Long term follow up of patients after allogeneic stem cell transplantation and transfusion of HSV-TK transduced T-cells

Abstract

Allogeneic stem cell transplantation (allo-HSCT) is one of the curative treatments for hematologic malignancies, but is hampered by severe complications, such as acute or chronic graft-versus-host-disease (aGvHD; cGvHD) and infections. CD34-selection of stem cells reduces the risk of aGvHD, but also leads to increased infectious complications and relapse. Thus, we studied the safety, efficacy, and feasibility of transfer of gene modified donor T-cells shortly after allo-HSCT in two clinical trials between 2002 and 2007 and here we compare the results to unmodified donor leukocyte infusion (DLI). The aim of these trials was to provide patients with the protection of T-cells after T-cell-depleted allo-HSCT in the matched or mismatched donor setting with an option to delete transduced T-cells, if severe aGvHD occurred within the trial period. Donor-T-cells were transduced with the replication-deficient retrovirus SFCMM-3, expressing HSV-TK and the truncated ΔLNGFR for selection of transduced cells. Transduced cells were transfused either after day +60 (matched donors) or on day +42 (haploidentical donors). Nine patients were included in the first trial (MHH; 2002 until 2007), two were included in TK007 (2005–2009) and six serves as a control group for outcome after haploidentical transplantation without HSV-TK-transduced DLI. Three patients developed acute GvHD, two had grade I of the skin, one had aGvHD on day +131 (post-HSCT; +89 post-HSV-TK DLI) grade II, which was successfully controlled by ganciclovir (GCV). Donor chimerism was stabilized after transfusion of the transduced cells in all patients treated. Functionality of HSV-TK gene expressing T-cells was shown by loss of bcr-able gene expression as well as by control of cytomegalovirus-reactivation. To date, six patients have relapsed and died, two after a second hematopoietic stem cell transplantation without T-cell depletion or administration of unmodified T-cells. Eleven patients (seven post-HSV-TK DLI) are alive and well to date.

Immune Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation

“…Thus, ex vivo T-cell depletion by either CD34 + cell selection or CD3 + /CD19 + cell depletion has not been routinely performed and repletion protocols have been widely studied [e.g., HSV-Tk-transduced T cell transfer, other donor lymphocyte infusion-based protocols (109, 110)]. In vivo T cell reducing or impairing agents include ATG [e.g., ATG-Fresenius; Germany, or thymoglobulin (thymo); Genzyme; USA] or anti-CD52 antibody (alemtuzumab or campath), a particularly powerful reagent for immunosuppression (108, 111).…”

Engineering Therapeutic T Cells: From Synthetic Biology to Clinical Trials

“…An alternative method of controlling CAR T cell activity and specificity is to make a universal CAR T cell whose CAR receptor can be docked with an antibody or antibody fragment that gives the cell different specificity (Figure 2c). This approach has been described by multiple groups using a variety of docking interactions, such as avidin-biotin, antibody-small molecule, and antibody-peptide binding pairs (119–123). However, these studies also showed the precise orientation of the antigen-binding components of these receptors affects CAR activity.…”

“…In the initial report, the successfully transduced cells were positively selected using a truncated version of the nerve growth factor receptor that was coexpressed with the viral thymidine kinase (139). In the initial investigation and in subsequent clinical trials using similar HSV-TK systems, patients who received modified donor T cells after allogeneic stem cell transplants and subsequently developed GVHD were successfully treated with ganciclovir (123). However, an anti-HSV-TK immune response has been described in some patients, which in some cases led to immune-mediated elimination of the genetically modified allogeneic T cells.…”

Current status of ex vivo gene therapy for hematological disorders: a review of clinical trials in Japan around the world

“…In the TK suicide gene/ prodrug system, only alloreactive gene-modified T cells that proliferate actively during GVHD are killed by GCV, whereas resting transduced T cells and untransduced cells are spared. TK gene therapy has proven to be safe, with no documented adverse events related to the gene-transfer procedure, including appearance of replication-competent retroviruses or genotoxic effects of vector integration [61][62][63][64][65][66][67][68][69][70][71].…”