Evolution of the NCI antibody-drug conjugate portfolio: from chemical engineering to clinical complexity

Antibody-drug conjugates (ADCs) have transcended their status as experimental pharmacophores to become a cornerstone of precision oncology. However, the trajectory of federal investment driving this clinical renaissance remains largely unmapped. Understanding the evolution of National Cancer Institute (NCI) funding priorities is critical to identifying how resource allocation has shaped-and must continue to adapt to-the shifting challenges of drug development.

We performed a longitudinal analysis of the NCI grant portfolio spanning 2001 to 2025. To deconstruct the semantic evolution of the field, we employed BERTopic, a transformer-based topic modeling technique. This multi-dimensional approach correlated funding flux with institutional distribution, clinical study designs, and the technical specifications of investigated agents.

Our analysis delineates a distinct biphasic growth pattern, where a strategic inflection point in 2016 catalyzed an exponential surge in investment, synchronous with the clinical validation of second-generation platforms. Semantically, the field has undergone a profound structural maturation: research priorities have pivoted from foundational linker chemistry toward addressing the biological complexities of resistance mechanisms and integrating ADCs with immuno-oncology. Despite this translational momentum, we uncover a critical methodological disconnect; Analysis of experimental model systems across the full portfolio reveals that in vivo models represent the most prevalent explicit model type (24.0%, n = 94), followed by 2D cell line models (19.4%, n = 76), with organoid and 3D culture systems accounting for a small but growing proportion of recently funded projects (0.5%, n = 2). The limited adoption of organoid systems to date likely reflects the more recent emergence of these technologies rather than a deliberate funding gap.

NCI funding has evolved in parallel with the clinical maturation of ADCs. This evolution reflects a bidirectional relationship between public investment and regulatory milestones, in which early FDA approvals catalyzed renewed federal focus on the biological bottlenecks limiting first-generation agents, while the post-2013 portfolio demonstrates a marked emergence of combination therapy and immuno-oncology integration research. However, sustaining this wave of innovation requires a strategic realignment. Future investment must bridge the identified gap in preclinical modeling fidelity, where organoid and 3D culture systems remain markedly underrepresented.