Progression risk among responders to PD-1/PD-L1 blockade is primarily stratified by response depth: A nationwide cohort study of 2127 patients with melanoma, RCC, and NSCLC.

PURPOSE: Among responders to PD-1/PD-L1 blockade, it remains unclear whether tumour type and traditional baseline patient and tumour characteristics provide additional prognostic information for progression risk beyond response depth.

METHODS

In this nationwide, population-based cohort study, we identified adults with metastatic melanoma (MM), renal cell carcinoma (RCC), or non-small cell lung cancer (NSCLC) treated with PD-1/PD-L1 monotherapy or dual checkpoint blockade. Analyses were restricted to responders by investigator-assessed RECIST (complete or partial response) with outcomes administratively censored at 5 years. Prespecified baseline and on-treatment variables were evaluated for associations with progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier and Cox models and assessed for consistency across tumour types.

RESULTS

Among 2127 responders, PFS trajectories within response depth categories (complete response and partial response) were highly similar across MM, RCC, and NSCLC. Prespecified variables with prognostic value in the overall population, including performance status and treatment line, provided limited additional prognostic information once response depth was known. Depth of response (complete vs partial) was the strongest independent factor associated with progression risk within each tumour cohort.

CONCLUSIONS

Among patients with MM, RCC, or NSCLC who achieved an objective response to PD-1/PD-L1 blockade, tumour type and traditional baseline prognostic factors provided limited additional stratification of progression risk once response depth was known. These findings suggest that, within the tumour types studied, response durability is primarily associated with response depth rather than other known clinical features, supporting prospective evaluation of response-guided follow-up strategies and interventions designed to deepen responses.