What will Chris do? Look for him to do some cost cutting. The 48-year-old, who was passed over for the top job at Glaxo, today takes over from Gerard le Fur, who was ousted in September after setbacks with the Acomplia obesity pill and the Plavix blood thinner, Bloomberg News writes.

Sanofi, which is based in Paris, lags in cost cutting and introducing new meds to replace big-sellers facing generic competition, the news service writes. Viehbacher, who is credited with uniting Glaxo’s North American operations after a merger with SmithKline Beecham eight years ago, is well suited to overhaul Sanofi’s performance, according to Bob Ingram, a former Viehbacher mentor. “He really created a unified culture,” Ingram tells Bloomberg.

Sanofi’s problems began four years ago during a protracted takeover of Aventis, Mirabaud Pereire Holdings analyst Nick Turner tells Bloomberg. Sanofi won the contest after Novartis decided against a bid because the French government favored the creation of a so-called national champion. And all of Sanofi’s top managers come from Sanofi-Synthelabo.

“The fact that you’re bringing a non-French manager with no axe to grind from either the Sanofi or Aventis side shows there is a change of attitude,” Marc Booty of Pictet Asset Management tells Bloomberg. “A lot of areas were perceived to be untouchable within the group. (The management change) “should create a shift in investor sentiment - that it’s no longer going to be run as a national treasure but could be run as a lean and mean corporate.”

Sanofi’s biggest failure was Acomplia, the obesity pill Chairman Jean-Francois Dehecq once predicted would generate more than $3 billion in annual sales. The French drugmaker last month halted all human trials of the drug after European health authorities said psychiatric side effects made the medicine too dangerous for use.

Sanofi had pressed ahead with tests on thousands of patients, hoping to win approval as a diabetes treatment, even after an FDA panel last year rejected the medicine because of risks including depression and suicide. Sanofi’s shares have fallen more than 30 percent since the setback and are down about 31 percent this year.

Sales slipped for four consecutive quarters. And last week, the FDA scheduled a March 18 hearing on the Multaq heart drug, delaying Sanofi’s plan to start selling the medicine in the first quarter.

Known for being outspoken, Viehbacher this year railed against Massachusetts after a ban was proposed on gifts to doctors (back story). As a PhRMA board member, he then led industry efforts to craft voluntary guidelines to curb such practices. The trade group announced the revised marketing code in July.

“Those were difficult conversations,” PhRMA president Billy Tauzin, 65, a former Republican representative from Louisiana, tells Bloomberg. “It took young, aggressive, forward-thinking leaders like Chris to talk to companies who resisted change. He’s been so forthright. He made a dramatic difference in a short period of time.”

Viehbacher is also credited with leading Glaxo out of a crisis with the Avandia diabetes drug that lost sales after a report of heart risks last year. He was the public face of Glaxo in an ensuing debate over Avandia’s safety, doing media interviews and speaking at regulatory hearings.

After the setback, Viehbacher masterminded Glaxo’s $1.65 billion purchase of Reliant Pharmaceuticals to gain the Lovaza heart med. He also led US expansion of Glaxo’s vaccine and oncology businesses. In February last year, he initiated a licensing deal valued as high as $640 million with U.S. biotechnology company XenoPort to get an experimental treatment for restless legs syndrome.

At Sanofi, he will serve under Dehecq, who has steered the French drugmaker through dozens of acquisitions over more than three decades. “I’m not so sure it’s that common for a miracle worker to come in and turn a company around,” Mirabaud’s Turner said. “The flexibility he might have for a wide-ranging restructuring plan is a bit limited. Sanofi has been too parochial for too long.”

Since departing Glaxo, Viehbacher has met with analysts and sales teams from at least one major investment bank to hear their views and concerns about Sanofi. Analysts at Morgan Stanley last week upgraded the French drugmaker to “overweight” from “equal weight” in anticipation of more cost-cutting at the company.

“Sanofi-Aventis is well known for keeping drugs in the pipeline until the last minute,” Natixis analysts including Philippe Lanone wrote in a note to investors in September. The strategy, which has been “very negative in the vast majority of cases,” has helped make the company the fourth-highest spender on research and development among major global pharmaceutical companies, he wrote.

“Productivity could be improved both by discontinuing some ongoing projects but also by making organization changes and rationalizing costs,” Lanone wrote. For example, Sanofi has said that it has 30 R&D sites, which according to Lanone is more than double that of its peers.