The FDA slapped GlaxoSmithKline with a warning letter for a series of Dear Healthcare Practitioner letters promoting Tykerb.

The Nov. 21 warning said the three letters – two to doctors and one to oncology nurses – “omit and minimize the most serious and important risk information for Tykerb and selectively present efficacy information.”

The GSK letters went out to healthcare practitioners in March as part of the launch campaign for the drug, indicated for the treatment of HER2+ metastatic breast cancer. Signed by Paolo Paoletti, MD, SVP, GSK Oncology Medicine Development Center, the letters advise healthcare practitioners of the drug’s availability, offering efficacy and adverse events data and promoting GSK’s Tykerb Cares access program.

But FDA said the letters omitted warnings and precautions from the product insert – most seriously, that on the risk of decreased left ventricular ejection fraction, as well as cautions for pregnant patients, those with severe hepatic impairment and those who have or could develop QT prolongation, while glossing over the dangers of diarrhea for Tykerb patients.

In addition, the agency said GSK overstated Tykerb’s efficacy by presenting “only the more favorable of the two distinct analyses of the effect of Tykerb in breast cancer” in the letters.