The FDA warned healthcare professionals about potential medication errors resulting from confusion with the nonproprietary name for the recently approved breast cancer drug ado-trastuzumab emtansine (Kadcyla; also known as T-DM1).
The FDA noted that in various online publications and in different medical electronic systems the drug is sometimes referred to incorrectly as trastuzumab, which is the active ingredient in the older breast cancer drug Herceptin, which had a different dosing and a different treatment schedule.
The FDA-approved nonproprietary name for Kadcyla is “ado-trastuzumab emtansine” but the prefix “ado-” is often dropped, which may lead to the confusion with trastuzumab (ie, Herceptin) the FDA notes that it is therefore important to keep the prefix with the nonproprietary name when referring to Kadcyla, when prescribing the medication, and in electronic medical records (EMRs) or any online or other publications. The FDA notes that some third-party publications, compendia references, health information systems (ie, EMR systems and other systems used for pharmacy prescription processing, wholesaler ordering, and pharmacy ordering), and various websites are incorrectly using “trastuzumab emtansine” and omitting the “ado-” prefix.
Although no medication errors related to confusion between Kadcyla and Herceptin have been reported since the approval of Kadcyla on February 22, 2013, such errors did occur during the clinical trials that evaluated the safety and efficacy of the drug before its approval, according to the FDA. The agency advises health plans, pharmacists, and prescribers to implement strategies to warn against and look for any confusion between the 2 drugs in electronic systems, and when needed, to correct the error.
Furthermore, the FDA insists that ado-trastuzumab emtansine should not be substituted for or used with trastuzumab. The recommended dose of Kadcyla is 3.6 mg/kg, administered by intravenous infusion every 3 weeks for a total of 21 days. This drug should not be prescribed at higher doses. By contrast, the recommended dose of Herceptin is significantly higher, up to 8 mg/kg per loading dose, followed by a maintenance dose of 6 mg/kg every 3 weeks. These drugs may not be used concomitantly. (May 6, 2013)
