Participants received panitumumab 6 mg/kg and irinotecan 180 mg/m² administered by intravenous (IV) infusion every 2 weeks until disease progression or intolerance of panitumumab, irinotecan or both.

The first infusion of panitumumab will occur on Cycle 1 Day 4. On Cycle 2 Day 1, panitumumab will be administered on the same day as irinotecan and every 2 weeks thereafter.

To analyze the effect, if any, that panitumumab had on the pharmacokinetics of irinotecan, the Cmax of irinotecan administered alone (Cycle 1) and with concomitant panitumumab (Cycle 2) was measured. Plasma samples were assayed by a validated high performance liquid chromatography (HPLC)-fluorescence method for the measurement of irinotecan. The lower limit of quantitation (LLOQ) was 2 ng/mL.

To analyze the effect, if any, that panitumumab had on the pharmacokinetics of irinotecan, the AUCinf of irinotecan administered alone (Cycle 1) and with concomitant panitumumab (Cycle 2) was measured.

To analyze the effect, if any, that panitumumab had on the pharmacokinetics of irinotecan, the AUClast of irinotecan administered alone (Cycle 1) and with concomitant panitumumab (Cycle 2) was measured.

Adverse events of special interest include infusion reactions, integument toxicities, diarrhea, stomatitis, hypomagnesemia, and pulmonary, vascular, and cardiac toxicities. Infusion reactions were defined as 1. Prespecified signs and symptoms indicating a possible infusion reaction (derived from Common Terminology Criteria for Adverse Events (CTCAE) definitions of allergic reaction/hypersensitivity and cytokine release syndrome/acute infusion reaction) with onset day coincident with any study drug infusion and which resolved the day of, or the day after, onset; 2. incidence of AE with terms consistent with the panitumumab US package insert (USPI) (any event within 24 hours of an infusion during the clinical study described as allergic reaction or anaphylactoid reaction, or any event occurring on the first day of dosing described as allergic reaction, anaphylactoid reaction, fever, chills, or dyspnea).

Data are summarized overall and by treatment phase.

Participants received panitumumab 6 mg/kg and irinotecan 180 mg/m² administered by intravenous (IV) infusion every 2 weeks until disease progression or intolerance of panitumumab, irinotecan or both.

To analyze the effect, if any, that panitumumab had on the pharmacokinetics of irinotecan, the Cmax of irinotecan administered alone (Cycle 1) and with concomitant panitumumab (Cycle 2) was measured. Plasma samples were assayed by a validated high performance liquid chromatography (HPLC)-fluorescence method for the measurement of irinotecan. The lower limit of quantitation (LLOQ) was 2 ng/mL.

The pharmacokinetic analysis set included all participants who received panitumumab 6 mg/kg and irinotecan 180 mg/m² without dose reductions or delays and who completed the blood sample collection for pharmacokinetic analysis during cycles 1 and 2.

Participants received panitumumab 6 mg/kg and irinotecan 180 mg/m² administered by intravenous (IV) infusion every 2 weeks until disease progression or intolerance of panitumumab, irinotecan or both.