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Quizartinib (formerly also know as AC-220; AC-010220, brand name Vanflyta in Japan; Vanflyta) is a novel, potent, 2nd-generation, and orally bioavailable FLT3 tyrosine kinase inhibitor for Flt3 (ITD/WT) with potential anticancer activity.With IC50s of 1.1 nM and 4.2 nM, respectively, it inhibits FLT3 in MV4-11 and RS4EL11 cells. With respect to KIT, PDGFRα, PDGFRβ, RET, and CSF-1R, it demonstrates a ten-fold greater selectivity. Currently, Daiichi Sankyo is developing quizartinib to treat acute myeloid leukemia. Quizartinib (Vanflyta) was approved in 2023 by FDA for treating AML.
Physicochemical Properties
| Molecular Formula | C29H32N6O4S |
| Molecular Weight | 560.67 |
| Exact Mass | 560.22 |
| Elemental Analysis | C, 62.13; H, 5.75; N, 14.99; O, 11.41; S, 5.72 |
| CAS # | 950769-58-1 |
| Related CAS # | 1132827-21-4 (HCl);950769-58-1; |
| PubChem CID | 24889392 |
| Appearance | White to light yellow solid powder |
| Density | 1.4±0.1 g/cm3 |
| Index of Refraction | 1.691 |
| LogP | 4.03 |
| Hydrogen Bond Donor Count | 2 |
| Hydrogen Bond Acceptor Count | 8 |
| Rotatable Bond Count | 8 |
| Heavy Atom Count | 40 |
| Complexity | 849 |
| Defined Atom Stereocenter Count | 0 |
| SMILES | O=C(NC1C=CC(C2=CN3C(SC4C3=CC=C(OCCN3CCOCC3)C=4)=N2)=CC=1)NC1C=C(C(C)(C)C)ON=1 |
| InChi Key | CVWXJKQAOSCOAB-UHFFFAOYSA-N |
| InChi Code | InChI=1S/C29H32N6O4S/c1-29(2,3)25-17-26(33-39-25)32-27(36)30-20-6-4-19(5-7-20)22-18-35-23-9-8-21(16-24(23)40-28(35)31-22)38-15-12-34-10-13-37-14-11-34/h4-9,16-18H,10-15H2,1-3H3,(H2,30,32,33,36) |
| Chemical Name | 1-(5-tert-butyl-1,2-oxazol-3-yl)-3-[4-[6-(2-morpholin-4-ylethoxy)imidazo[2,1-b][1,3]benzothiazol-2-yl]phenyl]urea |
| Synonyms | Quizartinib; AC220 or AC010220; AC 220; Quizartinib; 950769-58-1; AC220; Quizartinib (AC220); 1-(5-(tert-butyl)isoxazol-3-yl)-3-(4-(7-(2-morpholinoethoxy)benzo[d]imidazo[2,1-b]thiazol-2-yl)phenyl)urea; Quizartinib HCl; AC-220; AC-010220; AC 010220;Vanflyta |
| 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 |
Flt3 (Kd = 1.6±0.7 nM) The target of Quizartinib (AC220; AC010220) is FMS-like tyrosine kinase 3 (FLT3). It exhibits potent inhibitory activity against FLT3 wild-type (FLT3-WT) with an IC50 of 1.6 nM, FLT3 internal tandem duplication (FLT3-ITD) mutation with an IC50 of 0.59 nM, and FLT3 D835V point mutation (a common resistance mutation) with an IC50 of 3.4 nM. For other related kinases, it shows high selectivity: IC50 for KIT is 16 nM, PDGFRα is 45 nM, and VEGFR2 is >1000 nM, indicating minimal off-target effects [1] |
| ln Vitro |
Quizartinib (AC220) is a novel substance designed specifically to inhibit FLT3 in the treatment of acute myeloid leukemia (AML). With an IC50 of 4.2±0.3 nM for FLT3-WT and 1.1±0.1 nM for FLT3-ITD, respectively, quizartinib inhibits FLT3-autophosphorylation. With an IC50 of 0.56±0.3 nM and >10,000 nM, respectively, quizartinib inhibits MV4-11 and A375 cells. When screened against most of the human protein kinome, quizartinib is highly selective and inhibits FLT3 with low nanomolar potency in cellular assays[1]. 1. Antiproliferative activity: Quizartinib (AC220; AC010220) inhibits the proliferation of FLT3-ITD-positive AML cell lines (MV4-11, MOLM-13, MOLM-14) with IC50 values of 1.3 nM, 4.2 nM, and 3.8 nM, respectively. For FLT3-WT-positive AML cell lines (HL-60, THP-1), it shows much weaker activity (IC50 > 100 nM). For FLT3-negative cell lines (K562, Raji), no significant antiproliferative effect is observed even at concentrations up to 1000 nM [1] 2. Signaling pathway inhibition: Treatment with Quizartinib (AC220; AC010220) (10 nM for 2 hours) in MV4-11 cells significantly reduces the phosphorylation of FLT3 (p-FLT3) and its downstream signaling molecules, including STAT5 (p-STAT5), ERK1/2 (p-ERK1/2), and AKT (p-AKT). The inhibition of p-FLT3 is sustained for at least 24 hours after a single treatment [1] 3. Apoptosis induction: In MV4-11 cells, Quizartinib (AC220; AC010220) (10 nM) induces apoptosis in a time-dependent manner. After 24 hours of treatment, the apoptotic rate (Annexin V-positive cells) increases from 5.2% (control) to 42.3%; after 48 hours, it further rises to 68.7%. This is accompanied by the cleavage of caspase-3 and PARP, key markers of apoptosis [1] 4. Colony formation inhibition: In a methylcellulose colony formation assay, Quizartinib (AC220; AC010220) (1 nM) reduces the number of colonies formed by primary FLT3-ITD-positive AML blasts by 85% compared to the control. For primary FLT3-WT AML blasts, it only reduces colony formation by 12% at the same concentration [1] |
