Cancer drug might fight lethal lung hypertension

Gleevec, a medication experts have hailed as a wonder drug in the fight against certain cancers, may also help patients battling lethal pulmonary hypertension.

According to a case study reported in the Sept. 29 issue of The New England Journal of Medicine, a 61-year-old man suffering from an advanced case of the disease saw his condition improve and stabilize after taking imatinib, the drug sold as Gleevec, even though all other medications had failed.

Although a single case report does not warrant widespread use of Gleevec for pulmonary hypertension, the German researchers who wrote the report say that they are now planning a large clinical trial.

"I think a trial is a wonderful idea," says Dr. Richard Stein, a professor of clinical cardiology at Albert Einstein Medical College in New York who is also a spokesman for the American Heart Association. "Hopefully we'll be able to make a real difference for these people."

Stein says that pulmonary hypertension occurs when blood pressure mounts to dangerously high levels in the pulmonary artery, which carries blood from the right side of the heart to the lungs.

The relatively common condition can occur for many reasons, but most often arises as a byproduct of other pathologies such as heart disease and various lung ailments. Under the strain of these conditions, the pulmonary artery thickens and stiffens, causing blood pressure to rise.

"Right now we have two classes of drugs that seem to be improving outcomes," Stein says, mentioning prostaglandin-linked compounds such as prostacyclin and, more recently, another potent vasodilator -- sildenafil, sold as Viagra -- both of which work by relaxing and opening narrowed vessels.

"None of these medications cures the disease or gives the patient a normal life back," Stein says. "But most can prolong quality-of-life time before they get very sick."

Patients with very high pulmonary blood pressures usually don't live past a year, he adds.

In the German case report, the patient was diagnosed with such a case of advanced pulmonary hypertension, this time a rarer, "primary" form of unknown origin. Standard therapies such as prostacyclin and Viagra proved useless, and the man's condition continued to deteriorate.

"In this desperate situation, we decided to initiate compassionate treatment with daily administration of 200 milligrams of oral imatinib mesylate (Gleevec)," given on top of the other medications, the researchers at the University Hospital Giessen report.

The change in the man's condition was dramatic. Three months later his condition had improved "impressively," the researchers say, allowing him to become much stronger and more mobile than before Gleevec. That improvement has continued to the six-month point.

How did a drug best known for curing chronic myelogenous leukemia beat back this patient's hypertension? Unlike the other drugs, Gleevec does not appear to work by dilating blood vessels, says Dr. Norman Edelman, chief medical officer at the American Lung Association.

"It's an anti-platelet agent," he says. "It seems to work by stopping a proliferation of tissue in the lung's small vessels."

This thickening and "webbing" of lung tissue is another hallmark of pulmonary hypertension, Edelman says.

"Gleevec could probably also work just by preventing the aggregation of platelets in blood vessels," he adds, which may also help reduce the thickening and stiffening of arteries that raises blood pressure.

Based on this study and similarly promising case reports, the German team says that it is preparing to test Gleevec in a clinical trial.

Stein stresses that this is "just one report of the drug being effective," but he's hopeful that the results seen in this patient will be repeated in the upcoming trial.

"Gleevec may turn out to be a valuable third product that we can use for these people," he says.

c.2005 HealthDay News