This study has four parts. Part 1 is a dose escalation of BDC-1001 as a single agent to determine the maximum tolerated dose (MTD), recommended Phase 2 dose (RP2D), or maximum protocol dose (MPD) recommended for Part 3. In Part 3, the selected dose will be administered as monotherapy to patients with selected advanced malignancies. Part 2 is a dose escalation of BDC-1001 in combination with nivolumab to determine the maximum tolerated dose (MTD), recommended Phase 2 dose (RP2D), or maximum protocol dose (MPD) recommended for Part 4. In Part 4, the selected dose will be administered in combination with nivolumab to patients with selected advanced malignancies.
Patient must have an advanced solid tumor with documented HER2-protein expression or gene amplification for which approved therapies have been exhausted or are not clinically indicated. Measurable disease as determined by RECIST v.1.1. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. Tumor tissue (archival or collected prior to the study start) available for exploratory biomarker evaluation.
Key Exclusion Criteria:
History of severe hypersensitivity to any ingredient of the study drug(s), including trastuzumab or other monoclonal antibody. Previous treatment with a TLR 7, TLR 8 or a TLR 7/8 agonist. Impaired cardiac function or history of clinically significant cardiac disease Human Immunodeficiency virus (HIV) infection, active hepatitis B infection, or hepatitis C infection. Active SARS-CoV-2 infection Untreated central nervous system (CNS), epidural tumor or metastasis, or brain metastasis.
Other protocol defined inclusion/exclusion criteria may apply.