The U.S. Food and Drug Administration (FDA) has approved Isturisa (osilodrostat) to treat adults with Cushing’s disease who either cannot undergo pituitary gland surgery or have undergone the surgery but still have the disease.
Cushing’s disease is a rare endocrine disorder due to over production of adrenocorticotropin hormone (ACTH) from a benign pituitary tumor that in turn leads to excessive cortisol.
First-line treatment for person’s with Cushing’s disease is surgical removal of the causal lesion. However, if surgery is not an option or has failed, other treatment options are available (e.g., repeat transsphenoidal surgery, radiotherapy, medical therapy, and bilateral adrenalectomy) as well as FDA-approved medications — Korlym (mifepristone) for persons with endogenous Cushing’s disease who have type 2 diabetes or glucose intolerance and Signifor (pasireotide) for person with Cushing’s disease for whom pituitary surgery is not an option or has not be effective. And now adults with Cushing disease have a newer option, osilodrostat.
Osilodrostat blocks 11-beta-hydroxylase and thereby inhibits cortisol synthesis directly.
The drug’s approval was largely based on a 24-week, single-arm, open-label clinical trial involving 137 adults with Cushing disease. At the end of this 24-week period, approximately half of patients had cortisol levels within normal limits. A total of 71 patients from that study later entered an eight-week, randomized, double-blind, placebo-controlled study and at the end of that study, 86% of patients receiving osilodrostat maintained cortisol levels within normal limits (compared to 30% of patients taking the placebo).
The most common reported side effects with osilodrostat were adrenal insufficiency, headache, vomiting, nausea, fatigue and edema.
Osilodrostat is an oral tablet that should be taken twice, as directed by a health care provider. After treatment has started, the dosage may be require adjusting, depending upon the patient’s response.
Visit our Cushing’s Disease Learning Center, to learn more about this rare disorder,
