In this population , after a median follow-up of @ months , in line with the initial analysis , the addition of cetuximab was associated with numerically higher , but not statistically significant , rates of complete response ( @ % versus @ % , p = @ ) , @-year progression-free survival ( @ % versus @ % , hazard ratio ( HR ) @ , p = @ ) and @-year overall survival ( @ % versus @ % , HR @ , p = @ ) .