UPDATE 1-Discovery Labs' cystic fibrosis drug gets orphan status

* Says to apply for orphan designation in Europe

* Shares up 20 pct in premarket trade

Nov 1 (Reuters) - Biotech company Discovery Laboratories Inc (DSCO.O) said its experimental drug for the treatment of cystic fibrosis received orphan drug designation from U.S. health regulators, sending its shares up about 20 percent.

Last month, the company said the drug -- aerosolized KL4 surfactant -- was found to be safe and well-tolerated in a mid-stage trial. [ID:nSGE69E0HA]

Surfactants are produced naturally in the lungs and are essential for breathing. Discovery Labs' KL4 surfactant technology produces a synthetic surfactant that is structurally similar to pulmonary surfactant.

Cystic fibrosis is an inherited chronic disease that affects 30,000 patients in the United States and nearly 70,000 worldwide.

It is caused by a genetic mutation that leads to the production of thick, viscous mucus that clogs the lungs, leading to problems such as repeated lung infections and lung damage.

Orphan drug designation is granted by the U.S. Food and Drug Administration to drugs that treat a condition affecting less than 200,000 Americans, and gives the drugmaker marketing exclusivity of seven years in the country, upon approval.

Warrington, Pennsylvania-based Discovery Laboratories shares, which have lost about 4 percent of their value since the mid-stage study results, closed at 20 cents Friday on Nasdaq. (Reporting by Rajarshi Basu in Bangalore; Editing by Aradhana Aravindan)