Study of Cabiralizumab in Patients With Pigmented Villonodular Synovitis / Diffuse Type Tenosynovial Giant Cell Tumor

Inclusion Criteria:

- Histologically confirmed diagnosis of inoperable PVNS/ dt-TGCT or potentially
resectable tumor that would result in unacceptable functional loss or morbidity as
determined by a qualified surgeon or multi-disciplinary tumor board (must be
documented in the CRF during screening)

- Measurable PVNS/dt-TGCT by RECIST 1.1 on MRI

- ECOG performance status <1

Exclusion Criteria:

- Prior therapy with an anti-CSF1R antibody

- Prior therapy with PLX3397 unless discontinued for intolerance (i.e., non-progression
on prior kinase inhibitor)

- Liver function tests (including ALT, AST, and total bilirubin), outside of the range
of local laboratory normal at Screening

- Inadequate organ or bone marrow function

- History of congestive heart failure or myocardial infarction <1 year prior to first
study dose administration

- Significant abnormalities on ECG at Screening

- Contraindications to MRI and use of intravenous gadolinium-based contrast agents

- Creatine Kinase ≥ 1.5x the upper limit of normal

- Positive test for latent TB at Screening (Quantiferon test)

- Active known or suspected autoimmune disease