A Study to Assess CLBR001+ABBV-461 in Subjects With Locally Advanced or Metastatic Breast Cancer

Inclusion Criteria

• Refractory or relapsed locally advanced or metastatic breast cancer
• Exhaused all standard of care therapy options
• Measurable disease at time of screening in accordance with RECIST v1.1 criteria
• Women or men age ≥18 years of age at time of consent
• ECOG performance status 0 or 1
• Must provide a biopsy sample obtained during the screening period, following the end of the most recent prior line of therapy
• Adequate hematological, renal, and liver function

Exclusion Criteria

• History of a clinically significant infection within 4 weeks prior to consent
• Active bacterial, viral, and/or fungal infection
• Prior allogeneic stem cell transplant
• Prior lentiviral- or retroviral-based therapy including CAR-T cell therapy
• Prior lymphodepleting or T-cell cytotoxic therapy within 3 months of enrollment
• Subjects receiving attenuated vaccines within 4 weeks of consent or need for live vaccine within 12 months of starting study therapy
• History of significant cardiovascular conditions within the past 6 months
• Subjects with a prior history of or concurrent malignancy whose natural history or treatment has the potential to interfere with either the safety or efficacy assessment of the investigational regimen