Engineering Lentiviral Constructs for Advanced Therapy Medicinal Product (ATMP) Programs

Executive Summary

For European biotechs advancing gene function studies, the design and production of custom lentiviral vectors present distinct technical and regulatory considerations. An effective vector requires precise promoter selection, transgene optimization, and integrated safety features to generate reliable data for early-stage ATMP programs. Franklin Biolabs provides highly characterized, custom-designed lentiviral vectors from our >100,000 sq ft facility, enabling robust target validation and functional genomics research aligned with future Investigational Medicinal Product Dossier (IMPD) requirements.

Designing Lentiviral Vectors for Stable Gene Expression

Lentiviral vectors are a primary tool for establishing stable, long-term gene expression in both dividing and non-dividing cells. This characteristic makes them exceptionally well-suited for developing stable cell lines for target validation or creating complex in vivo models for functional genomics.

The efficacy of these studies depends on the quality and design of the vector construct. A tailored approach is necessary to achieve the desired biological outcome. Key design elements include:

• Promoter Selection: Choosing between a constitutive promoter (e.g., CMV, EF1a) for broad expression or a tissue-specific promoter to restrict transgene expression to target cell populations.

• Transgene Optimization: Modifying the genetic payload through codon optimization to enhance protein expression levels within the target system.

• Safety Features: Incorporating a SIN design in the LTRs is a standard measure to reduce the potential for activating nearby proto-oncogenes following integration.

Integrating these design elements requires a comprehensive understanding of both vector production methodologies and the analytical assays needed to verify construct integrity and performance.

Foundational Principles Informing Vector Engineering

Our engineering philosophy draws from foundational principles established across the viral vector field. Insights from AAV development, for example, provide a framework for addressing universal challenges in vector efficacy and safety that are directly applicable to lentiviral construct design.

The direct link between vector efficacy and a tangible biological outcome, demonstrated in early gene transfer studies (PMID: 17180118), reinforces the value of rational construct design. Similarly, structural biology work that provides a platform for engineering vectors to evade pre-existing antibody responses (PMID: 24704217) highlights a core concept: understanding a vector’s fundamental properties allows for its modification to overcome specific biological barriers. We apply these principles to all custom vector projects.

Production and Analytics for Research-Grade Vectors

Following sequence verification of the plasmid DNA, high-titer lentiviral particles are produced via transient transfection of HEK293 cells. The vectors are then purified and subjected to a panel of analytical tests to determine titer, purity, and identity. This rigorous characterization ensures that each batch of custom vector provides the consistency and reliability needed for long-term studies supporting programs aiming for their first regulatory filing.