Part 3: Exploratory evaluation of the safety and efficacy of the rilotumumab and ganitumab monotherapy following treatment with panitumumab in Part 2. In Part 3, eligible participants who terminated panitumumab treatment in the Panitumumab Alone arm of Part 2 due to disease progression or intolerability could be randomized 1:1 into 2 double-blind cohorts: 10 mg/kg rilotumumab or 12 mg/kg ganitumab.