PI3Kα (Ki = 2 nM); PI3Kδ (Ki = 3 nM); PI3Kγ (Ki = 10 nM); PI3Kβ (Ki = 46 nM); mTOR (Ki = 70 nM)

GDC-0084 has excellent human metabolic stability in microsomal and hepatocyte incubations and demonstrated inhibition of pAKT, a key signal within the PI3K pathway, in normal brain tissue[1]. With an IC50 ranging from 0.3 to 1.1 μM, GDC-0084 has been shown to suppress the growth of several glioma cells in vitro. With a free fraction (%) in CD-1 mouse plasma of 29.5±2.7 (n=3) when tested at 5 M, GDC-0084 binding to plasma proteins is weak. A higher free fraction of 6.7% (±1; n=3)[2] indicates stronger binding to the brain tissues of CD-1 mice.

GDC-0084 markedly inhibits the PI3K pathway in mouse brain, causing up to 90% suppression of the pAkt signal. GDC-0084 effectively inhibits tumor growth in the U87 and GS2 orthotopic models by 70% and 40%, respectively. The PI3K pathway is effectively inhibited by the distribution of GDC-0084 in intracranial tumors and the brain. It is being tested on humans, and the exposures at doses that are safe are similar to those linked to effective doses in mouse models[2].

Enzymatic activity of PI3Kα is measured using a fluorescence polarization assay that monitors formation of the product 3,4,5-inositoltriphosphate molecule (PIP3) as it competes with fluorescently labeled PIP3 for binding to the GRP-1 pleckstrin homology domain protein. An increase in phosphatidyl inositide-3-phosphate product results in a decrease in fluorescence polarization signal as the labeled fluorophore is displaced from the GRP-1 protein binding site. PI3Kα is expressed and purified as heterodimeric recombinant protein. PI3Kα is assayed under initial rate conditions in the presence of 10 mM Tris (pH 7.5), 25 uM ATP, 9.75 uM PIP2, 5% glycerol, 4 mM MgCl2, 50 mM NaCl, 0.05% (v/v) Chaps, 1 mM dithiothreitol, 2% (v/v) DMSO at a 60 ng/mL concentration of PI3Kα. After assay for 30 min at 25°C, reactions are terminated with a final concentration of 9 mM EDTA, 4.5 nM TAMRA-PIP3, and 4.2 ug/mL GRP-1 detector protein before reading fluorescence polarization on an Envision plate reader. IC50s are calculated from the fit of the dose-response curves to a 4-parameter equation. Apparent Kis, where measured, are determined at a fixed concentration of ATP near the measured Km for ATP for PI3Kα, and are calculated by fitting of the dose-response curves to an equation for tightbinding competitive inhibition.

For transport studies, cells are seeded on 24-well Millicell plates 4 days prior to use(polyethylene terephtalate membrane, 1 μm pore size) at a seeding density of 1.3×105 cells/ml). Tests are conducted on GDC-0084 at 5 μM in both the apical-to-basolateral (A-B) and basolateral-to-apical (B-A) directions. In a transport buffer made up of 10 mM HEPES in Hanks' balanced salt solution, the substance is dissolved. As a marker for the integrity of monolayers and paracytic layers, Lucifer Yellow is employed. Utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, the concentrations of GDC-0084 in the donor and receiving compartments were found. After a 2-hour incubation, the apparent permeability (Papp) in the apical to A-B and B-A directions is calculated.

Male Sprague−Dawley rats or female CD-1 mice
1 mg/kg（i.v.）;5 or 25 mg/kg(p.o.)
i.v. or p.o.

[1]. ACS Med Chem Lett . 2016 Feb 16;7(4):351-6.

[2]. Drug Metab Dispos . 2016 Dec;44(12):1881-1889.

GDC-0084 is under investigation in clinical trial NCT03696355 (Study of GDC-0084 in Pediatric Patients With Newly Diagnosed Diffuse Intrinsic Pontine Glioma or Diffuse Midline Gliomas).
Paxalisib is a phosphatidylinositol 3-kinase (PI3K) inhibitor with potential antineoplastic activity. paxalisib specifically inhibits PI3K in the PI3K/AKT kinase (or protein kinase B) signaling pathway, thereby inhibiting the activation of the PI3K signaling pathway. This may result in the inhibition of both cell growth and survival in susceptible tumor cell populations. Activation of the PI3K signaling pathway is frequently associated with tumorigenesis. Dysregulated PI3K signaling may contribute to tumor resistance to a variety of antineoplastic agents.

