By Marius Meland ( July 19, 2005, 12:00 AM EDT) -- Litigation challenging patents on branded drugs has increased exponentially since the passage of the Drug Price Competition and Patent Term Restoration Act of 1984 (commonly referred to as the "Hatch Waxman Act").  As a result of the Act, branded drug manufacturers have faced challenges from generic drug companies to their pharmaceutical patents.  This is not surprising.  The drafters of the Hatch Waxman Act intended and fully anticipated that patent litigation would be a direct result of the Act.  The purpose of the Act was to expedite the debut of generic versions of drugs to the market.  The Act provided means for generic drug companies to bring a generic drug to market the day following expiration of the branded drug company's patent, or means to challenge patents held by the branded drug manufacturers prior to expiration, if those patents are invalid or unenforceable.  Certain downstream repercussions of the Act have come about, however, that the drafters may not have foreseen. ...