Navoximod (NLG-​919, GDC-0919) is a potent indoleamine-(2,3)-dioxygenase (IDO) pathway inhibitor (Ki/EC50: 7 nM/75 nM).

Using IDO-expressing human monocyte-derived dendritic cells (DCs) in allogeneic mixed lymphocyte reaction (MLR) reactions, Navoximod potently blocks IDO-induced T cell suppression and restores robust T cell responses (ED50: 80 nM). Similarly, using IDO-expressing mouse DCs from tumor-draining lymph nodes, Navoximod abrogates IDO-induced suppression of antigen-specific T cells (OT-I) in vitro (ED50: 120 nM) [1]. Navoximod inhibits the IDO activity in a concentration-dependent manner with an EC50 of 0.95 μM. PEG2k-Fmoc-NLG(L) is less active (EC50: 3.4 μM) in inhibiting IDO compared with free Navoximod while PEG2k-Fmoc-NLG(S) is least active (EC50>10 μM). Coculture of IDO+tumor cells with splenocytes isolated from BALB/c mice leads to significant inhibition of T-cell proliferation. This inhibition is significantly attenuated when the mixed cells are treated with Navoximod. PEG2k-Fmoc-NLG(L) is also active in reversing the inhibitory effect of tumor cells although slightly less potent than Navoximod [3].

In mice, a single oral administration of Navoximod reduces the concentration of plasma and tissue Kyn by ~50%. In vivo, in mice bearing large established B16F10 tumors, administration of Navoximod markedly enhances the anti-tumor responses of naïve, resting pmel-1 cells to vaccination with cognate hgp100 peptide plus CpG-1826 in IFA. In this stringent established-tumor model, Navoximod plus pmel-1/vaccine produces a dramatic collapse of tumor size within 4 days of vaccination (~95% reduction in tumor volume compared to control animals receiving pmel-1/vaccine alone without Navoximod) [1]. When combined with Temozolomide (TMZ)+radiation therapy (RT), both Navoximod and 1-methyl-D-tryptophan (D-1MT, indoximod) enhance survival relative to mice treated with TMZ+RT alone [2].

Mice are anesthetized with 4% isoflurane, and the surgical plane of anesthesia is maintained with 2% isoflurane in oxygen. Mice are immobilized in a stereotactic frame for tumor implantation. Briefly, the skull is shaved and exposed with a 0.5 cm skin incision. With the antiseptic technique, 10^5 GL261 cells (suspended in 3 μL RPMI-1640) are injected at the following coordinates with respect to the bregma on the right side (antero-posterior, -2 mm; medio-lateral, 2 mm; dorsoventral, 3 mm). This placement reproducibly yielded tumor growth in a paracortical area of the posterolateral right frontal lobe. Tumor-bearing mice are treated with combinations of oral DL-1MT (2 mg/mL D-1MT mixed with 2 mg/mL L-1MT) in drinking water, D-1MT (4 mg/mL) in drinking water, Navoximod (6 mg/mL) in drinking water, intraperitoneal cyclophosphamide, intraperitoneal temozolomide, and/or total-body radiation (500 cGy from a 137Cs source), as detailed in figure legends. Mice are observed daily and sacrificed when they became ill or moribund [2].

GDC-0919

99.81% 

316.37 

>95% as determined by SDS-PAGE

C18H21FN2O2

1402837-78-8