Patients who have been diagnosed with advanced widespread emphysema and whose only current option is to wait for a lung transplant may now have a less invasive alternative to transplant surgery — one that involves poking small holes in the patient’s lungs for trapped air to escape.
Broncus Technologies (Mountain View, California) recently started its Exhale Airway Stents for Emphysema (EASE) trial to explore an investigational procedure called airway bypass, which uses drug-eluting stents to keep the new pathways in the lung open for trapped air to escape. This in turn, may relieve severe emphysema symptoms such as shortness of breath, Broncus said.
“The problem with emphysema is decades of smoking, that’s part one,” Cary Cole, CEO of Broncus, told Medical Device Daily.
While a healthy lung looks like a “solid piece of meat,” Cole described an emphysema patient’s lung as looking more like tumbleweed because there is so much tissue destruction. Because lung tissue is used to hold open a person’s airways, if there is too much tissue destruction the small airways are collapsed, Cole said, making it difficult for the person to exhale all the air trapped in their lungs.
According to the company, leading pulmonologists and thoracic surgeons at medical centers around the world are participating in the EASE Trial to study the safety and effectiveness of airway bypass in people struggling with severe homogenous (or diffuse) emphysema. During the trial, patients are randomized two-to-one to the treatment group (receiving bronchoscopy with placement of the drug-eluting stents) or the control group (undergoing only a bronchoscopy procedure). The trial is underway at 15 research institutions with more than 20 patients already randomized. At least 225 patients will be enrolled at up to 45 institutions during the next 12 to 18 months, the company said.
For patients in the treatment group receiving airway bypass, the doctor advances a flexible bronchoscope (a long, thin tube with a visual tip) through the mouth into the airways. Then a small listening device called a Doppler catheter will be inserted through the tube to identify a place in the airway wall that is away from blood vessels. Next, a small needle (about the size of a sewing needle) will be inserted through the tube to poke holes in the airway wall for trapped air to escape. There the doctor will insert an Exhale drug-eluting stent — made by Broncus — through the tube and into the new passageway to keep it from closing over time. The stent is made out of stainless steel mesh, is covered with drug-infused silicone and is smaller than the eraser on the end of a pencil, the company said. The stent, which is similar to what cardiologists use in heart disease patients to keep their arteries open, provides the scaffolding to keep the new pathway open long-term, Cole said.
Cole said the patients enrolled in the trial will receive up to six of these stents throughout their lungs, but not every patient will get that many.
Broncus signed a license agreement in 2005 with Angiotech Pharmaceuticals (Vancouver, British Columbia) to use Angiotech’s paclitaxel technology with its own Exhale system (Medical Device Daily, June 3, 2005).
According to Broncus, the study will determine if patients experience an improvement in dyspnea (shortness of breath) and lung function. The procedure, like many other bronchoscopic procedures, is done under deep sedation or general anesthesia, and the patient returns home the next day.
But the procedure is not without risks. Cole said that bleeding is a concern because of the lung’s many blood vessels, and pneumothorax — a collection of air or gas in the chest or pleural space that causes part or all of a lung to collapse — is another risk. That’s why the doctors doing the procedure try to avoid the blood vessels and the pleural area, he said.
Emphysema is a chronic, progressive, and irreversible lung disease characterized by the destruction of lung tissue. The loss of the lungs’ natural elasticity and the collapse of airways in the lung combine to make exhalation ineffective, leaving the emphysema sufferer with hyperinflation because they can’t get air out of their lungs. Breathing becomes inefficient and patients are always short of breath — making even nominal physical activities difficult.
After the airway bypass procedure, Cole said a patient with emphysema might feel like they had been drowning and all of a sudden they had come up to the top of the water and could breath out.
This devastating disease afflicts tens of millions of people worldwide with more than 3 million sufferers in the U.S. There is no cure for emphysema.
“The EASE Trial is important because airway bypass may help patients with widespread emphysema whose disease has destroyed tissue throughout the lung. For this patient population, the only current surgical option is lung transplantation,” said Joel Cooper, MD, developer of the airway bypass procedure and chief of the Division of Thoracic Surgery at the University of Pennsylvania Health System (Philadelphia). Cooper is also a co-principal investigator of the EASE trial and a financial consultant to Broncus. “By creating new pathways for airflow with the airway bypass procedure, we hope to reduce hyperinflation, improve lung function, and restore the mechanics of breathing.”
Ten institutions in the U.S. and five others around the world are recruiting patients for the EASE trial. Involvement in the study will last from about 15 months up to 5 years (depending on if the patient is randomized to the control or the treatment group) and include 8 to 16 physician appointments. All study-related medical procedures will be carried out at no charge to the patient and patients will be closely monitored throughout the trial. Participants will also receive at least 14 weeks of pulmonary rehabilitation therapy, Broncus noted.