Cetuximab-IRDye800CW (University Medical Center Groningen)

Bone sarcomas are devastating primary bone cancers that mostly affect children, young adults, and the elderly. These aggressive tumors are associated with poor survival, and surgery remains the mainstay of treatment. Surgical planning is increasingly informed by positron emission tomography (PET), and tumor margin identification during surgery is aided by near-infrared fluorescence (NIRF) imaging, yet these investigations are confounded by probes that lack specificity for sarcoma biomarkers. We report the development of a dual-modal (PET/NIRF) immunoconjugate ([⁸⁹Zr]Zr-DFO-anti-MT1-MMP-IRDye800CW) that targets MT1-MMP, a matrix metalloproteinase overexpressed in high-grade sarcomas. [⁸⁹Zr]Zr-DFO-anti-MT1-MMP-IRDye800CW was synthesized via site-specific chemoenzymatic glycan modification, characterized, and isolated in high specific activity and radiochemical purity. Saturation binding and immunoreactivity assays indicated only minor perturbation of binding properties. A novel mouse model of dedifferentiated chondrosarcoma based on intrafemoral inoculation of HT1080 WT or KO cells (high and low MT1-MMP expression, respectively) was used to evaluate target binding and biodistribution. Fluorescence and Cerenkov luminescence images of [⁸⁹Zr]Zr-DFO-anti-MT1-MMP-IRDye800CW showed preferential uptake in HT1080 WT tumors. Ex vivo gamma counting revealed that uptake in MT1-MMP-positive tumors was significantly higher than that in control groups. Taken together, [⁸⁹Zr]Zr-DFO-anti-MT1-MMP-IRDye800CW is a promising dual-modal sarcoma imaging agent for pre-operative surgical planning and intraoperative surgical guidance.

Intratumoural metabolic demands result in excessive angiogenic cytokine release leading to unorganised vasculature. Resultant fluid dynamics oppose blood flow and drug penetration due to a marked increase in interstitial fluid hydrostatic pressure. It is hypothesised that anti-angiogenic therapy may function to 'prune' vasculature and lead to improved chemotherapeutic penetration. Subcutaneous, OSC19 tumour bearing mice (n = 5/dose/agent) were administered varying doses of an anti-mouse VEGFR2 (DC101) or an anti-mouse VEGFR3 (31C1) -3 d, -1 d, 0 d, +1 d and +3 d prior to 200 µg of cetuximab fluorescently labelled with IRDye800CW. Fluorescence imaging of tumours was performed 10 d post cetuximab-IRDye800CW dose to monitor therapeutic uptake. Co-administration of dual anti-angiogenic agents at 50-50%, 75-25% and 25-75% using optimal dose and time (-1 d 10 mg/kg anti-VEGFR2 and -1 d 40 mg/kg anti-VEGFR3) was also evaluated. In order to establish vessel normalisation, NG2 (pericyte marker) and CD31 (endothelial cells) ratios were assessed during immunohistochemical staining of tumour sections. Twenty-mg/kg anti-VEGFR3 + 5 mg/kg anti-VEGFR2 significantly (p < .0005) reduced tumour size (-73%) compared to control (59%). The 20 mg/kg anti-VEGFR3 + 5 mg/kg anti-VEGFR2 and 30 mg/kg anti-VEGFR3 + 2.5 mg/kg anti-VEGFR2 significantly (p < .0004) improved percent-injected cetuximab-IRDye800CW dose/gram tumour tissue compared to other groups. Adjuvant, dual anti-angiogenic therapy targeting VEGFR2 and VEGFR3 significantly enhances tumour chemotherapeutic uptake compared to control.