Phase II study of Lutetium-177-labeled anti-Carbonic Anhydrase IX monoclonal antibody girentuximab in patients with advanced renal cell carcinoma.

e14014 Background: Despite recent advances in treatment of metastatic clear cell renal cell carcinoma (ccRCC), the search for alternative treatment modalities, which can induce durable responses with milder toxicity profiles continues. A phase II radioimmunotherapy (RIT) trial with 177lutetium (177Lu)-girentuximab was initiated, based on the encouraging results of a phase I study, to evaluate the efficacy of this RIT approach in patients with metastatic ccRCC. Methods: In this single-center, non-randomized phase II trial, patients with progressive metastatic ccRCC received RIT with 2.4 GBq 177Lu-labeled anti-CAIX antibody, girentuximab, if targeting of the antibody was observed after a diagnostic injection with 111Indium labeled girentuximab. Patients were eligible for another treatment cycle if they had at least stable disease (SD) on evaluation after 3 months according to RECIST v.1.1 and did not have prolonged grade 4 hematological toxicity. Retreatment was at 75% of the previous activity dose with a m...