LBA-5 ANCHOR CRC: a single-arm, phase 2 study of encorafenib, binimetinib plus cetuximab in previously untreated BRAF V600E-mutant metastatic colorectal cancer
Grothey, A.;Tabernero, J.;Taieb, J.;Yaeger, R.;Cutsem, E. Van;et.al.
Background BRAFV600E mutations are identified in 8-15% of metastatic colorectal cancer (mCRC) patients and confer a poor prognosis. In patients with BRAFV600E-mutant mCRC, the combination of encorafenib (ENCO) + cetuximab (CETUX) ± binimetinib (BINI) in second- and third-line therapy has demonstrated improved outcomes compared to standard therapies (BEACON CRC study). The ANCHOR CRC study was designed to investigate the triplet combination (ENCO + BINI + CETUX) in the first line setting of this population. Methods ANCHOR CRC is an open-label, single arm, two-stage design, phase 2 study in patients with BRAFV600E-mutant mCRC who did not receive any prior systemic therapy for metastatic disease. Patients received ENCO 300 mg orally QD + BINI 45 mg orally BID and CETUX IV weekly (250mg/m2 after a first dose of 400mg/m2) for the first 28 weeks and then once every two weeks (500mg/m2). The primary endpoint was confirmed Objective Response Rate (cORR) based on local review; secondary endpoints included duration of response (DOR), progression-free survival (PFS), overall survival (OS) and safety. Analysis for Stage 1 was performed after the first 40 evaluable patients with a centrally confirmed BRAFV600E mutation had completed four post-baseline tumor assessments or discontinued. At least 12 responses in Stage 1 were needed to initiate Stage 2 and to enroll 50 additional patients to complete the recruitment with a total of 90 patients in the study. Stage 1 analysis results are presented here. Results Forty-one BRAFV600E-mutant mCRC patients with a median age of 67 years old (61% of the patients were ≥ 65 years old) were enrolled in Stage 1 and received the triplet combination as first line metastatic treatment. At study entry, 56% of patients presented with ECOG PS 1, 78% had metastases to at least 2 organs and 51% had peritoneal metastasis. Forty patients were evaluable for efficacy (BRAFV600E mutation was not centrally confirmed for one patient). The investigator assessed cORR was 50% (95% confidence interval [CI], 33.8-66.2) with 85% of patients having a decrease in tumor size. The investigator measured median PFS was 4.9 months (95% CI, 4.4-8.1). Adverse events were consistent with those observed in prior studies with this triplet combination. Grade 3 or higher adverse events were seen in 68% of patients, the most common being: diarrhea (15%), acute kidney injury (12%) and anemia (12%). Conclusion The ANCHOR CRC study is the first prospective study using a BRAF inhibitor-based therapy in first line BRAFV600E-mutant mCRC. Despite the high risk features of the population enrolled in Stage 1, including high proportion of patients ≥ 65 years old and advanced stage at diagnosis (multiple metastatic sites with frequent peritoneal carcinomatosis), most patients had tumor regression. The safety profile was acceptable and toxicities remained manageable. The Stage 1 analysis exceeded the minimal number of confirmed responses and proceeded to enroll 54 additional patients in Stage 2 to complete the study recruitment.
Grothey, A., Tabernero, J., Taieb, J., Yaeger, R., Yoshino, T., Maiello, E., Fernandez, E. E., Casado, A. R., Ross, P., André, T., Kato, T., Ruffinelli, J., Graham, J., Van den Eynde, M., Vera, R., Jean, B., Roussel, E. C., Cahuzac, C., Issiakhem, Z., et al. (2020). LBA-5 ANCHOR CRC: a single-arm, phase 2 study of encorafenib, binimetinib plus cetuximab in previously untreated BRAF V600E-mutant metastatic colorectal cancer. Annals of Oncology, 31(3), S242-S243. https://doi.org/10.1016/j.annonc.2020.04.080 (Original work published 2020)