Intermittent chemotherapy plus either intermittent or continuous cetuximab for first-line treatment of patients with KRAS wild-type advanced colorectal cancer (COIN-B): a randomised phase 2 trial.
BACKGROUND
Advanced colorectal cancer is treated with a combination of cytotoxic drugs and targeted treatments. However, how best to minimise the time spent taking cytotoxic drugs and whether molecular selection can refine this further is unknown. The primary aim of this study was to establish how cetuximab might be safely and effectively added to intermittent chemotherapy.


METHODS
COIN-B was an open-label, multicentre, randomised, exploratory phase 2 trial done at 30 hospitals in the UK and one in Cyprus. We enrolled patients with advanced colorectal cancer who had received no previous chemotherapy for metastases. Randomisation was done centrally (by telephone) by the Medical Research Council Clinical Trials Unit using minimisation with a random element. Treatment allocation was not masked. Patients were assigned (1:1) to intermittent chemotherapy plus intermittent cetuximab or to intermittent chemotherapy plus continuous cetuximab. Chemotherapy was FOLFOX (folinic acid and oxaliplatin followed by bolus and infused fluorouracil). Patients in both groups received FOLFOX and weekly cetuximab for 12 weeks, then either had a planned interruption (those taking intermittent cetuximab) or planned maintenance by continuing on weekly cetuximab (continuous cetuximab). On RECIST progression, FOLFOX plus cetuximab or FOLFOX was recommenced for 12 weeks followed by further interruption or maintenance cetuximab, respectively. The primary outcome was failure-free survival at 10 months. The primary analysis population consisted of patients who completed 12 weeks of treatment without progression, death, or leaving the trial. We tested BRAF and NRAS status retrospectively. The trial was registered, ISRCTN38375681.


RESULTS
We registered 401 patients, 226 of whom were enrolled. Results for 169 with KRAS wild-type are reported here, 78 (46%) assigned to intermittent cetuximab and 91 (54%) to continuous cetuximab. 64 patients assigned to intermittent cetuximab and 66 of those assigned to continuous cetuximab were included in the primary analysis. 10-month failure-free survival was 50% (lower bound of 95% CI 39) in the intermittent group versus 52% (lower bound of 95% CI 41) in the continuous group; median failure-free survival was 12.2 months (95% CI 8.8-15.6) and 14.3 months (10.7-20.4), respectively. The most common grade 3-4 adverse events were skin rash (21 [27%] of 77 patients vs 20 [22%] of 92 patients), neutropenia (22 [29%] vs 30 [33%]), diarrhoea (14 [18%] vs 23 [25%]), and lethargy (20 [26%] vs 19 [21%]).


CONCLUSIONS
Cetuximab was safely incorporated in two first-line intermittent chemotherapy strategies. Maintenance of biological monotherapy, with less cytotoxic chemotherapy within the first 6 months, in molecularly selected patients is promising and should be validated in phase 3 trials.
Imperial College Healthcare NHS Trust, London, UK.
Harpreet
H
Wasan
MRC Clinical Trials Unit at UCL, London, UK. Electronic address: a.meade@ucl.ac.uk.
Angela M
AM
Meade
Cardiff University, Cardiff, UK.
Richard
R
Adams
Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK.
Richard
R
Wilson
MRC Clinical Trials Unit at UCL, London, UK.
Cheryl
C
Pugh
MRC Clinical Trials Unit at UCL, London, UK.
David
D
Fisher
MRC Clinical Trials Unit at UCL, London, UK.
Benjamin
B
Sydes
MRC Clinical Trials Unit at UCL, London, UK.
Ayman
A
Madi
Essex County Hospital, Colchester, UK.
Bruce
B
Sizer
Imperial College Healthcare NHS Trust, London, UK.
Charles
C
Lowdell
University of Birmingham, Birmingham, UK.
Gary
G
Middleton
University Hospital of Wales, Cardiff, UK.
Rachel
R
Butler
MRC Clinical Trials Unit at UCL, London, UK.
Richard
R
Kaplan
Cancer Research UK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, UK.
Tim
T
Maughan
D000368:Aged; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage* / Q000009:adverse effects; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage* / Q000009:adverse effects; D000068818:Cetuximab; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000401:mortality; D018572:Disease-Free Survival; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D053208:Kaplan-Meier Estimate; D002955:Leucovorin / Q000008:administration & dosage / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009944:Organoplatinum Compounds / Q000008:administration & dosage / Q000009:adverse effects; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D016896:Treatment Outcome; D018631:ras Proteins / Q000235:genetics
D061067:Antibodies, Monoclonal, Humanized; C117307:KRAS protein, human; D009944:Organoplatinum Compounds; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins; D000068818:Cetuximab; D002955:Leucovorin; D005472:Fluorouracil