Balixafortide (POL-6326), a synthetic cyclopeptide derived from polyphemusin, is a novel, potent and orally bioavailable inhibitor of CXC chemokine receptor 4 (CXCR4, IC 50=10 nM) with anticancer activity. CXCR4 is a member of the G-coupled protein receptor (GPCR) transmembrane receptor class. Balixafortide is a very potent, well tolerated and highly selective next generation CXCR4 antagonist derived over the past decade through multiple rounds of optimization starting from the natural product polyphemusin. Clinical proof-of-concept was achieved in a Ph 1/2 study in combination with Eribulin in metastatic HER2-neg breast cancer. The anti-cancer effects and pluripotent action of Balixafortide may include sensitization of tumor cells to chemotherapy, suppression of metastatic spread, inhibition of angiogenesis, and activation of the immune system.

Physicochemical Properties

Molecular Formula	C84H118N24O21S2
Molecular Weight	1864.1
Exact Mass	1862.83
Elemental Analysis	C, 49.00; H, 5.53; F, 7.75; N, 15.24; O, 19.58; S, 2.91
CAS #	1051366-32-5
Related CAS #	Balixafortide TFA; 1051366-32-5
PubChem CID	138752609
Sequence	Cyclo(Ala-Cys-Ser-Ala-{D-Pro}-{Dab}-Arg-Tyr-Cys-Tyr-Gln-Lys-{D-Pro}-Pro-Tyr-His) (Disulfide bridge: Cys2-Cys9)
SequenceShortening	Cyclo(ACSA-{D-Pro}-{Dab}-RYCYQK-{D-Pro}-PYH) (Disulfide bridge: Cys2-Cys9)
Appearance	Solid powder
LogP	-3.5
Hydrogen Bond Donor Count	24
Hydrogen Bond Acceptor Count	29
Rotatable Bond Count	23
Heavy Atom Count	131
Complexity	3970
Defined Atom Stereocenter Count	16
SMILES	C[C@H]1C(=O)N[C@H]2CSSC[C@@H](C(=O)N[C@H](C(=O)C(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@H]3CCCN3C(=O)[C@@H](NC(=O)[C@@H](NC2=O)CO)C)CCN)CCCNC(=N)N)CC4=CC=C(C=C4)O)NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@H]5CCCN5C(=O)[C@@H]6CCCN6C(=O)[C@@H](NC(=O)[C@@H](NN1)CC7=CN=CN7)CC8=CC=C(C=C8)O)CCCCN)CCC(=O)N)CC9=CC=C(C=C9)O
InChi Key	OYWQJZAVFWOOBF-WBMPNIIXSA-N
InChi Code	InChI=1S/C84H118N24O21S2/c1-44-70(116)102-62-41-130-131-42-63(77(123)98-57(35-46-14-20-50(110)21-15-46)69(115)68(114)53(10-5-31-91-84(88)89)94-73(119)56(28-30-86)97-79(125)64-11-6-32-106(64)81(127)45(2)93-76(122)61(40-109)101-78(62)124)103-74(120)58(36-47-16-22-51(111)23-17-47)99-72(118)55(26-27-67(87)113)95-71(117)54(9-3-4-29-85)96-80(126)65-12-7-33-107(65)83(129)66-13-8-34-108(66)82(128)60(37-48-18-24-52(112)25-19-48)100-75(121)59(105-104-44)38-49-39-90-43-92-49/h14-25,39,43-45,53-66,104-105,109-112H,3-13,26-38,40-42,85-86H2,1-2H3,(H2,87,113)(H,90,92)(H,93,122)(H,94,119)(H,95,117)(H,96,126)(H,97,125)(H,98,123)(H,99,118)(H,100,121)(H,101,124)(H,102,116)(H,103,120)(H4,88,89,91)/t44-,45-,53-,54-,55-,56-,57-,58-,59-,60-,61-,62-,63-,64+,65+,66-/m0/s1
Chemical Name	3-[(1R,4S,7S,10S,16S,22R,25S,28S,31S,34R,37S,40S,43S,46R,52S,55S)-25-(4-aminobutyl)-43-(2-aminoethyl)-40-(3-carbamimidamidopropyl)-55-(hydroxymethyl)-10,31,37-tris[(4-hydroxyphenyl)methyl]-7-(1H-imidazol-5-ylmethyl)-4,52-dimethyl-3,8,11,17,23,26,29,32,35,38,39,42,45,51,54,57-hexadecaoxo-59,60-dithia-2,5,6,9,12,18,24,27,30,33,36,41,44,50,53,56-hexadecazapentacyclo[32.23.4.012,16.018,22.046,50]henhexacontan-28-yl]propanamide
Synonyms	Balixafortide; POL 6326; POL6326; POL6326; Cyclo(L-alanyl-L-cysteinyl-L-seryl-L-alanyl-D-prolyl-(2S)-2,4-diaminobutanoyl-L-arginyl-L-tyrosyl-L-cysteinyl-L-tyrosyl-L-glutaminyl-L-lysyl-D-prolyl-L-prolyl-L-tyrosyl-L-histidyl), cyclic (2->9)-disulfide; Balixafortide [INN]; Balixafortide [USAN]; 11-Dideuterolinoleic acid; Balixafortide(POL6326); POL6326
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	CXCR4 ( IC50 < 10 nM )
ln Vitro	Benaxafortide significantly reduces pERK/pAKT signaling in the lymphoma lines Jurkat (IC50 < 400 nM) and Namalwa (IC50 < 200 nM). In MDA MB 231 breast cancer cells (IC50 < 20 nM), Namalwa and Jurkat cells (IC50 < 10 nM), benaxafortide effectively inhibits SDF-1 dependent chemotaxis (Table 1)[1].
