Conceptual comparison between monoclonal antibody-drug conjugates (ADCs) and polyclonal drug conjugates (pPDCs).
| Feature | ADCs | pPDCs |
|---|---|---|
| Antibody composition | Single, defined monoclonal antibody recognizing one epitope | Mixture of immunoglobulins (IGs) or IG-derived frameworks recognizing multiple epitopes |
| Epitope coverage | Single-epitope targeting; vulnerable to antigen loss or mutation | Multi-epitope recognition; potentially more resilient to tumor heterogeneity |
| Target specificity | High specificity for a predefined surface antigen | Broader targeting spectrum shaped by endogenous immune selection |
| Tumor heterogeneity handling | Limited; reduced efficacy if antigen expression is heterogeneous | Conceptually better suited to heterogeneous tumors due to polyclonality |
| Immunogenicity risk | May require humanization; risk of anti-drug antibody formation | Potentially lower if derived from endogenous or patient-matched IGs |
| Manufacturing complexity | Highly controlled but expensive and time-intensive | Conceptually simpler frameworks, but standardization remains challenging |
| Drug-antibody ratio (DAR) | Precisely controlled and well-characterized | More variable; requires optimization and validation |
| Pharmacokinetics | Well-characterized and predictable | Less well-defined; requires systematic investigation |
| Clinical maturity | Multiple FDA-approved ADCs across solid tumors | Exploratory and early-stage; limited clinical validation |
| Applicability in K-Ras-mutant CRC | Limited, as effective surface targets are scarce | Potential relevance through intracellular targeting or neoantigen association |
| Primary limitations | Antigen escape, toxicity, cost, resistance | Variability, regulatory complexity, need for robust validation |
| Current role | Established therapeutic modality | Emerging therapeutic modality |
| Positioning of current study | — | Computational and proteomic feasibility assessment for CRC-specific pPDC design |