GDC-0623 (G868) is a novel, potent, orally bioactive, selective, and non-ATP-competitive (allosteric) MEK1 inhibitor that may have anticancer effects. With a Ki of 0.13 nM, it blocks MEK1. Both mutant BRAF and mutant KRAS can be effectively treated with GDC-0623. The RAF-MEK complex is stabilized and MEK is made to dimerize. The RAS/RAF/MEK/ERK signaling pathway, which controls cell growth, is important for MEK activity, and constitutive activation of this pathway has been linked to numerous cancers.

Physicochemical Properties

Molecular Formula	C16H14FIN4O3
Molecular Weight	456.21
Exact Mass	456.009
Elemental Analysis	C, 42.12; H, 3.09; F, 4.16; I, 27.82; N, 12.28; O, 10.52
CAS #	1168091-68-6
Related CAS #	1168091-68-6
PubChem CID	42642654
Appearance	Light yellow to gray solid powder
Density	1.8±0.1 g/cm3
Index of Refraction	1.703
LogP	4.16
Hydrogen Bond Donor Count	3
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	6
Heavy Atom Count	25
Complexity	461
Defined Atom Stereocenter Count	0
SMILES	IC1C=CC(=C(C=1)F)NC1=C(C(NOCCO)=O)C=CC2=CN=CN12
InChi Key	RFWVETIZUQEJEF-UHFFFAOYSA-N
InChi Code	InChI=1S/C16H14FIN4O3/c17-13-7-10(18)1-4-14(13)20-15-12(16(24)21-25-6-5-23)3-2-11-8-19-9-22(11)15/h1-4,7-9,20,23H,5-6H2,(H,21,24)
Chemical Name	5-(2-fluoro-4-iodoanilino)-N-(2-hydroxyethoxy)imidazo[1,5-a]pyridine-6-carboxamide
Synonyms	G-868; GDC 0623; G868; GDC 0632; GDC0632; G 868
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	MEK1 (Ki = 0.13 nM)
ln Vitro	GDC-0623 (RG 7421) and G-573 are able to prevent MEK phosphorylation by CRAF in vitro, and able to block MEK phosphorylation by BRAF(V600E)[1]. Although GDC-0623 (RG 7421) is a powerful, ATP-uncompetitive MEK1 inhibitor, it exhibits distinct changes in cellular activity when compared to the other two inhibitors, with only a 6-fold reduction in EC50[2].
ln Vivo	GDC-0623 (RG 7421) (40 mg/kg, p.o.) exhibits %TGI, or percent tumour growth inhibitionin MiaPaCa-2 xenograft model. In all three KRAS models, GDC-0623 (RG 7421) and G-573 exhibit stronger antitumor activity than GDC-0623 (RG 7421)[1].
Enzyme Assay	In 15 μL of kinase buffer (20 mM MOPS pH 7.2, 25 mM beta glycerol phosphate, 5 mM EGTA, 1 mM sodium orthovanadate, 1 mM DTT, 100 μM ATP, 15 mM MgCl2), 0.14 μM of purified inactive recombinant MEK-1 (Upstate) protein is preincubated with inhibitors. 1 ng of BRAF, CRAF, or BRAF V600E is added to the reaction in a total volume of 20 μL after 10 minutes of incubation at 30°C. Also added are 0.5 μg of inactive recombinant ERK2. The reaction is stopped by adding Laemmle sample buffer following a 30-minute incubation period at 30°C. SDS-PAGE analysis of the level of phosphor-MEK provides an indication of the enzyme activity. SuperSignal West Pico Chemiluminescent Substrate allows the visualization of immunoreactive proteins.
Cell Assay	The QuickChange site-directed mutagenesis kit is used to produce the S212P and S212A mutants of Flag-MEK1. HCT116 cells express N-terminally Flag-tagged MEK-1 from mammalian expression vectors. The following day, 1.8×106 HCT116 cells are plated in a 10 cm plate and lipofectamine 2000 is used to transfect the cells with 17 g of expression constructs. After 48 hours, cells are harvested and lysed in 100 L cell extraction buffer after being treated with inhibitors for the indicated times. SDS-PAGE is used to examine the cell lysates from each sample. Immunoreactive proteins are examined using SuperSignal West Pico Chemiluminescent Substrate after membranes have been incubated with phospho-MEK S221, phospho-ERK1/2, and phospho-MEK1 primary antibodies.
