A Study of INCB059872 in Relapsed or Refractory Ewing Sarcoma

Inclusion Criteria:

- Histologically or cytologically confirmed diagnosis of Ewing sarcoma and have
progressed on or after standard therapies.

- Must not be a candidate for potentially curative therapy or standard-of-care approved
therapy.

- Measurable disease by computed tomography or magnetic resonance imaging based on
RECIST 1.1 as determined by site radiology.

- Eastern Cooperative Oncology Group performance status 0 to 2.

- Willingness to avoid pregnancy or fathering children.

Exclusion Criteria:

- Receipt of anticancer medications, anticancer therapies, or investigational drugs
within protocol-defined intervals before the first administration of study drug.

- Must have recovered (≤ Grade 2 or at pretreatment baseline) from adverse events (AEs)
from previously administered therapies except for stable chronic toxicities (≤ Grade
2) not expected to resolve.

- Untreated brain or central nervous system (CNS) metastases or brain/CNS metastases
that have progressed.

- Prior radiotherapy within 2 weeks of study treatment. A 1-week washout period is
permitted for palliative radiation to non-CNS disease with medical monitor approval.

- Laboratory values outside the protocol-defined range at screening.

- History or evidence of bleeding disorder or active clinically significant bleeding
requiring medical intervention.