The U.S. Food and Drug Administration has sent a letter to patients and doctors warning them about the risk of developing a serious form of pneumonia associated with use of the antibiotic, Cubicin, which is produced by Lexington-based Cubist Pharmaceuticals Inc.

The FDA letter read, in part, “Healthcare professionals should closely monitor patients being treated with Cubicin for eosinophilic pneumonia. Patients receiving Cubicin should immediately contact their healthcare professional if they develop a new or worsening fever, cough, shortness of breath, or difficulty breathing.”


The risk of developing what is known as eosinophilic pneumonia has been part of the Cubicin product label since 2007. The FDA is now releasing new data showing seven cases of the illness, most likely associated with use of Cubicin, between 2004 and 2010. The FDA also identified 36 possible cases of eosinophilic pneumonia associated with Cubicin use.

 “This will require a change to the product label and we are working with the FDA on that,” Cubist spokesman Francis McLoughlin said.

The FDA said that the new product insert must include more prominent information on the potential risk of eosinophilic pneumonia, a rare but serious condition whereby a type of white blood cell (eosinophil) fills the lungs. It is potentially fatal if not treated quickly, according to the FDA.

McLoughlin said the side effect is very rare, which is defined by the FDA as less than one case in 10,000. Cubicin  was approved in 2003, initially to treat serious skin infections. In 2006, it was approved to treat bloodstream infections, including Methicillin-resistant Staphylococcus aureus (MRSA).

Earlier this month, Cubist reported it had met its safety objectives in a Phase 2 study of Cubicin as a treatment intended for prosthetic joint infections.