Phase I safety and pharmacokinetic (PK) study of sunitinib (S) in combination with ifosfamide (I) in patients (pts) with advanced solid tumors (STs)

e13520 Background: S is a tyrosine kinase inhibitor (TKI) of PDGFR, VEGFR and KIT. As combinations of VEGFR-TKI with cytotoxic therapy are promising, this phase I study aimed to determine the recommended phase II dose (RP2D) of S in combination with 2 different I schedules. Methods: Pts with progressive STs, good PS, organ function, and no standard therapy available, were eligible. I (3 g/m2/day, 72h CIV (I*3), every 3 wks) was combined with continuous S. S was started at 12.5 mg/day and to be escalated in serial cohorts of 3–6 pts. RP2D was exceeded if ≥ 1/3 pts experienced dose-limiting toxicity (DLT) within the 1st cycle. After establishing the RP2D of S with I*3, feasibility of this S dose with I at 1.2 g/m2/day for 5 days CIV (I*5) every 3 wks was assessed without further scheduled dose-escalation. At RP2D, additional patients were enrolled to assess PK. Circulating endothelial cells (CECs) were measured prior to the 1st, 3rd and 6th cycle. Results: 26 pts (36–68 yrs) were accrued. 12.5 mg S was not ...