Neoadjuvant OX40 therapy in patients with head and neck cancer induces profound changes in tumor-infiltrating lymphocytes

Abstract

Abstract OX40 is a member of the tumor necrosis factor (TNF) receptor family and, as a co-stimulatory molecule, enhances T-cell proliferation, survival and memory formation. We have also shown that it induces robust antitumor responses in patients with metastatic disease. To examine the effect of OX40 stimulation on the immune response in cancer patients, 16 head and neck squamous cell carcinoma (HNSCC) patients were enrolled in a neoadjuvant phase Ib trial and received anti-OX40 infusion 2 days, 1 week and 2 weeks prior to surgical resection. To evaluate changes in the tumor microenvironment (TME), tissue and peripheral blood samples were obtained prior to infusion and at time of surgery. Assessment of changes in tumor infiltrating lymphocyte (TIL) and peripheral blood populations were performed by flow cytometry and fluorescent multiplex immunohistochemistry (IHC). OX40 administration was well tolerated with low toxicity. Activation and proliferation of CD4+ and CD8+ memory T-cell populations in both the TME and periphery peaked between 12 and 19 days after OX40 infusion, as demonstrated by increased levels of Ki67, CD38 and ICOS. In the TIL, expression of CD39, ICOS and PD-1 was increased on CD4+ T cells in most patients and the frequency of tumor-reactive CD39+CD103+ CD8+ T cells was increased in some patients. IHC analysis revealed striking changes in tissue integrity and increased lymphocyte infiltrates in 4/16 patients. With this study, we have found that neoadjuvant OX40 immunotherapy is feasible and safe in patients with HNSCC and results in robust activation and proliferation of T cells within the tumor. Based on these findings, we are now comparing the transcriptome and changes in TIL repertoire and metabolism before and after treatment.