Defining the Quality Attributes for Tumor-Infiltrating Lymphocyte Medicinal Products.

Area of Science:

• Cellular immunotherapy
• Pharmaceutical development
• Regulatory science

Background:

• Tumor-infiltrating lymphocyte (TIL) medicinal products (MPs) demonstrate potential in treating solid tumors, particularly metastatic melanoma.
• Current development focuses on immunological mechanisms, but a pharmaceutical perspective is crucial for regulatory approval.
• Establishing well-defined TIL MPs requires identifying and optimizing quality attributes (QAs) impacting safety and efficacy.

Purpose of the Study:

• To outline the initial steps of the quality-by-design workflow for TIL MP pharmaceutical development.
• To structure key quality attributes within a quality target product profile (QTPP) considering regulatory expectations.
• To propose critical QAs and considerations for developing TIL MPs based on literature and regulatory standards.

Main Methods:

• Defining the active pharmaceutical ingredient (API) of TIL MPs as CD45+CD3+ cells.
• Analyzing identity attributes correlated with clinical efficacy to describe in vivo functionalities.
• Structuring QAs within a QTPP framework, encompassing quantity, identity, purity, microbiological assays, and biological activity.

Main Results:

• Four in vivo functionalities (tumor recognition, cytotoxic capacity, tumor homing, persistence) associated with TIL MoA and clinical effectiveness are described.
• The quantification and limitations of potency assays for these functionalities are discussed.
• A QTPP serves as a foundation for developing control strategies for regulatory approval and improved patient access.

Conclusions:

• A pharmaceutical development perspective, focusing on QAs and a QTPP, is essential for TIL MP regulatory approval.
• Understanding and controlling QAs, including in vivo functionalities, can lead to more robust and effective TIL MPs.
• Harmonizing TIL MP development through a unified QTPP can facilitate comparisons and advance the creation of safer, more efficacious therapies.