Norvatis has received US FDA approval for osilodrostat (Isturisa) oral tablets in treating adults with Cushing’s disease who cannot undergo pituitary gland surgery or have undergone the surgery but still have the disease.
Cushing’s disease is a condition caused by a pituitary tumour which releases too much of adrenocorticotropin hormone (ACTH) which in turn stimulates the adrenal gland to produce an excessive amount of cortisol.
Osilodrostat acts by directly addressing the overproduction of cortisol by blocking the enzyme known as 11-beta-hydroxylase and preventing cortisol synthesis in the patients.
“Cushing’s disease is a rare condition where excessive cortisol production puts the patients at risk for other medical issues,” say Dr Mary Thanh Hai, acting director of the Office of Drug Evaluation II in the FDA’s Center for Drug Evaluation and Research. “By helping patients achieve normal cortisol levels, this medication is an important treatment option for adults with Cushing’s disease.”
The disease is most common among adults between the ages of 30 to 50, and it affects women three times more often than men.
Cushing’s disease can cause significant health issues, such as high blood pressure, obesity, type 2 diabetes, blood clots in the legs and lungs, bone loss and fractures, a weakened immune system and depression.
The trial to evaluate the safety and effectiveness of the drug in treating Cushing’s disease involved 137 adult patients consisting of about three-quarters women with a mean age of 41 years.
The patients received a starting dose of 2 milligrams of osilodrostat twice a day that could be increased every two weeks up to 30 mg twice a day by 24-weeks.
At the end of 24 weeks, about half of the patients had cortisol levels within normal limits.
The FDA reported that 86% of the patients who received osilodrostat maintained cortisol levels within normal limits compared to 30% of patients who underwent a placebo at the end of the withdrawal study.
The most common side effects reported in the clinical trial for osilodrostat were adrenal insufficiency, headache, vomiting, nausea, fatigue and oedema (swelling caused by fluid retention). Hypocortisolism (low cortisol levels), QTc prolongation (a heart rhythm condition) and elevations in adrenal hormone precursors (inactive substance converted into a hormone) and androgens (hormone that regulates male characteristics) may also occur in people taking the drug.
The FDA recommends osilodrostat to be taken by mouth twice a day, in the morning and evening as directed by a health care provider. After treatment has started, a provider may re-evaluate dosage, depending upon the patient’s response.
Osilodrostat received Orphan Drug Designation, which is a special status granted to a drug intended to treat a rare disease or condition.