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Abstract 1039 Poster Board I-61 Background: The inhibitor of apoptosis protein (IAP) survivin is central in integrating proliferative and cell cycle regulatory networks. In leukemic cells, survivin mediates survival as well as resistance to chemotherapeutics and Flt-3 inhibitors. Experimentally targeting survivin has shown anti-leukemic activity and is a postulated therapeutic approach. Herein we report a clinical trial with the novel survivin and cdc2 (CDK1) inhibitor Terameprocol (EM-1421) in patients (pts) with advanced hematological malignancies. As little is known about in-vivo up- and downstream regulatory pathways of survivin and it's inhibition, specimens from pts were collected for correlative pharmacodynamic (PD) marker analysis. Methods: Open-label, single agent, phase I dose escalation study of Terameprocol (T) in pts with advanced, relapsed or refractory hematological malignancies (AML, ALL, MDS, advanced CLL or CML). Pts age > 18 years with adequate organ function and performance status (ECOG) ≤ 1were treated with 1000, 1500 and 2200 mg of intravenous Terameprocol 3x/week (wk) for 2 of 3 wks in cohorts of 3 pts to establish the safety, maximum tolerated dose (MTD) and to assess pharmacokinetics at the studied dose schedule (primary objectives). Secondary objectives were to select the recommended phase 2 dose (RP2D) and to assess anti-leukemic activity and PD marker regulation (baseline, cycle 1 day 5 and 12, end of study). Results: Between 8/2007 and 3/2009, sixteen pts (4 female, 12 male) with a median age of 68.5 years (range 42-78) and median of 2 prior regimens (range 0-5) were enrolled. Most pts had AML (n=13), 7 pts primary and 6 pts secondary or treatment related AML; one pt each had CML-BP, T-ALL and MDS. Ten pts had unfavorable or complex cytogenetics including 6 pts with 5q/7q and 2 pts with 11q23 aberrations. Four, 5 and 6 pts were treated at the 1000, 1500 and 2200 mg dose cohorts respectively. One pt did not start treatment on study. 15 pts received ≥ 1 dose/cycle, 6 of whom (38%) received ≥ 2 cycles of T (range 1-5). Common possible or probable treatment related adverse events (AE) were grade 1 or 2 headache (n=3, 20%), transaminitis (grade 2 n=2, grade 3 n=2) and pruritus (n=2). Treatment related serious AE's (SAE) was a grade 4 pneumonia in 1 pt. Non-drug related SAE's ≥ grade 3 or 4 included sepsis/febrile neutropenia (n=3), pneumonia (n=2), dyspnea (n=2), cerebral hemorrhage (n=1), confusion/mental status change (n=1), cardiac arrest (n=1) and AML progression (n=3) leading to death in 2 pts. No AE/SAE was felt to constitute a dose limiting toxicity (DLT) per protocol definition. However, due to grade 3 transaminitis observed in 2 pts together with concerns of compromised respiratory status of pts treated at the 2200 mg cohort, the investigators determined the maximum tolerated dose (MTD) to be 1500 mg 3x/week for 2 of 3 weeks, which is also the recommended RP2D. One heavily pretreated pt (3 prior regimens) with CML-BP myeloid, achieved a partial remission (1500 mg) and transfusion independence for 5 cycles prior to disease progression. Hematological improvement (HI-E, HI-P) was seen in 1 pt (1000 mg), and 5 pts had stable disease. Surprisingly, Cmax of T at 1500 mg was higher than at 2200 or 1000 mg. Overall concentrations of T were in the same range as measured in previous studies of T in solid tumors (daily x5), indicating adequate drug exposure at the schedule studied. PD samples at indicated time points were collected and are currently being analyzed to assess the effects of T on survivin, cdc2/CDK1 and survivin associated regulatory genes. Conclusion: The novel small molecule surivin inhibitor Terameprocol can be safely administered to pts with advanced leukemias. Sufficient drug exposure was seen in pts and the MTD and RP2D were established for future studies. Clinical activity was observed in a pt with myeloid CML-BP and potentially in pts with AML. Interestingly, previous work showed an association between progression to advanced stages of CML and survivin expression. Data on correlative PD marker experiments will be presented. Disclosures: Tibes: Erimos Pharmaceuticals : Research Funding. McDonagh:Erimos: Research Funding. Frazer:Erimos Pharmaceuticals: Employment. Mohrland:Erimos Pharmaceuticals: Employment. Von Hoff:Erimos Pharmaceuticals: Consultancy.