On December 10, 2007, WLF called on DDMAC to withdraw a warning letter sent to GSK regarding GSK’s allegedly improper promotion of Tykerb, a drug approved by FDA for treating breast cancer. DDMAC alleged that letters GSK sent to doctors regarding Tykerb were misleading because they omitted important risk information and overstated efficacy. WLF’s letter to DDMAC alleged that DDMAC’s action was inappropriate, because Tykerb’s recognized risks were fully disclosed. DDMAC also faulted GSK’s letters for overstating efficacy because they discussed an efficacy evaluation by the drug’s IRC without fully disclosing efficacy data from a second, somewhat less favorable evaluation. WLF’s response noted that the GSK letters explicitly disclosed that a second efficacy evaluation was less favorable. WLF said that, in light of GSK’s disclosure, it is incumbent on DDMAC — before charging that promotional material is misleading — to develop some evidence that doctors have actually been misled.