Study of PULSAR-ICI +/- IMSA101 in Patients With Oligoprogressive Solid Tumor Malignancies

Patients shall be enrolled in 2 treatment arms as follows: 1. 15 patients in the control arm (PULSAR-ICI alone) 2. 30 patients in the experimental arm (PULSAR-ICI + IMSA101) PULSAR-ICI with or without IMSA101 treatment will be administered to the patients in Cycles 1, 2, and 3, and thereafter only standard of care ICI monotherapy will be administered to all patients. Each treatment cycle will be 28 days in duration for Cycles 1, 2 and 3, then per standard of care monotherapy thereafter based on the product labels of the prescribed ICI. The study will start with a safety run-in portion at 2 dose levels for the experimental arm, followed by a randomized portion for both treatment arms. The safety run-in shall employ a 3+3 safety run-in component. All patients will be followed throughout the study for drug tolerability and safety by collecting clinical and laboratory data, including adverse events (AEs) using Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0 criteria, SAEs, concomitant medications, and vital signs. All patients will be assessed for anti-tumor efficacy at screening, prior to the end of Cycle 3, and at 8-week intervals thereafter based on radiographic assessments (all outcome measures per RECIST Version 1.1 and iRECIST). Tumor types and the corresponding treatment combinations to be evaluated will be identified prior to the first patient enrolled. All patients will continue to receive their assigned treatment throughout the study until the occurrence of disease progression (based on iRECIST), death, or other unacceptable treatment-related toxicity, or until the study is closed by the sponsor.