Figure 8. Combination antitumor activity of PLX4720/anti-CD137 against de novo BRAF^V600E-driven mouse melanomas.

Groups of Braf^V600E transgenic mice (n = 6–7) were induced for localized melanoma by 4-HT application on day 0. Mice received vehicle or PLX4720 (20 mg/kg i.p.) daily from day 28 to 49. Some groups of mice additionally received cIg or anti-CD137 (100 μg i.p.) on days 28, 32, 36, 40, 44, and 48. (A) At the indicated time, tumor sizes (height; mm) were recorded and represented as the mean ± SEM. Statistical differences in tumor sizes between different groups of mice were determined by a Mann-Whitney test (**P < 0.01; ^#P < 0.0001). (B) At day 49, tumors were excised and weighed. Statistical differences in tumor weights between different groups of mice were determined by a Mann-Whitney test (*P < 0.05, PLX4720 and clg compared with vehicle and anti-CD137; ^#P < 0.001, vehicle and clg compared with PLX4720 and clg [P = 0.0004] or PLX4720 and anti-CD137 [P = 0.0001] and vehicle and anti-CD137 compared with PLX4720 and anti-CD137 [P = 0.0008]). Data shown are pooled from 2 independent experiments. Individual symbols represent individual tumors; horizontal bars indicate the mean.