Infigratinib (BGJ398)

The enzymatic kinase activity is assessed by measuring the phosphorylation of a synthetic substrate by the purified GST-fusion FGFR3-K650E kinase domain, in the presence of radiolabeled ATP. Enzyme activities are measured by mixing 10 μL of a 3-fold concentrated BGJ398 solution or control with 10 μL of the corresponding substrate mixture (peptidic substrate, ATP and [γ³³P]ATP). The reactions are initiated by addition of 10 μL of a 3-fold concentrated solution of the enzyme in assay buffer. The final concentrations of the assay components are as following: 10 ng of GST-FGFR3-K650E, 20 mM Tris-HCl, pH 7.5, 3 mM MnCl₂, 3 mM MgCl₂, 1 mM DTT, 250 μg/mL PEG 20000, 2 μg/mL poly(EY) 4:1, 1% DMSO and 0.5 μM ATP (γ-[³³P]-ATP 0.1 μCi). The assay is carried out according to the filter binding (FB) method in 96-well plates at room temperature for 10 minutes in a final volume of 30 μL including BGJ398. The enzymatic reactions are stopped by the addition of 20 μL of 125 mM EDTA, and the incorporation of ³³P into the polypeptidic substrates is quantified as following: 30 μL of the stopped reaction mixture are transferred onto Immobilon-PVDF membranes previously soaked for 5 minutes with methanol, rinsed with water, soaked for 5 min with 0.5% H₃PO₄, and mounted on vacuum manifold with disconnected vacuum source. After spotting, vacuum is connected, and each well rinsed with 0.5% H₃PO₄ (200 μL). Free membranes are removed and ished four times on a shaker with 1% H₃PO₄ and once with ethanol. Membranes are dried and overlaid with addition of 10 μL/well of a scintillation fluid. The plates are eventually sealed and counted in a microplate scintillation counter. IC50 values are calculated by linear regression analysis of the percentage inhibition of the BGJ398.

Murine BaF3 cell lines

0 μM-0.1 μM

48 hours

Murine BaF3 cell lines, whose proliferation and survival has been rendered IL-3-independent by stable transduction with tyrosine kinases activated either by mutation or fusion with a dimerizing partner, are cultured in RPMI-1640 media supplemented with 10% FBS, 4.5 g/L glucose, 1.5 g/L sodium bicarbonate, and Pen/Strep. Cells are passaged twice weekly. BGJ398-mediated inhibition of BaF3 cell proliferation and viability is assessed using a Luciferase bioluminescent assay. Exponentially growing BaF3 or BaF3 Tel-TK cells are seeded into 384-well plates (4250 cells/well) at 50 μL/well using a μFill liquid dispenser in fresh medium. BGJ398 is serially diluted in DMSO and arrayed in a polypropylene 384-well plate. Then 50 nL of BGJ398 are transferred into the plates containing the cells by using the pintool transfer device, and the plates incubated at 37 °C (5% CO₂) for 48 hours. Then 25 μL of Bright-Glo are added, and luminescence is quantified using an Analyst-GT. Custom curve-fitting software is used to produce a logistic fit of percent cell viability as a function of the logarithm of inhibitor concentration. The IC50 value is determined as the concentration of BGJ398 needed to reduce cell viability to 50% of a DMSO control.

Athymic nude-nu mice bearing parental RT112 cell line

10 mg/kg/qd and 30 mg/kg/qd

Oral administration