title: Panitumumab and irinotecan versus irinotecan alone for patients with KRAS wild-type, fluorouracil-resistant advanced colorectal cancer (PICCOLO): a prospectively stratified randomised trial.
abstract: BACKGROUND
  Therapeutic antibodies targeting EGFR have activity in advanced colorectal cancer, but results from clinical trials are inconsistent and the population in which most benefit is derived is uncertain. Our aim was to assess the addition of panitumumab to irinotecan in pretreated advanced colorectal cancer.
  
  
  METHODS
  In this open-label, randomised trial, we enrolled patients who had advanced colorectal cancer progressing after fluoropyrimidine treatment with or without oxaliplatin from 60 centres in the UK. From December, 2006 until June, 2008, molecularly unselected patients were recruited to a three-arm design including irinotecan (control), irinotecan plus ciclosporin, and irinotecan plus panitumumab (IrPan) groups. From June 10, 2008, in response to new data, the trial was amended to a prospectively stratified design, restricting panitumumab randomisation to patients with KRAS wild-type tumours; the results of the comparison between the irinotcan and IrPan groups are reported here. We used a computer-generated randomisation sequence (stratified by previous EGFR targeted therapy and then minimised by centre, WHO performance status, previous oxaliplatin, previous bevacizumab, previous dose modifications, and best previous response) to randomly allocate patients to either irinotecan or IrPan. Patients in both groups received 350 mg/m(2) intravenous irinotecan every 3 weeks (300 mg/m(2) if aged ≥70 years or a performance status of 2); patients in the IrPan group also received intravenous panitumumab 9 mg/kg every 3 weeks. The primary endpoint was overall survival in KRAS wild-type patients who had not received previous EGFR targeted therapy, analysed by intention to treat. Tumour DNA was pyrosequenced for KRASc.146, BRAF, NRAS, and PIK3CA mutations, and predefined molecular subgroups were analysed for interaction with the effect of panitumumab. This study is registered, number ISRCTN93248876.
  
  
  RESULTS
  Between Dec 4, 2006, and Aug 31, 2010, 1198 patients were enrolled, of whom 460 were included in the primary population of patients with KRASc.12-13,61 wild-type tumours and no previous EGFR targeted therapy. 230 patients were randomly allocated to irinotecan and 230 to IrPan. There was no difference in overall survival between groups (HR 1·01, 95% CI 0·83-1·23; p=0·91), but individuals in the IrPan group had longer progression-free survival (0·78, 0·64-0·95; p=0·015) and a greater number of responses (79 [34%] patients vs 27 [12%]; p<0·0001) than did individuals in the irinotecan group. Grade 3 or worse diarrhoea (64 [29%] of 219 patients vs 39 [18%] of 218 patients), skin toxicity (41 [19%] vs none), lethargy (45 [21]% vs 24 [11%]), infection (42 [19%] vs 22 [10%]) and haematological toxicity (48 [22%] vs 27 [12%]) were reported more commonly in the IrPan group than in the irinotecan group. We recorded five treatment-related deaths, two in the IrPan group and three in the irinotecan group.
  
  
  CONCLUSIONS
  Adding panitumumab to irinotecan did not improve the overall survival of patients with wild-type KRAS tumours. Further refinement of molecular selection is needed for substantial benefits to be derived from EGFR targeting agents.
  
  
  BACKGROUND
  Cancer Research UK, Amgen Inc.
authors.affiliation: Cancer Medicine and Pathology, University of Leeds, Leeds, UK. m.seymour@ncrn.org.uk
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Seymour
authors.forename: Sarah R
authors.initials: SR
authors.lastname: Brown
authors.forename: Gary
authors.initials: G
authors.lastname: Middleton
authors.forename: Timothy
authors.initials: T
authors.lastname: Maughan
authors.forename: Susan
authors.initials: S
authors.lastname: Richman
authors.forename: Stephen
authors.initials: S
authors.lastname: Gwyther
authors.forename: Catherine
authors.initials: C
authors.lastname: Lowe
authors.forename: Jennifer F
authors.initials: JF
authors.lastname: Seligmann
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wadsley
authors.forename: Nick
authors.initials: N
authors.lastname: Maisey
authors.forename: Ian
authors.initials: I
authors.lastname: Chau
authors.forename: Mark
authors.initials: M
authors.lastname: Hill
authors.forename: Lesley
authors.initials: L
authors.lastname: Dawson
authors.forename: Stephen
authors.initials: S
authors.lastname: Falk
authors.forename: Ann
authors.initials: A
authors.lastname: O'Callaghan
authors.forename: Kim
authors.initials: K
authors.lastname: Benstead
authors.forename: Philip
authors.initials: P
authors.lastname: Chambers
authors.forename: Alfred
authors.initials: A
authors.lastname: Oliver
authors.forename: Helen
authors.initials: H
authors.lastname: Marshall
authors.forename: Vicky
authors.initials: V
authors.lastname: Napp
authors.forename: Phil
authors.initials: P
authors.lastname: Quirke
mesh_terms: D000368:Aged; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D002166:Camptothecin / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000401:mortality / Q000473:pathology; D004252:DNA Mutational Analysis; D018572:Disease-Free Survival; D004334:Drug Administration Schedule; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D000077146:Irinotecan; D008297:Male; D008875:Middle Aged; D009154:Mutation; D000077544:Panitumumab; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D013997:Time Factors; D016896:Treatment Outcome; D006113:United Kingdom; D018631:ras Proteins / Q000235:genetics*
chemical_list: D000911:Antibodies, Monoclonal; D000964:Antimetabolites, Antineoplastic; D000970:Antineoplastic Agents; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D000077544:Panitumumab; D000077146:Irinotecan; C512478:EGFR protein, human; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins; D005472:Fluorouracil; D002166:Camptothecin