Peggy Peck

October 28, 2004

Oct. 28, 2004 (Seattle) — Preliminary results from the Epidemiology and Natural History of Asthma and Treatment Registry (TENOR) suggest that serum IgE levels correlate with lung function and with response to bronchodilator treatment, according to TENOR investigator Katie Miller, MS, an epidemiologist with Genentech in San Francisco, California.

Ms. Miller presented the findings here at a late-breaking clinical trials session at CHEST 2004, the 70th annual meeting of the American College of Chest Physicians. TENOR is jointly funded by Genentech Inc. and Novartis Pharmaceuticals Corp.

Noting that TENOR is "an observational study with no assigned treatment," Ms. Miller said the study has enrolled 4,756 asthma patients at 283 participating clinical sites nationwide. Entry criteria for the three-year study require that patients "have severe or difficult to treat asthma." Difficult to treat is defined as patients who have had two or more unscheduled physician visits for asthma management in the previous 12 months as well as evidence of chronic high use of inhaled steroids, use of three or more asthma medications and use of 5 mg or more of oral prednisone for asthma control.

Of the TENOR enrollees, 634 are aged six to 12 years; 423 are aged 13 to 17 years; and 3,019 are aged 18 years or older.

"The average baseline IgE levels in the youngest cohort is 184.4 Ku/L, while in adolescents it is 215.1 IgE Ku/L, and in adults it is 86 IgE Ku/L," Ms. Miller said. For the purposes of the study, a threshold of 100 Ku/L is used so that IgE levels above 100 Ku/L are defined as high, she explained.

In addition to baseline measurements, IgE was measured before and after bronchodilation, Ms. Miller said. "In all age categories, IgE levels declined as lung function improved postbronchodilation."

Asked if decline in IgE level correlated with clinically apparent changes in symptoms, Ms. Miller said that those data are not available. But she added that the TENOR data may eventually provide evidence of the utility of IgE as a marker for asthma clinical status.

Thomas Fitzgerald, MD, a pulmonologist at Walter Reed Army Medical Center in Washington, D.C., told Medscape that few clinicians use IgE to assess patients. "Ask about IgE and you'll find that most of us don't check it," he said. Dr. Fitzgerald cochaired the late-breaking clinical trials session with Alexander Niven, MD, a pulmonologist at Madigan Army Medical Center in Tacoma, Washington.

Dr. Niven agreed that IgE is underused. He noted that when he checks "IgE in my atopic patients, I am usually surprised by the serum levels," suggesting that serum IgE may not track clinical symptoms.

Both Drs. Fitzgerald and Niven pointed out that Genentech and Novartis make omalizumab (Xolair), an asthma drug that targets IgE.

CHEST 2004: Late-breaking clinical trials session. Presented Oct. 27, 2004.

Reviewed by Gary D. Vogin, MD


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