Dec 31 (Reuters) - The U.S. Food and Drug Administration has declined to approve Corcept Therapeutics' drug for the treatment of a rare hormonal disorder, the company said on Wednesday.

Shares of the drugmaker were down 50.2% in morning trading.

The company said the FDA could not arrive at a favorable benefit-risk assessment for the hormone-blocking oral treatment, known as relacorilant, without Corcept providing additional evidence of effectiveness.

The company was seeking approval for relacorilant as a treatment for patients with hypertension secondary to hypercortisolism.

Hypercortisolism, also known as Cushing's syndrome, occurs when the body is exposed to high cortisol activity.

Corcept had submitted trial data that showed that relacorilant made improvements in a wide array of hypercortisolism's signs and symptoms.

"We will meet with the FDA as soon as possible to discuss the best path forward," said Joseph Belanoff, Corcept's CEO.

Main symptoms of hypercortisolism include a fatty hump between the shoulders, a rounded face, and pink or purple stretch marks on the skin. People with Cushing's also experience diabetes, high blood pressure, muscle weakness and immune suppression.

Relacorilant is a selective cortisol modulator designed to block the effects of cortisol, while avoiding certain off‑target hormonal effects.

Corcept is also studying the drug in a variety of serious disorders including ovarian and prostate cancer. Its other drug known as Korlym is approved to treat high blood sugar caused by hypercortisolism in adults with endogenous Cushing's syndrome.

Other approved treatments for Cushing's syndrome include Isturisa by Recordati and Xeris Biopharma's Recorlev.