Franz Humer could hardly have picked a better moment to announce his plans to step down as chief executive of Roche and concentrate on the chairmanship.

In the 12 years since he joined the company as head of its dominant pharmaceuticals division, the Swiss group has risen to become one of the world’s most profitable – and envied – drugs companies. Much of that stems from decisions taken by others, and some to luck. But a large portion of Roche’s success is attributable to Mr Humer’s skill and judgment in making many of the right calls, and relatively few wrong ones.