51: Multi-site study of treatment outcomes of metastatic mit family translocation renal cell carcinoma (tRCC) patients treated with immune-checkpoint inhibitor combinations.
Co-director, Kidney Cancer Research Program, Assistant Professor, Oncology Johns Hopkins University, United States
Background: Metastatic tRCCs are rare and aggressive tumors with limited treatment options. Recent data showed promising activity of immune-checkpoint inhibitor (ICI) combinations, however, it remains unclear if ICI plus tyrosine-kinase inhibitors (ICI+TKI) have better outcomes versus dual ICI combinations (ICI+ICI).
Methods: Retrospective analysis was performed on patients with metastatic tRCC at 4 participating institutions. Eligible patients included metastatic tRCC who received ICI combination therapies. Translocations involving the TFE3 and TFEB genes were confirmed by florescence in situ hybridization (FISH). Treatment outcomes were recorded from starting ICI combination therapy. Radiological responses were based on investigator’s assessment. The study aims were to evaluate treatment outcomes, including objective response rate (ORR), treatment free survival (TFS), and overall survival (OS) among ICI+TKI and ICI+ICI groups.
Results: 22 patients with metastatic tRCC who received ICI combinations were identified, all with TFE3 rearrangement. Most patients were females (68%) with a median age of 41 years (16-79) at the time of diagnosis. ICI combinations included ICI+TKI (n=14, 64%) and ICI+ICI (n=8, 36%). 64% of patients received ICI combinations as first line therapy. In the evaluable patients for the efficacy analysis, ORR in the ICI+TKI group was 6/11 (54%) while in ICI+ICI group was 1/7 (14%). With a median follow-up of 32.4 months, median TFS was 6.2 months in the ICI+TKI group and 1.2 months in the ICI+ICI group (P=0.12). Median OS was 15.6 months in the ICI+TKI group and 36.7 months in the ICI+CI group (P=0.9).
Conclusions: With the limitations of the small sample size and retrospective nature, ICI+TKI resulted in higher ORR and TFS in comparison to ICI+ICI, however median OS was numerically longer in the ICI+ICI group. Larger studies are needed to validate these findings.
