The U.S. Food and Drug Administration (FDA) issued a statement advising clinicians to avoid using the antibiotic azithromycin in patients with certain cancers who have undergone an allogeneic hematopoietic cell transplantation (alloHCT).
The warning against the drug, which is used to treat infections affecting the lungs, sinuses, and skin, 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%) who received long-term treatment with azithromycin experienced relapsed disease, compared with 48 patients (20.8%) who received a placebo (p values not provided). Ninetyfive 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 (p values not provided).
Researchers concluded that longterm azithromycin use increased risks of relapse and death in patients who underwent alloHCT, 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.