URMC-099 exhibits a moderate terminal elimination half-life (t1/2=1.92 h, 2.14 h and 2.72 h for C57 BL/6 mice (10 mg/kg, oral dosing), C57 BL/6 mice (2.5 mg/kg, iv), C57 BL/6 mice (10 mg/kg, iv))^[1].

URMC-099 (URMC099) is evaluated for its impact on tumor formation in vivo using a well-established mouse xenograft model of breast cancer brain metastasis. In this study, eGFP8.4 cells are injected into the left ventricle of immunodeficient nu/nu mice, followed by treatment with either URMC-099 (10 mg/kg) or vehicle alone every 12 hours for 20 days. This dosage is selected based on its demonstrated efficacy in inhibiting MLK3 in mice, penetrating the blood-brain barrier effectively, and potently inhibiting phosphorylation of Jun N-terminal kinase (JNK) in brain tissue. Then, mice are euthanized, and the number of brain metastases (BM) is quantified. Each treatment group comprises fifteen mice. Brain metastases are detected in 60% of mice, consistent with previous findings using this xenograft model. Notably, URMC-099 treatment significantly increases the total number of brain metastases in mice (p<0.05, two-tailed t-test). A similar trend is observed for micrometastases, while the number of macrometastases remains statistically comparable between mice treated with URMC-099 and those given vehicle alone^[2].

The impact of URMC-099 (URMC099) on the in vitro proliferation of "brain homing" MDA-MB-231 BR cells expressing eGFP (eGFP8.4) and their parental cell line, MDA-MB-231, is assessed. Both cell groups are exposed to either 200 nM URMC-099 or vehicle alone. Cells treated with URMC-099 exhibit comparable growth rates to those treated with the vehicle. Cell viability exceeds 99% in all instances^[2].