Telaglenastat (CB-839) hydrochloride is a first-in-class, reversible, and orally active inhibitor of glutaminase 1 (GLS1). It selectively inhibits the splice variants of GLS1, specifically KGA (kidney-type glutaminase) and GAC (glutaminase C), as compared to GLS2. Telaglenastat hydrochloride has an IC50 of 23 nM for endogenous glutaminase in mouse kidney and 28 nM in the brain. In addition, it induces autophagy and exhibits antitumor activity.

Telaglenastat (CB-839) (0.1-1000 nM; 72 hours) has antiproliferative activity in HCC1806 and MDA-MB-231 cells with IC 50 s of 49 nM and 26 nM, respectively[1]. Telaglenastat (CB-839) (1 μM; 72 hours) activates caspase 3/7 and induces apoptosis in MDA-MB-231 and HCC1806 cells[1]. Cell Proliferation Assay[1]Cell Line: HCC1806, MDA-MB-231 cells Concentration: 0.1, 1, 10, 100, 1000 nM Incubation Time: 72 hours Result: Has a potent effect on the proliferation of the two TNBC cell lines (IC 50 of 49 nM and 26 nM for HCC1806 and MDA-MB-231 cells). Apoptosis Analysis[1]Cell Line: MDA-MB-231, HCC1806 cells Concentration: 1 μM Incubation Time: 72 hours Result: Caspase 3/7 activation.

Telaglenastat (CB-839) (200 mg/kg; p.o.; twice daily for 28 days) has antitumor activity in xenograft models of TNBC[1]. Animal Model: Female nu/nu mice with age 4–6 weeks (TNBC patient-derived xenograft model)[1]Dosage: 200 mg/kg Administration: Oral administration; twice daily for 28 days Result: Suppressed tumor growth by 61% relative to vehicle control at the end of study.