A review.Monoclonal antibodies (mAbs) have been one of the great successes of modern medicine, and biotechnol.'s greatest medical achievement.Of the 500 protein drugs in clin. testing today, no fewer than 300 are mAbs.In 2005, BCC estimated the worldwide market for mAbs at $15 billion, or nearly one-quarter of the world protein therapeutics market (1), while sales of therapeutic mAbs were projected to grow to $26 billion by 2010, an annual average growth rate of 11%.Interestingly, mAbs enjoy a long product life-cycle.According to a report by Arrowhead Publishers (2), sales of the three oldest mAbs on the market today (Rituxan, Remicade and Synagis), all approved in the late 1990s, are still growing.