A Phase I Study of IGN523 in Subjects With Relapsed or Refractory AML

Primary Objectives:

- Evaluate the safety and tolerability of IGN523 administered weekly

- Determine the MTD and dose limiting toxicity (DLT) of IGN523 when administered weekly
during the DLT Evaluation Period

- Identify a recommended Phase 2 dose (RP2D) of IGN523 on the basis of safety, PK, and PD
data

Secondary Objectives:

- Assess the incidence of antibody formation to IGN523

- Characterize the PK of IGN523 in subjects with relapsed or refractory AML

- Perform a preliminary assessment of the anti-leukemic activity of IGN523 in subjects
with relapsed or refractory AML

- Perform a preliminary assessment of biologic markers that might predict IGN523
anti-leukemic activity

Estimated Enrollment: 50 Study Start Date: February 2014 Estimated Study Completion Date:
March 2016 Estimated Primary Completion Date: September 2015 (Final data collection for
primary outcome measure)

Inclusion Criteria:

- Relapsed or treatment-refractory AML

- Eastern Cooperative Oncology Group status 0-2

- Life expectancy of at least 12 weeks

- Adequate baseline renal and hepatic function

- Measurable disease (eg, peripheral blasts greater than 5%)

Exclusion Criteria:

- Chronic myelogenous leukemia in blast crisis

- Monoclonal therapy within 4 weeks, or chemotherapy or radiotherapy within 2 weeks

- Unresolved acute toxicity from prior anti-cancer therapy

- Prior allogeneic stem cell transplant and active graft-versus-host disease requiring
systemic immunosuppressive therapy within 15 days prior to screening

- History of severe allergic or anaphylactic reactions to monoclonal antibody therapy

- Known current leptomeningeal or central nervous system (CNS) involvement of leukemia