ln Vivo	Balixafortide has been optimized with balanced plasma protein binding, increased plasma and microsomal stability, and favorable mouse absorption, distribution, metabolism, and excretion (ADME) properties in mind[1].
Enzyme Assay	Balixafortide was tested in a HTRF-based CXCR4 ligand binding assay, in functional assays (Calcium flux and beta arrestin), and further profiled in a large panel of other receptors including CXCR7. Effects on tumor cell sensitization were followed with an intracellular pERK / pAKT signaling assay. Tumor cell migration was assessed by chemotaxis assays, and inhibition of angiogenesis was determined by HUVEC sprouting. Evidence for immune cell activation came from evaluation of corresponding marker such as interferon gamma. Balixafortide was in detail profiled in an extensive in vitro ADME panel[1].
Cell Assay	Balixafortide binds CXCR4 with high affinity (IC50 < 10nM). It blocks beta arrestin recruitment and Calcium flux with IC50s < 10nM. A high 1000-fold selectivity window was demonstrated in a large panel of receptors including CXCR7. Balixafortide potently inhibits pERK / pAKT signaling in the lymphoma lines Namalwa (IC50 < 200 nM) and Jurkat (IC50 < 400 nM). Balixafortide efficiently blocks SDF-1 dependent chemotaxis of MDA MB 231 breast cancer cells (IC50 < 20 nM), Namalwa and Jurkat cells (IC50 < 10 nM). Receptor occupancy wash-out studies with competitive antibody 12G5 revealed prolonged binding of Balixafortide to CXCR4. In addition, Balixafortide was optimized for favorable mouse and human ADME properties with balanced plasma protein binding, greater plasma and microsomal stability[1].
Animal Protocol	C57BL/6NCrl wild-type (WT) mice, domestic (DanBred hybrid) female pigs 8 mg/kg, 3 mg/kg IV
References	[1]. Anti-tumor cell activity and in vitro profile of the next generation CXCR4 antagonist Balixafortide. Ann Oncol. 2018 Oct;29 Suppl 8:viii103. [2]. Mobilization of hematopoietic stem cells with the novel CXCR4 antagonist POL6326 (balixafortide) in healthy volunteers-results of a dose escalation trial. J Transl Med. 2017 Jan 3;15(1):2.
Additional Infomation	Balixafortide is under investigation in clinical trial NCT03786094 (Pivotal Study in HER2 Negative, Locally Recurrent or Metastatic Breast Cancer). Balixafortide is an orally bioavailable inhibitor of CXC chemokine receptor 4 (CXCR4) with receptor binding and hematopoietic stem cell-mobilization activities. Balixafortide binds to the chemokine receptor CXCR4, thereby preventing the binding of stromal derived factor-1 (SDF-1 or CXCL12) to the CXCR4 receptor and subsequent receptor activation. This may induce the mobilization of hematopoietic stem and progenitor cells from the bone marrow into blood. CXCR4, a chemokine receptor belonging to the G protein-coupled receptor (GPCR) gene family, plays an important role in chemotaxis and angiogenesis and is upregulated in several tumor cell types; CXCL12/CXCR4 interaction induces retention of hematopoietic cells in the bone marrow. Drug Indication Treatment of breast cancer

Solubility Data

Solubility (In Vitro)

Water: ~100 mg/mL

Solubility (In Vivo)

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. Injection Formulations (e.g. IP/IV/IM/SC) 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). 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) Oral Formulations 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). 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 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	0.5365 mL	2.6823 mL	5.3645 mL
	5 mM	0.1073 mL	0.5365 mL	1.0729 mL
	10 mM	0.0536 mL	0.2682 mL	0.5365 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.