Prognostic significance of K-Ras mutation rate in metastatic colorectal cancer patients

none24noIntroduction: Activating mutations of K-Ras gene have a well-established role as predictors of resistance to anti-EGFR monoclonal antibodies in metastatic colorectal cancer (mCRC) patients. Their prognostic value is controversial, and no data regarding the prognostic value of mutation rate, defined as the percentage of mutated alleles/ tumor sample, are available. We aimed to evaluate the prognostic value of K-Ras mutation rate in a homogenous cohort of mCRC patients receiving first-line doublet plus bevacizumab. Patients and Methods: This retrospective study enrolled 397 K-Ras mutant mCRC patients from 6 Italian centers, and 263 patients were fully evaluable for our analysis. K-Ras mutation rate was assessed by pyrosequencing. Patients with less than 60% of cancer cells in tumor tissue were excluded. No patients received anti-EGFR containing anticancer therapy, at any time. Median mutation rate was 40% and was adopted as cut-off. The primary and secondary endpoints were PFS and OS respectively. Results: At univariate analysis, K-Ras mutation rate higher than 40% was significantly associated with lower PFS (7.3 vs 9.1 months; P < 0.0001) and OS (21 vs 31 months; P = 0.004). A multivariate model adjusted for age at diagnosis, site of origin of tumor tissue (primary vs metastases), referral center, number of metastatic sites, and first-line chemotherapy backbone, showed that K-Ras mutation rate remained a significant predictor of PFS and OS in the whole population. Discussion: Our data demonstrate an association between K-Ras mutation rate and prognosis in mCRC patients treated with bevacizumab-containing first-line therapy. These data deserve to be verified in an independent validation set.openVincenzi B.; Cremolini C.; Sartore-Bianchi A.; Russo A.; Mannavola F.; Perrone G.; Pantano F.; Loupakis F.; Rossini D.; Ongaro E.; Bonazzina E.; Dell'Aquila E.; Imperatori M.; Zoccoli A.; Bronte G.; Maglio G.D.; Fontanini G.; Natoli C.; Falcone A.; Santini D.; Onetti-Muda A.; Siena S.; Tonini G.; Aprile G.Vincenzi, B.; Cremolini, C.; Sartore-Bianchi, A.; Russo, A.; Mannavola, F.; Perrone, G.; Pantano, F.; Loupakis, F.; Rossini, D.; Ongaro, E.; Bonazzina, E.; Dell'Aquila, E.; Imperatori, M.; Zoccoli, A.; Bronte, G.; Maglio, G. D.; Fontanini, G.; Natoli, C.; Falcone, A.; Santini, D.; Onetti-Muda, A.; Siena, S.; Tonini, G.; Aprile, G

Sensitivity to Entrectinib Associated with a Novel LMNA-NTRK1 Gene Fusion in Metastatic Colorectal Cancer

In metastatic colorectal cancer (CRC), actionable genetic lesions represent potential clinical opportunities. NTRK1, 2, and 3 gene rearrangements encode oncogenic fusions of the tropomyosin-receptor kinase (TRK) family of receptor tyrosine kinases in different tumor types. The TPM3-NTRK1 rearrangement is a recurring event in CRC that renders tumors sensitive to TRKA kinase inhibitors in preclinical models. We identified abnormal expression of the TRKA protein in tumor and liver metastases of a CRC patient refractory to standard therapy. Molecular characterization unveiled a novel LMNA-NTRK1 rearrangement within chromosome 1 with oncogenic potential, and the patient was treated with the pan-TRK inhibitor entrectinib, achieving partial response with decrease in hepatic target lesions from 6.8 and 8.2cm in longest diameter to 4.7 and 4.3cm, respectively. To our knowledge, this is the first clinical evidence of efficacy for therapeutic inhibition of TRKA in a solid tumor, illuminating a genomic-driven strategy to identify CRCs reliant on this oncogene to be clinically targeted with entrectinib

Prognostic significance of KRAS mutation rate in metastatic colorectal cancer patients.

No abstract availabl

Efficacy of Retreatment with Oxaliplatin-Based Regimens in Metastatic Colorectal Cancer Patients: The RETROX-CRC Retrospective Study

Background: oxaliplatin with fluoropyrimidine is a “mainstay” regarding the upfront treatment of metastatic colorectal cancer (mCRC). In contrast, the efficacy and safety of oxaliplatin-based regimens in late-care settings have been poorly reported. Methods: we identified a real-world mCRC patient cohort who were re-treated with oxaliplatin, and in which clinicopathological features were retrospectively analyzed to identify efficacy–predictive determinants (RETROX-CRC study). Results: of 2606 patients, 119 fulfilled the eligibility criteria. Oxaliplatin retreatment response rate (RR) and disease control rate (DCR) were 21.6% (CI 14.4–31.0%), and 57.8% (CI 47.7–67.4). A trend towards better RR and DCR was observed among patients who had first oxaliplatin in an adjuvant setting; a poorer outcome was observed if two or more intervening treatments were delivered. Median progression-free survival (PFS) was 5.1 months (95%CI 4.3–6.1), reducing to 4.0 months (95%CI 3.07–5.13) if oxaliplatin was readministered beyond third-line (HR 2.02; 1.25–3.25; p = 0.004). Safety data were retrieved in 65 patients (54.6%); 18.5% (12/65) and 7.7% (5/65) had G3–4 toxicities. Toxicities led to discontinuation in 34/119 (28.6%). Conclusions: oxaliplatin retreatment produced further RR in around one-fifth of patients and DCR 57.8%. Efficacy decreased in more pre-treated patients and around one-third of patients discontinued treatment due to adverse events. Translational studies improving patient selection are warranted

The Evolutionary Landscape of Treatment for BRAFV600E Mutant Metastatic Colorectal Cancer

The BRAFV600E mutation is found in 8&ndash;10% of metastatic colorectal cancer (mCRC) patients and it is recognized as a poor prognostic factor with a median overall survival inferior to 20 months. At present, besides immune checkpoint inhibitors (CPIs) for those tumors with concomitant MSI-H status, recommended treatment options include cytotoxic chemotherapy + anti-VEGF in the first line setting, and a combination of EGFR and a BRAF inhibitor (cetuximab plus encorafenib) in second line. However, even with the latter targeted approach, acquired resistance limits the possibility of more than an incremental benefit and survival is still dismal. In this review, we discuss current treatment options for this subset of patients and perform a systematic review of ongoing clinical trials. Overall, we identified six emerging strategies: targeting MAPK pathway (monotherapy or combinations), targeting MAPK pathway combined with cytotoxic agents, intensive cytotoxic regimen combinations, targeted agents combined with CPIs, oxidative stress induction, and cytotoxic agents combined with antiangiogenic drugs and CPIs. In the future, the integration of new therapeutic strategies targeting key players in the BRAFV600E oncogenic pathways with current treatment approach based on cytotoxic chemotherapy and surgery is likely to redefine the treatment landscape of these CRC patients