National Institutes of Health scientists are set to launch the first government-sponsored clinical trial in people with asthma.
The trial is aimed at determining what dose of the 2009 H1N1 influenza vaccine is needed to induce a protective immune response in people with asthma, especially those with severe disease.
"People with severe asthma often take high doses of glucocorticoids that can suppress their immune system, placing them at greater risk for infection and possibly serious disease caused by 2009 H1N1 influenza virus," said National Institute of Allergy and Infectious Diseases (NIAID) director Dr. Anthony S. Fauci.
"We need to determine the optimal dose of 2009 H1N1 influenza vaccine that can be safely administered to this at-risk population and whether one or two doses are needed to produce an immune response that is predictive of protection," he added.
After approval from the Food and Drug Administration, the clinical trial will be conducted at seven sites across the United States that participate in National Heart, Lung, and Blood Institute's (NHLBI) Severe Asthma Research Program.
The program already has a well-characterized group of participants with mild, moderate or severe asthma who may be eligible for this new study.
These groups are largely distinguished by the amount and frequency of glucocorticoids needed to control asthma symptoms.
People with mild disease may not need glucocorticoids, or may require low doses of inhaled glucocorticoids; those with moderate asthma need low to moderate doses of inhaled glucocorticoids; and those with severe asthma need high doses of inhaled glucocorticoids and frequently use oral glucocorticoids as well.
Individuals who already have been infected with 2009 H1N1 influenza or have received a 2009 H1N1 influenza vaccination will not be eligible for the study.
"The results of this study will have immediate implications for individuals with severe asthma as well as those who have milder asthma," said NHLBI Director Dr. Elizabeth G. Nabel.
Early results from other clinical trials of 2009 H1N1 influenza vaccines in healthy adults have shown that a single 15-microgram dose of 2009 H1N1 influenza vaccine without adjuvant is well tolerated and induces a strong immune response in most participants.
The same vaccine also generates an immune response that is expected to be protective in healthy children ages 10 to 17 years.
People who have severe asthma may be particularly at risk for infection with the 2009 H1N1 influenza virus.
The vaccine to be used in the trial, manufactured by Novartis, contains inactivated 2009 H1N1 influenza virus and therefore cannot cause anyone to become infected with the virus.