Systemic clinical tumor regressions and potentiation of PD1 blockade with in situ vaccination

Nat Med. 2019 May;25(5):814-824. doi: 10.1038/s41591-019-0410-x. Epub 2019 Apr 8.

Abstract

Indolent non-Hodgkin's lymphomas (iNHLs) are incurable with standard therapy and are poorly responsive to checkpoint blockade. Although lymphoma cells are efficiently killed by primed T cells, in vivo priming of anti-lymphoma T cells has been elusive. Here, we demonstrate that lymphoma cells can directly prime T cells, but in vivo immunity still requires cross-presentation. To address this, we developed an in situ vaccine (ISV), combining Flt3L, radiotherapy, and a TLR3 agonist, which recruited, antigen-loaded and activated intratumoral, cross-presenting dendritic cells (DCs). ISV induced anti-tumor CD8+ T cell responses and systemic (abscopal) cancer remission in patients with advanced stage iNHL in an ongoing trial ( NCT01976585 ). Non-responding patients developed a population of PD1+CD8+ T cells after ISV, and murine tumors became newly responsive to PD1 blockade, prompting a follow-up trial of the combined therapy. Our data substantiate that recruiting and activating intratumoral, cross-priming DCs is achievable and critical to anti-tumor T cell responses and PD1-blockade efficacy.

Publication types

  • Clinical Trial, Phase I
  • Clinical Trial, Phase II
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Animals
  • Antigen Presentation
  • CD8-Positive T-Lymphocytes / immunology
  • Cancer Vaccines*
  • Carboxymethylcellulose Sodium / analogs & derivatives
  • Carboxymethylcellulose Sodium / therapeutic use
  • Cell Line, Tumor
  • Combined Modality Therapy
  • Dendritic Cells / immunology
  • Female
  • Humans
  • Immunotherapy, Adoptive
  • Lymphoma, B-Cell / immunology
  • Lymphoma, B-Cell / pathology
  • Lymphoma, B-Cell / therapy*
  • Male
  • Membrane Proteins / immunology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Middle Aged
  • Poly I-C / therapeutic use
  • Polylysine / analogs & derivatives
  • Polylysine / therapeutic use
  • Programmed Cell Death 1 Receptor / antagonists & inhibitors
  • Programmed Cell Death 1 Receptor / immunology
  • Toll-Like Receptor 3 / agonists
  • Vaccination

Substances

  • Cancer Vaccines
  • Membrane Proteins
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor
  • TLR3 protein, human
  • Toll-Like Receptor 3
  • flt3 ligand protein
  • Polylysine
  • poly ICLC
  • Carboxymethylcellulose Sodium
  • Poly I-C