Therapeutic efficiency of combination therapy with [Lys40(Ahx-DTPA-111In)NH
]-exendin-4 and vatalanib. (A) The combination therapy reduces tumor burden by up to 97% (*p < 0.05, Kruskal-Wallis test) compared to the single-modality treatment. (B) The combination therapy and monotherapy with vatalanib reduce the microvessel density significantly compared to monotherapy with [Lys40(Ahx-DTPA-111In)NH2]-exendin-4 (p < 0.05, Newman-Keuls post-test). (C) H&E staining of tumors upon treatment. Histology confirms tumor regression in the combination therapy arm, while normal islets are unaffected. (D) CD31 immunohistochemical staining on tumor sections. Vessels persist under anti-angiogenic therapy, but vessel density is reduced. Size bars, 100 μm.