448P - Efficacy of combinations of BRAF inhibitors and anti-EGFR antibodies in metastatic colorectal carcinoma (mCRC) patients with mBRAF in the real clinical practice

Background

Combination of BRAF inhibitors and anti-EGFR antibodies is a standard of 2^nd and subsequent line of treatment in pts with mBRAF mCRC. We performed analysis of prospective multicentric database of pts with mBRAF metastatic CRC to evaluate the efficacy of such approach in the real clinical practice.

Methods

We analyzed a database of pts with mCRC in 7 cancer clinics in Russia and chose pts with 2^nd and subsequent lines. The primary endpoints were progression free survival (PFS) and overall survival (OS), which were calculated from the time of starting systemic treatment. Analysis was performed with the SPSS v.20 software package.

Results

The study included 73 pts with mBRAF. All pts had V600 mutations; female - 70%, average age - 69 years (20-79), MSI-H -10%; the right-sided primary tumor – 53%; the primary tumor was removed in 81%, adjuvant chemotherapy was administered in 32%; lung metastases – in 29%, liver - 53%, peritoneal metastases – in 44%; metastasectomy was performed in 22% pts. The first line was FOLFOXIRI in 19%. BRAF inhibitors and anti-EGFR were administered in 30 pts (42%): in the 2^nd line – 18 (60%), 3^rd line – 7 (23%), 4-5^th lines – 5 (17%). Chemotherapy was administered in the 2^nd line in 43 (58%) pts: with bevacizumab or aflibercept in 52%. In pts with BRAF inhibitors and anti-EGFR treatment ORR was 27%, with 7% CR, disease control rate was 60%, median PFS was 4 months (95% CI 1,2-6,8), and OS – 11 months (95% CI 8,5-13,4). There were no statistical differences between chemotherapy group and combinations of BRAF inhibitors and anti-EGFR treatment in 2^nd line neither in PFS (HR 1,3, 95% CI 0,7-2,5, p=0,4) or OS (R 1,4, 95% CI 0,52-4,0, p=0,5)

Conclusions

treatment with BRAF inhibitors and anti-EGFR antibodies shows the same efficacy as in BEACON study in pts with mutant BRAF mCRC in real clinical practice. However, there were no survival benefit in comparison with another systemic treatment in the 2^nd line, this suggests we need a prospective randomized study to compare BRAF inhibitors combinations and chemotherapy with anti-VEGF agents in the 2nd line of treatment.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.