Medical Therapies in Cushing’s Syndrome

Chapter

The Hypothalamic-Pituitary-Adrenal Axis in Health and Disease

pp 165-179

Date: 03 December 2016

Medical Therapies in Cushing’s Syndrome

Abstract

Medical therapy has an important, albeit secondary, role in patients with Cushing’s syndrome. While medications are not currently used as definitive therapy of this condition, they can be very effective in controlling hypercortisolism in patients who fail surgery, those who are not surgical candidates, or those whose tumor location is unknown. Medical therapies can be particularly helpful to control hypercortisolism in patients with Cushing’s disease who underwent radiation therapy and are awaiting its salutary effects.

Currently available treatment options include several steroidogenesis inhibitors (ketoconazole, metyrapone, mitotane, etomidate), which block one or several steps in cortisol synthesis in the adrenal glands, centrally acting agents (cabergoline, pasireotide), which decrease ACTH secretion, and glucocorticoid receptor antagonists, which are represented by a single agent (mifepristone). With the exception of pasireotide and mifepristone, available agents are used “off-label” to manage hypercortisolism. Several other medications are at various stages of development and may offer additional options for the management of this serious condition.

As more potential molecular targets become known and our understanding of the pathogenesis of Cushing’s syndrome improves, it is anticipated that novel, rationally designed medical therapies may emerge. Clinical trials are needed to further investigate the relative risks and benefits of currently available and novel medical therapies and examine the potential role of combination therapy in the management of Cushing’s syndrome.

Keywords

Cabergoline, Etomidate, Ketoconazole, Levoketoconazole, Metyrapone, Mifepristone, Mitotane, Osilodrostat, Pasireotide, Pituitary adenoma

Osilodrostat for Cushing’s

The study looked at a drug to treat Cushing’s disease. The article, in the journal Pituitary, is called Osilodrostat, a potent oral 11β-hydroxylase inhibitor: 22-week, prospective, Phase II study in Cushing’s disease.
Fleseriu M, Pivonello R, Young J, Hamrahian AH, Molitch ME, Shimizu C, Tanaka T, Shimatsu A, White T, Hilliard A, Tian C, Sauter N, Biller BM, Bertagna X.
Pituitary. 2015 Nov 5. [Epub ahead of print]

Abstract

PURPOSE:
In a 10-week proof-of-concept study (LINC 1), the potent oral 11β-hydroxylase inhibitor osilodrostat (LCI699) normalized urinary free cortisol (UFC) in 11/12 patients with Cushing’s disease. The current 22-week study (LINC 2; NCT01331239) further evaluated osilodrostat in patients with Cushing’s disease.

METHODS:
Phase II, open-label, prospective study of two patient cohorts. Follow-up cohort: 4/12 patients previously enrolled in LINC 1, offered re-enrollment if baseline mean UFC was above ULN. Expansion cohort: 15 newly enrolled patients with baseline UFC > 1.5 × ULN. In the follow-up cohort, patients initiated osilodrostat twice daily at the penultimate efficacious/tolerable dose in LINC 1; dose was adjusted as needed. In the expansion cohort, osilodrostat was initiated at 4 mg/day (10 mg/day if baseline UFC > 3 × ULN), with dose escalated every 2 weeks to 10, 20, 40, and 60 mg/day until UFC ≤ ULN. Main efficacy endpoint was the proportion of responders (UFC ≤ ULN or ≥50 % decrease from baseline) at weeks 10 and 22.

RESULTS:
Overall response rate was 89.5 % (n/N = 17/19) at 10 weeks and 78.9 % (n/N = 15/19) at 22 weeks; at week 22, all responding patients had UFC ≤ ULN. The most common AEs observed during osilodrostat treatment were nausea, diarrhea, asthenia, and adrenal insufficiency (n = 6 for each). New or worsening hirsutism (n = 2) and/or acne (n = 3) were reported among four female patients, all of whom had increased testosterone levels.

CONCLUSIONS:
Osilodrostat treatment reduced UFC in all patients; 78.9 % (n/N = 15/19) had normal UFC at week 22. Treatment with osilodrostat was generally well tolerated.

KEYWORDS:
11β-hydroxylase; Cortisol; Cushing’s; LCI699; Osilodrostat