A Clinical Trial of the Safety and Anti-Tumor Activity of AB-201 in Subjects With Advanced HER2+ Solid Tumors

Inclusion Criteria: ECOG performance status 0 to 1. Histologically confirmed HER2 expressed breast or gastric/GEJ cancer IHC ≥ 2+ within 6 months prior to study entry. Confirmed diagnosis of an advanced/unresectable or metastatic HER2+ breast or gastric/GEJ cancer that is refractory to, or intolerable of standard treatment, or for which no standard treatment is available. Must have received prior cancer therapy: Subjects with breast cancer must have received ≥ 2 prior systemic therapies; subjects with gastric/GEJ cancer must have received ≥ 1 prior systemic therapy(ies); subjects with IHC 3+ or IHC 2+/ISH+ cancers must have received previous treatment with a HER2-targeting therapy. Exclusion Criteria: Known past or current malignancy other than inclusion diagnosis. Known clinically significant cardiac disease. Active central nervous system (CNS) metastases, or involvement of the CNS, unless there is a history of at least 3 months of sustained remission. Unresolved toxicities from prior anticancer therapy. Ongoing uncontrolled systemic infections requiring antibiotic, anti-fungal, or anti-viral therapy. History of sensitivity or intolerance to cyclophosphamide or fludarabine. Pregnant or lactating females and subjects of both sexes who are not willing to practice birth control from the time of consent through 6 months after administration of the last AB-201 dose. Severe disease progression or health deterioration within 2 weeks prior to lymphodepletion regimen.