Phase Ib study of NGR–hTNF, a selective vascular targeting agent, administered at low doses in combination with doxorubicin to patients with advanced solid tumours

Background: Asparagine–glycine–arginine–human tumour necrosis factor (NGR–hTNF) is a vascular targeting agent exploiting a tumour-homing peptide (NGR) that selectively binds to aminopeptidase N/CD13, overexpressed on tumour blood vessels. Significant preclinical synergy was shown between low doses of NGR-TNF and doxorubicin. Methods: The primary aim of this phase I trial was to verify the safety of low-dose NGR–hTNF combined with doxorubicin in treating refractory/resistant solid tumours. Secondary objectives included pharmacokinetics (PKs), pharmacodynamics, and clinical activity. In all 15 patients received NGR–hTNF (0.2–0.4–0.8–1.6 μ g m −2 ) and doxorubicin (60–75 mg m −2 ), both given intravenously every 3 weeks. Results: No dose-limiting toxicity occurred and the combination was well tolerated. Around two cases of neutropenic fevers, lasting 2 days, and two cases of cardiac ejection-fraction drops, one asymptomatic and the other symptomatic, were registered. Only 11% of the adverse events were related to NGR–hTNF and were short-lasting and mild-to-moderate in severity. There was no apparent PK interaction and the shedding of soluble TNF-receptors did not increase to 0.8 μ g m −2 . One partial response (7%), at dose level 0.8 μ g m −2 , and 10 stable diseases (66%), lasting for a median duration of 5.6 months, were observed. Conclusions: NGR–hTNF plus doxorubicin was administered safely and showed promising activity in patients pre-treated with anthracyclines. The dose level of 0.8 μ g m −2 NGR–hTNF plus doxorubicin 75 mg m −2 was selected for phase II development.