Over the past decade Sanofi-Aventis has filed more than 20 suits seeking to ward off generic competition for its Allegra franchise. It won a major victory on June 14 when a court granted a preliminary injunction to prevent Dr. Reddy's from launching a generic version of Allegra-D 24 Hour (fexofenadine 180 mg/pseudoephedrine 240 mg).

The U.S. District Court for the District of New Jersey ruled that Sanofi and its partner Albany Molecular Research had shown a high likelihood of success in their suit claiming Dr. Reddy's extended release product infringes AMR's patent, No. 7,390,906, on a process for preparing fexofenadine.

Dr. Reddy's said it "strongly disagrees" with the court's decision and plans to appeal.

The case is part of a morass of Allegra litigation that illustrates how complex and vast patent battles have become as numerous generic companies try to move in on a blockbuster.

Sanofi has filed six other suits against Dr. Reddy's, and additional suits against Impax, Mylan, Barr, Teva, Sandoz, Sun and Wockhardt alleging infringement of various patents relating to Allegra (fexofenadine) and Allegra-D 12 Hour (fexofenadine 60 mg/pseudoephedrine 120 mg). According to a 2009 Cowen report on the generics industry, the key Allegra patent, composition patent 5,578,610, expires in May 2014.

Dr. Reddy's Selling Generic Allegra At Risk

Teva and Barr (which Teva has since acquired) launched a generic version of the single entity formulation at-risk in September 2005 after a court granted them summary judgment of non-infringement of three Allegra patents and summary judgment of invalidity of another patent. At that time Allegra had annual sales of approximately $1.4 billion. In January 2006, the court denied Sanofi's motion for a preliminary injunction to block the generic.

In 2008, Sanofi entered a settlement agreement involving Barr and Teva's generic Allegra and Barr's proposed generic version of Allegra-D-12 Hour. Under the agreement, Teva launched generic Allegra-D 12-Hour in November 2009.

While Dr. Reddy's has been enjoined from launching generic Allegra-D 24 Hour, it has been selling generic versions of the single entity product at-risk since April 2006. In a filing with the Securities and Exchange Commission, the company said this is the only product it has launched in the United States prior to the resolution of outstanding patent litigation.

Mylan is also selling generic Allegra at-risk. The generic makers must feel they have a strong case against Allegra patents as few companies launch while a patent dispute is ongoing. In January, RBC Capital Markets issued a report on litigation success rates in the pharmaceutical industry. It calculated that there were six at-risk launches in 2009 and 28 since 2003. Teva was the leader, conducting 12 of the 28 at-risk launches.

As for other Allegra litigation, Sanofi dismissed its suits against Sandoz in February after Sandoz changed its patent certifications for two ANDAs from Paragraph IV to Paragraph III. Twenty other Allegra suits remain pending. Sanofi attorney Liza Walsh, of Connell Foley, listed the cases in a status letter to the court last month.

Sanofi Would Rather Fight And Switch

Dr. Reddy's is the only company facing litigation over the Allegra D-24 formulation and the '906 patent. Albany Molecular Research was issued the '906 patent in June 2008 and filed suit against Dr. Reddy's in September 2009. FDA approved Dr. Reddy's generic product on May 17.

In a court filing, Dr. Reddy's argued that the '906 patent did not issue until 15 years after the filing of the earliest of the priority patents and applications. It said the patent was a continuation from a series of applications, the first of which was filed on June 24, 1993.

Allegra generated net sales of €731 million in 2009. The company reported that during the first quarter of 2010, sales for Allegra fell 27.1 percent to €171 million due to the launch of Allegra D-12 generics in November 2009. U.S. sales of Allegra for the quarter dropped by 58.8 percent to €33 million.

The company does not break out sales of Allegra-D-24 and a figure for 2010 sales of D-24 was redacted in a June 14 letter to the court. The letter, submitted by Sanofi's attorney, addressed the amount of bond Sanofi might be required to post in response to the preliminary injunction against Dr. Reddy's. The letter noted that Sanofi had already posted $10 million in security and was set to post an additional $5 million.

While Sanofi continues its numerous patent battles, it is preparing for a shift in the Allegra market. The company filed an application with FDA in March to switch the single-entity formulation from a prescription to an over-the-counter product. The company recently acquired Chattem to build an OTC business in the U.S. and manage the Allegra brand (¹ Also see "Sanofi-Aventis Will Enter U.S. OTC Market By Paying $1.9 Billion For Chattem" - Pink Sheet, 21 December, 2009.).

- Brenda Sandburg ( ² b.sandburg@elsevier.com )

Sanofi Blocks Launch Of Dr. Reddy's Generic Allegra-D 24 Hour; 20 Suits Are Pending Over Other Formulations

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