SAN FRANCISCO (AP) — Biotherapeutic drug company Dyax Corp. has received FDA approval to market Kalbitor for treatment of the genetic disorder hereditary angioedema in patients 16 years and up. The rare disorder is characterized by the accumulation of fluids outside of the blood vessels, which causes swelling in extremities, the intestinal tract or airway. Dyax shares soared in after-hours trading, rising $1.33 or 38 percent, after finishing regular trading down 23 cents, or 6.2 percent, at $3.50. Dyax said the drug is the first injectable treatment approved for the disorder in the U.S. The company said that as part of the approval the company set up a program to inform users about the risk of anaphylatic shock and the importance of determining the difference between hypersensitivity to the drug and a hereditary angioedema attack. The drug is also being evaluated for the prevention of blood loss during a certain type of heart surgery by Dyax’s partner, Cubist Pharmaceuticals.