Relationships Of Peripheral Blood Lymphocyte Counts (Pblc) With Antitumor Activity Of Ngr-Htnf Given In Combination With Chemotherapy (Ct)

3038 Background: Antitumor effects of NGR-hTNF (N), a tumor-targeted antivascular agent, are driven at low dose by an early vessel stabilization that greatly enhances both intratumoral CT uptake and T-cell infiltration. Synergism with CT was shown in immunocompetent mice, but not in nude mice lacking functional T cells. Methods: By an individual patient pooled analysis of 396 patients (pts) from 7 ph II trials in 6 tumor types, we estimated the effects of baseline PBLC on the antitumor activity of N (with or without CT) and CT alone. Low dose N (0.8 μg/m2) was given in combination with CT in 171 pts. Control groups of 140 and 85 pts receiving N and CT alone, respectively, were also analyzed. CT was doxorubicin or a platinum-based regimen. In all trials, response to therapy was assessed every 6 weeks by RECIST. Endpoints of interest were response rate (RR, complete plus partial response), disease control rate (DCR, RR plus stable disease), duration of response (DOR) and progression-free survival (PFS). In logistic and Cox regression analyses, PBLC data were dichotomized in high or low levels by the median cutpoint (1.5/mL; 95% CI, 1.4-1.6). Multivariate models included age, sex, PS and tumor type as covariates. Results: In both N-alone and CT-alone groups, there was no statistically significant difference in treatment effect according to baseline PBLC. Conversely, high PBLC were related to better treatment outcome in the N plus CT group, compared to low PBLC. In this N plus CT group, high PBLC (vs low) were associated with higher RR (OR=2.8; 95% CI, 1.2-6.3; p=.01) and DCR (OR=2.6; 1.3-4.9; p=.004), and with longer DOR (HR=0.39; 0.16-0.96; p=.04) and PFS (HR=0.60; 0.43-0.85; p=.004). For high vs low PBLC, RR was 29% vs 14%, DCR 76% vs 57%, median DOR 8.2 vs 6.3 months, and median PFS 5.0 vs 3.0 months, respectively. On multivariate analyses, high PBLC remained an independent predictor of increased RR (OR=2.7; p=.01) and DCR (OR=2.6; p=.005), and improved DOR (HR=0.36; p=.04) and PFS (HR=0.60; p=.005). Conclusions: Consistently with preclinical data, these results highlight the potential value of PBLC in predicting tumor response to NGR-hTNF in combination with CT, which merits further clinical validation Clinical trial information: NCT00994097-NCT00484432-NCT00484276-NCT00484211-NCT00483509-NCT00483080-NCT01358071.