10. Sanofi

The big news: Sanofi and its partner Regeneron received approval for the first PCSK9 inhibitor to come to market in the U.S.: Praluent. But Praluent's sales to date haven't awed analysts. It only generated $7 million in Q4 2015, compared to analyst predictions of $23 million. Plus Sanofi's heritage in dia­betes is under siege. CEO Olivier Brandicourt estimates that sales of diabetes drugs will slump 4% to 8% each year through 2018, owing both to increased pricing pressure and generic competition for Lantus. Sanofi also ended its marketing agreement for MannKind's Afrezza. Then, in November, Sanofi announced it would embark on a cost-cutting campaign, slashing $1.7 billion in costs and moving its headquarters out of Central Paris to Gentilly. To add to the bad news, Praluent's intellectual property may be in flux. The company faced a setback in March when a federal jury rejected a Regeneron challenge, ruling that Amgen's Repatha patents were valid. The decision could cost Sano­fi and Regeneron a 5% to 10% royalty on Praluent sales.