Nov 19 (Reuters) - The U.S. health regulator has extended the review of Bristol Myers Squibb"s (BMY.N) oral heart disease drug candidate mavacamten, which the company acquired in its $13 billion buyout of MyoKardia last year. The U.S. Food and Drug Administration (FDA) has not asked for any additional data and will now decide on the drug by April 28 next year, Bristol Myers said in a statement on Friday. Mavacamten is intended for the treatment of obstructive hypertrophic cardiomyopathy, an inherited condition characterized by thickening of heart muscles, which is a common cause of sudden cardiac arrest in young people. The FDA was originally set to decide on the drug in January, but informed the company earlier this month that it would need additional time to assess the treatment"s safety information. Mavacamten met the main and secondary goals in a late-stage study, demonstrating improvements in symptoms and quality of life for patients with the disease.