Gly469Ala, the point mutation of BRAF, is possible to induce conformational change, in which BRAF inhibitor can no longer affect the active function of this oncogenic molecule. Or, this mutation is not at all functional and does not affect the responsiveness to BRAF inhibitor.  

I agree with Fr. Moritz comment. The available BRAF-targeting drugs such as , vemurafenib and dabrafenib are especially effective for the point mutation of V600E (valine (V) being substituted for by glutamate (E) at codon 600). Depending on the mutation, as I mentioned preciously, the conformation change makes it impossible for those drugs to show clinical benefit.