Taletrectinib adipate (DS-6051b) is a potent, orally bioactive, next-generation selective ROS1/NTRK inhibitor. Taletrectinib has strong inhibitory effects on recombinant ROS1, NTRK1, NTRK2 and NTRK3 with IC50 of 0.207, 0.622, 2.28 and 0.98 nM respectively. Taletrectinib also inhibits ROS1 G2032R and other crizotinib-resistant ROS1 mutants.
On June 11, 2025, the Food and Drug Administration approved taletrectinib (Ibtrozi, Nuvation Bio Inc.), a kinase inhibitor, for adults with locally advanced or metastatic ROS1-positive non-small cell lung cancer (NSCLC).

Physicochemical Properties

Molecular Formula	C29H34FN5O5
Molecular Weight	551.61
Exact Mass	551.254
Elemental Analysis	C, 63.14; H, 6.21; F, 3.44; N, 12.70; O, 14.50
CAS #	1505515-69-4
Related CAS #	Taletrectinib free base;1505514-27-1
PubChem CID	72694302
Appearance	Typically exists as white to off-white solids at room temperature
LogP	3-[4-[((2R)-2-Aminopropyl)oxy]phenyl]-N-[(1R)-1-(3-fluorophenyl)ethyl]imidazo[1,2-b]pyridazin-6-amine monoadipate
Hydrogen Bond Donor Count	4
Hydrogen Bond Acceptor Count	10
Rotatable Bond Count	12
Heavy Atom Count	40
Complexity	645
Defined Atom Stereocenter Count	2
SMILES	C[C@H](COC1=CC=C(C=C1)C2=CN=C3N2N=C(C=C3)N[C@H](C)C4=CC(=CC=C4)F)N.C(CCC(=O)O)CC(=O)O
InChi Key	DORJQZDOULKINH-QNBGGDODSA-N
InChi Code	InChI=1S/C23H24FN5O.C6H10O4/c1-15(25)14-30-20-8-6-17(7-9-20)21-13-26-23-11-10-22(28-29(21)23)27-16(2)18-4-3-5-19(24)12-18;7-5(8)3-1-2-4-6(9)10/h3-13,15-16H,14,25H2,1-2H3,(H,27,28);1-4H2,(H,7,8)(H,9,10)/t15-,16-;/m1./s1
Chemical Name	3-[4-[((2R)-2-Aminopropyl)oxy]phenyl]-N-[(1R)-1-(3-fluorophenyl)ethyl]imidazo[1,2-b]pyridazin-6-amine monoadipate
Synonyms	DS-6051B; DS 6051B; Taletrectinib; 1505515-69-4; DS-6051b; Taletrectinib adipate; DS-6051B adipate; 6KLL51GNBG; Taletrectinib adipate [USAN]; 1505515-69-4 (adipate); DS6051B. AB-106; AB106; AB 106; Taletrectinib adipate;
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: Please store this product in a sealed and protected environment, avoid exposure to moisture.
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	ROS1/NTRK
ln Vitro	The half-life of taletrectinib (1-1000 nM; 72 hours) against Ba/F3-TPM3-NTRK1, Ba/F3-ETV6-NTRK1, -NTRK2, -NTRK3, or KM12 cells is approximately 3–20 nM [1]. In U-118-MG cells, taletrectinib (0.001-1000 nM; 2 hours) dose-dependently inhibits ROS1 autophosphorylation [1]. ROS1 autophosphorylation in JFCR-165, JFCR-168, and MGH193-1B cells is efficiently inhibited by taletrectinib [1]. Phosphorylated NTRK1 is somewhat inhibited by taletrectinib at 10 nM and totally inhibited at 100 nM. Recombinant ROS1, NTRK1, and NTRK3 are potently inhibited by taletrectinib at subnanomolar concentrations in an ATP-competitive manner. When 1 mM ATP is present, 0.2 μM taletrectinib almost totally inhibits 160 kinases, including ACK, ALK, DDR1, and LTK, but not the other 152 kinases [1]. CRISPOTINIB-resistant ROS1 secondary mutations, such as the G2032R solvent front mutation, are effectively inhibited by taletrectinib [1].
ln Vivo	Taletrectinib adipate (DS-6051b) (25 -200 mg/kg; oral; once daily for 18 days) shows anti-tumor activity[1]. Taletrectinib (6.25 -200 mg/kg; oral; once daily for 8 days) inhibits NTRK-rearranged cancer in Balb-c nu/nu mice harboring KM12 cells[1]. Taletrectinib (3-100 mg/kg; oral; once daily for 4 days) shows rapid tumor regression in wild-type (WT) and G2032R mutant Ba/F3 mice without severe weight loss[1].