Animal Protocol	Colo205 xenografts are created by injecting 6–8 week old female nude (nu/nu) mice with 5×106 cells resuspended in Hank's Balanced Salt Solution (HBSS) subcutaneously (s.c.) into the rear right flank. In order to create NCI-H2122 xenografts, 6–8 week old female nu/nu mice are injected with 1×107 cells that have been resuspended in Hank's Balanced Salt Solution (HBSS) and matrigel (growth factor reduced). In order to start an A375 or MiaPaca-2 xenograft, 1 mm3 tumor fragments from the corresponding passaged tumors are injected subcutaneously (s.c.) into the flank of athymic nu/nu mice. When tumors have grown to approximately 200 mm3, mice are randomized and treated with either vehicle (methylcellulose 0.1% tween 80 0.1% (MCT)), GDC-0973 (at 10 mg/kg), GDC-0623 (RG 7421) (at 40 mg/kg), or G-573 (at 100 mg/kg). All MEK inhibitor doses corresponded to maximally tolerated doses (MTDs), which did not cause weight loss of more than 15% to 20% of body weight. Using digital calipers and the equation (L×W×W)/2, tumor volumes are calculated. Tumor growth inhibition (%TGI) is calculated as a proportion of the area under the fitted curve (AUC) for the corresponding dose group daily in comparison to the vehicle. Animal weights are measured twice a week, and mice are taken out of the study if they lose ≥20% or more of their body weight. Complete responses (CRs) are defined as any tumor demonstrating a 100% reduction in tumor volume at any point during the study, whereas partial responses (PRs) are defined as any tumor demonstrating a ≥ 50% decrease in tumor volume.
References	[1]. Mechanism of MEK inhibition determines efficacy in mutant KRAS- versus BRAF-driven cancers. Nature. 2013 Sep 12;501(7466):232-6. [2]. Elucidating the Mechanisms of Formation for Two Unusual Cytochrome P450-Mediated Fused Ring Metabolites of GDC-0623, a MAPK/ERK Kinase Inhibitor. Drug Metab Dispos. 2015 Dec;43(12):1929-1933.
Additional Infomation	GDC-0623 is a member of the class of imidazopyridines that is imidazo[1,5-a]pyridine substituted by (2-fluoro-4-iodophenyl)amino and (2-hydroxyethoxy)aminoacyl groups at positions 5 and 6. It is a potent ATP non-competitive inhibitor of MEK1 (Ki = 0.13nM) and also has efficacy against both mutant BRAF and mutant KRAS. It is in clinical development for treatment of patients with locally advanced or metastatic solid tumors. It has a role as an EC 2.7.12.2 (mitogen-activated protein kinase kinase) inhibitor, an antineoplastic agent and an apoptosis inducer. It is a substituted aniline, a member of monofluorobenzenes, an organoiodine compound, an imidazopyridine, a secondary amino compound, a hydroxamic acid ester and a primary alcohol. GDC-0623 has been used in trials studying the treatment of Solid Cancers. MEK Inhibitor GDC-0623 is an orally active, selective MEK inhibitor with potential antineoplastic activity. MEK inhibitor GDC-0623 specifically inhibits mitogen-activated protein kinase kinase (MEK or MAP/ERK kinase), resulting in inhibition of growth factor-mediated cell signaling and tumor cell proliferation. MEK is a key component of the RAS/RAF/MEK/ERK signaling pathway that regulates cell growth; constitutive activation of this pathway has been implicated in many cancers.

Solubility Data

Solubility (In Vitro)

DMSO: ~91 mg/mL (~199.5 mM) Water: <1 mg/mL Ethanol: ~5 mg/mL(~11.0 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.48 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (5.48 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: Methylcellulose 0.1% tween 80 0.1% (MCT): 5mg/mL  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.1920 mL	10.9599 mL	21.9197 mL
	5 mM	0.4384 mL	2.1920 mL	4.3839 mL
	10 mM	0.2192 mL	1.0960 mL	2.1920 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.