A Study of the Safety and Pharmacokinetics of AGS-22M6E in Subjects With Malignant Solid Tumors That Express Nectin-4

AGS-22M6E and ASG-22CE are fully human monoclonal antibody conjugated to a cytotoxic agent monomethyl auristatin E (MMAE) targeting Nectin-4 (Agensys code name AGS-22). The main difference between AGS-22M6E and ASG-22CE is the change in cell line for antibody production. AGS-22M6E and ASG-22CE will be administered at mg/kg doses based on the subjects weight at baseline and doses will not change unless the subjects weight changes by ≥ 10% from their baseline weight or the investigational product Dosage Assessment criteria is met. Subjects will be prescreened for Nectin-4 expression prior to undergoing screening procedures for the main study. Subjects with tumors positive for Nectin-4 expression may be screened for eligibility into the main study. The dose escalation period is estimated to take between 12 and 18 months depending on whether 3 or 6 subjects are enrolled in a given dose cohort, and the availability of consenting subjects. Subjects will be treated in the dose escalation phase of the study until the maximum tolerated dose (MTD) and recommended dose for expansion (RDE) has been determined by the data review team (DRT). After the RDE has been determined, subjects will be enrolled into 1 of 3 expansion cohorts. There will be 3 expansion cohorts, each targeting a specific cancer (i.e.,Breast, Bladder and Lung plus other solid tumor cancers). The DRT may recommend stopping the study, adjusting the dose or amending the trial at any time. The clinical bridging to the ASG-22CE involves treating the subjects with ASG-22CE, irrespective of cancer type, at the next lowest dose level previously determined to be safe for AGS-22M6E. After the initial subjects are treated at the bridging dose with ASG-22CE and have completed the safety assessment, future subjects will only be treated with ASG-22CE throughout the remainder of the study. A disease assessment will be performed by the investigator at Week 8 (± 14 days). Subjects without evidence of disease progression may continue to receive treatment until disease progression or intolerability.