A Study to Evaluate Safety and Efficacy of AMB-05X Injections in Subjects With TGCT

Inclusion Criteria

• Subject ≥ 18 years
• TGCT with only 1 joint involvement
• Symptomatic Measurable disease of at least 1 cm based on RECIST v1.1
• Stable prescription of analgesic regimen
• Agrees to follow contraception guidelines
• Women of childbearing potential must have a negative pregnancy test
• Adequate hematologic, hepatic, and renal function

Exclusion Criteria

• Prior investigational drug use within 4 weeks or 5 half-lives of Baseline
• Previous use of therapeutics targeting CSF1 or CSF1R or oral tyrosine kinase inhibitors within 3 months prior to Baseline
• History of extensive or reconstructive surgery on the affected joint
• Active cancer (either currently or within 3 mo before Baseline) that requires/required therapy (e.g., surgery, chemotherapy, or radiation therapy)
• Metastatic or malignant transformation of TGCT
• Hepatitis C virus (HCV) or hepatitis B virus (HBV) or human immunodeficiency virus (HIV)
• Known active tuberculosis
• Significant concomitant arthropathy in the affected joint, serious illness, uncontrolled infection, or a medical or psychiatric history
• Women who are breastfeeding
• A screening Fridericia-corrected QT interval (QTcF) ≥ 470 ms
• MRI contraindications (e.g., pacemaker, loose metallic implants)
• History of hypersensitivity to any ingredient of the study drug
• History of drug or alcohol abuse within 3 months before baseline
• Any other severe acute or chronic medical or psychiatric condition or clinically significant laboratory abnormality that may increase the risk associated with study participation/treatment or interfere with interpretation of study results and, in the Investigator's opinion, make the subject inappropriate for this study
• Subjects who, in the Investigator's opinion, should not participate in the study for any reason, including if there is a question about their ability to comply with study requirements