Radiotherapy in Combination With Checkpoint Inhibition for Patients With Metastatic Kidney Cancer

The study expects to accrue the 15 patients over a 3-4 year period. Patients with oligoprogressive disease (≤5 lesions) after treatment with Anti-PD1 / Anti-CTLA-4 will continue Anti-PD1 (nivolumab). All patients will have a mandatory PD-L1 PET (Pre-treatment and Week 12). All patients will undergo baseline biopsy (just before the administration of IMSA101 of the same lesion to be injected). SAbR will be delivered in 3 fractions at 12 Gy every 4 weeks (PULSAR regimen) to all progressing lesions. One lesion will also receive 3 intratumoral injections of IMSA101 (C1D1, C1D8, C1D15, C2D1, C3D1) immediately after radiation either on the same day or within 72 hours after the PULSE. Selected Phase 2 dosing of IMSA101 (1200mcg) will be utilized. At disease progression, patients have the option to undergo additional imaging and tissue/blood collections.