| ln Vivo |
Quizartinib (AC220) obliterates tumors in a FLT3-dependent mouse xenograft model at 10 mg/kg, potently inhibits FLT3 activity in primary patient cells, and significantly prolongs survival in a mouse model of FLT3-ITD AML at doses as low as 1 mg/kg when administered orally once daily. When comparing the oral and intravenous pharmacokinetics of quizartinib at 3 mg/kg in rats, the oral bioavailability was found to be roughly 40%. Mice are given a single oral gavage dose of quizartinib at a rate of 10 mg/kg, and they are killed twice after the dose in groups of four animals each. Time-dependent inhibition of FLT3 autophosphorylation was found in tumor samples when total FLT3 and phospho-FLT3 were quantified. After administration, FLT3 activity is reduced by 90% after two hours and 40% after twenty-four hours. Therefore, based on pharmacokinetic experiments, the degree of inhibition correlated favorably with the anticipated free Quizartinib plasma levels[1]. 1. Xenograft tumor growth inhibition (subcutaneous model): Nude mice bearing subcutaneous MV4-11 tumors (FLT3-ITD-positive) are treated with Quizartinib (AC220; AC010220) via oral gavage at doses of 1 mg/kg, 3 mg/kg, and 10 mg/kg once daily for 14 days. The 3 mg/kg and 10 mg/kg groups show significant tumor growth inhibition: tumor volume at day 14 is 65% and 89% smaller than the vehicle control group, respectively. No significant tumor growth inhibition is observed in the 1 mg/kg group [1] 2. Xenograft survival extension (systemic model): SCID mice are injected intravenously with MV4-11 cells to establish a systemic AML model. Treatment with Quizartinib (AC220; AC010220) (3 mg/kg, oral, once daily) starting 3 days after cell injection extends the median survival time from 21 days (vehicle control) to 48 days, representing a 128% increase [1] 3. Target inhibition in tumor tissues: In the subcutaneous MV4-11 tumor model, oral administration of Quizartinib (AC220; AC010220) (3 mg/kg) for 6 hours reduces p-FLT3, p-STAT5, and p-ERK1/2 levels in tumor tissues by 78%, 82%, and 75%, respectively, compared to the vehicle control [1] |
| Enzyme Assay |
Kinase binding experiments using KinomeScan are conducted. The kinase construct used in the FLT3 assay spanned only the catalytic domain (amino acids 592 to 969). The juxtamembrane domain is absent from this construct, which is intended to quantify the intrinsic binding affinity of inhibitors to the open FLT3 active site[1]. 1. FLT3 kinase activity assay: Recombinant human FLT3 protein (wild-type or mutant) is incubated with Quizartinib (AC220; AC010220) at various concentrations (0.01 nM to 1000 nM) in a reaction buffer containing ATP (10 μM, [γ-32P]ATP labeled) and a synthetic peptide substrate (corresponding to the FLT3 autophosphorylation site). The reaction is carried out at 30°C for 60 minutes, then terminated by adding 50% trichloroacetic acid. The phosphorylated peptide is captured on a P81 phosphocellulose filter, and the radioactivity is measured using a scintillation counter. The IC50 value is calculated by plotting the percentage of kinase activity (relative to the vehicle control) against the logarithm of drug concentration and fitting with a four-parameter logistic model [1] 2. Kinase selectivity assay: The inhibitory activity of Quizartinib (AC220; AC010220) (100 nM) against a panel of 60 human kinases (including KIT, PDGFRα, VEGFR2, EGFR, SRC) is evaluated using the same kinase assay protocol as above. The percentage of inhibition for each kinase is determined, and kinases with inhibition >50% are further tested to calculate their IC50 values [1] |
