Distinct pathways of disease progression with dual checkpoint blockade versus immunotargeted therapy in metastatic renal cell carcinoma.

[BACKGROUND] Patterns of progression under immuno-oncology regimens in metastatic renal cell carcinoma (mRCC) remain poorly described. This study characterizes site-specific disease progression in patients receiving first-line dual immunotherapy or immunotargeted therapy.

[METHODS] This retrospective, observational cohort study included patients with clear-cell metastatic renal cell carcinoma treated between 2018 and 2024 with standard-dose regimens of nivolumab-ipilimumab (IO-IO) or pembrolizumab-axitinib and avelumab-axitinib combinations (IO-axitinib). The primary endpoint was the occurrence of new metastatic lesions at progression. Secondary endpoints included progression by >20% increase in target lesion size.

[RESULTS] Of 334 patients identified, 233 were evaluable for analysis. Radiographic progression occurred in 86.3% of IO-IO and 60% of IO-axitinib. Development of new metastatic lesions was more frequent with Nivo-Ipi (39.3% vs. 22.2%), most commonly involving the lungs and bones. In contrast, IO-axitinib combinations showed a greater propensity for progression through enlargement of pre-existing lesions (77.8% vs. 60.7%), accompanied by the emergence of new adrenal gland metastases. Across both treatment groups, lymph nodes emerged as the most frequent new site of disease progression.

[CONCLUSIONS] Nivo-Ipi was associated with more frequent development of new metastatic lesions, particularly in the lungs, bones, and lymph nodes, while axitinib-based combinations more often resulted in regrowth of existing disease with higher rates of adrenal involvement.