STANFORD, Calif. – A lung disease known as idiopathic pulmonary fibrosis strikes without warning and often kills within only a few years. The Stanford University School of Medicine is one of 75 North American and European medical centers conducting a clinical trial to test if injections of a synthetic protein, which is also naturally produced by the immune system, can increase survival time for patients with this condition.
"This is a very frustrating disease," said Susan Jacobs, the medical school's director of clinical research in pulmonary and critical care medicine. "People are very symptomatic with breathlessness and cough and there are currently no effective treatments."
Glenn Rosen, MD, associate professor of pulmonary and critical care medicine and director of the Interstitial Lung Disease Program at Stanford University Medical Center, is the principal investigator of the study, called the INSPIRE trial. The trial is sponsored by InterMune of Brisbane, Calif., which is providing the interferon gamma protein that is being used in the tests. Rosen is also a consultant for the company.
"The INSPIRE trial offers patients an opportunity to be part of an important study which will determine if interferon gamma improves survival," said Rosen, who runs a laboratory that examines the cellular pathways that become overactive in this disease.
"The trial also offers an opportunity to learn more about the natural history of idiopathic pulmonary fibrosis and enhance our understanding of the disease," he said.
Idiopathic pulmonary fibrosis, or IPF, develops from damage to the alveoli, the tiny air sacs in the lungs that exchange oxygen from inhaled air for carbon dioxide in the blood. Pulmonary fibrosis can develop from dozens of causes, including exposure to such environmental assaults as asbestos, metal dust or even molds.
In situations in which there is nothing in a patient's history that explains the development of fibrosis, it is known as idiopathic, medical terminology for "unknown cause."
The majority of the pulmonary fibrosis cases fall into the category of idiopathic, according to the Coalition for Pulmonary Fibrosis. The group estimates that 83,000 people in the United States have IPF, with around 31,000 new cases annually.
Whatever the cause, pulmonary fibrosis begins with an over-reactive healing response to something irritating the lungs. The alveoli become inflamed and fibrous scar tissue forms in the surrounding regions. The scarring process makes breathing difficult and reduces oxygen transfer to the blood.
No cure exists for IPF. Anti-inflammatory medications can sometimes help, but less than 10 to 15 percent of patients respond to the treatment enough to halt the scarring process, according to Jacobs and Rosen.
Despite treatment, most patients deteriorate and eventually their lungs fail. The average survival time following diagnosis is a few years; two-thirds of patients die within five years of diagnosis. The only definitive treatment for the disease is a lung transplant, but suitable donor lungs are rare and long-term survival is less than 50 percent.
In the quest for a treatment for IPF, speculation that it may be an autoimmune disease led to the idea that interferon gamma might help, as it has been used with some success in other autoimmune diseases such as multiple sclerosis. Interferon gamma is a member of naturally occurring proteins produced by the immune system to help the body launch an attack against foreign invaders. There are three classes of interferons: alpha, beta and gamma, and each of these classes has different, although sometimes overlapping, effects.
A previous clinical trial testing interferon gamma in the treatment of IPF found that while there was not an improvement in breathing ability as the disease progressed, there was a trend toward better survival in the group receiving the treatment. Jacobs said interferon gamma might offer some kind of immune protective effect.
To test the treatment in a longer-running study involving more people, a total of 600 participants will be enrolled at the centers –10 at Stanford – and the trial will run for two years following the enrollment of the last person.
Adults between the ages of 40 and 79 who have been diagnosed with IPF in the past 48 months may be eligible to participate in the INSPIRE trial. Those who meet eligibility requirements and who are enrolled will receive either interferon gamma or a placebo by subcutaneous injection three times a week for a minimum of two years. Neither the researchers nor the study participants will know who receives the active drug.
Participants will be taught to administer the injection to themselves and will need to come to Stanford five times in the first three months, then return once every three months for the duration of the study. For more information call (650) 725-8082.
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