Research Studies

Primary Objective: (1) Evaluate the safety, tolerability, and define the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of losartan in combination with sunitinib in pediatric and adult patients with relapsed or refractory osteosarcoma. Secondary Objectives: (1) Describe the pharmacokinetics (PK) of losartan when given in combination with sunitinib in pediatric and young adult patients with relapsed or refractory osteosarcoma. (2) Describe the pharmacodynamic (PD) effects of losartan and sunitinib, specifically effects on monocyte migration, plasma CCL2 levels, and changes to the peripheral CCR2+ monocyte population, when given in combination in pediatric and adult patients with relapsed or refractory osteosarcoma. (3) Describe the preliminary antitumor activity of losartan in combination with sunitinib in pediatric and adult patients with relapsed or refractory osteosarcoma. Exploratory Objectives: (1) Describe changes to peripheral T cell populations including CD4+, CD8+, and regulatory T cells, which occurs with treatment of losartan and sunitinib. (2) Describe changes to peripheral immune-related cytokines/chemokines such as TGF-β, IFNγ and VEGF with treatment of losartan and sunitinib. (3) Characterize tumor-infiltrating leukocytes, micro-vessel density, and immune-related gene expression in resected pulmonary metastases of patients treated with losartan and sunitinib.