Table 1.

Patients' clinical characteristics

Patient IDTreatmentDuration of treatmentPre-EGFR therapy samplePost-EGFR therapy sample# KRAS mutant alleles/total
#1Panitumumab12 mo (Aug 2010 to Aug 2011)Para-aortic lymphnodes: KRAS wt, MET wtLiver metastasis: MET ampl, KRAS wtPlasma ctDNA: KRAS wt (0/16,900 events)
#2Panitumumab13 mo (Mar 2010 to Apr 2011)Liver metastasis: KRAS wt, MET wtLiver metastasis: MET ampl, KRAS wtPlasma ctDNA: KRAS wt (0/126,700 events)
#3Cetuximab + irinotecan12 mo (Feb 2011 to Feb 2012a)Liver metastasis: KRAS wt, MET wtbLung metastasis: MET ampl, KRAS wtPlasma ctDNA: KRAS wt (0/114,600 events)
#4Cetuximab + irinotecan6 mo (Mar 2011 to Sep 2011)Abdominal lymphnode: KRAS wt, MET n.a.Liver metastasis: KRAS wt, MET wtPlasma ctDNA not availablec
#5Cetuximab + irinotecan22 mo (May 2009 to Mar 2011)Colon: KRAS wt, MET wtLiver metastasis: KRAS p.G13D, MET wtPlasma ctDNA: KRAS p.G13D (1,355/33,300 events)
#6Panitumumab6 mo (Dec 2009 to Jun 2010)Colon: KRAS wt, MET wtLiver metastasis: KRAS p.G12V, MET wtPlasma ctDNA KRAS p.G12V (37/5,500 events)
#7Panitumumab8 mo (Jan 2010 to Sep 2010)Colon: KRAS wt, MET wtLiver metastasis: KRAS p.G13D, MET wtPlasma ctDNA KRAS p.G13D (27/9,400 events)

Abbreviations: ctDNA, circulating tumor DNA; wt, wild-type; n.a., not available.

  • aPatient #3 received cetuximab monotherapy from May 2011 to February 2012 (after receiving cetuximab + irinotecan from February to May 2011).

  • bThe preexistence of single and rare MET-amplified cells was observed by FISH analysis in the pre-cetuximab sample from patient #3.

  • cKRAS was found to be wild-type in the DNA from the liver metastatic biopsy obtained after anti-EGFR treatment (0 of 165,000 events).