Background: The triple PDGFRα/β, VEGFR1-3, FGFR1-3 angiokinase inhibitor BIBF 1120 (B) is active in ovarian cancer (OC). This phase I/II trial evaluates tolerability and efficacy of B combined with pegylated liposomal doxorubicin hydrochloride (D) in platinum-resistant OC. Methods: The primary endpoints (EPs) are to determine the maximum-tolerated dose (MTD, phase I) and response rate (RR, phase II) to D+B. Secondary EPs were PFS, toxicities and rate of clinical benefit. Translational EPs were treatment effects on circulating hematopoietic stem and progenitor cells (CHSPCs), containing 2 phenotypically distinct populations; pro-angiogenic (p) CHSPCs (ViViD^-CD14^-glyA^-CD34⁺AC133⁺CD45^dimCD31⁺ cells) and non-angiogenic (n) CHSPCs (ViViD^-CD14^-glyA^-CD34⁺AC133^-CD45^dimCD31⁺ cells). Eligible pts had measurable OC, primary peritoneal (PP), fallopian tube and uterine (phase I only) cancer, up to 3 prior regimens, ECOG PS of 0-1 and normal end-organ function. B was given orally BID and D was given IV at 40mg/m²every 28 days. 3+3 dose escalation was used, starting with B at 150mg BID. Results: Eleven pts were enrolled in phase I. Median age was 59 (range 26-82); 8 pts had OC, 2 uterine and 1 PP cancer. Histologic types: serous (73%), endometrioid (18%) and mucinous (9%) carcinoma. Dose level+1 (B at 150mg BID) was not tolerated due to grade 3 fatigue, and grade 2 diarrhea, causing treatment interruption (DLT). Among 6 pts at dose level-1 (B at 100mg BID), 1 pt with history of chemotherapy induced myelosupression had grade 4 neutropenia (DLT). Other toxicities were diarrhea (36.4%), fatigue (36.4%), vomiting (27.3%), headache (27.3%), allergic reaction (9.1%) and oral pain (9.1%). Three pts had PRs, 3 SD and 4 disease progression; 1 was not evaluable. A decrease in the pCHSPC/nCHSPC ratio was observed after 1 cycle (1.58, n=8) compared to baseline (1.68, n=10, p=0.4). At treatment discontinuation, the pCHSPC/nCHSPC ratio was 1.97 (n=4). Analyses are ongoing. Conclusions: In summary, D+B is tolerated at 40mg/m² and 100mg BID. An expanded cohort using generic liposomal doxorubicin and B at level -1 is planned before initiation of the phase II cohort. Clinical trial information: NCT01485874.