438P - First line treatment patterns in BRAFV600E-mutant metastatic colorectal cancer patients (mCRC): The CAPSTAN European retrospective study

Background

8-12% of mCRC patients harbour a BRAF ^V600E mutation (BRAF^MT), which confers a poor prognosis. In the first-line setting, there is no specific treatment for BRAF ^MT -mCRC, although a doublet or triplet chemotherapy (CT) plus bevacizumab is recommended by European guidelines. CAPSTAN is a retrospective, multicentre, observational study to describe effectiveness and safety of first-line regimens in BRAF ^MT mCRC patients in Europe.

Methods

BRAF ^MT , unresectable mCRC patients who initiated first-line treatment between 2016 and 2018 were included. The primary endpoint was the description of first-line treatment patterns. Secondary endpoints included effectiveness (ORR, PFS, OS) and description of BRAF mutation testing procedures.

Results

259 patients were eligible for analysis. The median age was 66 years and the majority were female (58.3%). 52.9% of patients had right sided tumour and BRAF ^MT was confirmed using mostly PCR (46.1%) or NGS (38.3%). 59.5% had an assessment of microsatellite instability (MSI) status of which 23.4% were MSI. Majority of patients (73.8%) received doublet CT in first line (28.2% doublet CT alone, 38.2% doublet CT + anti-VEGF, 7.3% doublet CT + anti-EGFR). Only 18.5% of patients received a triplet CT (3.1% triplet CT alone, 14.7% triplet CT + anti-VEGF and 0.8% triplet CT + anti-EGFR). Main first-line treatments received were FOLFOX + Bevacizumab, FOLFOX alone and FOLFOXIRI + Bevacizumab (26.6%, 18.9% and 13.1% respectively). The median duration of first-line treatment was 4.86 months and disease progression was the main reason for treatment discontinuation (62.6%). 52.5% of patients received a second line of treatment. Further efficacy and safety data will be presented at the meeting.

Conclusions

Results showed that the majority of BRAF^MT mCRC patients were treated with a doublet CT (with or without TT) as first line. Treatment duration for these patients was short and highlights the aggressive nature of BRAF^MT mCRC. The incidence of MSI patients identified is in line with recent data suggesting approximately 20% of BRAF^MT patients have a high level of MSI.

Clinical trial identification

Editorial acknowledgement

The medical writing was provided by Claire Plantet from Pierre Fabre.

Legal entity responsible for the study

Pierre Fabre.

Funding

Pierre Fabre.

Disclosure

E. Martinelli: Financial Interests, Personal, Invited Speaker: AstraZeneca; Amgen; Bayer; Merck Serono; Roche; Sanofi; Servier; Pierre Fabre; Financial Interests, Personal, Advisory Board: AstraZeneca; Amgen; Bayer; Merck Serono; Roche; Sanofi; Servier; Pierre Fabre; D. Tougeron: Financial Interests, Personal, Advisory Role: BMS; MSD Oncology; Merck Serono. C. Castagné: Financial Interests, Personal, Full or part-time Employment: Pierre Fabre. A. Zkik: Financial Interests, Personal, Full or part-time Employment: Pierre Fabre. S. Khan: Financial Interests, Personal, Full or part-time Employment: Pierre Fabre. D. Arnold: Financial Interests, Personal, Advisory Board: Bayer; BMS; Lilly; Merck (EMD); Sanofi; Servier; Sirtex; Terumo; Roche; Financial Interests, Personal, Invited Speaker: Bayer; Merck (EMD); Roche; Sanofi; Servier; Sirtex; Terumo; Financial Interests, Institutional, Other, investigator and researcher in data-generating activities: Bayer; Mologen; Roche; Symphogen. All other authors have declared no conflicts of interest.