EAST HANOVER, N.J. ( TheStreet) -- Novartis ( NVS) it will seek regulatory approval by the end of the year for a new drug to treat Cushing's disease based on positive results from a phase III study released Wednesday. The Novartis drug, SOM230, reduced the level of the stress hormone cortisol in a phase III trial that enrolled patients with Cushing's, a disease in which a benign tumor on the adrenal gland causes the body to produce excess cortisol, the company announced. Only the higher of two doses of SOM230 met the study's primary endpoint -- normalized levels of cortisol after six months of treatment. SOM230's side effect profile included 39% of patients reporting high blood sugar (hyperglycemia) and 18% reporting diabetes. Other side effects include diarrhea in 58% of patients and nausea reported by 38% of patients. Novartis said most side effects reported were mild to moderate but didn't offer any further details. Cushing's is a relatively rare disease affecting between 2,000 and 3,000 patients in in the U.S., with equal numbers in Europe. Cushing's patients suffer from severe cardiovascular and metabolic disease that is often fatal. No drugs are currently approved to treat the disorder, although Cushing's patients are typically treated first with radiation or surgery. Corcept Therapeutics ( CORT), a small U.S.-based drug maker, is testing its own drug, Corlux, in a phase III study of patients with Cushing's disease. Results from the study are expected in December. Earlier Wednesday, Novartis received FDA approval for Gilenya, the first multiple sclerosis drug administered as a pill. --Written by Adam Feuerstein in Boston. >To contact the writer of this article, click here: Adam Feuerstein. >To follow the writer on Twitter, go to http://twitter.com/adamfeuerstein. >To submit a news tip, send an email to: firstname.lastname@example.org.