Study of the CD40 Agonistic Monoclonal Antibody APX005M

Key Inclusion Criteria: * Histologically documented diagnosis of solid tumor * For subjects in the every 2 week and every 1 week dosing cohorts histologically or cytologically documented diagnosis of urothelial carcinoma, melanoma, squamous cell carcinoma of the head and neck, non-small cell lung cancer, or any solid tumor with high microsatellite instability status (MSI-high) * No known effective therapy options are available * Measurable disease by RECIST 1.1 * ECOG performance status of 0 or 1 * Adequate bone marrow, liver and kidney function * No toxicities related to prior treatment related toxicities with the exception of alopecia and neuropathy * Negative pregnancy test for women of child bearing potential Key Exclusion Criteria: * Any history of or current hematologic malignancy * Major surgery or treatment with any other investigational agent within 4 weeks * Uncontrolled diabetes or hypertension * History of arterial thromboembolic event * History of congestive heart failure, symptomatic ischemia, conduction abnormalities uncontrolled by conventional intervention, or myocardial infarction * Active known clinically serious infections