French drug manufacturer Sanofi-Aventis has revealed its profits may fall this year after a rival to its blood thinning drug Lovenox received US approval.

Stock in the company decreased by 4.3% on 23 July after the US Food and Drug Administration approved a copy of Lovenox from Novartis AG and Momenta Pharmaceuticals, although a 0.5% recovery was on 26 July.

Earnings per share could decline as much as 4% in comparison to the estimated increase of between 2% and 5%, according to the drug manufacturer.

Losing patent protection over Lovenox is thought to be a reason why Sanofi-Aventis made a takeover approach for US-based Genzyme two weeks ago.