r84 Inhibits VEGFR2 Figure 5. Extended r84 therapy controls tumor growth without induction of toxicity. 5 million PANC-1 tumor cells were injected subcutaneously into NOD/SCID mice. Tumor bearing (TB) and non tumor bearing (NTB) mice received long-term 12-week therapy with 50 mg/kg/ week r84 or a control IgG. Following 12-weeks of therapy, animals were sacrificed and organs and blood were collected for toxicity analysis. n = 5 animals per group. A, Hematoxylin and eosin staining of formalin-fixed, paraffin-embedded kidney and liver sections demonstrated that control of tumor growth is achieved without induction of kidney or liver histopathologic changes. B, Blood chemistry analysis of serum samples collected from mice at sacrifice indicated that r84 treatment does not induce changes in serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), or blood urea nitrogen (BUN) as compared to control IgG therapy and to age-matched Na¨ıve animals that did not have tumor and never received antibody therapy. Immunocompetent Kras/INK4a mice that spontaneously develop pancreatic cancer were treated for eight weeks with PLoS ONE | www.plosone.org 10 August 2010 | Volume 5 | Issue 8 | e12031