The Patentability of Enantiomers: Implications for the Pharmaceutical Industry

¶1 When it comes to sales figures, Big Pharma certainly lives up to its reputation. A recent study estimates worldwide pharmaceutical sales exceed $600 billion.1 The United States is by far the single largest market for pharmaceutical products,2 where companies invest hundreds of millions of dollars in drug discovery3 and boast annual sales of $252 billion.4 ¶2 What may come as more of a surprise is that a large portion of pharmaceutical sales is derived from a class of molecules called chiral molecules,5 which have unique qualities that make them particularly interesting from a legal standpoint. The importance of chiral drugs cannot be overstated. Worldwide sales of chiral drugs reached more than $159 billion in 2002,6 a figure which is expected to increase to over $200 billion by 2008.7 In fact, chiral molecules comprise more than half the drugs approved worldwide,8 including many of the world’s top-selling drugs.9 For example, Lipitor® and Zocor® (the world’s first and fifth top selling drugs in 2005)10 contain chiral molecules as the active pharmaceutical ingredient.11 Other well-known chiral pharmaceuticals include ibuprofen, (sold under