OBI-3424 (TH-3424) is a precursor that is selectively converted to a potent DNA alkylating agent by AKR1C3 (aldehyde-keto reductase 1C3). OBI-3424 is recommended for use in studies pertaining to acute lymphoblastic leukemia (ALL), castration-resistant prostate cancer, and hepatocellular carcinoma.

Physicochemical Properties

Molecular Formula	C21H25N4O6P
Molecular Weight	460.420165777206
Exact Mass	460.15
Elemental Analysis	C, 54.78; H, 5.47; N, 12.17; O, 20.85; P, 6.73
CAS #	2097713-68-1
PubChem CID	126961329
Appearance	Solid powder
LogP	2.2
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	8
Rotatable Bond Count	8
Heavy Atom Count	32
Complexity	737
Defined Atom Stereocenter Count	1
SMILES	C[C@H](C1=CC(=C(C=C1)[N+](=O)[O-])OC2=CC=CC(=C2)C(=O)N(C)C)OP(=O)(N3CC3)N4CC4
InChi Key	NWGZZGNICQFUHV-OAHLLOKOSA-N
InChi Code	InChI=1S/C21H25N4O6P/c1-15(31-32(29,23-9-10-23)24-11-12-24)16-7-8-19(25(27)28)20(14-16)30-18-6-4-5-17(13-18)21(26)22(2)3/h4-8,13-15H,9-12H2,1-3H3/t15-/m1/s1
Chemical Name	3-[5-[(1R)-1-[bis(aziridin-1-yl)phosphoryloxy]ethyl]-2-nitrophenoxy]-N,N-dimethylbenzamide
Synonyms	AST 3424; AST-3424; AST3424; OBI 3424; OBI3424; OBI-3424
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 Note: This product requires protection from light (avoid light exposure) during transportation and storage.
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	OBBI-3424 exhibits strong cytotoxicity against the H460 lung cancer cell line with an IC50 of 4.0 nM. OBI-3424 has strong cytotoxicity, with IC50 values in the low nM range, especially against T-ALL cell lines that express high levels of AKR1C3 [1]. Strong cell killing is also exerted by OBI-3424 against ALL PDXs; the median IC50 values for B-ALL, T-ALL, and ETP-ALL were 60.3 nM, 9.7 nM, and 31.5 nM, respectively[1].
ln Vivo	Treatment with OBI-3424 (0.5-2.5 mg/kg; ip; once weekly; for 3 weeks) causes regressions in mice with Parkinson's disease and prolongs the event-free lifespan of the mice[1].
Animal Protocol	Animal/Disease Models: Female NSG mice (20-25 g) bearing patient-derived xenografts (PDX)[1] Doses: 0.5 mg/kg, 1 mg/kg, 2.5 mg/kg Route of Administration: intraperitoneal (ip)injection ; once weekly; for 3 weeks Experimental Results: Resulted in prolongation of mouse event-free survival.
References	[1]. OBI-3424, a Novel AKR1C3-Activated Prodrug, Exhibits Potent Efficacy against Preclinical Models of T-ALL. Clin Cancer Res. 2019 Jul 15;25(14):4493-4503.
Additional Infomation	OBI-3424 is under investigation in clinical trial NCT04315324 (Study to Test Akr1c3-activated Prodrug OBI-3424 (OBI-3424) in Patients With Relapsed/refractory T-cell Acute Lymphoblastic Leukemia (T-ALL)). AKR1C3-activated Prodrug AST-3424 is a small-molecule nitro-benzene, aldo-keto reductase 1C3 (AKR1C3)-activated prodrug of N,N'-bisethylenephosphoramidate, a DNA bis-alkylating agent, with potential antineoplastic activity. Upon intravenous administration, AKR1C3-activated prodrug AST-3424 is converted to its active form by AKR1C3, which is upregulated in certain tumor cell types while not expressed in normal healthy cells. The active metabolite selectively binds to and alkylates DNA in AKR1C3-overexpressing tumor cells, resulting in DNA base pair mismatching, interstrand crosslinking and inhibition of DNA repair and synthesis, cell-cycle arrest, and apoptosis. As the expression of AKR1C3 is restricted to tumors, AST-3424 is selectively converted to its active metabolite in tumor cells only while its conversion in normal, healthy tissue is absent; this allows for an increased cytotoxic effect of the alkylating agent in tumor cells while decreasing its toxicity.

Solubility Data

Solubility (In Vitro)

DMSO : ~50 mg/mL (~108.6 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 5 mg/mL (10.86 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 50.0 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 (5.43 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 (5.43 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.1719 mL	10.8596 mL	21.7193 mL
	5 mM	0.4344 mL	2.1719 mL	4.3439 mL
	10 mM	0.2172 mL	1.0860 mL	2.1719 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.