Background: Survivin is a microtubule-associated protein implicated in both preservation of cell viability and regulation of mitosis in tumor cells. It is over-expressed in melanoma, breast, and non-Hodgkin’s lymphoma. YM155 is a first in class survivin inhibitor. Methods: The study had 2 parts: Part 1 established the dose of docetaxel that was tolerable in combination withYM155 at 5 mg/m²/day continuous infusion over 168 hours q 3 weeks. Part 2 utilized the dose of docetaxel established in Part 1 to further evaluate the tolerability and activity of the combination. The primary endpoint was 6-month progression-free survival (PFS). Secondary endpoints were overall response rate, 1-year overall survival (OS), time from first response to progression, clinical benefit rate, time to response, and safety. Results: 64 patients with metastatic melanoma were treated with docetaxel followed by continuous infusion YM155. 7 patients were treated with 100mg/m² of docetaxel and 57 patients were treated with 75mg/m² of docetaxel. Median age was 59, with 44 men and 20 women treated. 6-month PFS per Independent Review Committee (IRC) was 34.8% (95% CI 21.3 – 48.6%). Overall objective response rate per IRC was 12.5%, with no complete responses (CR) and 8 patients with partial responses (PR). The Stable disease (SD) rate was 51.6%, leading to a clinical benefit rate (CR + PR + SD) of 64.1%. Estimated 1-year overall survival is 50.5%. 87.5% of patients experienced a Grade 3 (G3) or Grade 4 (G4) event attributable to either YM155 or docetaxel. The clinically pertinent G3 or 4 toxicities occurring in greater than 5% of patients treated included neutropenia (59.4%), febrile neutropenia (12.5%), mucositis (9.4%), fatigue (7.8%), diarrhea (6.3%), and dehydration (6.3%). There were 3 deaths on study, all attributable to disease progression. Conclusions: YM155 is a novel agent that shows modest activity when combined with docetaxel in patients with melanoma. YM155 was generally well tolerated, but the pre-determined primary endpoint for efficacy was not achieved.