By Ludwig Burger (Reuters) -Roche’s head of diagnostics, Thomas Schinecker, is to take over as group chief executive next year, replacing Severin Schwan, who will become chairman after rejuvenating the Swiss drugmaker’s suite of treatments. Chairman Christoph Franz will not seek re-election after nine years as non-executive board chairman at the next annual shareholder meeting in March 2023, the Swiss drugmaker said in a statement on Thursday. Austrian-born Schwan, who became CEO in 2008, oversaw a strong share price performance as Roche diversified away from its traditional focus on cancer, o…