Company: Genzyme (Now part of Sanofi)
Based: Lexington, MA
R&D budget: $866.6M (€628M)
Change from 2009: -0.1%
Net sales spent on R&D: 18%

Genzyme was bought by Sanofi for about $20 billion, helping propel the Big Pharma company into rare diseases as it looks to in-license other such programs.

Like Roche and Genentech, Sanofi is looking to Genzyme to continue developing biologics, making the company a key U.S. player in the market in one swift move. One of the bones of contention that had initially kept the two companies from striking a deal was a big disagreement over the future of the MS drug Lemtrada. But positive late-stage data has added a shine to its future. Sanofi's Chris Viehbacher recently tapped R&D vet David Meeker to run the company.

But you won't see the subsidiary back on this list next year. Instead, look for the R&D budget to boost Sanofi's expense line.