Phase II study of NGR-hTNF, a selective vascular targeting agent (VTA), administered as single agent in patients (pts) with colorectal cancer (CRC) refractory to standard regimens

Abstract

4088 Background: NGR-hTNF is a VTA exploiting a tumor-homing peptide (NGR) that selectively binds to an aminopeptidase N/CD13 overexpressed by tumor blood vessels. In preclinical models, NGR-hTNF showed antitumor activity both at low and at high doses. Methods: Pts with CRC resistant/refractory to standard treatments, including biological agents, were treated with low-dose NGR-hTNF given intravenously at 0.8 μg/m2 as 1-hour infusion every 3 weeks (q3w). This phase II trial had a 2-stage design with 16 and 27 pts to be enrolled after first and second stage, respectively. Progression-free survival (PFS) was the primary end-point with reassessment performed q6w. Results: From January to May 2007, 33 pts with radiologically- documented progressive disease after last therapy were evaluated over 111 cycles (range, 1–10). Pts characteristics were: median age: 65 years (range, 53 to 79); M/F 16/17; PS 0/1 26/7. Median number of prior regimens was 3 (range, 2 to 5). Eight pts (25%) were pre-treated with ≥4 lines and 22 (67%) with biological agents. Neither grade 3–4 treatment-related adverse events nor toxicity-related deaths were observed. Main grade 1–2 toxicities per patient were infusion-related chills (47%) and transient blood pressure increase (9%). One partial response (3%) lasting 5 months and 12 stable diseases (36%) were reported. Median PFS was 2.5 months (95% CI, 2.2–2.8). In a post-hoc analysis, no differences in PFS were detected according to baseline characteristics. With a median follow-up time of 18.4 months (95% CI, 18.3–18.5), 11 pts (33%) were still alive. Median overall survival (OS) was 13.1 months and the 2-year OS rate was 22%. In the subset of stable or responder pts, the median PFS and OS were 3.8 months and 15.4 months, respectively. The 6-month PFS rate in the prior-biological and biological-naïve cohorts was 5% and 20%, respectively, whereas 1-year OS rate was 41% and 72%, respectively. Conclusions: Based on the favorable toxicity profile and disease control in heavily pre-treated CRC patients, NGR-hTNF will be further developed in combination with standard chemotherapy. [Table: see text]