BRAF Inhibitor Encorafenib And Cetuximab Real Life Investigation of Next Generation CRC Treatment

The presence of a BRAFV600E mutation is a marker of poor prognosis in patients with mCRC and associated with a median overall survival (mOS) of approximately 12 to 14 months compared to 20 to 25 months for pa-tients with BRAF wild-type tumors. After 1st line therapy, treatment out-comes with standard therapy are poor in patients with BRAF-mutated mCRC, with response rates (ORR) of ≤ 11%, a median progression-free survival (mPFS) between 1.8 and 2.8 months, and a mOS between 4.1 and 6.2 months.

Failure to achieve adequate survival outcomes with standard treatment regimens in patients with BRAF-mutated mCRC has encouraged efforts to combine multiple targeted therapies: With 665 randomized patients, the BEACON CRC trial represents the largest trial and is currently the only phase III study in patients with BRAFV600E-mutant mCRC. After a safety lead in for dose confirmation of the triplet regimen, the phase III part was per-formed with a total of 665 patients, randomized 1:1:1 to either receive encorafenib plus binimetinib and cetuximab (triplet) or encorafenib plus cetuximab (doublet) or FOLFIRI / IRI plus cetuximab (control).

The BEACON CRC study met its primary endpoints Overall Response Rate (ORR) and Overall Survival (OS) comparing Encorafenib + Binimetinib + Cetuximab vs. Chemotherapy + Cetuximab (ORR: 26 vs. 2%, p<0.001; OS: median 9.0 vs. 5.4 months, HR 0.52, p<0.001). The BEACON CRC study was alpha-controlled also for the secondary endpoint comparing Encorafenib + Cetuximab vs. Chemotherapy + Cetuximab in terms of ORR and OS and showed a statistically significant advantage (ORR: 20 vs. 2%, p<0.001; OS: median 8.4 vs. 5.4 months, HR 0.60, p<0.001). In terms of safety, the overall frequency of adverse events grade 3/4 was 58% (En-corafenib + Binimetinib + Cetuximab) vs. 50% (Encorafenib + Cetuximab) vs. 61% (Chemotherapy + Cetuximab). Analysis of Quality of Life data resulted in a longer maintenance of Quality of Life in the Encorafenib + Binimetinib + Cetuximab arm and the Encorafenib + Cetuximab arm com-pared to Chemotherapy + Cetuximab. Between Encorafenib + Binimetinib + Cetuximab and Encorafenib + Cetuximab, no relevant differences were reported. With a longer Follow-Up (12.8 months) the updated OS data showed a median OS of 9.3 months in both the Encorafenib + Binimetinib + Cetuximab arm and the Encorafenib + Cetuximab arm compared to 5.9 months in the control arm. Updated ORR rates were 27% in the triplet arm (p<0.0001 vs. control), 20% in the doublet arm (p<0.0001 vs. control) and 2% in the control arm. The safety and tolerability were adequate, manage-able and consistent with the known profiles of BRAF-, MEK-, and EGFR-inhibitors. Regarding the triplet combination, the most common adverse events of any grade were diarrhea (triplet: 62%; control: 48%), dermatitis acneiform (triplet: 49%; control: 39%), nausea (triplet: 45%; control: 41%), and vomiting (triplet: 38%; control: 29%). Regarding the doublet combina-tion, the most common adverse events of any grade were nausea (34%), diarrhea (33%), fatigue (doublet 30%; triplet 33%; control 27%) and derma-titis acneiform (29%).

The most common updated grade ≥3 adverse events regarding the triplet combination were diarrhea (triplet: 11%; control: 10%), abdominal pain (triplet: 6%; control: 5%), nausea (triplet: 5%; control: 2%,vomiting (triplet: 5%; control: 3%) and intestinal obstruction (triplet 5%; control 3%). With the doublet regimen, the most common updated grade ≥3 adverse events were intestinal obstruction (doublet 5%), asthenia (doublet 4%; triplet 4%; control 5%), fatigue (doublet 4%; triplet 2%; control 5%), diarrhea (3%) and abdominal pain (3%).

Based on these data, it is expected that the European Medicines Agency (EMA) will approve encorafenib plus cetuximab for the treatment of adult patients with metastatic BRAFV600E-mutant CRC, who have received prior systemic therapy.

Data from pivotal clinical trials are usually based on a selected patient population in order to provide standardized results in the given indication. However, after marketing authorization usage in a broader patient popula-tion is to be expected. Therefore, BERINGCRC - designed as a prospective (allowing initial retrospective documentation), longitudinal, non-interventional study - will investigate the real-world effectiveness, quality of life, safety and tolerability of encorafenib and cetuximab in BRAFV600E-mutant mCRC patients, who have received prior systemic therapy.