Target-anchored platform concentration and uneven developmental consolidation in systemic solid-tumor radioligand...

Radioligand therapy (RLT) has expanded rapidly across oncology, yet it remains unclear whether this expansion reflects broad multi-target maturation or continued concentration within a limited number of clinically deployable target-defined platforms. We hypothesized that contemporary systemic solid-tumor RLT development remains concentrated in a small number of more consolidated platforms rather than representing diffuse multi-target maturation.

This retrospective trial-level observational analysis used a prespecified Trialtrove export generated on March 23, 2026, restricted to Therapeutic Area = Oncology and Mechanism of Action = Radioemitter, with observational studies excluded. The raw export yielded 1341 oncology radioemitter trial records. Row-level platform-consistency curation excluded residual hematologic records, locoregional or intracavitary radiotherapies, non-targeted bone-seeking radiopharmaceuticals, and diagnostic-only studies, yielding a broad solid-tumor radioemitter universe of 558 trials. Additional exclusion of systemic radioligand records without a stably identifiable molecular target in the export fields produced a target-anchored systemic RLT universe of 513 trials. Future/planned records beyond 2025 were excluded from the historical main-text figure universe, leaving 462 trials. All eligible trials were included regardless of current status or achieved study phase; phase was used only as a descriptive grouping variable. Developmental consolidation was assessed descriptively across disease niche coherence, radionuclide strategy, scaffold architecture, and progression beyond early-phase exploration.

PSMA (n = 179) and somatostatin receptor (SSTR; n = 128) together accounted for 307 of 462 historical trials (66.5%). Disease positioning remained strongly target-centered, with PSMA overwhelmingly prostate-focused and SSTR concentrated in neuroendocrine tumors. PSMA and SSTR showed marked Lu-177 predominance, whereas newer target families were more radionuclide-heterogeneous. SSTR was almost entirely peptide-based, whereas PSMA spanned small-molecule/ligand, peptide, and antibody/engineered-protein formats. Phase 2 or later development was reached by 44.7% of PSMA trials and 52.3% of SSTR trials, but by only 11.1% of FAP trials, none of GRPR trials, 30.0% of CAIX trials, and 16.4% of trials in the broader other-target group.

Current systemic solid-tumor RLT development is characterized less by broad multi-target maturation than by marked platform concentration with uneven developmental consolidation. In this descriptive framework, trial growth alone is insufficient to indicate platform maturity; more informative is whether a target can sustain a coherent disease niche, a workable radionuclide strategy, a deployable carrier format, and advancement beyond early-phase exploration.