The U.S. Food and Drug Administration (FDA) is warning against the use of the antibiotic azithromycin in certain patients who have undergone an allogeneic hematopoietic cell transplantation (alloHCT). The agency advised that the drug, used to treat infections affecting the lungs, sinuses, and skin, should not be given to alloHCT recipients with cancers of the blood or lymph nodes.
The warning is based on preliminary results from a clinical trial of 480 patients with cancers of the blood and lymph nodes who underwent alloHCT. During the trial, 77 patients (32.9 percent) who received long-term treatment with azithromycin experienced relapsed disease, compared with 48 patients (20.8 percent) who received a placebo. Ninety-five patients receiving azithromycin died, leading to a two year-survival rate of 56.6 percent, compared with 66 patients in the control group, leading to a two-year survival rate of 70.1 percent.
Researchers concluded that long-term azithromycin use increased risks of relapse and death in alloHCT patients, forcing them to prematurely end the trial after 13 months. However, the investigators could not determine the mechanism through which azithromycin increased these risks.
In its warning, the FDA stated that azithromycin is not approved for and should not be used to prevent the inflammatory lung condition bronchiolitis obliterans syndrome. Pfizer, the manufacturer of azithromycin, has also issued a letter to health-care providers warning them of the potential risks of the treatment.
Source: FDA Safety Announcement, August 3, 2018.