On Jul. 29, 1999, Gilead Sciences and NeXstar Pharmaceuticals announced the closing of their agreement whereby Gilead acquired NeXstar in an all-stock transaction. NeXstar stockholders received 0.3786 of a share of Gilead for each share of NeXstar stock or a total of $550 million in Gilead Sciences stock.

NeXstar, headquartered in Boulder, Colo., was engaged in the discovery, development, manufacture, and commercialization of products to treat serious and life-threatening illnesses. NeXstar had research, development, and manufacturing facilities in San Dimas, CA, and marketing subsidiaries worldwide.