Strategies for managing ACTH dependent mineralocorticoid excess induced by abiraterone.

BACKGROUND: Abiraterone strongly inhibits androgen synthesis but may lead to an increase in mineralocorticoid hormones that may impair its long term tolerability in patients with prostate cancer. How to implement available therapies in the management and prevention of these potential side effects is a matter of current clinical research. METHODS: The acute and long term consequences of mineralocorticoid excess and the effects of available treatments have been reviewed. Prospective studies in which abiraterone was employed were identified to assess the frequency and severity of the mineralocorticoid excess syndrome and the efficacy of ameliorating therapeutic approaches. RESULTS: Glucocorticoids to inhibit the ACTH increase that drives mineralocorticoid synthesis and mineralocorticoid receptor (MR) antagonists can be used in the management of the abiraterone-induced mineralocorticoid excess syndrome. Phase I and II trials of abiraterone without additional therapies revealed that mineralocorticoid excess symptoms occur in the majority of patients. Eplerenone, a specific MR antagonist, seems to be effective but it does not control the mineralocorticoid excess. Glucorticoid supplementation to control ACTH drive is therefore needed. In several randomized trials the addition of prednisone (10mg daily) to abiraterone was not able to prevent mineralocorticoid excess syndrome in many cases and thus cannot be considered the gold standard. CONCLUSION: At present, the best conceivable treatment for managing the abiraterone-induced mineralocorticoid excess consists of the administration of glucocorticoid replacement at the lowest effective dose ± MR antagonists and salt deprivation. The drug doses should be modulated by monitoring blood pressure, fluid retention and potassium levels during therapy.