Navoximod

NLG919 potently blocks IDO-induced T-cell suppression and restored robust T-cell responses with ED50 of 80 nM. Similarly, using IDO-expressing mouse DCs from tumor-draining lymph nodes, NLG919 abrogated IDO-induced suppression of antigen-specific T cells (OT-I) in vitro, with ED50 of 120 nM. ^[1]

NLG919 increases the cytotoxic activity toward B16-F10 cells in the presence of pretreatment with interferon (IFN)-γ in vitro.^[3]

B16-F10 cells are diluted to 1 × 10⁵ cells/mL with DMEM supplemented with 10% FBS and seeded at 2 mL per well into 6-well plates. The culture medium is replaced with fresh growth medium with or without 25 ng/mL IFN-γ for 10–12 h after seeding. After incubation with IFN-γ for 24 h, the medium is replaced with fresh medium containing 100 nM NLG919, 3 nM PTX, or a combination of 100 nM NLG919 and 3 nM PTX, and medium containing 0.1% DMSO is used as the vehicle treatment. PTX at 3 nM is a concentration with low inhibition rate (IR) of cell growth about 20%. At 0, 12, 24, 48, and 72 h after addition of drugs, cells are washed to remove dead cells and particles. Adherent cells are trypsinized and counted using a CountStar IC1000 Automated Cell Counter (Ruiyu-Biotech). Viability of the counted cells is confirmed by 0.1% blue exclusion. The effect of NLG919 and PTX on the growth of cells is analyzed by plotting cell growth curves using viable cell numbers against time.

In mice, a single oral administration of NLG919 reduces the concentration of plasma and tissue Kyn by ~ 50%. In mice bearing B16F10 tumors, NLG919 markedly enhances the antitumor responses of naive, resting pmel-1 cells to vaccination with cognate hgp100 peptide plus CpG-1826 in IFA.^[1]

Immune competent mice are injected orthotopically with genetically engineered murine glioma cells and treated with GDC-0919 alone or combined with RT. GDC-0919 demonstrates potent inhibition of this node and effectively crosses the blood brain barrier. Although GDC-0919 as a single agent does not demonstrate anti-tumor activity, it has a strong potential for enhancing RT response in glioblastoma, which is further augmented with a hypofractionated regimen.^[2]