DR GOVINDAN: So just a few basics for those who are listening. Number 1, the common mutations we talk about are the exon 19 deletion, L858R. These are the ones that are common. Ninety percent, 85% to 90% have this mutation. That number is going to change, because in the past we’ve been looking for exon 19 deletion, L858R. Now when we do this next-gen sequencing looking at the entire length of the gene, we are going to be finding more and more uncommon mutations than exon 19, 20, 21, 18, et cetera.
So the question here is that: How good is afatinib in those uncommon EGFR mutations? So the group that presented the data at the Sydney meeting (Proc WCLC 2013;Abstract O03.05)looked at the 75 patients who had this uncommon mutation, EGFR mutation, from the 3 LUX-Lung studies, LUX-Lung 2, LUX-Lung 3 and LUX-Lung 6, and asking a question: How good is afatinib in these patients?
So the bottom line is they broke this group into 3 sets, the de novo T790M mutations. Second, exon 20 insertions, and the rest that happen, exon 18, 19, 20, 21, et cetera.
So the bottom line is: If you have the de novo T790M mutation, the response rate, partial and complete response rate to afatinib is about 14%. And with exon 20 insertion, just about half, around 8%. But the other mutations, 18, 19, 20, 21, that’s about 70%. Not bad. Seventy percent response rate with afatinib. And the duration of response ranged from 7 to 11 months. The highest was, of course, in the other mutation category. And the lowest was in the exon 20 insertion, 7 months. And de novo T790M mutation, they were 8 months. And the disease control rate was about 65% in both the groups. So patients who have T790M had some stable disease. Didn’t have a response. And the disease control rate is about 65%, even in the T790M mutation, afatinib, and exon 20 insertions about 65%.
The bottom line, other mutations did very well, as good as the sensitive mutations, not so good with T790M and exon 20 insertions with afatinib.