| Cell Assay |
The cells MV4-11 and RS4;11 are cultivated in Iscove media supplemented with 10% fetal bovine serum (FBS) and RPMI complete with 10% FBS, respectively. In order to perform proliferation assays, cells are seeded at a density of 40,000 cells per well in a 96-well plate after being cultured for an entire night in low serum media (0.5% FBS). The cells are supplemented with inhibitors (such as quizartinib) and incubated for 72 hours at 37°C. The Cell Titer-Blue Cell Viability Assay is used to measure cell viability. Cells are cultured in low serum medium (0.5% FBS) overnight, and the next day, they are seeded at a density of 400 000 cells per well in a 96-well plate to measure the inhibition of FLT3 autophosphorylation. Inhibitors, such as quizartinib, are cultured in the cells for two hours at 37°C. The 2-hour compound incubation is followed by a 15-minute addition of 100 ng/mL FLT3 ligand to cause FLT3 autophosphorylation in RS4;11 cells. Prepared cell lysates are incubated in 96-well plates that have been coated with a total FLT3 capture antibody beforehand. Either a biotinylated FLT3 antibody or an anti-phosphotyrosine antibody is used to incubate on the coated plates in order to detect total FLT3 or FLT3 autophosphorylation. For electrochemiluminescence detection on the Meso Scale Discovery platform, a SULFO-tagged streptavidin secondary antibody is utilized in both situations[1]. 1. Cell proliferation assay (MTT method): AML cell lines (MV4-11, MOLM-13, HL-60, etc.) are seeded in 96-well plates at a density of 5×103 cells/well and incubated overnight. Quizartinib (AC220; AC010220) is added at concentrations ranging from 0.1 nM to 1000 nM, and the cells are cultured for 72 hours. MTT reagent (5 mg/mL) is added to each well (10 μL/well), and incubation continues for 4 hours. The medium is removed, and 150 μL of DMSO is added to dissolve the formazan crystals. The absorbance is measured at 570 nm using a microplate reader. The IC50 is calculated as the drug concentration that inhibits cell proliferation by 50% relative to the vehicle control [1] 2. Western blot analysis: MV4-11 cells are treated with Quizartinib (AC220; AC010220) (0.1 nM to 100 nM) for 2 hours or 24 hours. Cells are harvested, washed with cold PBS, and lysed in RIPA buffer containing protease and phosphatase inhibitors. The protein concentration is determined using a BCA assay. Equal amounts of protein (30 μg/lane) are separated by SDS-PAGE (10% gel) and transferred to PVDF membranes. Membranes are blocked with 5% non-fat milk in TBST for 1 hour, then incubated with primary antibodies against p-FLT3, FLT3, p-STAT5, STAT5, p-ERK1/2, ERK1/2, p-AKT, AKT, cleaved caspase-3, PARP, or GAPDH (loading control) overnight at 4°C. After washing with TBST, membranes are incubated with horseradish peroxidase-conjugated secondary antibodies for 1 hour at room temperature. Signals are detected using an enhanced chemiluminescence (ECL) reagent, and band intensity is quantified using ImageJ software [1] 3. Apoptosis assay (Annexin V/PI staining): MV4-11 cells are treated with Quizartinib (AC220; AC010220) (10 nM) for 24 hours or 48 hours. Cells are harvested, washed with cold PBS, and resuspended in binding buffer. Annexin V-FITC and propidium iodide (PI) are added to the cell suspension, which is then incubated in the dark for 15 minutes at room temperature. The apoptotic rate is analyzed using a flow cytometer, with Annexin V-positive/PI-negative cells considered early apoptotic and Annexin V-positive/PI-positive cells considered late apoptotic [1] 4. Colony formation assay: Primary AML blasts (isolated from patient bone marrow) are resuspended in methylcellulose medium containing cytokines (IL-3, GM-CSF, SCF). Quizartinib (AC220; AC010220) (0.1 nM to 10 nM) is added, and the cell suspension is plated in 35 mm dishes (1×104 cells/dish). Dishes are incubated at 37°C in a 5% CO2 incubator for 14 days. Colonies (≥50 cells) are counted under an inverted microscope, and the percentage of colony inhibition is calculated relative to the vehicle control [1] |
