PFS was also significantly longer in patients with EGFR-positive immunohistochemistry who were treated with erlotinib ( n = 307 ) compared with EGFR-positive patients given placebo ( n = 311 ; median PFS 12.3 weeks in the erlotinib group vs 11.1 weeks in the placebo group ; HR 0.69 , 0.58-0 .82 ; p < 0.0001 ) .
