HER2 (IC50 = 59 nM); EGFR (IC50 = 92 nM)

Neratinib shows no action against tyrosine kinase c-Met[1], Akt, cyclin D1/cdk4, cyclin E/cdk2, cyclin B1/cdk1, IKK-2, MK-2, PDK1, c-Raf, and Tpl-2, among other serine-threonine kinases[1].
Neratinib is much less active in cell lines that express neither EGFR nor HER-2 (3T3, MDA-MB-435, and SW620), and it inhibits the proliferation of cell lines that exhibit high levels of HER-2 (3T3/neu, SK-Br-3, and BT474)[1].
Neratinib (0-2 nM, 12-16 h) arrests BT474 cell cycle at G1-S phase[1].
Neratinib causes cyclin D1 levels to be down-regulated, Akt and MAPK phosphorylation to be inhibited, and p27 to be induced[1].

Neratinib (HKI-272) exhibits anticancer properties against cancer cells that express high levels of EGFR or HER-2 (0-80 mg/kg/day; i.e., 42 days)[1].
In vivo, HKI-272 is active in HER-2- and EGFR-dependent tumor xenograft models when dosed orally on a once daily schedule. On the basis of its favorable preclinical pharmacological profile, HKI-272 has been selected as a candidate for additional development as an antitumor agent in breast and other HER-2-dependent cancers.[1]

Prepared as 10 mg/mL stocks in DMSO, neratinib is diluted in 25 mM HEPES (pH 7.5; 0.002 ng/mL–20 μg/mL). In 96-well ELISA plates, purified recombinant COOH-terminal fragments of HER2 (amino acids 676-1255) or epidermal growth factor receptor (EGFR) (amino acids 645-1186) are diluted in 100 mM HEPES (pH 7.5) and 50% glycerol. The mixture is then incubated with increasing concentrations of Neratinib in 4 mM HEPES (pH 7.5), 0.4 mM MnCl2, 20 μM sodium vanadate, and 0.2 mM DTT for 15 minutes at room temperature. 40 μM ATP and 20 mM MgCl2 are added to start the kinase reaction, which is then left to run at room temperature for an hour. Wash the plates, then use anti-phospho-tyrosine antibodies (15 ng/well) labeled with europium to detect phosphorylation. Using a Victor2 fluorescence reader (excitation wavelength of 340 nm and emission wavelength of 615 nm), the signal is detected following the washing and enhancement stages. An inhibition curve is used to determine the concentration of Neratinib (IC50) at which receptor phosphorylation is inhibited by 50%.

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Activity of HER-2 and EGFR cytoplasmic domains was measured by an autophosphorylation assay using time-resolved fluorometry. Compounds were prepared as 10 mg/ml stocks in DMSO and diluted in 25 mm HEPES (pH 7.5; 0.002 ng/ml–20 μg/ml). Enzyme [diluted in 100 mm HEPES (pH 7.5) and 50% glycerol] was incubated with inhibitor in 4 mm HEPES (pH 7.5), 0.4 mm MnCl2, 20 μm sodium vanadate, and 0.2 mm DTT for 15 min at room temperature in 96-well ELISA plates. The kinase reaction was initiated by the addition of 40 μm ATP and 20 mm MgCl2 and allowed to proceed for 1 h at room temperature. Plates were washed, and phosphorylation was detected using Europium-labeled anti-phospho-tyrosine antibodies (15 ng/well; Wallac). After washing and enhancement steps according to the manufacturer’s recommendations, signal was detected using a Victor2 fluorescence reader (excitation wavelength 340 nm, emission wavelength 615 nm). The concentration of compound that inhibited receptor phosphorylation by 50% (IC50) was calculated from inhibition curves.[1]

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Assays for other kinases were performed using recombinant enzymes expressed in bacterial, insect, or human cell lines. All enzymes used were serine-threonine kinases, except c-Met, KDR, src (tyrosine kinases), and MEK1 (dual specificity). Substrates used were peptides (Akt, IKK-2, MK2, PDK1, src, and Tpl2), proteins (cyclin D1/CDK4, cyclin E/CDK2, cyclin B1/CDK1, and c-Raf), poly(glutamic acid4-tyrosine) (KDR), or the kinase itself (autophosphorylation; c-met). Phosphorylation was measured using TMB peroxidase substrate for cyclin/cyclin-dependent kinase (cdk), LabChip for MK-2, or DELPHIA/LANCE for all others.[1]

Different concentrations of Neratinib are applied to cells (3T3, 3T3/neu, A431, BT474, SK-Br-3, MDA-MB-435, and SW480) for a period of either two or six days. A protein-binding dye called sulforhodamine B is used to measure cell proliferation. In short, cells are thoroughly cleaned with water after being fixed with 10% trichloroacetic acid. After staining the cells with 0.1% sulforhodamine B, they are rinsed in 5% acetic acid. After solubilizing the protein-associated dye in 10 mM Tris, the absorbance is calculated at 450 nM. Inhibition curves are used to calculate the concentration of neratinib (IC50) that inhibits cell proliferation by 50%.

