A multifunctional role for adjuvant anti-4-1BB therapy in augmenting antitumor response by chimeric antigen receptor T cells

Sherly Mardiana, Liza B John, Melissa A. Henderson, Clare Y. Slaney, Bianca von Scheidt, Lauren Giuffrida, Alexander J Davenport, Joseph A. Trapani, Paul J. Neeson, Sherene Loi, Nicole M Haynes, Michael H. Kershaw, Paul A. Beavis, Phillip K. Darcy

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60 Citations (Scopus)


Adoptive immunotherapy utilizing chimeric antigen receptor (CAR) T cells has demonstrated high success rates in hematologic cancers, but results against solidmalignancies have been limited to date, due in part to the immunosuppressive tumor microenvironment. Activation of the 4-1BB (CD137) pathway using an agonistic α-4-1BB antibody is known to provide strong costimulatory signals for augmenting and diversifying T-cell responses.Wetherefore hypothesized that a combination of α-4-1BB and CAR T-cell therapy would result in improved antitumor responses. Using a human-Her2 self-antigen mouse model, we report here that α-4- 1BB significantly enhanced CAR T-cell efficacy directed against the Her2 antigen in two different established solid tumor settings. Treatment also increased the expression of IFNg and the proliferation marker Ki67 in tumor-infiltrating CAR T cells when combined with α-4-1BB. Strikingly, α-4-1BB significantly reduced host immunosuppressive cells at the tumor site, including regulatory T cells and myeloid-derived suppressor cells, correlating with an increased therapeutic response. We conclude that α-4-1BB has a multifunctional role for enhancing CAR T-cell responses and that this combination therapy has high translational potential, given current phase I/II clinical trials with α-4-1BB against various types of cancer.

Original languageEnglish
Pages (from-to)1296-1309
Number of pages14
JournalCancer Research
Issue number6
Publication statusPublished - 15 Mar 2017

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