Atovaquone demonstrates in vivo antitumor activity in a murine model of multiple myeloma. (A) Following establishment of U266 tumor xenografts, mice were treated orally with vehicle (N = 7), atovaquone (N = 6), or brand-name Mepron suspension (N = 7). Tumor volume was assessed 3 times per week. Data are means ± standard error, and P values represent comparisons of atovaquone and Mepron to vehicle by 2-tailed Wilcoxon rank-sum test. ^#P < .10; *P < .05; **P < .01. (B) Kaplan-Meier survival plot of the mice described for panel A. P values comparing atovaquone or Mepron survival curves to that of vehicle were computed by 2-tailed log-rank test.