Pilot Clinical Trial of Adoptive Immunotherapy with Chimeric, Co-Stimulated Tumor-Infiltrating Lymphocytes after Allogeneic Hematopoietic Stem Cell Transplantation.

Treatment of refractory or recurrent malignancy with donor lymphocyte infusion (DLI) after allogeneic hematopoietic stem cell transplantation (alloHSCT) is often not curative, with graft-vs-tumor (GVT) effects frequently accompanied by graft-versus-host disease (GVHD), requiring immune suppression that compromises efficacy. After alloHSCT, chimeric T lymphocytes infiltrating residual tumor (chimeric TIL) may provide enhanced antigen specificity and maintain tumor-specific homing. Compared with DLI, they may have a better GVT effect with less GVHD. Based on the success of autologous TIL therapy for melanoma, we tested the hypothesis that enhanced GVT with limited GVHD could be achieved through administration of ex-vivo activated chimeric TIL after alloHSCT. Preclinical TIL production carried out on several tumor types from non-transplanted patients demonstrated effective T cell isolation, expansion and activation using anti-CD3/CD28 bead co-stimulation, yielding a 10- to 30-fold expansion of CD3⁺ cells. Clinical evaluation of chimeric TIL therapy was initiated with a 51 year-old woman for metastatic breast cancer whose disease progressed after a T cell-depleted reduced-intensity alloHSCT with delayed DLI from a 6/6 HLA-matched sibling donor and subsequent conventional therapy plus DLI. Two weeks after administration of unmanipulated DLI, two thoracic metastases were surgically removed. T cells were liberated from 9.4 cm of tumor using enzymatic digestion and mechanical dispersion, lymphocyte-enriched by density gradient separation, and expanded for 14 days through co-stimulation with anti-CD3/CD28-coated magnetic beads (3:1 bead-to-total nucleated cell ratio) and media containing IL-2 (100 or 1000 IU/mL). This process yielded 42.5 x 10⁶ cells, 33% expressing CD3, and generated 14.7 x 10⁹ chimeric TIL, 85% expressing CD3 (a 3.1-log T cell expansion). There was no tumor contamination of the T cell product by immunohistochemistry. Flow cytometry demonstrated that the CD4/CD8 T cell ratio increased from 1.3 to 1.9 after expansion. Three infusions of the chimeric TIL product were given in a dose-escalating manner (5, 25 and 100 x 10⁶ CD3⁺ cells/kg). A fourth infusion was given in conjunction with low-dose IL-2 (6mu SQ per day x 3D). CT scan performed after each infusion monitored disease response, with progressive disease the indication for the next dose administration. No infusion-related or delayed toxicities were observed, except for rigors following IL-2 administration. The patient shows no evidence of GVHD, even after the highest dose of 10⁸ allogeneic T cells. Evaluation of the remaining thoracic lesion demonstrated progressive disease after the first two chimeric TIL dose-levels, transient disease stability one month after the third dose-level, and stable disease one month after the fourth dose with IL-2. This is the first clinical report of the application of chimeric TIL and represents a novel approach for developing new forms of adoptive immunotherapy in the setting of alloHSCT.