ISPY-P1.01:Evaluating the Safety of Weekly Paclitaxel With Trastuzumab Duocarmazine (SYD985) in Patients With Metastatic Cancer

Inclusion Criteria: * Signed informed consent and for collection of archival FFPE blocks (freshly cut 14 unstained tumor slides would be acceptable) obtained prior to any study specific assessments and procedures. * Histologic diagnosis: Biopsy-proven solid malignancy diagnosis of one of the below mentioned types, that is advanced. * ER, PgR and HER2 measurements should be performed according to institutional guidelines, in a CLIA-approved setting, when indicated. Cut-off values for positive/negative staining should be in accordance with current ASCO/CAP (American Society of Clinical Oncology/College of American Pathologists) guidelines2-4 published in 2017 for Gastroesophageal Adenocarcinoma, and in 2018 for breast cancer. For other histologic types, HER2 assessment will follow local institutional criteria. Patients with breast cancer and equivocal HER2 in situ hybridization results according to current ASCO/CAP guidelines are eligible.. Cohort A (de-escalation): * HER2 POSITIVE: breast, gastroesophageal adenocarcinoma, colorectal, ovarian, endometrial and urothelial tumors * HER2 LOW: breast (irrespective of HR status) * Cohort B (expansion): * HER2 POSITIVE: breast * HER2 LOW: breast (irrespective of HR status) * Prior therapy: disease has progressed after at least one line of standard/approved therapy in the advanced setting: * Histology: Breast HER2 pos * Prior treatment lines allowed * Must have received at least a taxane and trastuzumab for advanced/metastatic disea…