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Emory joins NIH clinical trial studying biomarker for lower respiratory infection

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Holly Korschun

Emory University researchers will enroll volunteers in a new clinical trial that could help improve treatment decisions for lower respiratory tract infections. The study aims to determine whether low blood levels of the protein procalcitonin can reliably show whether a person’s lower respiratory tract infection will improve without antibiotic treatment.

Lower respiratory tract infections (LRTIs) can cause a variety of symptoms, including persistent coughing, wheezing, chest pain, fever, and rapid or difficult breathing. Health care providers often prescribe a course of antibiotics as standard treatment without knowing for certain whether an infection is bacterial or viral. Taking antibiotics for viral infections is not only ineffective but can also cause potential side effects and promote antimicrobial resistance.

Procalcitonin is normally produced by the healthy human body in minute quantities, and serves as a precursor to calcitonin, a hormone that helps regulate calcium levels. Currently, medical professionals use high procalcitonin blood levels to help diagnose bacterial sepsis, a life-threatening complication of infection that triggers inflammation throughout the body. The researchers leading the new clinical trial theorize that low procalcitonin levels in patients with LRTIs may indicate that the infection is viral, not bacterial.

The study is supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. The study was developed by the NIAID-supported Antibacterial Resistance Leadership Group in collaboration with bioMérieux.

The study is being led by Duke University and is being conducted through three NIAID-funded Vaccine and Treatment Evaluation Units and three VA Health Care Systems, with a total of five sites enrolling participants in Georgia, North Carolina, and Texas. At Emory, the study will be conducted at Emory University Hospital and Atlanta Veterans Affairs Medical Center. Nadine Rouphael, MD, is Atlanta principal investigator and site leader at Emory, and Ruxana Sadikot, MD, is site leader at the Atlanta VA.

“We believe this study could be very important in helping health care providers determine the most effective treatment for lower respiratory tract infection,” says Rouphael. “This would not only provide patients with a better outcome, but would help prevent unnecessary antibiotic use and antibiotic resistance.”

Participants will be 18 years of age or older with suspected LRTIs and low procalcitonin blood levels (0.25 ng/mL or less). The patients’ blood will be tested for procalcitonin levels using bioMérieux’s VIDAS® BRAHMS PCT™ test. As many as 420 patients will be randomized to receive either a five-day regimen of the oral antibiotic azithromycin (500 mg as a single dose on day one followed by 250 mg once daily for four days) or placebo. Patients whose symptoms worsen will be immediately referred for appropriate care. At day five, all the patients will be evaluated for improvement in their symptoms. Additional follow-up with the patients will occur on days 11 and 28.

If no significant difference in improvement rates between volunteers treated with azithromycin and those receiving placebo is found, this will suggest that low procalcitonin levels could identify patients with viral infections and prevent unnecessary antibiotic treatment for these individuals. If the volunteers given antibiotics tend to recover faster or better than those given placebo, however, this will indicate that low procalcitonin levels are not a reliable biomarker to guide the treatment of LRTIs.

The NIAID contract number for the study is HHSN272201300018I

For more information about the study, please visit using the identifier NCT03341273.

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