Dr Reddy’s Labs has filed an Abbreviated New Drug Application (ANDA) with the US FDA for Rosiglitazone Maleate tablets, equivalent to 2mg, 4mg and 8mg, with a paragraph IV certification on two of the three Orange Book patents listed for the drug. According to a company press release, Dr Reddy’s notified GlaxoSmithKline (GSK), upon which the latter filed a lawsuit against the company in the New Jersey District Court, alleging patent infringement on the `803 patent.

Rosiglitazone Maleate is the generic version of GlaxoSmithKline’s Avandia, indicated for the management of type-2 diabetes, helping the body use the insulin that it is already producing. The brand has annual sales of about $ 1.1 billion in the US market.

According to Dr Reddy’s statement, it believes that it has the first-to-file status on all the three dosage strengths, and if successful in its litigation, will enjoy a 180-day marketing co-exclusivity pursuant to the July 2003 FDA guidance on 180-day exclusivity when multiple ANDAs are filed on the same day.

The London-based GSK’s shares fell on Tuesday on the London Stock Exchange (LSE), after Apotex, a privately-held Canadian company, launched a generic version of GSK’s Paxil, an anti-depressant, in the US market. Paxil had sales of $ 2.23 billion in 2002.