A Study of JNJ-79032421 Targeting Mesothelin for Advanced Stage Solid Tumors

Inclusion Criteria: * Histologically or cytologically confirmed diagnosis of one of the following unresectable/locally advanced or metastatic solid tumors: a) Ovarian cancer includes high grade serous epithelial ovary, fallopian tube, or primary peritoneal cancer. Participants must have progressed after at least 2 prior lines of systemic therapy and have either, i) platinum-refractory disease (ie, persistent disease following completion of platinum-based primary chemotherapy); or ii) platinum-resistant recurrent disease; b) Primary pleural or peritoneal mesothelioma. Sarcomatoid and well differentiated papillary histologies are not allowed. Participants must have progressed after at least 1 prior line of systemic therapy; c) Pancreatic ductal adenocarcinoma. Other histologies and mixed histologies are not allowed. Participants must have progressed after at least 1 prior line of systemic therapy. * Measurable or evaluable disease: a) Part 1: Measurable or evaluable disease; b) Part 2: At least one measurable lesion per RECIST v1.1. Participants with mesothelioma must have disease measurable per mRECIST v1.1. * Can have a prior or concurrent second malignancy (other than the disease under study) whose natural history or treatment is unlikely to interfere with any study endpoints of safety or the efficacy of the study treatment(s) * Eastern Cooperative Oncology Group (ECOG) performance status grade of 0 or 1. * Selected participants in the pharmacokinetic and pharmacodynamic (PK/PD) cohorts (Part 1) as well as selected participants in Part 2 must agree to undergo mandatory tumor biopsies. Exclusion Criteria: * History of known central nervous system (CNS) or leptomeningeal involvement. * Left ventricular ejection fraction on screening echocardiogram below normal institutional limits. * History of talc pleurodesis for pleural effusion within 3 months of starting study treatment. * Concurrent empyema of the lung pleural space requiring antibiotics or chest tube or evidence of resultant fistula formation. * History of hyperthermic intraperitoneal chemotherapy (HIPEC) within 6 months of starting study treatment.