Post-Induction Management in Patients With Left-Sided RAS and BRAF Wild-Type Metastatic Colorectal Cancer Treated With First-Line Anti-EGFR-Based Doublet Regimens: A Multicentre Study

Multicenter, single-arm, phase II study of the continuous use of panitumumab in combination with FOLFIRI after FOLFOX for RAS wild-type metastatic colorectal cancer - Exploratory sequential examination of acquired mutations in circulating cell-free DNA

This multicenter single-arm, phase II study evaluated the efficacy and safety of uninterrupted panitumumab usage combined with cytotoxic doublets for unresectable/metastatic colorectal cancer (mCRC). Additionally, clinical value of the RAS/BRAF mutation status in circulating cell-free DNA (ccfDNA) was evaluated; this evaluation was measured independently of the protocol treatment. Eligible patients with RAS wild-type mCRC who had received the first-line panitumumab plus FOLFOX treatment were recruited and administered continuous panitumumab combined with FOLFIRI. Progression-free survival (PFS) at 6 months was the primary endpoint, with threshold and expected values of 35% and 50%, respectively. In total, 54 patients were enrolled between October 2017 and October 2019. The crude 6-month PFS rate was 37.0%, with a 4.8-month median PFS. The response rate and disease control rate were 16.7 % and 50.0%, respectively. Notably, of the 54 participants, 17 showed RAS/BRAF mutations until the end of the protocol treatment, and of the 22 patients with progressive disease as their best response, 10 possessed RAS/BRAF mutations in their plasma ccfDNA at baseline. The median PFS significantly differed among patients harboring tumors with BRAF and RAS mutations and those with wild-type tumors. In conclusion, this study failed to show the expected efficacy of the continuous panitumumab use in the second-line treatment. Liquid biopsy discriminated the duration of PFS according to the mutation status. The effectiveness of continuous treatment with panitumumab should be evaluated in patients with RAS/BRAF wild-type mCRC determined by liquid biopsy at the start of the second-line treatment.

Concurrent RAS and RAS/BRAF V600E Variants in Colorectal Cancer: More Frequent Than Expected? A Case Report

The assessment of RAS and BRAF mutational status is one of the main steps in the diagnostic and therapeutic algorithm of metastatic colorectal cancer (mCRC). Multiple mutations in the BRAF and RAS pathway are described as a rare event, with concurrent variants in KRAS and BRAF genes observed in approximately 0.05% of mCRC cases. Here, we report data from a case series affected by high-risk stage III and stage IV CRC and tested for RAS and BRAF mutation, treated at our Medical Oncology Unit. The analysis of KRAS, NRAS (codons 12, 13, 59, 61, 117, 146), and BRAF (codon 600) hotspot variants was performed in 161 CRC tumors from August 2018 to September 2021 and revealed three (1.8%) patients showing mutations in both KRAS and BRAF (V600E), including two cases with earlier CRC and one with metastatic disease. We also identified one patient (0.6%) with a mutation in both KRAS and NRAS genes and another one (0.6%) with a double KRAS mutation. Notably, the latter was characterized by aggressive behavior and poor clinical outcome. The mutational status, pathological features, and clinical history of these five CRC cases are described. Overall, this study case series adds evidence to the limited available literature concerning both the epidemiological and clinical aspects of CRC cases characterized by the presence of concurrent RAS/BRAF variants. Future multicentric studies will be required to increase the sample size and provide additional value to results observed so far in order to improve clinical management of this subgroup of CRC patients.

The Role of Anti-EGFR Monoclonal Antibody in mCRC Maintenance Therapy

Background: Epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs) combined with chemotherapy in patients with RAS (rat sarcoma viral oncogene homolog) wild-type metastatic colorectal cancer (mCRC) can alleviate and stabilize the disease, effectively prolong the progression-free survival (PFS) and overall survival (OS), and improve the overall response rate (ORR), which is the first-line treatment standard scheme for RAS wild-type mCRC currently. However, whether anti-EGFR mAb can be used for the maintenance treatment after the first-line treatment of mCRC remains controversial. We reviewed the recent studies on anti-EGFR mAb. The contents include five parts, introduction, anti-EGFR mAb in mCRC and its status in first-line therapy, establishment of the maintenance treatment pattern after the standard first-line treatment for mCRC, research progress of anti-EGFR mAb in mCRC maintenance therapy, and conclusion. More studies support the maintenance treatment of anti-EGFR mAb, but some researchers raise the problems about high cost and drug resistance. Despite lack of the maintenance evidence of anti-EGFR mAb, especially lack of large-scale phase III prospective clinical trials, with the emergence of new evidence and more accurate screening of treatment-dominant groups, maintenance therapy with anti-EGFR mAb monotherapy or anti-EGFR mAb combined with fluorouracil-based schemes after first-line chemotherapy combined with anti-EGFR mAb therapy might strive for more treatment opportunities, optimize treatment strategies and prolong treatment continuity, and finally, lead to more survival benefit for suitable patients.

A multicenter study of skin toxicity management in patients with left-sided, RAS/BRAF wild-type metastatic colorectal cancer treated with first-line anti-EGFR-based doublet regimen: is there room for improvement?

BACKGROUND

Skin toxicity in patients affected by metastatic colorectal cancer (mCRC) treated with epidermal growth factor receptor (EGFR) inhibitors is well known. However, ad hoc ESMO guidelines have only recently been published.

AIM AND METHODS

To describe the management (pre-emptive or reactive) of anti-EGFR-related cutaneous adverse events (AEs), in a real-life clinical context, in a selected population of patients with left-sided, metastatic RAS/BRAF wild-type mCRC treated with doublet chemotherapy plus anti-EGFR monoclonal antibody (i.e., panitumumab or cetuximab) as first-line regimen at 22 Institutions. The measured clinical outcomes were treatment-related adverse events, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

RESULTS

Of 515 patients included in the analysis, 173 (33.6%) received a pre-emptive and 342 (66.4%) a reactive treatment. The median follow-up period for the overall population was 30.0 months. A significantly lower incidence of any grade acneiform rash was found in the pre-emptive compared to the reactive cohort both in the overall population (78.6% vs 94.4%, p < 0.001) and in patients treated with panitumumab (76.1% vs 93.7%, p < 0.001) or cetuximab (83.3% vs 95.4%, p = 0.004), respectively. A lower incidence of any grade (41.6% vs 50.9%, p = 0.047) but a higher incidence of G3-G4 (9.2% vs 4.7%, p = 0.042) paronychia/nail disorders were found in the pre-emptive compared to the reactive cohort. Nevertheless, a lower rate of patients within the reactive compared to the pre-emptive cohort was referred to dermatological counseling (21.4% vs 15.3%, respectively, p = 0.001). A higher rate of anti-EGFR therapy modification was needed in the pre-emptive compared to the reactive cohort (35.9% vs 41.6%, respectively, p < 0.001). The pre-emptive approach did not reduce the efficacy of antineoplastic therapy compared to the reactive in terms of ORR (69.2% vs 72.8%), median PFS (12.3 vs 13.0 months), and median OS (28.8 vs 33.5 months).

CONCLUSION

Although recommended by international guidelines, the pre-emptive approach of anti-EGFR-related skin toxicity in mCRC patients still appears less adopted in daily clinical practice, compared to the reactive one. A wider reception and application of this indication is desirable to improve patients' quality of life without compromising the continuity and efficacy of antineoplastic therapy.