Panitumumab monotherapy as a second-line treatment in metastasised colorectal cancer: a single centre experience.
OBJECTIVE
To report our clinical experience of panitumumab monotherapy as a second-line treatment for patients with metastatic colorectal cancer (mCRC).


METHODS
This retrospective, descriptive study included a series of consecutive patients receiving panitumumab monotherapy (6 mg/kg 2 weekly) at a single centre in the Netherlands between June 2009 and November 2011. All patients had wild-type KRAS tumours, had progressed during first-line fluoropyrimidine-based therapy and were not candidates for, or refused, standard second-line therapy (usually irinotecan in the Netherlands). Prophylactic medication was given for epidermal growth factor receptor inhibitor-associated skin toxicities.


RESULTS
Thirty-one patients were treated during this period. The most commonly administered first-line mCRC regimen was capecitabine/oxaliplatin/bevacizumab (18/31 patients; 58.1%). Patients received a mean of 7.9 (range 1-18) panitumumab cycles. The median progression-free survival was 3.4 (95% confidence interval 2.4, 4.4) months. The median overall survival estimates were 11.4 (95% confidence interval 1.2, 21.6) months from the initiation of panitumumab monotherapy. Ten patients experienced partial responses according to Response Evaluation Criteria In Solid Tumors (RECIST; objective response rate: 32.3%); disease was controlled (objective response or stable disease) in 15 patients (48.4%). Carcinoembryonic antigen (CEA) responses (two consecutive ≥10% decreases from baseline) occurred in 11/29 patients (37.9%); all of whom had >50% decreases in CEA levels. All patients with an objective response at week 12 had CEA reductions at weeks 6 and 12. The only adverse events were grade 1/2 skin toxicities (61.3%) and gastrointestinal complaints (6.5%); three other patients (9.7%) experienced both skin and gastrointestinal complaints.


CONCLUSIONS
Panitumumab monotherapy seems to be a safe and active second-line treatment for patients with wild-type KRAS mCRC, with activity in line with that seen for irinotecan monotherapy, but with less toxicity. CEA may provide a useful early indicator of response to panitumumab.
Catharina Hospital Eindhoven, Eindhoven, The Netherlands. Electronic address: Irene.v.hellemond@catharinaziekenhuis.nl.
I E G
IE
van Hellemond
Catharina Hospital Eindhoven, Eindhoven, The Netherlands.
G J
GJ
Creemers
Catharina Hospital Eindhoven, Eindhoven, The Netherlands.
L J C
LJ
van Warmerdam
Amgen BV, Breda, The Netherlands; Merck Serono, Darmstadt, Germany.
F A
FA
de Jong
Catharina Hospital Eindhoven, Eindhoven, The Netherlands; St Radboud University Medical Centre, Nijmegen, The Netherlands.
R H T
RH
Koornstra
D000368:Aged; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000473:pathology; D018572:Disease-Free Survival; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D000077544:Panitumumab; D012189:Retrospective Studies
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D000077544:Panitumumab
Carcinoembryonic antigen; Metastatic colorectal cancer; Monotherapy; Panitumumab; Response