Avutometinib (Ro 5126766) is a first-in-class dual MEK/RAF inhibitor that allosterically inhibits BRAF^V600E, CRAF, MEK, and BRAF (IC₅₀: 8.2, 56, 160 nM, and 190 nM, respectively).

Avutometinib (Ro 5126766) is an allosteric inhibitor that binds directly to MEK and prevents its phosphorylation by RAF through the formation of a stable RAF-MEK complex. Ro 5126766 inhibits both the phosphorylation of MEK by RAF and the activation of ERK by MEK. In cell-free MEK and RAF kinase assays, Avutometinib effectively inhibits activation of ERK2 by MEK1 with an IC₅₀ of 160 nM (SD=±0.043) and inhibits the phosphorylation of MEK1 protein by BRAF (IC₅₀=190 nM, SD=±0.003), BRAF^V600E (IC₅₀=8.2 nM, SD=±0.0015), and CRAF (IC₅₀=56 nM, SD=±0.016). Avutometinib effectively inhibits both MEK and ERK phosphorylation in a panel of human tumor cell lines including KRAS/HRAS and BRAF mutant cell lines and KRAS/HRAS and BRAF wild-type cells. In order to investigate whether the mevalonate pathway affects the sensitivity to MEK inhibitors, human breast cancer MDA-MB-231 cells harboring KRAS and BRAF mutations are treated Avutometinib, with or without statins, which inhibits HMG-CoA reductase, the rate-limiting enzyme in the mevalonate pathway. The combined treatment of Avutometinib with XU 62-320 demonstrates more significant reduction in cell growth in a dose-dependent manner than the single treatment of Avutometinib. The marked combined effects of Avutometinib at 40 nM and XU 62-320 at 0.3 μM is also confirmed on the suppression of the colony formation of the cells.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

In KRAS-mutant xenograft models, Avutometinib (Ro 5126766) inhibits growth and causes tumor regressions more effectively than another allosteric MEK inhibitor, PD0325901. Preclinical data from a series of human tumor mouse xenograft models indicates an ED₅₀ for Ro 5126766 of 0.03 to 0.23 mg/kg and an ED₉₀ of 0.15 to 1.56 mg/kg. These effective doses are associated with target trough concentrations of 17 to 133 ng/L and 87 to 901 ng/mL, respectively. . In this experiment, Avutometinib or PD0325901 is administrated at their maximum tolerated dose (MTD) in the HCT116 model (1.5 and 25 mg/kg, respectively). These doses inhibit pERK and ERK signaling output at similar degrees in the tumors from the drug-treated mice at 4 hours from the first drug administration. Moreover, in HCT116 models, the ED₅₀ for Avutometinib and PD0325901 are 0.056 and 0.80 mg/kg, respectively. Therefore, the doses used for this experiment are 26.8- and 31.3-fold higher doses than the 50% effective doses, respectively. Daily oral administration of either drug causes significant tumor regression of each these tumors. However, whereas inhibition of tumor growth is maintained for the entire 28-day treatment period in Avutometinib-treated mice, tumor models receiving PD0325901 become refractory after 10 days of treatment.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

In KRAS-mutant xenograft models, Avutometinib (Ro 5126766) inhibits growth and causes tumor regressions more effectively than another allosteric MEK inhibitor, PD0325901. Preclinical data from a series of human tumor mouse xenograft models indicates an ED₅₀ for Ro 5126766 of 0.03 to 0.23 mg/kg and an ED₉₀ of 0.15 to 1.56 mg/kg. These effective doses are associated with target trough concentrations of 17 to 133 ng/L and 87 to 901 ng/mL, respectively. . In this experiment, Avutometinib or PD0325901 is administrated at their maximum tolerated dose (MTD) in the HCT116 model (1.5 and 25 mg/kg, respectively). These doses inhibit pERK and ERK signaling output at similar degrees in the tumors from the drug-treated mice at 4 hours from the first drug administration. Moreover, in HCT116 models, the ED₅₀ for Avutometinib and PD0325901 are 0.056 and 0.80 mg/kg, respectively. Therefore, the doses used for this experiment are 26.8- and 31.3-fold higher doses than the 50% effective doses, respectively. Daily oral administration of either drug causes significant tumor regression of each these tumors. However, whereas inhibition of tumor growth is maintained for the entire 28-day treatment period in Avutometinib-treated mice, tumor models receiving PD0325901 become refractory after 10 days of treatment.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

• . Martinez-Garcia M, et al. First-in-human, phase I dose-escalation study of the safety, pharmacokinetics, and pharmacodynamics of RO5126766, a first-in-class dual MEK/RAF inhibitor in patients with solid tumors. Clin Cancer Res. 2012 Sep 1;18(17):4806-19.  [Content Brief]

  . Iizuka-Ohashi M, et al. Blockage of the mevalonate pathway overcomes the apoptotic resistance to MEK inhibitors with suppressing the activation of Akt in cancer cells. Oncotarget. 2018 Apr 13;9(28):19597-19612.  [Content Brief]

  . Ishii N, et al. Enhanced inhibition of ERK signaling by a novel allosteric MEK inhibitor, CH5126766, that suppresses feedback reactivation of RAF activity. Cancer Res. 2013 Jul 1;73(13):4050-4060.  [Content Brief]