Background: Preclinical data suggest that combined Ang1/2 and mTOR blockade has synergistic anti-cancer activity. The combination of Tr (inhibits angiogenesis by preventing interaction of Ang1/2 with Tie2) with the mTOR inhibitor T was evaluated in pts with advanced solid tumors to determine safety, tolerability, maximum tolerated dose (MTD), pharmacodynamics and preliminary antitumor activity. Methods: Pts were enrolled using 3+3 design. Tr and T were dosed on Day 1 (D1), 8, 15 and 22 of a 28-day cycle. Peripheral blood was collected for evaluation of Tie2-expressing monocytes (TEMs) and thymidine phosphorylase (TP) (an angiogenic enzyme increased in TEMs upon Tie2 stimulation) by flow cytometry. Tumor response was assessed every 2 cycles. Results: 13 pts have been enrolled, 6 at dose level (DL) 1 (15mg/kg Tr + 25mg T) and 7 (1 died from disease before DLT assessment) at DL -1 (15mg/kg Tr + 20mg T). Median age was 57yrs, ECOG 0-1, median previous chemotherapy lines 3 (range 1-8). In DL 1, 1/6 pts experienced DLT (Grade (Gr) 2 pneumonitis). In view of frequent Gr2 adverse events (AEs) in DL 1, DL -1 was evaluated with DLTs in 2/6 evaluable pts (Gr3 mucositis and intolerable Gr2 limb edema preventing start of cycle 2 within 14 days). The most common related AEs (all Gr across both DL) were: fatigue (77%), edema (69%), anorexia (62%), and nausea (54%). Common Gr≥3 AEs included lymphopenia (23%) and fatigue (23%). Of 10 evaluable pts, best RECIST responses were: 1 breast cancer pt (ER+/ HER2-/ PIK3CA mutant) with PR (now in cycle 9), 7 pts with SD, and 2 pts with PD. Four pts with ovarian cancer (1 PIK3CAmutant) had SD ≥11weeks with 2/3 pts (1 not evaluable) demonstrating GCIG response (>50% decrease in CA125). In preliminary analyses, TP expression in TEMs was decreased (mean -18%) in 4pts with tumor shrinkage, but increased (+6%) in 1pt with tumor growth, suggesting a trend between reduced TP and tumor response. Conclusions: The MTD was exceeded at 15mg/kg Tr and 20mg T weekly. The safety of 10mg/kg Tr and 20mg T weekly is currently being evaluated. The combination of Tr and T shows early signs of antitumor activity. TP expression in TEMs by flow cytometry as an early marker of treatment benefit warrants further evaluation. Clinical trial information: NCT01548482.