Natco Pharma, a Hyderabad based pharma major with net sales of over Rs
390 crore, has filed an abbreviated new drug application with the US
FDA for approval to market lenalidomide capsules in 5, 10, 15 and 25 mg
strengths prior to the expiration of various US patents. Natco's
lenalidomide capsules are the generic version of Celgene Corporation's
Revlimid.

The company notified Celgene that its ANDA requesting
approval from the FDA for a generic version of Revlimid contained a
paragraph IV certification asserting that various Revlimid patents are
invalid, unenforceable and/or not infringed. Lenalidomide, which is
presently marketed as Revlimid by Celgene, is a derivative of
thalidomide and is used in the treatment of multiple myeloma.
Lenalidomide has also shown efficacy in the class of hematological
disorders known as myelodysplastic syndromes (MDS).

The company
believes that it will entitled to 180 days of generic market
exclusivity for 25 mg strength. The market size of Revlimid in the USA
is estimated to be around US$1.5 billion, growing at 44 per cent
compared to last year.