Study of HuMab-5B1 (MVT-5873) in Subjects With Pancreatic Cancer or Other Cancer Antigen 19-9 (CA19-9) Positive Malignancies

Inclusion Criteria

• Inclusion Criteria [all groups] - Signed, informed consent - Age 18 or more years - Histologically or cytologically confirmed, locally-advanced or metastatic pancreatic ductal adenocarcinoma (PDAC) or other CA19-9 positive malignancies - Recovered from prior treatment related toxicity to at least Grade 1 with exception of Grade 2 alopecia or other Grade 2 toxicity with approval of the Medical Monitor - Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 or KPS of 100% to 80% - Adequate hematologic, hepatic, and renal function - Willingness to participate in collection of pharmacokinetic samples - Willingness to use adequate contraception throughout study and for a period of 3 months after last dose of MVT-5873 and for up to at least 9 months after the last Oxaliplatin dose. [Group A, C, and Group D Dose Escalation] - Evaluable or measurable disease based on RECISTv1.1 [Group A, C, and D] - Progression following treatment with standard of care for the subject's specific tumor type [Group C and D Dose Expansion and Group E Dose Escalation and Expansion] - Measurable disease based on RECISTv1.1 [Group C and D Dose Expansion, non-PDAC malignancies] - If serum CA19-9 levels (defined as < 1 U/mL or below the level of detection for institutional test used), subject must have confirmation of CA19-9 expression in their tumor prior to study entry (based on institutional determination of CA19-9) [Group E and F] - Candidates for mFOLFIRINOX based on accepted standard of care [Group F] - Histologically or cytologically confirmed PDAC - Macroscopically complete resection (R0 or R1 resection) performed between ≥21 and ≤84 days prior to Cycle 1, Day 1 (C1D1) - Baseline scans without evidence of disease (e.g., CT/MRI) - Serum CA19-9 ≤ 180 U/mL within 21 days of C1D1 - Full recovery from surgery and able to receive chemotherapy - Free of significant nausea and vomiting - No prior radiotherapy or chemotherapy Exclusion Criteria [Groups A, B, C, D, and E] - Brain metastases unless previously treated and well controlled for at least 3 months prior to study day 1 - Other known active cancer(s) likely to require treatment in the next two (2) years - Active, uncontrolled bacterial, viral, or fungal infection(s) requiring systemic therapy - Fewer than 28 days (or 5 half-lives for systemic agents, whichever is shorter) from prior anticancer therapy including chemotherapy, hormonal, investigational, and/or biological therapies and irradiation (except for ongoing hormonal therapy for prostate cancer) - Major surgery within 28 days of Study Day 1 - History of anaphylactic reaction to human, or humanized, antibody - Pregnant or currently breast-feeding - Known HIV, Hepatitis B or C-positive - Psychiatric illness/social situations that would interfere with compliance with study requirements - Significant cardiovascular risk (e.g., coronary stenting within 4 weeks, myocardial infarction within 6 months) [Group F] - Incomplete macroscopic tumor removal (R2 resection) - Other known active cancer(s) likely to require treatment in the next 2 years - Active, uncontrolled bacterial, viral, or fungal infection (s) requiring systemic therapy - History of anaphylactic reaction to human, or humanized, antibody - Pregnant or currently breast-feeding - Known HIV, Hepatitis B or C-positive - Psychiatric illness/social situations that would interfere with compliance with study requirements - Significant cardiovascular risk (e.g., coronary stenting within 4 weeks, myocardial infarction within 6 months) - Pre-existing neuropathy - Known homozygous for UGT1A1*28 mutation - Inflammatory disease of the colon or rectum, or occlusion or sub-occlusion of the intestine or severe postoperative uncontrolled diarrhea