Sanofi claims victory in enoxaparin antitrust suit
A federal judge has dismissed Amphastar Pharmaceuticals' cross-claims that two subsidiaries of Sanofi-Aventis engaged in anti-competitive conduct and unfair competition by obtaining and enforcing invalid patents related to Aventis' anti-clotting drug Lovenox (enoxaparin).

Judge Mariana Pfaelzer of the U.S. District Court for the Central District of California ruled that Amphastar's second amended counterclaims in the suit, Aventis Pharma and Aventis Pharmaceuticals, v Amphastar Pharmaceuticals, fail to show antitrust injury, according to court documents.

The lawsuit began in March 2003 when Amphastar filed an abbreviated new drug application with a Paragraph IV certification for generic Lovenox (enoxaparin sodium), according to the Washington Drug Letter (WDL). Aventis filed a patent infringement suit five months later in that California court.

Amphastar filed counterclaims for inequitable conduct, federal antitrust and state unfair competition violations, according to court documents. The antitrust and competition counterclaims were stayed as the court held hearings on Amphastar's inequitable conduct allegations.

Aventis owns two patents covering Lovenox, the '743 and the '618 patents, both of which cover a composition comprised of low molecular weight forms of heparin. The '618 patent was surrendered when the other patent, which expires in 2012, was issued. Aventis later became part of the Paris-based Sanofi-Aventis, which markets the drug.

Aventis lost its suit in the California court, but an appeals court ruled in April 2006 that a full trial was necessary to determine if the patent was invalid due to inequitable conduct, WDL reported. On remand, the court again ruled against Aventis, which appealed that decision to the U.S. Federal Court of Appeals for the Federal Circuit. When the appeals court upheld the inequitable conduct ruling, the stay on the counterclaims proceedings was lifted.

The Cucamonga, Calif.-based Amphastar maintains Aventis violated the Sherman Act by monopolizing the market for enoxaparin products in the U.S., according to court documents.

Amphastar filed comments on the citizen petition, stating that Aventis had changed its manufacturing process 17 times in eight years, "undermining its argument that the manufacturing process must be the same to result in the same active ingredient," according to court documents.

However, Pfaelzer ruled Amphastar did not meet the legal standard for proving Aventis' citizen petition amounted to antitrust violations, according to court documents, the WDL reported.

In addition, Amphastar did not show that it would have been able to obtain FDA approval for the product were the petition not filed, or that it would be able to enter the market quickly if it won approval, according to the WDL. Pfaelzer also said Amphastar undermined its arguments by stating it was "having difficulty obtaining 'the supply of components or compositions necessary for market approval or marketing of enoxaparin,'" according to court documents.