784210-88-4

Dose-finding studies with RGB-286638 identify 40 mg/kg/day IV treatment as the maximum tolerated dose in SCID mice. Five days IV treatment with RGB-286638 significantly suppresses MM tumor growth, with maximum TGI (%) noted at day 14 following end of treatment at 85.06% and 86.34% in the 30 mg/kg and 40 mg/kg treated cohorts respectively. The log10 cell kill (LCK Td: 4.5 days) is 1.6 for both treated groups. RGB-286638 treatment is also associated with improved survival, evidenced by first death at day 24 in controls versus day 43 in both treated groups. No toxic deaths occurred during this study: maximum percentage of body weight (BW) loss is observed on day 5 (8.4%) at 30 mg/kg dosage schedule, and on day 15 (9.9%) after 40 mg/kg dosing, with weight recovery in the following two weeks^[1].