There’s an old maxim in journalism that three is a trend. But five? And in just a few months? That’s how many cfo’s have left big drugmakers so far this year. The latest to leave is AstraZeneca’s Jon Symonds (see this), who will join Goldman Sachs amid turmoil over the drugmaker’s decision to boost its pipeline with the controversial MedImmune deal. These folks are turning over faster than R&D chiefs with dry pipelines.

Here are the others, in clockwise order:

Merck’s Judy Lewent, who lost out in the horse race to succeed the embattled Ray Gilmartin as ceo.
Amgen’s Richard Nanula, who’s departure occurs amid SEC investigations and numerous marketing scandals;
Pfizer’s Alan Levin, who some believe Jeff Kindler wants to replace with a higher-profile type;
Wyeth’s Ken Martin, who called himself a ‘cog’ in a corporate wheel and is leaving to pursue personal interests;

There’s no reason to automatically assume that these cfo’s were singled out as fall guys for specific disasters, although failure to win investor confidence, of course, is good reason to throw a finance chief overboard. But as drugmakers continue to wilt under pressure, remaking the team is paramount and changing a cfo can be seen as a symbolic gesture.

So who’s next?

Hat tip to the Health Blog.