The prevalence RAS and BRAF mutations among patients in the Middle East and Northern Africa with metastatic colorectal cancer.

Abstract

598 Background: Anti-EGFR therapies are recommended for metastatic colorectal cancer (mCRC) patients with confirmed wild-type RAS (exons 2, 3, 4 of KRAS and NRAS) status. There is limited published information on the prevalence of RAS mutations using real world data. The objective of this study was estimate the prevalence of RAS and BRAF mutations among patients with mCRC in the Middle East and Northern Africa (MENA) in an effort to inform the rationale for biomarker testing and treatment choice. Methods: The study included 1,669 patients from August 2013 to July 2015 with mCRC from Algeria, Bahrain, Egypt, Jordan, Kuwait, Lebanon, Libya, Morocco, Oman, Qatar, Saudi Arabia, and the United Arab Emeritus. Information on RAS mutation status was obtained from one pathology lab using High Resolution Melting Analysis. Extended RAS analysis was conducted in a subset of patients, including: overall RAS (exon 2, 3, 4 of KRAS and NRAS; n = 750), KRAS exon 2 (n = 750), KRAS exon 3 and 4 (n = 507), NRAS exon 2, 3, and 4 (n = 507), and BRAF exon 15 (n = 78). The proportion of patients with each mutation was summarized. Results: The overall RAS mutation in the full sample was 35.3% (n = 589/1669). The observed mutation for KRAS exon 2 in a subset of patients with extended RAS analysis (n = 750) was 32.4% (243/750). Out of the subjects with wild-type exon 2 (n = 507), the observed mutations rates were as follows: KRAS exon 4 (20/507 = 3.9%), KRAS exon 3 (13/507 = 2.6%), NRAS exon 2 (7/507 = 1.4%), NRAS exon 3 (6/507 = 1.2%), and NRAS exon 4 (0%). The prevalence of BRAF exon 15 was 3.8% (3/78). The most robust data on specific RAS mutations was obtained from Algeria, Egypt, and Saudi Arabia. The prevalence of KRAS exon 2 mutations in these countries was as follows: Algeria (n = 33/86 = 38.4%), Egypt (n = 83/303 = 27.4%), Saudi Arabia (n = 85/245 = 34.7%). Conclusions: To our knowledge, this is the first study to evaluate the prevalence of RAS and BRAF mutations in the Middle East using real world data. The results of this descriptive study illustrate that there is variation in the prevalence of RAS and BRAF mutations in MENA.