Fig. 6. Sequential ipafricept followed by paclitaxel reduces the paclitaxel resistant CSC population.

(A) OMP-OV40 was treated with ipafricept (45 mg/kg on days 1, 15, and 29) for three cycles total and/or with paclitaxel (15 mg/kg on days 5, 12, 19, 32, and 39). Thirteen days after the last ipafricept dose and 3 days after the last paclitaxel dose, tumors were processed into single cells for tumorigenicity study. *P < 0.01; **P < 0.001 combination versus chemotherapy. Data are means + SEM; n = 9 per group. (B) For the tumorigenicity study, tumors were collected from four mice per treatment group, as shown in (A), and these four tumors were mixed together to prepare the cells for the limiting dose serial transplantation assay in (B). Tumor cells were injected into recipient mice at two cell doses, 100 and 1000 cells (n = 9 to 10 mice per cell dose). The number of tumors that grew to more than 100 mm³ by day 78 after injection was used to calculate the CSC frequency. Data are means + SEM; ^‡P < 0.01, significant to control.