Sanofi-Aventis has turned to the courts in a bid to stop Novartis unit Sandoz and partner Momenta Pharmaceuticals from selling a generic version of its blockbuster anti-clotting drug Lovenox.

The US Food and Drug Administration today approved the first generic version of Lovenox (enoxaparin), which is used for multiple indications including prevention of deep vein thrombosis, last week but the French drugmaker was not convinced. Sanofi issued a statement saying the Momenta/Sandoz version "has not been assessed on the basis of an extensive clinical programme showing proven and comparable clinical efficacy and safety to Lovenox".

The company also noted that “regulations for biosimilars requiring comparative studies for low molecular weight heparins exist in Europe and Australia”. Sanofi added that it would avail itself of "appropriate analytical and clinical avenues to assess the quality, efficacy and safety of the product and is considering all appropriate legal options".

It has not wasted any time and the company has asked a court in the District of Columbia for a temporary restraining order and a preliminary injunction that would require the FDA to withdraw its approval. Sanofi is claiming that the agency’s decision was “arbitrary and capricious”, arguing that the FDA has failed to ensure that Sandoz's drug has the same active ingredient as Lovenox and improperly allowed the generic drugmaker to rely on Sanofi's proprietary information.

If not remedied, the FDA's decision will cause Sanofi “irreparable harm and may result in entry into the market of a generic product that is not clinically equivalent to Lovenox with respect to safety or efficacy”, the firm said.

The loss of Lovenox revenues is going to hit hard as the drug recorded US sales of $2.7 billion in 2009. However, Sanofi is putting on something of a brave face, noting that sales of the drug outside of the US have been growing faster than across the pond and represented more than 40% of total Lovenox turnover in 2009.

Nevertheless, “as a preliminary guidance”, Sanofi expects earnings per share for the 2010 “to be stable to down 4% versus 2009, at constant exchange rates”.

No clear news about Genzyme bid
Meantime, there are differing reports about the progress of Sanofi’s rumoured bid to takeover Genzyme Corp. Bloomberg claimed that the US biotech has rebuffed an approach but Reuters cited unnamed sources as saying that Genzyme has not responded to Sanofi and by definition not rejected any proposal.

Other observers believe that a sale of Genzyme is unlikely at the moment and the company itself said in May that it is only prepared to look at selling three non-core businesses - its genetic testing, diagnostic products and pharmaceutical intermediates divisions.