* Q2 Business net income up 4.2 percent, above expectations
* Analyst says Toujeo sales "underwhelming"
* CEO Brandicourt to unveil strategic plan on Nov.6, open to M&A
* Shares down 0.45 percent (Adds details, shares, comments)
By Matthias Blamont and Noëlle Mennella
PARIS, July 30 (Reuters) - Sanofi reported lower second quarter sales for its strategic diabetes division on Thursday, hurt by continued pricing pressure in the United States, but it's biotech arm Genzyme recorded another quarter of double-digit growth, enabling the French drugmaker to beat forecasts overall.
Forced to agree to increased rebates to maintain market share of Lantus, a blockbuster insulin drug whose patent expires this year in the U.S, Sanofi said sales in its diabetes branch declined 3.8 percent at constant currency rates to around 2 billion euros ($2.1 billion).
Total sales of Toujeo, a next-generation basal insulin launched at the end of March in the U.S, amounted to 13 million euros in the second quarter and to 20 million euros in the first half. Tim Anderson, an analyst with Bernstein who rates Sanofi as "outperform", described the Toujeo figures as "underwhelming".
Sanofi has several new diabetes product launches underway, and it announced positive data from new treatment LixiLan on Wednesday.
But the group warned in April that revenue in the diabetes division would fall this year.
Consequently, ambitions for the division should be at the center of attention when Sanofi unveils a five-year strategic plan on Nov. 6, the group's first under new Chief Executive Olivier Brandicourt.
On July 15, Sanofi said it would adopt a simplified structure centred around five global business units starting in January 2016.
Investors will also be on the lookout for more details on possible future acquisitions.
"Sanofi has a strong balance sheet which allows the group to potentially tap into M&A opportunities to further boost its growth profile", Brandicourt told journalists in a conference call.
The company said second-quarter business net profit rose 4.2 percent at constant rates, or 19.7 percent on a reported basis, to 1.84 billion euros, helped by a weak euro and strong performances in Genzyme, whose sales grew 26.6%.
Analysts had been expecting on average a net profit of 1.73 billion euros. Growth was also strong in emerging markets, vaccines and animal health.
Genzyme, acquired by Sanofi in 2011 in a $20 billion transaction, saw sales of its multiple sclerosis treatment Aubagio leap 80.4 percent. The drug became Genzyme's largest brand this quarter.
Shares in Sanofi were down 0.45% at 97.560 euros at 0845 GMT.
The company maintained its guidance for stable to slightly growing 2015 profit.
One Paris-based analyst who asked not to be named said investors had been hoping for improved guidance.
Editing by Andrew Callus