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Inhibition of phosphoinositide 3-kinase (PI3K) signaling is an appealing approach to treat brain tumors, especially glioblastoma multiforme (GBM). We previously disclosed our successful approach to prospectively design potent and blood-brain barrier (BBB) penetrating PI3K inhibitors. The previously disclosed molecules were ultimately deemed not suitable for clinical development due to projected poor metabolic stability in humans. We, therefore, extended our studies to identify a BBB penetrating inhibitor of PI3K that was also projected to be metabolically stable in human. These efforts required identification of a distinct scaffold for PI3K inhibitors relative to our previous efforts and ultimately resulted in the identification of GDC-0084 (16). The discovery and preclinical characterization of this molecule are described within.[1] Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. Limited treatment options have only marginally impacted patient survival over the past decades. The phophatidylinositol 3-kinase (PI3K) pathway, frequently altered in GBM, represents a potential target for the treatment of this glioma. 5-(6,6-Dimethyl-4-morpholino-8,9-dihydro-6H-[1,4]oxazino[4,3-e]purin-2-yl)pyrimidin-2-amine (GDC-0084) is a PI3K inhibitor that was specifically optimized to cross the blood-brain barrier. The goals of our studies were to characterize the brain distribution, pharmacodynamic (PD) effect, and efficacy of GDC-0084 in orthotopic xenograft models of GBM. GDC-0084 was tested in vitro to assess its sensitivity to the efflux transporters P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) and in vivo in mice to evaluate its effects on the PI3K pathway in intact brain. Mice bearing U87 or GS2 intracranial tumors were treated with GDC-0084 to assess its brain distribution by matrix-assisted laser desorption ionization (MALDI) imaging and measure its PD effects and efficacy in GBM orthotopic models. Studies in transfected cells indicated that GDC-0084 was not a substrate of P-gp or BCRP. GDC-0084 markedly inhibited the PI3K pathway in mouse brain, causing up to 90% suppression of the pAkt signal. MALDI imaging showed GDC-0084 distributed evenly in brain and intracranial U87 and GS2 tumors. GDC-0084 achieved significant tumor growth inhibition of 70% and 40% against the U87 and GS2 orthotopic models, respectively. GDC-0084 distribution throughout the brain and intracranial tumors led to potent inhibition of the PI3K pathway. Its efficacy in orthotopic models of GBM suggests that it could be effective in the treatment of GBM. GDC-0084 is currently in phase I clinical trials.[2]

C18H22N8O2

382.4197

382.1866

C, 56.53; H, 5.80; N, 29.30; O, 8.37

1382979-44-3

1382979-44-3

57384863

Solid powder

1.6±0.1 g/cm3

1.789

-0.76

117Ų

CC1(C2=NC3=C(N2CCO1)N=C(N=C3N4CCOCC4)C5=CN=C(N=C5)N)C

LGWACEZVCMBSKW-UHFFFAOYSA-N

InChI=1S/C18H22N8O2/c1-18(2)16-22-12-14(25-3-6-27-7-4-25)23-13(11-9-20-17(19)21-10-11)24-15(12)26(16)5-8-28-18/h9-10H,3-8H2,1-2H3,(H2,19,20,21)

5-(6,6-dimethyl-4-morpholino-8,9-dihydro-6H-[1,4]oxazino[4,3-e]purin-2-yl)pyrimidin-2-amine

Paxalisib; RG 7666; RG7666; RG-7666; GDC0084; Paxalisib [USAN]; 5-(6,6-dimethyl-4-morpholin-4-yl-8,9-dihydropurino[8,9-c][1,4]oxazin-2-yl)pyrimidin-2-amine; 5-(6,6-Dimethyl-4-morpholino-8,9-dihydro-6H-[1,4]oxazino[4,3-e]purin-2-yl)pyrimidin-2-amine; CHEMBL3813842; GDC-0084; GDC 0084

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO: ~8 mg/mL (~20.9 mM)
Water: <1 mg/mL
Ethanol: <1 mg/mL

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)