HEALTH

Elan to Buy Athena for $638 Million in Stock: The Irish company, known mostly for improving drugs created by others, boosted its own portfolio by buying a maker of medicines for Parkinson’s disease and multiple sclerosis. Elan Corp.’s deal to acquire Athena Neurosciences Inc. of South San Francisco is one of a long string of mergers in the drug industry. It illustrates Elan’s strategy of diversification as a key to higher profit in an era of cost cutting spurred by health maintenance organizations and other managed health-care companies. Under the agreement, Athena’s stockholders will receive 0.2956 of one of Elan’s American depositary shares for each common share owned. Elan, with U.S. headquarters in Gainesville, Ga., is a leader in drug delivery--the science of making medicines easier to take.