Depression therapy is one of thelargest drug therapy markets in the worldtoday. The World Health Organization predictsthat, by 2020, depression will be thesecond-largest cause of the global healthburden. According to a report by AdvanceTechMonitor, the market for antidepressantdrugs continues to grow,although the rate of growth has sloweddown in recent years due to genericscompetition. By the end of this decade,however, several major branded antidepressantswill be coming off patent,opening the door to more generic medicinesto treat depression.
Global sales of branded antidepressantsrose over $14 billion in 2004, with venlafaxine(Effexor) and sertraline (Zoloft)leading the way with sales of $3.3 billioneach. With the expiration of severalpatents of leading drugs for depression,however, the market share for the genericversions of these medicines increasedfrom 20% in 2000 to 42% in 2004, and thetrend is expected to continue. Venlafaxineand sertraline are both due to lose theirpatents within the next 5 years, and genericversions of these drugs are already inthe works and expected to be available inthe United States by 2010.