BRAF codons 594 and 596 mutations identify a new molecular subtype of metastatic colorectal cancer at favorable prognosis.

BACKGROUND: While the negative prognostic role of BRAF V600E mutation in metastatic colorectal cancer (mCRC) is well established, the impact of BRAF codons 594 and 596 mutations, occurring in <1% of CRCs, is completely unknown. The present work aims to describe clinical, pathological and molecular features and prognosis of BRAF codons 594 and 596 mutant mCRCs, compared with BRAF V600E mutant and wild-type ones. PATIENTS AND METHODS: Patients treated for mCRC at three Italian Institutions between October 2006 and October 2014, with available KRAS and NRAS codon 12, 13, 59, 61, 117 and 146 and BRAF codon 594, 596 and 600 mutational status, as detected by means of direct sequencing or matrix assisted laser desorption ionization time-of-flight MassArray, were included. RESULTS: Ten patients bearing BRAF codons 594 or 596 mutated tumors were identified and compared with 77 and 542 patients bearing BRAF V600E mutated and BRAF wild-type tumors, respectively. While BRAF V600E mutated tumors were more frequently right-sided, mucinous and with peritoneal spread, BRAF 594 or 596 mutated were more frequently rectal, nonmucinous and with no peritoneal spread. All BRAF 594 or 596 mutated tumors were microsatellite stable. Patients with BRAF codons 594 or 596 mutated tumors had markedly longer overall survival (OS) when compared with BRAF V600E mutated [median OS: 62.0 versus 12.6 months; hazard ratio: 0.36 (95% confidence interval 0.20-0.64), P = 0.002], both at univariate and multivariate analyses. CONCLUSIONS: BRAF codon 594 or 596 mutated mCRCs are different from BRAF V600E ones in terms of molecular features, pathological characteristics and clinical outcome. This is consistent with preclinical evidences of a kinase inactivating effect of these mutations. The role of CRAF in transducing the intracellular signal downstream BRAF 594 or 596 mutated proteins opens the way to further preclinical investigation.

Value of KRAS as prognostic or predictive marker in NSCLC: results from the TAILOR trial.

BACKGROUND: The prognostic and predictive role of KRAS mutations in advanced nonsmall-cell lung cancer (NSCLC) is still unclear. TAILOR prospectively assessed the prognostic and predictive value of KRAS mutations in NSCLC patients treated with erlotinib or docetaxel in second line. PATIENTS AND METHODS: NSCLC patients from 52 Italian hospitals were genotyped for KRAS and EGFR mutational status in two independent laboratories. Wild-type EGFR patients (N = 218) received first-line platinum-based chemotherapy and were randomly allocated at progression to erlotinib or docetaxel. Overall survival (OS) according to KRAS mutational status was the primary end point. RESULTS: KRAS mutations were present in 23% of TAILOR randomized cases. The presence of a KRAS mutation did not adversely affect progression-free (PFS) or overall (OS) survival [hazard ratio (HR) PFS = 1.01, 95% confidence interval (CI) 0.71-1.41, P = 0.977; OS = 1.24, 95% CI 0.87-1.77, P = 0.233], nor influenced treatment outcome (test for interaction: OS P = 0.965; PFS P = 0.417). Patients randomized to docetaxel treatment experienced longer survival independently from the KRAS mutational status of their tumors (HR: mutated KRAS 0.81, 95% CI 0.45-1.47; wild-type KRAS 0.79, 95% CI 0.57-1.10). CONCLUSION: In TAILOR, KRAS was neither prognostic nor predictive of benefit for either docetaxel or erlotinib. Docetaxel remains superior independently from KRAS status for second-line treatment in EGFR wild-type advanced NSCLC patients. CLINICAL TRIAL REGISTRATION: NCT00637910.

Activity of osimeRTInib in non-small-cell lung Cancer with UNcommon epidermal growth factor receptor mutations: retrospective Observational multicenter study (ARTICUNO).

BACKGROUND: Osimertinib represents the standard of care for the treatment of advanced non-small-cell lung cancer (NSCLC) harboring classical epidermal growth factor receptor (EGFR) mutations, constituting 80%-90% of all EGFR alterations. In the remaining cases, an assorted group of uncommon alterations of EGFR (uEGFR) can be detected, which confer variable sensitivity to previous generations of EGFR inhibitors, overall with lower therapeutic activity. Data on osimertinib in this setting are limited and strongly warranted. PATIENTS AND METHODS: The ARTICUNO study retrospectively evaluated data on osimertinib activity from patients with advanced NSCLC harboring uEGFR treated in 21 clinical centers between August 2017 and March 2023. Data analysis was carried out with a descriptive aim. Investigators collected response data according to RECIST version 1.1 criteria. The median duration of response, progression-free survival (mPFS), and overall survival were estimated by the Kaplan-Meier method. RESULTS: Eighty-six patients harboring uEGFR and treated with osimertinib were identified. Patients with 'major' uEGFR, that is, G719X, L861X, and S768I mutations (n = 51), had an overall response rate (ORR) and mPFS of 50% and 9 months, respectively. Variable outcomes were registered in cases with rarer 'minor' mutations (n = 27), with ORR and mPFS of 31% and 4 months, respectively. Among seven patients with exon 20 insertions, ORR was 14%, while the best outcome was registered among patients with compound mutations including at least one classical EGFR mutation (n = 13). Thirty patients presented brain metastases (BMs) and intracranial ORR and mPFS were 58% and 9 months, respectively. Amplification of EGFR or MET, TP53 mutations, and EGFR E709K emerged after osimertinib failure in a dataset of 18 patients with available rebiopsy. CONCLUSION: The ARTICUNO study confirms the activity of osimertinib in patients with uEGFR, especially in those with compound uncommon-common mutations, or major uEGFR, even in the presence of BMs. Alterations at the E709 residue of EGFR are associated with resistance to osimertinib.