FDA Halts Daptomycin Use in ReadyMed Pump

ReadyMed elastomeric infusion pumps should not be used to deliver the antibiotic daptomycin (Cubicin) because of a “potentially significant impurity” that has been identified in the antibiotic when stored in this particular pump, according to the Food and Drug Administration and manufacturer of the antibiotic.

In a notice posted on the FDA's MedWatch site, the FDA announced that 2-mercaptobenzothiazole (MBT) has been isolated from reconstituted Cubicin stored in the ReadyMed infusion pumps, which are manufactured by Cardinal Health Inc. MBT is used to manufacture rubber, “and has been reported to leach from rubber stoppers and syringe components into medicinal products in the past,” the FDA said.

However, no MBT has been found in reconstituted Cubicin in other standard infusion systems that have been tested.

Daptomycin for injection is marketed as Cubicin by Cubist Pharmaceuticals Inc. In a letter to health care professionals, the company advised against the use of the ReadyMed pumps “until this issue is addressed.”

The lab studies that detected MBT in samples of daptomycin stored in the ReadyMed pumps examined the stability of daptomycin reconstituted in 0.9% sodium chloride for injection and stored in the pumps at a concentration of 20 mg/mL for at least 10 days in refrigerated conditions. The company also did not detect MBT in samples of daptomycin stored in Eclipse pumps, another elastomeric infusion pump manufactured by the I-Flow Corp., but has not evaluated its stability in other elastomeric infusion pumps.

“The clinical significance of this finding is unknown,” according to the letter. Neither the letter nor the FDA mentions any reports of adverse events in patients associated with this finding. But the letter also says that cutaneous exposure to MBT has been associated with dermal sensitization, and that chronic administration of MBT has been associated with an increased risk of certain tumors in laboratory rodents.

Cubist Pharmaceuticals can be contacted at 866-793-2786. The MedWatch notice is available at www.fda.gov/medwatch/safety/2008/safety08.htm#cubicinwww.fda.gov/medwatch