title: Panitumumab after progression on cetuximab in KRAS wild-type metastatic colorectal cancer patients: a single institution experience.
abstract: OBJECTIVE
  Few data describe the activity of panitumumab after cetuximab-irinotecan-based regimen failure in patients with KRAS wild-type metastatic colorectal cancer (WT MCRC).
  
  
  METHODS
  The aim of this study is to assess if panitumumab has some activity in this setting.
  
  
  RESULTS
  We retrospectively analyzed 25 patients with KRAS WT MCRC who received panitumumab from July 2009 to January 2013 after progression on cetuximab. All patients had previously received cetuximab and irinotecan (20 patients) or oxaliplatin (5 patients). We withdrew cetuximab for intolerance in 4 patients (16%). Twenty-one patients (84%) who had previously responded to cetuximab (overall response rate [ORR] plus stable disease ≥5 months) received panitumumab off-label after progression on cetuximab because they were strongly motivated to continue treatment without chemotherapy. The median number of cycles of panitumumab was 7 (range 1-54). Only 20 patients were evaluable for ORR (5 patients received 1-2 cycles and then died). We observed 1 (5%) partial response, 5 (25%) stable disease, median duration 9 months. Median progression-free survival (PFS) and overall survival (OS) were 5 (3-28) and 8 (5-41) months, respectively. All patients were evaluable for toxicity. No patients developed anemia or neutropenia. One patient (4%) developed grade 2 thrombocytopenia, 8 patients (32%) grade 2-3 dry skin or rash, and 2 patients (8%) grade 2 nausea-vomiting (Common Terminology Criteria for Adverse Events version 4.03).
  
  
  CONCLUSIONS
  Our data, with all the limits of a retrospective analysis, show longer PFS and OS as compared to other series in the same setting, demonstrating that panitumumab has treatment effectiveness in patients with KRAS WT MCRC who progressed on prior cetuximab. Further confirmatory prospective studies with a larger series of patients are necessary.
authors.affiliation: Medical Oncology & Breast Unit, "A. Perrino" Hospital, Brindisi - Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Marino
authors.forename: Chiara
authors.initials: C
authors.lastname: Caliolo
authors.forename: Francesco
authors.initials: F
authors.lastname: Sponziello
authors.forename: Angelo
authors.initials: A
authors.lastname: Nacci
authors.forename: Annamaria
authors.initials: A
authors.lastname: Quaranta
authors.forename: Enrica
authors.initials: E
authors.lastname: Mazzoni
authors.forename: Stefania Eufemia
authors.initials: SE
authors.lastname: Lutrino
authors.forename: Pietro
authors.initials: P
authors.lastname: Rizzo
authors.forename: Nicola
authors.initials: N
authors.lastname: Calvani
authors.forename: Laura
authors.initials: L
authors.lastname: Orlando
authors.forename: Paola
authors.initials: P
authors.lastname: Schiavone
authors.forename: Palma
authors.initials: P
authors.lastname: Fedele
authors.forename: Maria
authors.initials: M
authors.lastname: D'Amico
authors.forename: Maria Concetta
authors.initials: MC
authors.lastname: Chetrì
authors.forename: Margherita
authors.initials: M
authors.lastname: Cinefra
authors.forename: Pasqualinda
authors.initials: P
authors.lastname: Ferrara
authors.forename: Saverio
authors.initials: S
authors.lastname: Cinieri
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000068818:Cetuximab / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000556:secondary; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D000077544:Panitumumab; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012189:Retrospective Studies; D016896:Treatment Outcome; D018631:ras Proteins / Q000235:genetics*
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D000077544:Panitumumab; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins; D000068818:Cetuximab