Improvement of survival in a murine melanoma model. (A) Treatment of B16 melanoma-bearing mice (n = 12–15 mice/group) with sunitinib, carboplatin, or vehicle was started when the average tumor size reached 0.4 cm³. Survivals of mice were closely monitored several times per day. (B) Tumor growth rates of sunitinib-, carboplatin-, or vehicle-treated groups (n = 12–15 mice/group). (C) When the average tumor size reached 0.4 cm³, tumor-bearing mice (n = 12–15 mice/group) were treated with sunitinib. At day 6 after treatment, sunitinib-treated mice received carboplatin or carboplatin plus sunitinib until the end of experiments. Vehicle-pretreated group followed by carboplatin was used as a control. (D) Kaplan–Meier survival curve of various treated groups under the regimen described in C. Dashed line marks pretreatment endpoint. (E and F) BM histology of various treated groups described in A–D. Dashed lines enclose bone matrix. (Bar = 100 μm.) (G) Quantification of density of BM cells (20× magnification, eight randomized fields per group). (H–J) RBC (H), hemoglobin (I), and WBC (J) in peripheral blood. *P < 0.05, **P < 0.01, ***P < 0.001. Data are shown as mean ± SEM.

Treatment of VEGF- or vector-T241 tumors with chemotherapeutic drugs. (A) Kaplan–Meier survival curve of carboplatin-treated VEGF-T241 and vector-T241 tumor-bearing mice (n = 8–10 mice/group). Carboplatin exhibited a marked lethal effect on VEGF-tumor bearing mice. (B) Kaplan–Meier survival curve of CTX-treated VEGF-T241 and vector-T241 tumor-bearing mice (n = 8–10 mice/group). (C) BM histology of carboplatin-, CTX-treated, and vehicle-treated groups described in A and B. Dashed lines encircle bone matrix. Arrowheads point to the residue hematopoietic islets attached to the bone matrix. (Bar = 50 μm.) (D) Quantification of density of BM cells (20× magnification, eight randomized fields per group). (E–G) RBC (E), hemoglobin (F), and WBC (G) in peripheral blood. *P < 0.05, **P < 0.01, ***P < 0.001. Data are shown as mean ± SEM.

Survival improvement by sequential treatment of T241 tumor-bearing mice with sunitinib followed by CTX. (A) Kaplan–Meier survival curve of VEGF-T241 tumor-bearing mice (n = 8–10 mice/group) that received sequential therapy of sunitinib followed by CTX or by a combination. Simultaneous delivery of both drugs and sunitinib followed by vehicle was used as control. (B) Quantification of density of BM cells (20× magnification, eight randomized fields per group). (C) BM histology of various treated groups described in A. Dashed lines enclose bone matrix. Arrowheads point to residual hematopoietic islets attached to bone matrix. (Bar, 100 μm.) **P < 0.01. Data are shown as mean ± SEM.

Tumor growth rate and survival of sunitinib-treated or nontreated VEGF or vector-transfected T241 fibrosarcoma. (A) Growth rates of VEGF-T241 and vector tumors. (B) Kaplan–Meier survival curve of VEGF-T241 and vector-T241 tumor-bearing mice (n = 8–10 mice/group). (C) Growth rates of sunitinib-treated VEGF-T241 and vector tumors. (D) Kaplan–Meier survival curve of sunitinib-treated VEGF-T241 and vector-T241 tumor-bearing mice (n = 8–10 mice/group). (E) BM histology of sunitinib-treated and nontreated groups described in A–D. Dashed lines enclose bone matrix. Arrowheads point to residual hematopoietic islets attached to bone matrix. (Bar = 50 μm.) (F) Quantification of density of BM cells (20× magnification, eight randomized fields per group). (G–I) RBC (G), hemoglobin (H), and WBC (I) in peripheral blood. Blue bars represent tumor-free, black bars represent non-treated, and red bars represent sunitinib-treated. *P < 0.05, ***P < 0.001. Data are shown as mean ± SEM.

Sequential treatment of T241 tumor-bearing mice with sunitinib followed by carboplatin significantly improves survival. (A) Kaplan–Meier survival curve of VEGF-T241 tumor-bearing mice (n = 8–10 mice/group) that received sequential therapy of sunitinib followed by carboplatin or by combination. Simultaneous delivery of both drugs and sunitinib followed by vehicle were used as controls. Sequential regimen of delivery sunitinib followed carboplatin markedly improved survival rates relative to rates in the group that received simultaneous combination therapy. (B) Quantification of density of BM cells (20× magnification, eight randomized fields per group). (C) BM histology of various treated groups described in A. Dashed lines enclose bone matrix. Arrowheads point to residual hematopoietic islets attached to bone matrix. (Bar, 100 μm.) (D–F) RBC (D), hemoglobin (E), and WBC (F) in peripheral blood. *P < 0.05, **P < 0.01, ***P < 0.001. Data are shown as mean ± SEM.

Schematic diagram of mechanisms underlying antiangiogenic and cytostatic drugs.