When Elias Zerhouni joined Sanofi as the head of R&D in January 2011, the former NIH director decided the pharma's pipeline needed to be pruned and refocused around disease pathways. Two years into the job, Zerhouni's late-stage housecleaning is evident, but the bigger changes to the pharma's drug discovery strategy will take three to five more years to bear fruit.

Sanofi is the product of dozens of small and large mergers, including a merger encouraged by the French government between Aventis S.A. and Sanofi-Synthelabo S.A. in 2004. These resulted in an amalgam of redundant and sometimes antiquated R&D capabilities spread across 25 facilities.