NGRhTNF, a new vascular targeting agent with a dual mechanism of action: preliminary clinical results

Abstract

13052 Background: NGRhTNF is a vascular targeting agent (VTA) exploiting a tumour homing peptide (CNGRCG) selectively binding solid tumor (lung, renal, and colorectal) neovasculature. NGRhTNF specific binding relies on dynamic interactions with TNF-receptors, aminopeptidase N (CD13) and a specific integrin: a combination of receptors expressed by the tumor neovasculature endothelium, but not on normal vessels. This combination provides NGRhTNF with unique biological properties: at low dose, increased tumor vascular permeability, and massive tumor necrosis at high dose. Mouse preclinical data confirmed these properties, revealing also strong synergy between low dose NGRhTNF and cytotoxic agents (antracyclines, platinum based compounds, etc.). Methods: Based on these data, a series of studies were designed. A multicentre phase I study with NGRhTNF as single agent -still in progress- aims at defining MTD and preliminary anticancer activity, within the EORTC network (EORTC 16041). A single center phase I study exploiting the low dose range (0.2–1.6 μg/m2) aims at defining safety and NGRhTNF activity on the tumor vascular permeability using DCE MRI (HSR NGR002). Results: Twelve advanced neoplastic patients were enrolled in the HSR NGR002 study. Up to the dose of 1.6 μg/m2, the only common toxicity was represented by constitutional symptoms such as infusion-associated chills (40%) of mild to moderate intensity. At the tested doses, NGRhTNF increased vascular permeability, as shown by changes in DCE MRI parameters (Ktrans and Kep), and modulated the expression of chemokines possessing antiangiogenic activity. NGRhTNF achieved stable disease in about 45% of highly refractory treated patients, and still ongoing long lasting disease control in 2 cases (7 and 9 months along with sharp decline of CA125 and VEGF). Conclusions: NGR-hTNF, a VTA with a unique mechanism of action, combines activity on tumor vascular permeability and direct anti-cancer effect. Preliminary data in humans confirm its favourable safety profile along with remarkable anticancer activity, thus rendering the agent suitable for a development program alone or in combination with chemotherapeutics. Phase II low dose combination studies will begin in 2006. [Table: see text]