Trial watch: IDO inhibitors in cancer therapy.
Indoleamine 2,3-dioxigenase 1 (IDO1) is the main enzyme that catalyzes the first, rate-limiting step of the so-called "kynurenine pathway", i.e., the metabolic cascade that converts the essential amino acidL-tryptophan (Trp) intoL-kynurenine (Kyn). IDO1, which is expressed constitutively by some tissues and in an inducible manner by specific subsets of antigen-presenting cells, has been shown to play a role in the establishment and maintenance of peripheral tolerance. At least in part, this reflects the capacity of IDO1 to restrict the microenvironmental availability of Trp and to favor the accumulation of Kyn and some of its derivatives. Also, several neoplastic lesions express IDO1, providing them with a means to evade anticancer immunosurveillance. This consideration has driven the development of several IDO1 inhibitors, some of which (including 1-methyltryptophan) have nowadays entered clinical evaluation. In animal tumor models, the inhibition of IDO1 by chemical or genetic interventions is indeed associated with the (re)activation of therapeutically relevant anticancer immune responses. This said, several immunotherapeutic regimens exert robust clinical activity in spite of their ability to promote the expression of IDO1. Moreover, 1-methyltryptophan has recently been shown to exert IDO1-independent immunostimulatory effects. Here, we summarize the preclinical and clinical studies testing the antineoplastic activity of IDO1-targeting interventions.
Gustave Roussy Cancer Campus ; Villejuif, France ; INSERM U1138 ; Paris, France ; Equipe 11 labellisée par la Ligue Nationale contre le Cancer; Centre de Recherche des Cordeliers ; Paris, France ; ; Université Paris-Sud/Paris XI; Orsay , Paris, France.
Erika
E
Vacchelli
Gustave Roussy Cancer Campus ; Villejuif, France ; INSERM U1138 ; Paris, France ; Equipe 11 labellisée par la Ligue Nationale contre le Cancer; Centre de Recherche des Cordeliers ; Paris, France ;
Fernando
F
Aranda
Gustave Roussy Cancer Campus ; Villejuif, France.
Alexander
A
Eggermont
INSERM U1138 ; Paris, France ; Equipe 13; Centre de Recherche des Cordeliers ; Paris, France ; Université Pierre et Marie Curie/Paris VI ; Paris, France.
Catherine
C
Sautès-Fridman
Université Paris Descartes/Paris V; Sorbonne Paris Cité ; Paris, France ; INSERM U970 ; Paris, France ; Pôle de Biologie; Hôpital Européen Georges Pompidou; AP-HP ; Paris, France.
Eric
E
Tartour
NewLink Genetics Co. ; Ames, IA USA.
Eugene P
EP
Kennedy
Department of Neurooncology; University Hospital Heidelberg and National Center for Tumor Diseases ; Heidelberg, Germany ; German Cancer Consortium (DKTK) Clinical Cooperation Unit Neuroimmunology and Brain Tumor Immunology; German Cancer Research Center (DKFZ) ; Heidelberg, Germany.
Michael
M
Platten
Gustave Roussy Cancer Campus ; Villejuif, France ; INSERM U1015; CICBT507 ; Villejuif, France.
Laurence
L
Zitvogel
INSERM U1138 ; Paris, France ; Equipe 11 labellisée par la Ligue Nationale contre le Cancer; Centre de Recherche des Cordeliers ; Paris, France ; ; Université Paris Descartes/Paris V; Sorbonne Paris Cité ; Paris, France ; Pôle de Biologie; Hôpital Européen Georges Pompidou; AP-HP ; Paris, France ; Metabolomics and Cell Biology Platforms; Gustave Roussy Cancer Campus ; Villejuif, France.
Guido
G
Kroemer
Gustave Roussy Cancer Campus ; Villejuif, France ; INSERM U1138 ; Paris, France ; Equipe 11 labellisée par la Ligue Nationale contre le Cancer; Centre de Recherche des Cordeliers ; Paris, France ; ; Université Paris Descartes/Paris V; Sorbonne Paris Cité ; Paris, France.
Lorenzo
L
Galluzzi
1-methyl-D-tryptophan; AHR, aryl hydrocarbon receptor; BIN1, bridging integrator 1; CTLA4, cytotoxic T lymphocyte associated protein 4; DC, dendritic cell; FDA, Food and Drug Administration; GCN2, general control non-derepressible 2; HCC, hepatocellular carcinoma; IDO, indoleamine 2,3-dioxigenase; IFNγ, interferon γ; INCB024360; Kyn, L-kynurenine; NK, natural killer; NLG919; ODN, oligodeoxynucleotide; TDO2, tryptophan 2,3-dioxigenase; TLR, Toll-like receptor; Treg, regulatory T cell; Trp, L-tryptophan; indoximod; interferon γ; peptide-based anticancer vaccines