Lauren Roesch

Antiviral T Cells for Adenovirus in the Pretransplant Period: A Bridge Therapy for Severe Combined Immunodeficiency.

Viral infections can be life threatening in patients with severe combined immunodeficiency (SCID) and other forms of profound primary immunodeficiency disorders both before and after hematopoietic stem cell transplantation (HSCT). Adoptive immunotherapy with virus-specific T cells (VSTs) has been utilized in many patients in the setting of HSCT, but has very rarely been attempted for treatment of viral infections before HSCT. Here we describe the use of VSTs in an infant with RAG1 SCID who had developed disseminated adenovirus which failed to improve on cidofovir. Adenovirus cleared following 2 doses of VSTs and marrow infusion from a matched unrelated donor, without incidence of graft versus host disease. T cell receptor-b sequencing demonstrated expansion of adenovirus-specific T cell fraction of the VSTs, suggesting that infusion facilitated viral clearance. This report suggests that VSTs are likely safe in the pre-HSCT period, and may be a useful bridge therapy for infants with SCID and persistent viral infections.

75. Development of an LMP-Specific T Cell Bank for Third Party Use as a Curative Strategy Post-Transplant Lymphoproliferative Disease After Solid Organ Transplant

EBV-associated tumors in the immune deficient host express type II and III latency antigens including latent membrane protein 1 (LMP1) and LMP2, which can serve as potential targets for immunotherapy. Several studies have documented the safety and efficacy of LMP-specific T cells for patients with EBV-associated malignancies, but clinical applications may be limited by the time to generate LMP-specific T cell products as well as the availability of an appropriate donor source. We hypothesize that the administration of “off the shelf” third party LMP-specific cytotoxic lymphocytes (LMP-CTLs) will rapidly restore EBV-specific T-cell immunity and prevent relapse in patients with post-transplant lymphoproliferative disease PTLD post solid organ transplant (SOT). To develop the third party T cell bank, we manufactured healthy donor-derived LMP-specific T cells from eligible donors with a wide range of HLA types in our good manufacturing practices (GMP) facility. This T-cell bank is for several clinical trials including a proposed multicenter Childrens Oncology Group (COG) trial (ANHL1522) for patients with PTLD after SOT. Currently, 15 LMP-specific T-cell products have been manufactured from healthy donors and released for third-party use using autologous monocytes and lymphoblastoid cell lines (LCL), transduced with an adenoviral vector expressing ΔLMP1 and LMP2. T-cell products were active against LMP2 (mean:172 SFU/1×10^5 cells; range:13-655), LMP1 (33; 1-322), and LCL (87; 0-424) as determined by IFN-γ ELISPOT assay. Epitope mapping of LMP-specific T cells using IFN-γ ELISPOT assay demonstrates that these products recognize a broad epitope repertoire within LMP1 and LMP2. At the time of cryopreservation, the T-cell products comprised a mean of 45% CD8+ T-cells, 35% CD4+ T-cells, and 9% NK cells. No B cells or monocytes were detected in the final products. Thus far, one patient with NK/T cell non-Hodgkin Lymphoma received third party LMP-specific T cells achieving a very good partial response. No infusion-related toxicities were observed, and LMP-specific T cells were detectable post-infusion. Thus, third party LMP-specific T cells appear to be a safe and promising therapeutic modality for patients with EBV-associated lymphomas, and a third party bank will make this therapeutic more readily available to patients with PTLD post-SOT.

685. Restoration of Antiviral Immunity Following Hematopoietic Stem Cell Transplantation with Virus-Specific T-Lymphocyte Therapy

Background: Adoptive immunotherapy using virus-specific cytotoxic T-lymphocyte (VST) products has been successful in restoring antiviral immunity after hematopoietic stem cell transplantation (HSCT). VST may be produced from a stem cell donor in 10-14 days using current rapid protocols, or banked, partially-HLA matched VST may be used as an “off the shelf” treatment. Objective: To evaluate the clinical efficacy of HSCT donor-derived VST and third-party VST for prevention or treatment of CMV, EBV, and adenovirus following HSCT. Design/Methods: VST were cultured from HSCT or third-party donors using a GMP-compliant rapid-manufacture protocol. VST were tested for specificity and non-alloreactivity via IFN-γ ELISpot and cytotoxicity assays. Patients were monitored for 45 days following infusion for toxicity and for up to 22 months for immune reconstitution. Results: Nineteen patients received VST on existing protocols, of which 15 products were derived from HSCT donors, and 6 were from partially matched, third-party donors. Sixteen patients were treated for CMV (N=11), EBV (N=5), and/or adenovirus infections(n=3), of which fourteen (88%) had partial or complete antiviral responses. Immune reconstitution against targeted viruses was seen using IFN-g ELISpot at a median time of 28 days following infusion. Three patients developed grade I-II GVHD within 45 days of VST infusion, all of which was treatment responsive. Sixteen of the 19 patients remain alive and free of active viral infection up to 22 months post-VST infusion. Conclusions: VST are effective for the restoration of antiviral following HSCT. Expansion of targeted viruses may further extend the utility of this therapy.