high IGF-I on stable long-acting release octreotide (OCT-LAR) (30 mg/28 days).


METHODS
34 patients (17 male, 25-85 years, 33 macroadenomas) were enrolled in this prospective study. OCT-LAR was administered as primary (n = 4) and as secondary (n = 30) treatment: after surgery (n = 16), after surgery + radiotherapy (RT) (n = 11), and after RT only (n = 3). Duration of OCT-LAR therapy prior to CAB was 24 +/- 12 months. The immunohistochemical features of the tumors disclosed GH/PRL co-secretion in 11/21 patients. 13 patients had high PRL levels prior to CAB. The initial CAB dose was 1.5 mg/week. No IGF-I normalization led to a dose increase to 3.5 mg/week. The OCT-LAR dose was kept stable during treatment. IGF-I, GH and PRL levels were compared before and after CAB association. OCT-LAR was withdrawn in patients who achieved IGF-I normalization, in order to assess the influence of CAB.


RESULTS
Comparing OCT-LAR to OCT-LAR/CAB treatment, there was a significant decrease in mean GH, IGF-I, %ULNR-IGF-I and PRL levels. During OCT-LAR/CAB treatment, IGF-I normalized in 19 patients (56%). IGF-I normalization was correlated to lowest IGF-I levels on OCT-LAR monotherapy, but not to baseline PRL levels or GH/PRL co-expression. OCT-LAR withdrawn in all who had achieved IGF-I normalization on combined therapy resulted in IGF-I elevation to abnormal levels in all patients. Gastrointestinal symptoms were reported by 12 patients.


CONCLUSIONS
OCT-LAR and CAB association has been shown to be an effective alternative therapy for those acromegalics who still have active acromegaly despite monotherapy with SA, mainly for those with lower pretreatment IGF-I concentrations. According to previous studies, the beneficial effects of CAB occur even when pretreatment PRL is normal and/or there is no tumor GH/PRL co-expression.
Neuroendocrine Unit, Division of Endocrinology and Metabolism, Hospital das Clinicas, University of São Paulo Medical School, São Paulo, Brazil.
Raquel S
RS
Jallad
Marcello D
MD
Bronstein
D000172:Acromegaly / Q000188:drug therapy* / Q000532:radiotherapy / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D000077465:Cabergoline; D003692:Delayed-Action Preparations; D004359:Drug Therapy, Combination; D004873:Ergolines / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome
D018931:Antineoplastic Agents, Hormonal; D003692:Delayed-Action Preparations; D004873:Ergolines; D013006:Growth Hormone; D000077465:Cabergoline; D015282:Octreotide