Enzyme Assay	Kinase selectivity profiling[1] An off-chip mobility shift assay was performed. The effect of DS-6051b at a concentration of 200 nM on 160 kinases was evaluated in the presence of 1 mM ATP and expressed as % inhibition. Inhibitory activities of DS-6051b on ACK, ALK, DDR1, DDR2, KIT, LTK, ROS1, NTRK1, NTRK2, NTRK3, and TXK were determined by the mobility shift assay. ATP concentration in the assay was set at the approximate Km value of each kinase for ATP or 1 mM. The IC50 values were estimated according to the four-parameter logistic model.
Cell Assay	Cell Viability Assay[1] Cell Types: TPM3-NTRK1-induced Ba/F3 cells, KM12 cells Tested Concentrations: 1-1000 nM Incubation Duration: 72 hrs (hours) Experimental Results: Inhibited TPM3-NTRK1-induced Ba/F3 cells and KM12 cells viability. Western Blot Analysis[1] Cell Types: U-118 MG cells (harboring FIG-ROS1 fusion gene) Tested Concentrations: 0.001-1000 nM Incubation Duration: 2 hrs (hours) Experimental Results: Dose dependently inhibited autophosphorylation of ROS1 in U-118-MG cells.
Animal Protocol	Animal/Disease Models: Balb-c nu/nu (nude) mice (bearing U-118 MG cells)[1] Doses: 25, 50, 100, and 200 mg/kg Route of Administration: Po; one time/day for 18 days Experimental Results: Effectively inhibited tumor growth at ≥25 mg/kg without significant body weight loss.
References	[1]. The new-generation selective ROS1/NTRK inhibitor DS-6051b overcomes crizotinib resistant ROS1-G2032R mutation in preclinical models. Nat Commun. 2019;10(1):3604. Published 2019 Aug 9. [2]. Safety and pharmacokinetics of DS-6051b in Japanese patients with non-small cell lung cancer harboring ROS1 fusions: a phase I study. Oncotarget. 2018;9(34):23729-23737. Published 2018 May 4.
Additional Infomation	Taletrectinib Adipate is the adiptate form of taletrectinib, a n orally available inhibitor of the receptor tyrosine kinases C-ros oncogene 1 (ROS1) and the neurotrophic tyrosine receptor kinase (NTRK) types 1, 2 and 3, with potential antineoplastic activity. Upon oral administration, taletrectinib binds to and inhibits ROS1 and the NTRK family members. This inhibition leads to a disruption of ROS1- and NTRK-mediated signaling and eventually inhibits the growth of tumor cells that are overexpressing ROS1 and/or NTRKs. ROS1, overexpressed in certain cancer cells, plays a key role in cell growth and survival of cancer cells. NTRK mutations or rearrangements play a key role in cancer progression. See also: Taletrectinib (annotation moved to).

Solubility Data

Solubility (In Vitro)

DMSO: 50 mg/mL (90.64 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.08 mg/mL (3.77 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 20.8 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: ≥ 2.08 mg/mL (3.77 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 20.8 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: ≥ 2.08 mg/mL (3.77 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 20.8 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	1.8129 mL	9.0644 mL	18.1288 mL
	5 mM	0.3626 mL	1.8129 mL	3.6258 mL
	10 mM	0.1813 mL	0.9064 mL	1.8129 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.