Adoptive cell therapy with autologous tumor infiltrating lymphocytes and low-dose Interleukin-2 in metastatic melanoma patients

Abstract

Background: Adoptive cell therapy may be based on isolation of tumor-specific T cells, e.g. autologous tumor infiltrating lymphocytes (TIL), in vitro activation and expansion and the reinfusion of these cells into patients upon chemotherapy induced lymphodepletion. Together with high-dose interleukin (IL)-2 this treatment has been given to patients with advanced malignant melanoma and impressive response rates but also significant IL-2 associated toxicity have been observed. Here we present data from a feasibility study at a Danish Translational Research Center using TIL adoptive transfer in combination with low-dose subcutaneous IL-2 injections.

Methods: This is a pilot trial (ClinicalTrials.gov identifier: NCT00937625) including patients with metastatic melanoma, PS ≤1, age <70, measurable and progressive disease and no involvement of the central nervous system. Six patients were treated with lymphodepleting chemotherapy, TIL infusion, and 14 days of subcutaneous low-dose IL-2 injections, 2 MIU/day.

Results: Low-dose IL-2 considerably decreased the treatment related toxicity with no grade 3-4 IL-2 related adverse events. Objective clinical responses were seen in 2 of 6 treated patients with ongoing complete responses (30+ and 10+ months), 2 patients had stable disease (4 and 5 months) and 2 patients progressed shortly after treatment. Tumor-reactivity of the infused cells and peripheral lymphocytes before and after therapy were analyzed. Absolute number of tumor specific T cells in the infusion product tended to correlate with clinical response and also, an induction of peripheral tumor reactive T cells was observed for 1 patient in complete remission.

Conclusion: Complete and durable responses were induced after treatment with adoptive cell therapy in combination with low-dose IL-2 which significantly decreased toxicity of this therapy.

Figure 1

Immune and clinical evaluation of patient 11.a) FACS plot from intracellular cytokine staining showing the percentage of interferon (IFN)-γ and tumor necrosis factor (TNF)-α producing CD3⁺CD8⁺T cells after incubation with autologous tumor cell lines or Staphylococcal Enterotoxin B (control). First row showing reactivity of tumor infiltrating lymphocytes (TIL) from the infusion product, second and third row showing reactivity of peripheral blood monocytes (PBMC) 1 week before infusion of TILs and 3 weeks after. b) PET/CT scan from 1 week before infusion of TILs and 8 weeks after infusion of TILs. Arrows outlining the measurable disease.

Figure 2

Infusion product tested for reactivity against a dendritic cell vaccine (patient 11).a) IFN-γ ELIspot analyses; Responses are defined as number of IFN-γ secreting cells per 3 x 10³ TILs. b) Intracellular cytokine staining; percentage of T cells staining double positive for IFN-γ and TNF-α (first column) or for CD8 and CD107a (second column) DC-mock: mock-transfected dendritic cell (negative control), vac: vaccine, tri: triple transfected, sur: survivin, hTERT: human Telomerase Reverse Transciptase, TIL: tumor infiltrating lymphocytes.