Female athymic (nude) mice, tumor xenograft[1]
10, 20, 40, 60 or 80 mg/kg/day
Gavage, 42 days

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Tumor Xenograft Studies.[1]
Tumor cells (maintained in tissue culture) or tumor fragments were implanted s.c. in the flanks of female athymic (nude) mice. For estrogen-dependent cell lines (BT474, MCF-7, and SK-OV-3), animals were implanted with hormone pellets (0.72 mg of 17-β estradiol, 60-day release) 1 week before implantation of tumors. Additionally, SK-OV-3 cells were suspended in Matrigel basement membrane matrix for implantation. Treatment was initiated after tumors had reached a size of 90–200 mg, following random assignment of the animals to different treatment groups (staging, day 0). For 3T3/neu xenografts, treatment was initiated the day after tumor implantation (day 0). HKI-272 was formulated in 0.5% methocellulose-0.4% polysorbate-80 (Tween 80) and administered daily, p.o., by gavage. Tumor mass [(length × width2)/2] was determined every 7 days. Tumor outgrowth in all xenograft studies, except 3T3/neu, was expressed as relative tumor growth: the ratio of the mean tumor mass to the mean tumor mass on day 0. Inhibition of tumor growth was calculated relative to vehicle-treated controls. Statistical significance of inhibition was demonstrated using one-tailed Student’s t test (equal variance) after log transformation of the data.[1]

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HER-2 Phosphorylation in Xenografts.[1]
Athymic female nude mice (5 animals/group) were implanted s.c. with BT474 tumor fragments (∼30 mm3). When tumors reached 200–300 mg, animals were given a single oral dose (40 mg/kg) of HKI-272 in pH 2.0 water. Tumors from control and treated animals were excised at 1, 3, 6, and 24 h and minced. Tumor fragments were suspended in 10 mm Tris (pH 7.5), 5 mm EDTA, 150 mm NaCl, 1% Triton X-100, 1% sodium deoxycholate, 0.1% SDS, 1 mm phenylmethylsulfonyl fluoride, 10 μg/ml pepstatin, 10 μg/ml leupeptin, 10 μg/ml aprotinin, 2 mm sodium vanadate, and 100 mm sodium fluoride and lysed by homogenization on ice with a polytron. After clarification by centrifugation, protein concentration in lysates was estimated using the Bio-Rad DC protein assay. Sixty μg of lysate pooled from each group were analyzed by SDS-PAGE and immunoblotting with phospho-tyrosine-specific antibodies. Pooled extracts were also immunoprecipitated using 4 μg of anti-HER-2 antibodies for 1 h at 4°C. Immune complexes were collected on protein A-agarose, washed, and analyzed by immunoblotting using phospho-tyrosine-specific antibodies. Extracts from individual tumors were analyzed to determine variability between animals.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
No information is available on the clinical use of neratanib during breastfeeding. Because neratanib and its metabolite are over 99% bound to plasma proteins, the amount in milk is likely to be low. The manufacturer recommends that breastfeeding be discontinued during neratanib therapy.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

[1]. Antitumor activity of HKI-272, an orally active, irreversible inhibitor of the HER-2 tyrosine kinase. Cancer Res, 2004, 64(11), 3958-3965.

Neratinib Maleate is the maleate salt form of neratinib, an orally available, quinazoline-based, irreversible inhibitor of both the receptor tyrosine kinases (RTKs) human epidermal growth factor receptor 2 (HER2; ERBB2) and human epidermal growth factor receptor (EGFR), with potential antineoplastic activity. Upon administration, neratinib targets and covalently binds to the cysteine residue in the ATP-binding pockets of both HER2 and EGFR. This inhibits their activity and results in the inhibition of downstream signal transduction events, induces cell cycle arrest, apoptosis and ultimately decreases cellular proliferation in HER2- and EGFR-expressing tumor cells. EGFR and HER2, RTKs that are mutated or overactivated in many tumor cell types, play key roles in tumor cell proliferation and tumor vascularization.
See also: Neratinib (has active moiety).

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Drug Indication
Nerlynx is indicated for the extended adjuvant treatment of adult patients with early stage hormone receptor positive HER2-overexpressed/amplified breast cancer and who are less than one year from the completion of prior adjuvant trastuzumab based therapy.

C34H33CLN6O7

673.11

672.209

C, 60.67; H, 4.94; Cl, 5.27; N, 12.49; O, 16.64

915942-22-2

Neratinib;698387-09-6

67307512

White to off-white solid powder

4

12

13

48

1000

0

C(/C(=O)O)=C/C(=O)O.N(C1C=CC(OCC2N=CC=CC=2)=C(Cl)C=1)C1=C(C#N)C=NC2=CC(=C(C=C12)NC(=O)/C=C/CN(C)C)OCC

VXZCUHNJXSIJIM-MEBGWEOYSA-N

InChI=1S/C30H29ClN6O3.C4H4O4/c1-4-39-28-16-25-23(15-26(28)36-29(38)9-7-13-37(2)3)30(20(17-32)18-34-25)35-21-10-11-27(24(31)14-21)40-19-22-8-5-6-12-33-22;5-3(6)1-2-4(7)8/h5-12,14-16,18H,4,13,19H2,1-3H3,(H,34,35)(H,36,38);1-2H,(H,5,6)(H,7,8)/b9-7+;2-1-

(Z)-but-2-enedioic acid;(E)-N-[4-[3-chloro-4-(pyridin-2-ylmethoxy)anilino]-3-cyano-7-ethoxyquinolin-6-yl]-4-(dimethylamino)but-2-enamide

HKI-272 maleate or PB272; HKI272; 915942-22-2; hki-272 maleate; Nerlynx; Neratinib maleate [MI]; UNII-9RM7XY23ZS; 9RM7XY23ZS; Neratinib (maleate); HKI 272; PB 272; PB-272 maleate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

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