Figure 6

Tumor growth delay is extended signficantly in niraparib + irinotecan combination treatment groups as compared to treatment with irinotecan alone. (Data from this figure is from the same experiment as in Figures 4 and 5, but has been separated for ease of viewing). Tumor growth delay and relapse after the withdrawal of niraparib and irinotecan treatment in the (A) HCT116 (MSI) and (B) HT29 xenograft models. Niraparib was dosed at 50, 25, or 10 mpk p.o. q.d., for 5 days and irinotecan was administered at 100 mpk i.p. on the 3rd day of every week for 4 weeks. After the 4^th week of dosing of both drugs, treatment was stopped and tumor growth was monitored bi-weekly until the average tumor volume for each group reached to an end-point of 1000 mm³. Relative tumor size (% versus Day 0) is shown with SEM in error bars. For each group, n = 7-10. (A) The average tumor volume for the 50, 25, and 10 mpk niraparib + irinotecan combination groups in the HCT116 model were significantly different from the irinotecan single agent group at day 70 when the average tumor size in the irinotecan single agent group reached the end-point of 1000 mm³ with P-values of .02, .02, and .03, respectively. (P value generated using a homoscedastic Student’s t-test.) (B) The average tumor volume for the 50, 25, and 10 mpk niraparib + irinotecan combination groups in the HT29 model were significantly different from the irinotecan single agent group at day 49 when the average tumor size in the irinotecan single agent group reached the end-point of 1000 mm³ with P-values of .05, .03, and .03, respectively. (P value generated using a homoscedastic Student’s t-test).