AbbVie for years delayed competition for its blockbuster drug Humira, at the expense of patients and taxpayers.  The key patent on the best-selling anti-inflammatory medication, used to treat conditions like arthritis, was expiring at the end of the year. Through its savvy but legal exploitation of the U.S. patent system, Humira’s manufacturer, AbbVie, blocked competitors from entering the market. Today, Humira is the most lucrative franchise in pharmaceutical history.