Blockbuster Drugs: The Rise and Decline of the Pharmaceutical IndustryFor the world's largest prescription drug manufacturers, the last few years have been a harrowing time. Recently, Pfizer's Lipitor, GlaxoSmithKline's Advair, AstraZeneca's Seroquel, and Sanofi Aventis and Bristol Myers Squibb's Plavix all came off patent in the crucial U. S. market. This so called patent cliff meant hundreds of billions of dollars in lost revenue and has pharmaceutical developers scrambling to create new drugs and litigating to extend