Nampt-IN-1 (LSN3154567) (LSN3154567) is a potent and selective NAMPT inhibitor. Nampt-IN-1 inhibits purified NAMPT with an IC50 of 3.1 nM.

NAMPT:3.1 nM, CSF1R:0.84 μM

LSN3154567 inhibits purified NAMPT with an IC50 of 3.1 nM. When tested against a panel of human kinases (>100; CEREP Kinase panel), it does not exhibit any significant activity (i.e.: IC50≥1 μM) against the kinases tested except CSF1R (IC50≈0.84 μM). To assess its anticancer activity, LSN3154567 is tested against a number of different types of cancer cell lines cultured in the absence or presence of nicotinic acid (NA) (10 μM). LSN3154567 exhibits a potent antiproliferative activity against many cell lines in the absence of NA.

When dosed orally with 2 mg/kg in mice, it has an exposure of 195 nM*hour in the plasma with a peak concentration of 57 nM (at 0.25 hour) and an oral bioavailability of 39%. When dosed intravenously with 2 mg/kg, it has a hepatic clearance of 158.73 mL/min/kg and a volume of distribution at 7.1 L/kg. The half-life of terminal elimination is estimated to be 2.76 hours. LSN3154567 exhibits a dose-dependent inhibition of NAD+ formation with estimated TED50 value of 2.0 mg/kg. Dogs are treated with LSN3154567 at 1 and 2.5 mg/kg. At these dose levels, the retinal toxicity is observed. Degeneration of the outer nuclear layer occurred in all four animals, but is less pronounced in the animals treated with 1 mg/kg.

The cell lines used as following: A2780 and KM-12, KMS-11 and MKN-74, OPM-2 and Kelly; and all other cancer cells. Cells are seeded in 96-well plates, cultured overnight, and treated with LSN3154567 (0.03 to 1,000 nM)±NA (10 μM) in duplicate at 37°C in 5% CO2 for 72 hours. Staurosporine (10 μM) is used as positive control. Cell viability is determined by a CytoTox-Glo Cytotoxicity assay kit.

Male CD-1 mice are dosed with LSN3154567 at 2 mg/kg intravenously in 20% Captisol (w/v), 25 mmol/L NaPO4, pH 2, q.s. formulation or 2 mg/kg orally in the same vehicle in a cross over design with 3-d wash period in between two arms. Blood samples are obtained through retro orbital at 0, 0.08 (IV only), 0.25, 0.75, 2, 4, 8, and 24 hours and frozen until analysis. For exposure analysis, blood samples (≈20 μL) are obtained through tail clipping at 0.5, 1, 2, 4, 8, and 24 hours. The samples are collected into EDTA-coated capillary tubes and spotted onto Whatman DMPK-C DBS collection cards.