Abstract 3765: IND-Enabling GLP study to support a clinical trial of dual adoptive cell therapy combining stem cells and T cells engineered with an NY-ESO-1 TCR

T cell receptor (TCR) engineered adoptive T cell transfer (ACT) has shown remarkable antitumor efficacy in several clinical trials. However, low persistence of modified cells limits long-term clinical responses. To overcome this hurdle, we propose a clinical trial co-administering genetically modified T cells and stem cells both expressing an NY-ESO-1 TCR such that the engrafted stem cells generate a source for constant renewal of modified T cells. Here we report a pre-clinical IND-enabling study performed at UCLA under Good Laboratory Practice (GLP) compliance to assess whether co-administration impacts (I) safety; (II) engraftment and cell lineage differentiation of gene modified stem cells; and (III) persistence of adoptively transferred T cells and stem cell-derived progeny. We performed 12 optimization studies to define the optimal conditions for TCR gene modified ACT and TCR gene modified hematopoietic stem cell (HSC) bone marrow transplantation (BMT). Sixty-four HLA-A2/kb transgenic mice were myelodepleted and received syngeneic BMT with Lineage depleted bone marrow (Lin-) cells transduced with the LV-NYESO-1 TCR/sr39TK and ACT with T cells transduced with the RV-NYESO-1 TCR. Control groups were as follows: untreated mice, mice receiving mock transduced Lin- cells and T cells, mice receiving transduced Lin- cells and mock transduced T cells, and mice receiving mock transduced Lin- cells and transduced T cells (n = 16 per group). Overall survival at 3 months was 87.5%; no significant differences in survival were observed among cohorts. After BMT we observed a decrease in body weight, elevation in creatinine kinase and transaminases, and gonadal germ cell ablation in all cohorts. Three months after BMT, all blood cell lineages were reconstituted in surviving mice. Using digital droplet PCR and flow cytometry, we confirmed that transduced stem cells engrafted and their progeny persisted long term. In the bone marrow, NY-ESO-1 TCR was expressed intracellularly among progenitor cells (Lin-, LSK and HSC) as well as all hematopoietic cell lineages within the spleen (CD8+ T cells, CD4+ T cells, NKT cells, B cells and granulocytes). Co-administration with gene modified T cells and stem cells did not affect engraftment, cell lineage differentiation or persistence of the gene modified stem cells. Moreover, co-administration with stem cells did not affect persistence of adoptively transferred T cells. These data demonstrate that 1) NY-ESO-1 TCR genetically modified stem cells engraft and differentiate into all hematopoietic cell lineage progeny, which persists at 3 months; 2) adoptively transferred NY-ESO-1 TCR T cells persist at 3 months; 3) co-administration of stem cells and T cells genetically modified to express an NY-ESO-1 TCR is safe and does not negatively impact stem cell engraftment, lineage differentiation and progeny persistence or T cell persistence. Citation Format: Cristina Puig-Saus, Giulia Parisi, Paige Krystofinski, Angel Garcia-Diaz, Salemiz Sandoval, James McCabe, Ruixue Zhang, Gardenia Cheung-Lau, Nhat Truong, Justin Saco, Sara Komenan, Agustin Vega-Crespo, Mignonette H Macabali, Begona Comin-Anduix, Beata Berent-Maoz, Donald Kohn, Paula Kaplan-Lefko, Antoni Ribas. IND-Enabling GLP study to support a clinical trial of dual adoptive cell therapy combining stem cells and T cells engineered with an NY-ESO-1 TCR [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3765. doi:10.1158/1538-7445.AM2017-3765