Cobimetinib racemate is the racemic mixture of Cobimetinib (GDC-0973, RG7420; XL-518; Cotellic), which is a novel, orally bioavailable, highly potent and selective small-molecule MEK1 inhibitor with antitumor activity. With an IC50 of 4.2 nM, it inhibits MEK1. In order to treat melanoma, cobimetinib was approved in 2015 as an anti-cancer drug to be used alone, in combination with vemurafenib, or in combination with both vemurafenib and atezolizumab. Extracellular signal-related kinase 2 (ERK2) phosphorylation and activation are inhibited, and tumor cell proliferation is decreased as a result of GDC-0973's specific binding to and inhibition of the catalytic activity of MEK1.

Physicochemical Properties

Molecular Formula	C21H21F3IN3O2
Molecular Weight	531.31
Exact Mass	531.063
CAS #	934662-91-6
Related CAS #	Cobimetinib;934660-93-2;Cobimetinib hemifumarate;1369665-02-0;Cobimetinib (R-enantiomer);934660-94-3;Cobimetinib-13C6 racemate
PubChem CID	51038893
Appearance	White to off-white solid
LogP	4.12
Hydrogen Bond Donor Count	3
Hydrogen Bond Acceptor Count	7
Rotatable Bond Count	4
Heavy Atom Count	30
Complexity	624
Defined Atom Stereocenter Count	0
SMILES	O=C(N1CC(C2CCCCN2)(O)C1)C1C(NC2C(F)=CC(I)=CC=2)=C(F)C(F)=CC=1
InChi Key	BSMCAPRUBJMWDF-UHFFFAOYSA-N
InChi Code	InChI=1S/C21H21F3IN3O2/c22-14-6-5-13(19(18(14)24)27-16-7-4-12(25)9-15(16)23)20(29)28-10-21(30,11-28)17-3-1-2-8-26-17/h4-7,9,17,26-27,30H,1-3,8,10-11H2
Chemical Name	[3,4-difluoro-2-(2-fluoro-4-iodoanilino)phenyl]-(3-hydroxy-3-piperidin-2-ylazetidin-1-yl)methanone
Synonyms	XL518 racemate, GDC-0973, RG7420 racemate;XL518; RG-7420; XL 518;GDC-0973; XL-518 racemate; GDC0973 racemate; GDC 0973; RG 7420racemate
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

ln Vitro	Cobimetinib shows strong activity on cell growth inhibtion in a broad panel of tumor types, particularly in BRAF or KRAS mutant cancer cell lines. GDC-0973 causes 888MEL and A2058 cells to undergo more apoptosis, pathway inhibition, and reduced viability when combined with GDC-0941. All BRAFV600E lines have increased levels of GLUT-1 on the cellular membrane following coadministration of GDC-0973 and vemurafenib.
ln Vivo	Cobimetinib (10 mg/kg, p.o.) and GDC-0973 and GDC-0941 together exhibit improved antitumor efficacy in mice with BRAFV600E and KRAS mutant tumors. Combining GDC-0973 and GDC-0941 results in lower levels of hexokinase II, c-RAF, Ksr, and p-MEK protein in mice with drug-resistant A375 xenografts.
Enzyme Assay	Cobimetinib (GDC-0973, RG7420) is a potent, selective and oral MEK1 inhibitor with an IC50 of 4.2 nM for MEK1.
Cell Assay	For 888MEL and A2058 cells, cobimetinib (GDC-0973) has EC50 values of 0.2 M and 10 M, respectively. Treatment of melanoma cells with EC50 concentrations of MEK and PI3K inhibitors (888MEL: 0.05 μM GDC-0973, 2.5 μM GDC-0941; A2058: 2.5 μM GDC-0973, 2.5 μM GDC-0941) lasts for 24 hours. In melanoma with constitutive MAPK activation in A375 cells, mitochondrial OXPHOS regulates the amount of cell death brought on by cobimetinib (100 nM).
Animal Protocol	1, 3, or 10 mg/kg 5 million WM-266-4 melanoma cells are resuspended in Hank balanced salt solution and implanted intradermally into the hind flank of female NCR nude mice. On days 11 or 13 after the implantation, xenograft mice with tumor volumes of approximately 100 to 120 mm3 are randomLy assigned to 8 groups (n=27 per group), 4 single dose groups and 4 multiple dose groups. One day after randomization and group assignment, mice in the single dose groups are given a single oral dose of vehicle (water for injection USP), 1, 3, or 10 mg/kg of Cobimetinib (GDC-0973, expressed as free base equivalents). Mice in the multiple dose groups are given daily oral doses of vehicle (water for injection USP), 1, 3, or 10 mg/kg of GDC-0973 for 14 days. Plasma and tumor samples (n=3 per time point) are collected from euthanized mice predose and at 2, 4, 8, 16, 24, 72, 120, and 168 hours postdose on day 1 (single dose groups) or day 14 (multiple dose groups). Samples are stored at 80°C until analysis. GDC-0973 concentrations in plasma and tumor lysates are determined using liquid chromatography/tandem mass spectrometry (LC/MS-MS). The dynamic range of the assay is 0.004 to 35 μM.
References	[1]. Intermittent administration of MEK inhibitor GDC-0973 plus PI3K inhibitor GDC-0941 triggers robust apoptosis and tumor growth inhibition. Cancer Res. 2012 Jan 1;72(1):210-9.
Additional Infomation	See also: Cobimetinib (annotation moved to).

Solubility Data

Solubility (In Vitro)

DMSO: ~100 mg/mL (~188.2 mM) Water: <1 mg/mL Ethanol: ~47 mg/mL (~88.46 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (4.71 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 (4.71 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: ≥ 2.5 mg/mL (4.71 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (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 corn oil and mix evenly. Solubility in Formulation 4: 5% DMSO+30% PEG 300+5% Tween 80+ddH2O: 5mg/mL  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	1.8821 mL	9.4107 mL	18.8214 mL
	5 mM	0.3764 mL	1.8821 mL	3.7643 mL
	10 mM	0.1882 mL	0.9411 mL	1.8821 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.