Sanofi has seen a drop in revenue for the third quarter as it contends with major patient expiries.    

Total sales fell by just over 3% at constant exchange rates, down to 9 billion euros. Overall pharmaceuticals sales fell 4.3% to 7 billion euros in the third quarter, impacted by the shedding of its former dermatology unit Dermik, European austerity measures and generic competition.

The firm’s once big selling drug, the blood thinner Plavix, lost US market exclusivity in May and has come under generic erosion in Europe, leading the drug to drop 10% in the quarter, down to 505 million euros.

Colorectal cancer drug Eloxatin also dropped 63% as generic competition began, down to just 129 million euros. Its troubled heart drug Multaq, once touted as a blockbuster but must now contend with safety concerns, actually dropped by 9%, down to just 65 million, depsite being on the market since 2010.

Global sales of hypertension drug Aprovel were down 26% to 334 million euro in the third quarter, reflecting generic competition in the USA and in Europe. In the USA, where the product lost its exclusivity on in March, sales declined 84 per cent.

But the good news is that the FDA approved Zaltrap for previously treated metastatic colorectal cancer, Aubagio for relapsing multiple sclerosis and Auvi-QTM for patients with life-threatening allergies, all of which should help push sales in the future.

Its biggest selling drug, the insulin Lantus, also grew by 20% to an impressive 1.3 billion euros. Plavix was also approved for two new indications in Japan, although this will do little to offset the loss from generic competition in Europe.

Sanofi’s chief executive Christopher Viehbacher said: “The loss of exclusivity for Eloxatin in August in the US marks the final step in the genericisation of our legacy blockbusters.

“The solid performance of our growth platforms - which account for over 70% of sales -coupled with tight cost control, allowed us to limit the impact of the patent cliff on business EPS1 this quarter. Furthermore, we continue to make progress with our pipeline with the launch of Zaltrap and Aubagio in the US and the FDA approval for Auvi-Q.”

The three months ended on 30 September were “the first full quarter with all three major patent expiries in 2012,” Stephen McGarry, an analyst at Societe Generale in London, wrote in a note to clients, adding that: “This year “represents the trough year for Sanofi’s earnings”.

Analysts do believe that Sanofi is weathering the patent expiry storm well, however, and has not dropped as much as its some of its rivals, with AstraZeneca seeing revenues fall by 15% this week and Lilly an eye-watering 30 per cent.