Tamiflu (Oseltamivir phosphate) was developed by Gilead, and receives royalties on the drug's sale from Roche Holding AG. Gilead has requested a federal court in Wilmington, Delaware to block generic versions of Tamiflu until its patent expires in 2017.
In February, Natco filed an Abbreviated New Drug Application with US FDA under Para-IV with US FDA and alleged that Gilead's patent on the drug is invalid and sent a notice to Gilead to that extent.
Natco was the first company to file an application with US FDA for the generic version of Tamiflu. According to reports, the revenues from Tamiflu clocked global annual sales in the region of USD 1 billion.
Natco is the 'first applicant' to file an ANDA for the generic version of Tamflu and may be entitled to 180 days of generic market exclusivity after approval. The company has tied up with the Luxemburg based Alvogen IPCO S.a.r.l., for marketing and sale of Oseltamivir phosphate in the USA.
Gilead has the basic patent rights of Oseltamivir phosphate until August 2, 2016.
Natco shares are being traded at Rs 252 on Bombay Stock Exchange today.