ZURICH: Novartis Chief Executive Joseph Jimenez will retire in 2018, with chief drug developer Vasant Narasimhan taking over as CEO starting in February, the Swiss drugmaker said on Monday. Jimenez, 58, is stepping down following a decade at Novartis after having successfully secured U.S. approval for a new gene therapy for leukemia last week but before Novartis returned to sales growth, which the company has forecast will resume in 2018. "After 10 wonderful years in Switzerland, my family is ready to return to Silicon Valley and the United States," said Jimenez, a Stanford University graduate. A Novartis employee since 2005, Narasimhan has increased his public presence at Novartis since becoming global head of drug development and chief medical officer in 2016.