The changes reflect a shift for the scientists who once dominated senior pharmaceuticals positions to give way to executives with backgrounds in marketing, legal or other more general business backgrounds.
To which Derek adds:
My take, for what it's worth, is that scientific training can be desirable in a drug company CEO, but it's not sufficient, or always even necessary. The skills needed don't overlap as much as you might think between science and management, even in a company that makes its living from science. The problem is, I don't think that the particular skills associated with law and MBA degrees are sufficient, either. Being good at running a large organization is a rather rare quality. And it's not always easy to recognize: some companies have issues (good ones or bad!) that will swamp most of the signals you might try to get about the qualities of their CEO.
What strikes me is the oddness of having lawyers in the top slot; the legal department isn't such a big customary route to the top job. But the environment has changed greatly. Fifty years ago, with the FDA pressing ever harder on efficacy, the most important thing in a pharma chief was probably knowing what went into making an effective drug. Twenty years ago, you needed to know how to market it to get the most money out of a very narrow patent window. These days, you need to be able to negotiate a fearsome political and regulatory environment.