Process development and validation of expanded regulatory T cells for prospective applications: an example of manufacturing a personalized advanced therapy medicinal product

Cristiana Lavazza,Sara Savelli,Silvia Budelli,Matteo Cescon,Lucia Catani,Marta Giulia Cannone,Lorenza Lazzari,Tiziana Montemurro,Francesca Ulbar,Rosaria Giordano,Gaetano La Manna,Mariele Viganò,Elisa Montelatici,Elisa Groppelli,Roberto M Lemoli

doi:10.1186/s12967-021-03200-x

Abstract

BackgroundA growing number of clinical trials have shown that regulatory T (Treg) cell transfer may have a favorable effect on the maintenance of self-tolerance and immune homeostasis in different conditions such as graft-versus-host disease (GvHD), solid organ transplantation, type 1 diabetes, and others. In this context, the availability of a robust manufacturing protocol that is able to produce a sufficient number of functional Treg cells represents a fundamental prerequisite for the success of a cell therapy clinical protocol. However, extended workflow guidelines for nonprofit manufacturers are currently lacking. Despite the fact that different successful manufacturing procedures and cell products with excellent safety profiles have been reported from early clinical trials, the selection and expansion protocols for Treg cells vary a lot. The objective of this study was to validate a Good Manufacturing Practice (GMP)-compliant protocol for the production of Treg cells that approaches the whole process with a risk-management methodology, from process design to completion of final product development. High emphasis was given to the description of the quality control (QC) methodologies used for the in-process and release tests (sterility, endotoxin test, mycoplasma, and immunophenotype).ResultsThe GMP-compliant protocol defined in this work allows at least 4.11 × 109 Treg cells to be obtained with an average purity of 95.75 ± 4.38% and can be used in different clinical settings to exploit Treg cell immunomodulatory function.ConclusionsThese results could be of great use for facilities implementing GMP-compliant cell therapy protocols of these cells for different conditions aimed at restoring the Treg cell number and function, which may slow the progression of certain diseases.

Highlights

A growing number of clinical trials have shown that regulatory T (Treg) cell transfer may have a favorable effect on the maintenance of self-tolerance and immune homeostasis in different conditions such as graftversus-host disease (GvHD), solid organ transplantation, type 1 diabetes, and others
Regulatory T (Treg) cells are an attractive type of advanced therapy medicinal product (ATMP) for adoptive cell therapy that can be used when the restoration of immunotolerance to self- or allo-antigens may prevent or even cure diseases [1,2,3].In murine models, expanded Treg cells have been shown to be effective for the induction of long-term tolerance to bone marrow transplantation, for the prevention of graft-versus-host disease (GvHD), and for prolonging heart and skin allograft survival [4,5,6,7]
As part of our collaborative interinstitutional ATMP development program for adoptive cell therapy in organ transplantation, in the present paper, we describe in detail some practical issues of the whole process for Treg cell expansion, starting from Good Manufacturing Practice (GMP) validation; in particular, the novel items are discussed [18, 20, 27,28,29,30,31,32,33,34,35]

Summary

Introduction

A growing number of clinical trials have shown that regulatory T (Treg) cell transfer may have a favorable effect on the maintenance of self-tolerance and immune homeostasis in different conditions such as graftversus-host disease (GvHD), solid organ transplantation, type 1 diabetes, and others. At the time of writing the present article, the safety and the potential clinical efficacy of ex vivo-expanded autologous polyclonal T reg cells are under evaluation in 48 clinical trials worldwide for indications such as end-stage kidney disease (KD), kidney or liver transplantation, type 1 diabetes, and GvHD [9] In these conditions, Treg cells could be a promising therapeutic tool to promote donor-specific transplant tolerance by exerting their immunomodulatory properties in controlling allograft rejection, for both therapeutic and preconditioning regimens, possibly allowing reduction and/or discontinuation of immunosuppressive drugs [10]. While both autologous and allogeneic T reg cells have been used in hematopoietic stem cell transplantation [12, 14], autologous cells are the preferred choice in solid organ transplantation [15]

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