- Edited inclusion criteria to clarify that qualifying patients should have received at least 2 prior systemic cytotoxic chemotherapy regimens for treatment of unresectable locally advanced or metastatic disease. Clarified that 1 of the prior systemic cytotoxic chemotherapy regimens must have contained gemcitabine and that patients must have met a list of specified criteria regarding the gemcitabine regimen; - Updated dose reduction/delay/discontinuation rules in the event of hematological toxicities, infusion reactions, or other toxicities of various grades, including clarification for reduced dosing, missed doses, coordination of gemcitabine dosing, and gemcitabine toxicity; - Clarified that 2 samples would be collected during the first treatment cycle and a third serum sample for pharmacokinetic assessments was to be collected at baseline for the determination of antibody levels; - Added additional language to describe the preparation and assay of radiolabeled 90Y-clivatuzumab tetraxetan at prescribed doses that exceeded 8 mL in a single 10-mL syringe. These doses would be prepared by using two 10-mL syringes, each adjusted to a final volume of 8 mL, which could be separately assayed and the activities combined; and - Clarified that adverse event (AE) reporting would continue for 30 days (not >30 days) after either the last dose of study drug or until the patient initiated alternative antineoplastic therapy not permitted during this study. Thereafter, AE reporting was to be limited to study drug-related events.

- Clarified that during Weeks 2, 3, and 4 of each treatment cycle, the weekly complete blood count should have been obtained prior to the 90Y-clivatuzumab tetraxetan or placebo control dose in order to evaluate for cytopenias that may have required the dose to be reduced, delayed, or discontinued; - Required Karnofsky Performance Status (KPS), patient weight, and the Functional Assessment of Cancer Therapy-Hepatobiliary (FACT-Hep) questionnaire evaluations on the fourth week of each treatment cycle in order to obtain additional data for analysis of treatment benefit; - Clarified that randomization was to be stratified on the basis of the number of prior treatments for either unresectable locally advanced or metastatic disease; - Removed wording regarding serum samples collected for determination of PAM4-reactive mucin, since this exploratory analysis was to no longer be performed by the Sponsor; and - Removed inadvertent reference to urinalysis which was not required in this study.