Sanofi's earnings for the fourth quarter have been hit by generics, though most of the patent cliff is behind the French drugmaker, which expects a return to growth in the second half of 2013.

Business net income, which excludes items, fell 27.1% to 1.57 billion euros (at constant exchange rates), principally due to loss of exclusivity on the bloodthinner Plavix (clopidogrel) and the antihypertensive Avapro (irbesartan), both partnered with Bristol-Myers Squibb, as well as on the antithrombotic Lovenox (enoxaparin) and the colorectal cancer drug Eloxatin (oxaliplatin). Turnover dipped 1.7% to 8.53 billion euros, while pharmaceutical sales decreased 4.8% to just over 7.00 billion euros.

Plavix brought in 503 million euros to Sanofi’s coffers, down 6.2%, while Avapro/Aprovel sank 34.1% to 212 million euros. The cancer drug Taxotere (docetaxel) slumped 17.3% to 125 million euros, while Lovenox fell 13.1% to 441 million euros. Eloxatin sales crashed 80% to 68 million euros.

On the bright side, the diabetes drug Lantus (insulin glargine) leapt 22.6% to 1.34 billion euros, while Jevtana (cabazitaxel) for prostate cancer contributed 60 million euros, an increase of 25.5%. Sales at Sanofi’s vaccines division were up 20.5% to 1.02 billion euros, while the consumer healthcare business brought in 732 million euros (+11.2%).

As for Sanofi's Genzyme unit, Cerezyme (imiglucerase) for Gaucher disease rose 26.1% to 171 million euros and Fabrazyme (agalsidase beta) for Fabry disease increased 74.5% to 84 million euros as the firm recovers from previous manufacturing problems.

Chief executive Chris Viehbacher (pictured) said 2012 "was a turning point for Sanofi with the loss of exclusivity in the USA for several significant legacy drugs". He argued that the company was able to obtain "nine significant regulatory approvals and submit six new files with regulatory agencies".

Mr Viehbacher said that although the financials in the first six months of the year will experience "a residual effect from patent expirations, we expect to resume growth in the second half of 2013".