Immunotherapy for Lymphoma Using T Cells Targeting Multiple Tumor Associated Antigens

Immunotherapy is emerging as a potent therapy for a range of hematologic malignancies. To extend this approach to individuals with Hodgkin's (HL) and non-Hodgkin's lymphoma (NHL) we developed a protocol for the generation of single T cell lines that simultaneously targeted a range of tumor associated antigens (TAAs) that are frequently expressed by these tumors, including PRAME, SSX2, MAGEA4, NY-ESO-1 and Survivin. We were consistently able to generate multiTAA-specific T cells by culturing PBMCs in the presence of a Th1-polarizing/pro-proliferative cytokine cocktail, using autologous DCs as APCs and loading them with pepmixes (15mer peptides overlapping by 11 aminos acids) spanning all 5 target antigens. The use of whole antigen increases the range of patient HLA polymorphisms that can be exploited beyond those matched to single peptides, while targeting multiple antigens simultaneously reduces the risk of tumor immune evasion.

To date 28 clinical-grade multiTAA-specific T cell lines have been generated comprising CD3+ T cells (mean 94±2%) with a mixture of CD4+ (mean 46±7%) and CD8+ (mean 46±6%) T cells, which expressed central and effector memory markers (CD45RO+/CD62L+/CCR7+ -- mean 22±5%; CD45RO+/CD62L+/CCR7- -- 12±4%; CD45RO+/CD62L-/CCR7- -- 35±6%) (n=28). The expanded lines recognized the targeted antigens PRAME, SSX2, MAGEA4, NY-ESO-1 and Survivin (range 1-354, 0-496, 0-330, 0-379 and 0-304 spot forming units (SFU)/2x10⁵ input cells, respectively in IFNg ELIspot, n=28). None of the lines reacted against non-malignant autologous recipient cells (3±3.7% specific lysis; E:T 20:1).

We have treated 18 patients to date: 9 with HL, 8 with aggressive NHL (diffuse large B-cell, mantle cell, or peripheral T cell lymphomas), and 1 with a composite lymphoma. Patients have received 0.5-2x10⁷ multiTAA-T cells/m² without adverse events. Of 11 patients who were infused as adjuvant therapy all but 1 remain in remission (range 1-24 months post-infusion). Seven patients have received multiTAA-specific T cells to treat active disease. Of these, 1 had transient disease stabilization followed by disease progression, 3 have stable disease 3-6 months post-multiTAA-specific T cells while the remaining 3 (all with HL) have all had complete responses, as assessed by PET imaging. These clinical responses correlated with the detection of tumor-reactive T cells in patient peripheral blood post-infusion directed against both targeted antigens as well as non-targeted TAAs including MAGEA2B and MAGE C1, indicating antigen/epitope spreading. Thus, infusion of autologous multiTAA-targeted T cells directed to PRAME, SSX2, MAGEA4, NY-ESO-1 and Survivin has been safe and provided clinical benefit to patients with lymphomas.