A drug that doctors use to treat high blood pressure in the lungs has been found to significantly improve damage caused by long-term smoking, according to the results of a clinical trial led by the University of Colorado Cancer Center.

The study's findings were presented at the International Association for the Study of Lung Cancer meeting in San Francisco on Aug. 2.

Researchers examined the lung biopsies of 152 people who had smoked at least 20 "pack years," or the equivalent of smoking one pack a day for 20 years, before and after six months of treatment with the oral version of a drug called Iloprost or a placebo.

Doctors commonly prescribe Iloprost to treat high blood pressure in the lungs, a condition called pulmonary hypertension. The treatment is similar to a body chemical called prostacyclin, which widens blood vessels to lessen blood pressure.

None of the 82 current smokers who entered the trial saw significant improvement in the signs of lung disease, but former smokers treated with Iloprost showed significant improvement, according to researchers.

"These results are exciting because they show we can actually keep former smokers from developing lung cancer with a drug that has been used routinely for other problems," said Robert Keith, the study's principal investigator.

Keith is an associate professor of pulmonary medicine at the UC Denver School of Medicine and associate chief of staff for research at the Denver Veterans Administration Medical Center. He said the next step is to test Iloprost in a larger, phase-three study to determine exactly who will benefit most from taking the drug.