Late-phase strategies to overcome limitations of PD-1/PD-L1 therapy: a clinical development trajectory through 2030

Inhibition of the PD-1/PD-L1 axis has become a clinical standard across multiple malignancies, yet durable benefit remains restricted to selected settings, and many biologically rational combinations fail to maintain clinical benefit in late-phase evaluation. This structured, registry-derived narrative review, supported by expert-guided interpretation, was designed to identify the most clinically meaningful development directions among strategies intended to overcome the limitations of PD-1/PD-L1 inhibitor therapy and most likely to generate practice-relevant late-phase readouts through 2030. We searched major international and regional clinical trial registries and applied harmonization, cross-registry deduplication, formal late-phase filtering, semi-automated prioritization, and manual documentation-based verification. The final analytic corpus was interpreted using a two-level framework: first, by the dominant clinicobiological barrier limiting PD-1/PD-L1 efficacy, and second, by three criteria of clinical promise - exposure and effect, manageable toxicity, and confirmable clinical benefit. This approach narrowed a registry-derived pool of more than 13, 000 PD-1/PD-L1 studies to 47 clinically relevant late-phase programs that define the most likely near-term development trajectory through 2030. Within this corpus, a narrower confirmatory subset emerged in which incremental clinical benefit is tested most directly in comparative designs. These programs represent the most plausible leading strategies of the next phase of PD-1/PD-L1-based clinical development and provide a clinically interpretable framework for prioritizing future translational and late-phase efforts.