Lupin Pharmaceuticals has received final approval from the US Food and Drug Administration (USFDA) to market the generic version of the anti-epileptic drug Keppra. The total sales of this drug in the US market is estimated to be $13 billion. Keppra was the patented drug of European drug maker UCB pharma. It lost the patent for this drug in 2008. The drug has been growing at 23% every year with a total sales of $1.74 billion