Biopharmaceutical giant AstraZeneca has hired a Sioux Falls company that plans to add 50 jobs to its growing workforce. MedVantx Pharmacy Services operates in relative obscurity in northeastern Sioux Falls. It opened in 2002 at 2503 E. 54th St. N. as a home-delivery pharmacy with four employees under the name AmeriPharm. At the time, the company mailed prescription drugs to patients on group health insurance plans. “It was tough at first. No question about it,” said general manager Ron Bertsch, who has led the office since it started. “We had no name.”