Pfizer Inc has filed a patent infringement suit against Hyderabad-based Hetero Drugs in a US court raising opposition against Indian pharma firm Hetero’s attempt to enter the lucrative market of its blockbuster drug, Sildenafil citrate, commonly called as Viagra, used for treatment of impotence and rare disease pulmonary arterial hypertension. Apart from the generic leader Teva Pharmaceuticals, this is the first time that an Indian pharma company has been sued over for this drug.
While confirming the development, a senior official from Hetero Drugs explained that the suit pertained to the manufacture of the generic version of the blockbuster drug. Incidentally, the market value of Viagra is estimated over $1.5 billion globally although there have been price erosions in the recent past. It is valued at $600 million in the US market alone and this particular litigation is confined to the US market. Its market value in the domestic market is less than R120 crore. However, since the matter is sub-judice, further details were not available.
Pfizer complained that Hetero has infringed the patent by filing an abbreviated new drug application (ANDA) seeking US Food and Drug Administration approval to make and sell 25-milligram, 50-milligram and 100-milligram. It is reported that Pfizer’s patent on sildenafil citrate expired in Brazil in 2010 and will expire in the United States in March 2012.
Hetero had filed the ANDA on June 17, 2011 with the FDA seeking approval to market the generic copies of Sildenafil citrate. The Pfizer suit says that Hetero was aware of the patent on the drug.