The U.S. Food and Drug Administration granted orphan drug status in February to selumetinib for use in patients with the genetic disorder neurofibromatosis type 1 (NF1), who often develop tumors of the peripheral nervous system. Twenty to 50 percent of NF1 patients develop tumors called plexiform neurofibromas in their peripheral nerve sheaths. Although these nerve tumors are benign, they can cause disfigurement, pain, restricted motion, loss of vision and other complications.