495P - Cetuximab (Cmab) plus irinotecan (I) versus panitumumab (Pmab) in patients with refractory metastatic colorectal cancer (mCRC) in Ontario

Date 08 October 2016
Event ESMO 2016 Congress
Session Poster Display
Topics Anticancer agents
Colon and Rectal Cancer
Therapy
Biological Therapy
Presenter Katarzyna Jerzak
Citation Annals of Oncology (2016) 27 (6): 149-206. 10.1093/annonc/mdw370
Authors K.J. Jerzak, C. Earle, Y. Ko, S. Berry, K.K. Chan
  • Medicine, Sunnybrook Odette Cancer Center, Sunnybrook HSC, M4N 3M5 - Toronto/CA

Abstract

Background

In the BOND trial (Cunningham et al, NEJM 2004) for refractory mCRC, the addition of I to an EGFR antibody improved tumor response rate and time to progression but not overall survival (OS). We assessed the "real world" efficacy and toxicity of combination versus monotherapy in i) all-comers and ii) older patients (pts) who are under-represented in randomized trials.

Methods

In Ontario, universal public funding is available for either Cmab + I combination or Pmab monotherapy only in pts with refractory non-mutated Kras mCRC. All pts diagnosed before Dec 2012 and treated with an EGFR antibody for mCRC were identified from the Ontario drug database and linked to the Ontario Cancer Registry and other administrative databases to ascertain baseline characteristics, health services utilization and outcomes. Multivariable Cox and logistic models were constructed to compare the time to treatment discontinuation, overall survival (OS), ED or hospital visits between Cmab + I and Pmab, adjusting for observable confounders (including age, gender, year of diagnosis, stage at presentation, duration of prior treatment in 1st and 2nd line, previous liver resection, rural residence and income quintile) using propensity score methods.

Results

1081 pts were identified (Cmab + I: 278, Pmab: 803); median age: 60 (21.1% >age 70), 36.4% female, 36.2% rectal cancer and 60.1% stage IV at presentation. After adjusting for confounders, the use of Cmab + I as compared to Pmab alone was associated with a prolonged time to treatment discontinuation [median: 3.5 mos vs. 2.8 mos, HR 0.63, 95%CI 0.53-0.75, p 

Conclusions

"Real world" data suggest a possible OS benefit with Cmab + I compared to Pmab alone, without an associated increase in toxicity. Pts age ≥70 appear to experience similar benefit and toxicity from combination therapy. These results suggest a need for adequately powered randomized trials to compare Cmab + I and Pmab like the ongoing ICECREAM study.

Clinical trial identification

N/A

Legal entity responsible for the study

N/A

Funding

N/A

Disclosure

All authors have declared no conflicts of interest.