Abstract 3020: Tumor pharmacokinetics of the metastatic cancer inhibitor MBQ-167 in mice

The Rho GTPases Rac and Cdc42 are potential targets against metastatic disease. Our group characterized the small molecule MBQ-167 as an effective dual Rac/Cdc42 inhibitor that reduces HER2 positive and triple negative tumor growth and metastasis in mice by ~90%. To continue validating this drug for FDA approval, we recently elucidated the plasma pharmacokinetics and the tissue distribution of MBQ-167 in mice (Maldonado et al., 2019). However, further studies are needed to characterize the tumor pharmacokinetics of MBQ-167 to determine drug exposure, time-to-peak, and the length of time that MBQ-167 remains in tumors after administration. The purpose of this study was to determine the tumor pharmacokinetics of MBQ-167 in a single dose input scheme (10 mg/kg BW) following intraperitoneal (IP) administration. Thirty-five female BALB/c mice (5 mice/group) were injected with 2.5 × 105 4T1 murine metastatic breast cancer cells at the mammary fat pad. After tumor establishment, a single dose of MBQ-167 (10 mg/kg BW) was administered via IP. Tumors were collected at 0.5, 1, 3, 6, 9,12, and 24 hours following drug administration. We used a validated bioanalytical method using supercritical fluid chromatography coupled with tandem mass spectrometry (SFC-MS/MS) to quantify MBQ-167 in tumors. Pharmacokinetic parameters were obtained by non-compartmental analysis using WinNolin® software. Pharmacokinetic analysis revealed that MBQ-167 has an elimination half-life (t1/2) of 8.64 hours in tumors, which is much longer than its half-life in plasma (2.17 hours), indicating preferential absorption and retention of this lipophilic small molecule in tumor tissues. The area under the curve (AUC0-t) was 4.39 %ID⋅hr/g with a maximum concentration (Cmax) of 1268.9 ng/g in tumors. Moreover, the time-to-peak concentration in tumors was 0.5 hours. Hence, this study supports the continued development of MBQ-167 as a potential anti-cancer therapeutic. Citation Format: Maria Del Mar Maldonado, Ailed M. Cruz-Collazo, Luis D. Borrero-Garcia, Gabriela T. Rosado-Gonzalez, Jean F. Ruiz-Calderon, Jorge Duconge, Suranganie Dharmawardhane. Tumor pharmacokinetics of the metastatic cancer inhibitor MBQ-167 in mice [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3020.