TUESDAY, May 20 (HealthDay News) -- The cancer drug sorafenib (Nexavar) shows promise as a treatment for pulmonary hypertension, according to a University of Chicago Medical Center study.

During the study, nine patients took the drug for 16 weeks at doses lower than those given to cancer patients. The patients also continued to take their standard medications.

Eight of the patients increased their ability to exercise, six showed significant improvements in their right ventricular ejection fraction (the ability of the heart to pump blood to the lungs), and four had a significant decrease in pulmonary artery pressures.

The most common side effects were diarrhea and hair loss.

The findings were expected to be presented May 20 at the American Thoracic Society annual meeting, in Toronto.

"This is not a disease where we are used to seeing people who have been stable on the strongest medications we have suddenly get better. We have drugs that may slow progression of the disease, but nothing that can stop or reverse the process," study author Dr. Mardi Gomberg-Maitland, an assistant professor of medicine, said in a prepared statement.

"To see these improvements in such a short time is quite promising. Although evaluation of this drug is at a very early stage, and this study focused on safety and tolerability, we are genuinely excited about the results," Gomberg-Maitland said.

Sorafenib was originally developed at the University of Chicago as a treatment for kidney cancer. Both cancer and pulmonary hypertension involve abnormal cell growth. In pulmonary hypertension, the abnormal cell growth occurs in blood vessels that lead to the lungs, causing the vessels to thicken and narrow. This means the heart has to work harder to pump blood to the lungs. This extra workload damages the heart.

Sorafenib appears to interfere with the abnormal cell growth seen in pulmonary hypertension.

Researchers are now organizing a multi-center trial of the drug in patients with pulmonary hypertension.

More information

The U.S. National Heart, Lung, and Blood Institute has more about pulmonary hypertension.

SOURCE: University of Chicago Medical Center, news release, May 19, 2008