Dynamic nature of BRAF or KRAS p.G12C mutations in second-line therapy for advanced colorectal cancer patients: do early and late effects exist?

INTRODUCTION: The mitogen-activated protein kinase (MAPK) signalling network aberrations in metastatic colorectal cancer (mCRC) generate intrinsic dynamic effects and temporal variations that are crucial but often overlooked in clinical trial populations. Here, we investigate the time-varying impact of MAPK pathway mutation genotype on each treatment line's contribution to the overall clinical course. METHODS: The PROMETEO study focused on mCRC patients undergoing second-line treatment at 20 hospitals. We evaluated genotypes and employed flexible models to analyse the dynamic effect of each mutation. RESULTS: We examined data derived from 1160 patients. The effects of KRAS G12C or G12V, and BRAF V600E are clearly time-varying, with unexpected consequences such as the deleterious effect of BRAF V600E vs other genotypes dissipating over time when subjects receive antiangiogenics, or KRAS G12V and G12C showing increasing aggressiveness over time. Thus, contrary to expectations, the 12-month survival rate from the second line for those who survived >6 months was 49.9% (95% CI, 32.7-67.3) for KRAS G12C and 59% (95% CI, 38.5-80.6) for BRAF V600E. CONCLUSIONS: The dynamic perspective is essential for understanding the behaviour of tumours with specific genotypes, especially from the second line onward. This may be relevant in patient monitoring and treatment decision-making, particularly in cases with distinct mutations.

Efficacy and safety of FOLFIRI/aflibercept in second-line treatment of metastatic colorectal cancer in a real-world population: Prognostic and predictive markers.

PURPOSE: The phase III VELOUR trial demonstrated efficacy with combined FOLFIRI-aflibercept in patients with metastatic colorectal cancer previously treated with oxaliplatin with or without bevacizumab versus placebo. The effect of FOLFIRI-aflibercept in routine clinical practice was evaluated. METHODS/PATIENTS: Overall survival (OS), progression-free survival (PFS), response and safety were analysed for 78 patients treated with FOLFIRI-aflibercept at six GITuD institutions. Exploratory analyses of prognostic and predictive markers of efficacy were performed. RESULTS: Patients had good general status (PS 0-1 96.2%), tumours were mostly RAS-mutant (75.6%), synchronous (71.8%), and left-sided (71.8%). Prior therapy included bevacizumab (47.4%) and anti-EGFR agents (12.8%). PFS was longer for metachronous than synchronous tumours (11.0 vs 5.0 months, P = 0.028), and for left-colon tumours (7.0 vs 3.0 months, P = 0.044). RAS-mutant status, first-line treatment and primary tumour surgery did not impact PFS. The disease control rate was 70.5%. The most common grade 3/4 toxicities were neutropenia (15.3%), asthenia (10.3%), diarrhea and mucositis (6.4% each). Dysphonia was reported in 39.7% of patients, and grade 3 hypertension in 3.8%. Development of hypertension (any grade) was significantly associated with a reduced risk of progression by multivariate analysis (HR = 2.7; 95%CI 1.3-5.4; P = 0.001). CONCLUSIONS: Efficacy with FOLFIRI-aflibercept in a real-life population was in line with results from the pivotal trial and toxicity was manageable with treatment adaptation. Survival outcomes were not impacted by primary tumour location, RAS-mutant status, first-line treatment or primary tumour surgery. Hypertension may be a surrogate marker of efficacy in this patient population.