Phase I study of NGR-hTNF, a selective vascular targeting agent, in combination with cisplatin in refractory solid tumors

Purpose: NGR-hTNF exploits the tumor-homing peptide asparagine-glycine-arginine (NGR) for selectively targeting TNF-alpha to an aminopeptidase N overexpressed on cancer endothelial cells. Preclinical synergism with cisplatin was displayed even at low doses. This study primarily aimed to explore the safety of low-dose NGR-hTNF combined with cisplatin in resistant/refractory malignancies. Secondary aims included pharmacokinetics (PKs), pharmacodynamics, and activity. Experimental Design: NGR-hTNF was escalated using a doubling-dose scheme (0.2-0.4-0.8-1.6 mu g/m(2)) in combination with fixed-dose of cisplatin (80 mg/m(2)), both given intravenously once every three weeks. PKs and circulating TNF-receptors (sTNF-Rs) were assessed over the first three cycles. Results: Globally, 22 patients (12 pretreated with platinum) received a range of one to ten cycles. Consistently with the low-dose range tested, maximum-tolerated dose was not reached. No dose-limiting toxicities (DLTs) were observed at 0.2 (n = 4) and 0.4 mu g/m(2) (n = 3). One DLT (grade 3 infusion-related reaction) was observed at 0.8 mu g/m(2). This dose cohort was expanded to six patients without further DLTs. No DLTs were noted also at 1.6 mu g/m(2) (n = 3). NGR-hTNF exposure increased dose-proportionally without apparent PK interactions with cisplatin. No shedding of sTNF-Rs was detected up to 0.8 mu g/m(2). At the dose level of 0.8 mu g/m(2), expanded to 12 patients for activity assessment, a platinum-pretreated lung cancer patient achieved a partial response lasting more than six months and five patients maintained stable disease for a median time of 5.9 months. Conclusions: The combination of NGR-hTNF 0.8 mu g/m(2) with cisplatin 80 mg/m(2) showed favorable toxicity profile and promising antitumor activity.