levoleucovorin and encorafenib

Encorafenib + cetuximab (E+C) is an effective therapeutic option in chemorefractory BRAFV600E metastatic colorectal cancer (mCRC). However, there is a need to improve the efficacy of this molecular-targeted therapy and evaluate regimens suitable for untreated BRAFV600E in patients with mCRC.. We performed a series of in vivo studies using BRAFV600E mCRC tumor xenografts. Mice were randomized to receive 5-fluoruracil (5-FU), irinotecan, or oxaliplatin regimens (FOLFIRI or FOLFOX), (E+C) or the combination. Patients received long-term treatment until disease progression, with deescalation strategies used to mimic maintenance therapy. Transcriptomic changes after progression on cytotoxic chemotherapy or targeted therapy were assessed.. Antitumor activity of either FOLFIRI or E+C was better as first-line treatment as compared with second-line, with partial cross-resistance seen between a cytotoxic regimen and targeted therapy with an average 62% loss of efficacy for FOLFIRI after E+C and a 45% loss of efficacy of E+C after FOLFIRI (P < 0.001 for both). FOLFIRI-treated models had upregulation of epithelial-mesenchymal transition (EMT) and MAPK pathway activation, where E+C treated models had suppressed MAPK signaling. In contrast, with chemotherapy with E+C, EMT and MAPK signaling remained suppressed. FOLFOX or FOLFIRI, each in combination with E+C, were the most active first-line treatments as compared with E+C or to chemotherapy alone. Furthermore, FOLFOX in combination with E+C as first-line induction therapy, followed by E+C ± 5-FU as maintenance therapy, was the most effective strategy for long-term disease control.. These results support the combination of cytotoxic chemotherapy and molecular-targeted therapy as a promising therapeutic approach in the first-line treatment of BRAFV600E mCRC.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Camptothecin; Cetuximab; Colonic Neoplasms; Colorectal Neoplasms; Fluorouracil; Humans; Leucovorin; Mice; Xenograft Model Antitumor Assays

The BEACON trial showed that combination therapy with encorafenib (BRAF inhibitor) and cetuximab (EGFR inhibitor) was associated with prolonged overall survival compared with standard chemotherapy in patients with metastatic BRAF variant colorectal cancer. However, the cost-effectiveness of using these agents in this clinical setting is unknown.. To create a cost-effectiveness model to compare doublet therapy (encorafenib plus cetuximab) with standard chemotherapy (cetuximab plus irinotecan or cetuximab plus folinic acid, fluorouracil, and irinotecan) in treating patients with metastatic BRAF variant colorectal cancer.. This economic evaluation constructed a Markov model to compare the lifetime cost and utility of doublet therapy and standard chemotherapy. Parametric survival modeling was used to extrapolate the effectiveness of each line of therapy from large clinical trials. One-way and probabilistic sensitivity analyses assessed the uncertainty in the model. Patients mirrored the cohorts in the BEACON trial: they had metastatic BRAF variant colorectal cancer and were followed up as they progressed through multiple lines of therapy, best supportive care, and death. Data collection and data analysis were performed from November 15, 2019, to July 14, 2020.. The main outcome was the incremental cost-effectiveness ratio, which was calculated using the cumulative cost and effectiveness in quality-adjusted life years (QALYs), of doublet therapy compared with standard chemotherapy.. The model patient cohort had a mean age of 61 years, and 53% of the patients were women, 66% had 1 previous line of therapy, and 8% had high microsatellite instability. Doublet therapy was associated with an improvement of 0.15 QALYs compared with standard chemotherapy. However, the incremental cost of doublet therapy was $78 233, leading to an incremental cost-effectiveness ratio of $523 374 per QALY gained. Concomitant decreases in the price of encorafenib and cetuximab are needed to achieve cost-effectiveness at a willingness-to-pay threshold of $150 000 per QALY gained.. This study found that doublet therapy for metastatic BRAF variant colorectal cancer was unlikely to be cost-effective under current pricing. Cost-effectiveness needs to be considered in clinical trial design, particularly when combining new therapies with non-cost-effective treatments that are coadministered without a fixed duration.

Topics: Antineoplastic Combined Chemotherapy Protocols; Carbamates; Cetuximab; Colorectal Neoplasms; Cost-Benefit Analysis; Female; Fluorouracil; Humans; Irinotecan; Leucovorin; Male; Markov Chains; Middle Aged; Neoplasm Metastasis; Proto-Oncogene Proteins B-raf; Quality-Adjusted Life Years; Sulfonamides