Abstract 4575: Correlates of clinical response following autologous stem cell transplant and adoptive immunotherapy with engineered T cells expressing an affinity-enhanced T cell receptor in patients with mutliple myeloma.

Background: Adoptive immunotherapy for cancer has been limited by lack of antigen specificity, low levels of target expression, and failure to break self-tolerance. We are conducting an early phase clinical trial (NCT01352286) attempting to overcome these barriers using T cells engineered with an HLA-A0201 restricted, affinity-enhanced TCR that recognizes an epitope expressed by the NY-ESO-1 and LAGE-1 cancer testis antigens; these cells are infused in the setting of profound lymphodepletion that accompanies high-dose chemotherapy with autologous stem cell transplant (aSCT) for patients with high risk or relapsed multiple myeloma (MM). Methods: Inclusion criteria include: 1) eligibility for aSCT, 2) PS of 0-2, 3) high risk MM or relapse after prior therapy, 4) HLA-A0201 positive, and 5) NY-ESO-1 and/or LAGE-1 positive tumor by PCR. CD25 depleted T cells are activated and expanded using anti-CD3/28 antibody conjugated microbeads, and genetically modified with a lentiviral vector. T cells are administered four days after high dose melphalan and two days following auto-SCT. Patients are evaluated for MM responses in accordance with the IMWG criteria at 6 weeks, and 3 and 6 months. At 3 months, patients with adequate marrow function start lenalidomide maintenance. Blood and marrow are monitored for persistence of engineered cells by qPCR and by surface expression of the NY-ESO-1 / LAGE-1 TCR using dextramer TM reagents. NY-ESO-1 and LAGE-1 antigen expression in marrow was assessed by qRT-PCR at baseline and post infusion. Results: As of November 2012, 21 patients have been enrolled, 15 have been infused; 4 were taken off study prior to infusion due to disease progression. An average of 2.7 x 10 9 engineered T cells were administered per patient (range 8.3 x 10 8 -4.2 x 10 9 ), and the average transduction efficiency was 33% (range 30%-45%). More than 50% (8/15) of patients have high risk chromosomal abnormalities, and 3 (20%) have received prior aSCT. At 3 months post aSCT, 73% of patients were in a very good partial response (VGPR) or better. Gastrointestinal toxicity resulting from autologous GVHD (aGVHD) occurred in a subset of patients at a higher rate than reported following aSCT alone or aSCT and T cell infusion, and was resolved in all cases. Infused T cells typically showed peak expansion in blood at day 14, followed by durable persistence in blood and marrow at 6-12 months in all but one patient. Disease progression is typically accompanied by very low levels or loss of engineered T cell persistence or loss of target antigen on tumor. Conclusions: We report for the first time that possible correlates of clinical response in this study include persistence of engineered T cells and loss of antigen, suggesting specific activity of the infused cells. Infusions are well tolerated with a possible risk of manageable aGVHD. Citation Format: Aaron P. Rapoport, Edward A. Stadtmauer, Dan T. Vogl, Brendan Weiss, Gwendolyn K. Binder-Scholl, Dominic P. Smethurst, Jeffrey Finkelstein, Irina Kulikovskaya, Minnal Gupta, Erica Suppa, Tatiana Mikheeva, Joanna E. Brewer, Alan D. Bennett, Andrew B. Gerry, Nick J. Pumphrey, Helen K. Tayton-Martin, Lilliam Ribeiro, Elizabeth Veloso, Zhaohui Zheng, Ashraf Z. Bados, Saul Yanovich, Gorgun Akpek, Karen Dengel, Naseem Kerr, Sunita Philip, Kelly-Marie Betts, Sandra Westphal, Bruce L. Levine, Bent K. Jakobsen, Carl H. June, Michael Kalos. Correlates of clinical response following autologous stem cell transplant and adoptive immunotherapy with engineered T cells expressing an affinity-enhanced T cell receptor in patients with mutliple myeloma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4575. doi:10.1158/1538-7445.AM2013-4575