Retrospective Analysis of Treatment Pathways in Patients With BRAF^V600E-mutant Metastatic Colorectal Carcinoma -...

Metastatic colorectal cancer (mCRC) is a heterogeneous disease with distinct molecular subtypes. The BRAF^V600E-mutation found in approximately 8-12% of mCRC patients is associated with poor prognosis. Guideline recommendations for this population are mostly based on small cohorts due to lack of clinical data. This retrospective analysis was designed to evaluate (approved) therapeutic approaches and algorithms in BRAF^V600E-mutant mCRC prior to approval of the targeted combination encorafenib plus cetuximab in Germany, Austria, and Switzerland.

Anonymized data from BRAF^V600E-mutant mCRC patients were analyzed retrospectively regarding 1^st-, 2^nd- and 3^rd-line treatment using descriptive statistics.

Forty-two patients were eligible for analysis (mean age 62.1 years, 47.6% female). At initial diagnosis, 20 patients (47.6%) were documented with right-sided tumors. Most patients (81.0%) were tested for BRAF before 1^st-line. Four patients (9.5%) showed high microsatellite instability (MSI-H). Based on 94 treatment lines, chemotherapy combined with targeted therapy (TT) was used mostly (61.7%), followed by chemotherapy alone (19.1%). Backbone therapies were most frequently FOLFOXIRI (27.7%), FOLFOX/CAPOX (22.3%), or FOLFIRI (20.2%). Anti-VEGF/VEGFR and anti-EGFR-treatments were used in 45.7% and 23.4% of patients, respectively. Across all treatment lines and types, the predominantly documented reason for discontinuation was lack of efficacy.

Combined chemotherapy+TT (anti-VEGF/VEGFR and anti-EGFR) played a predominant role in BRAF^V600E-mutated mCRC treatment prior to approval of the targeted combination encorafenib plus cetuximab. Since lack of efficacy was the major reason for treatment discontinuation, newly approved therapies including encorafenib plus cetuximab and - for MSI-H tumors - pembrolizumab represent urgently needed options for future mCRC patients.