Abstract A81: Adoptively transferred Chondromodulin 1/HLA-A:0201 allo-restricted T cell receptor transgenic CD8+ T cells are well tolerated and cause partial regression in a patient with disseminated Ewing Sarcoma

Abstract

Abstract Background: Patients with Ewing sarcoma (ES) metastatic to bone and bone marrow (BM) do not survive irrespective of therapy. We assessed toxicity, viability, BM homing and anti-tumor activity of adoptively transferred HLA-A*0201/chondromodulin 1 (CHM1) allo-restricted T cell receptor (TCR) transgenic CD8+ T cells in an ES patient with refractory disease including marrow. Patient and Methods: An twelve years old HLA-A2+ boy was diagnosed with ES of the right femur. After treatment according to the Euro-Ewing 2008 protocol he suffered early relapse 11 months after diagnosis. For relapse treatment he received MetaEICESS 2007 including consolidation with haploidentical stem cell transplantation (allo-SCT) from his HLA-A2- mother. Before and shortly after transplant the patient relapsed twice. Thereafter he suffered from progressive disease under combined rescue radiochemotherapy. Within one week after the last progression, he received 1 x 106/kg (1st transfer, d0) and 8.2 x 106/kg CHM1319-T cell receptor (TCR) transgenic donor CD8+ T cells (2nd transfer, d32; in combination with ipilimumab and nivolumab), respectively. A patient derived ES cell line was isolated. Results: CHM1319-TCR transgenic donor T cells showed specific in vitro lysis of the patient's ES cell line. One week after 1st transfer, CHM1319-TCR transgenic T cells stained CHM1319 multimer positive in BM but negative in peripheral blood (PB). After 2nd transfer, BM of posterior iliac spines as well as PB stained CHM1319 multimer positive at a high rate and RT-PCR and flow-cytometric CD99+/CD45- ES phenotype as well as partial PET-signal reduction were noted. Five further metastatic bone/ marrow compartments showed significant PET signal regression. The patient never developed GvHD symptoms and died of disease 10 weeks after 1st transfer due to resistant lung metastasis. Conclusions: CHM1319-TCR transgenic T cells home to affected BM and cause partial disease regression. These cells may proliferate in vivo for at least four weeks without causing GvHD. Citation Format: Uwe Thiel, Andreas Kirschner, Ingo Einspieler, Stefan Burdach. Adoptively transferred Chondromodulin 1/HLA-A:0201 allo-restricted T cell receptor transgenic CD8+ T cells are well tolerated and cause partial regression in a patient with disseminated Ewing Sarcoma. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A81.