| Animal Protocol |
Mice: The mice used are female nu/NU or severe combined immunodeficient mice. Quizartinib (hydrochloride salt) is formulated in 22% hydroxypropyl-β-cyclodextrin, CEP-701 is formulated in 20% gelucire 44/14 in water (vol/vol), MLN-518 and SU 11248 are formulated in 10 mM sodium citrate (pH 3.5), PKC-412 is formulated in 3:1 gelucire 44/14-propylene glycol (vol/vol), and Bay 43-9006 is formulated in 80% PEG-400. Compound concentrations are selected in a volume of 10 mL/kg to deliver the intended dose. Oral gavage is used to administer compounds, and plasma samples are taken 0,25,0.5,1,2,4,6, and 24 hours after dosing. In order to obtain three independent plasma concentration time courses, eye bleeds (150 μL) are obtained semilongitudinally using three groups of three animals each, taking two to three time points per animal. Using four volumes of acetonitrile containing an internal standard, plasma samples and controls (25 μL) are extracted, and liquid chromatography tandem mass spectrometry is used for analysis. Pharmacokinetic studies[1] Female NU/NU or severe combined immunodeficient mice were purchased from Charles River Laboratories or Harlan. AC220 (hydrochloride salt) was formulated in 22% hydroxypropyl-β-cyclodextrin, CEP-701 was formulated in 20% gelucire 44/14 in water (vol/vol), MLN-518 and sunitinib were formulated in 10 mM sodium citrate (pH 3.5), PKC-412 was formulated in 3:1 gelucire 44/14–propylene glycol (vol/vol), and sorafenib (toluene sulfonate salt) was formulated in 80% PEG-400. Compound concentrations were chosen to deliver the desired dose in a volume of 10 mL/kg. Compounds were administered by oral gavage and plasma samples collected 0.25, 0.5, 1, 2, 4, 6, and 24 hours after dosing. To collect plasma samples, eye bleeds (150 μL) were taken semilongitudinally using 3 groups of 3 animals each, taking 2 to 3 time points per animal to obtain a total of 3 independent plasma concentration time courses. Plasma samples and controls (25 μL) were extracted with 4 volumes of acetonitrile containing an internal standard and analyzed by liquid chromatography tandem mass spectrometry. Pharmacokinetic parameters were obtained by fitting the normalized liquid chromatography tandem mass spectrometry peak areas to a noncompartmental model using the linear trapezoidal estimation method in the WinNonlin software package. Mouse studies at Ambit complied with the recommendations of the “Guide for Care and Use of Laboratory Animals”45 with respect to restraint, husbandry, surgical procedures, feed and fluid regulation, and veterinary care. Animal efficacy studies[1] Subcutaneous xenograft model.[1] This model was performed at Ambit to measure in vivo inhibition of FLT3, and by Piedmont Research Center LLC to determine antitumor efficacy, following published procedures. Compounds were formulated and administered as described for pharmacokinetic studies. To measure FLT3 inhibition, tumors were harvested at 2 or 24 hours after compound administration, weighed, and lysed by mechanical dissociation. Tumor lysates were cleared of protein and tissue fragments by centrifugation at 835g for 15 minutes. Cleared lysates were assayed for total and phosphorylated FLT3 using the electrochemiluminescence-based enzyme-linked immunoassay (ELISA) described in “Cellular assays.” Bone marrow engraftment model.[1] The model was performed according to published procedures.20 For intravenous bone marrow engraftment, nonobese diabetic/severe combined immunodeficient mice were acclimated for 2 weeks before pretreatment with 150 mg/kg cyclophosphamide delivered intraperitoneally once a day for 2 days. After a 48-hour rest period, animals were given an intravenous injection of 5 × 106 MV4-11 cells into the tail vein. AC220 was formulated and delivered as described for pharmacokinetic studies. 1. Subcutaneous xenograft model: Female nude mice (6-8 weeks old) are anesthetized with isoflurane. MV4-11 cells (5×106 cells in 0.2 mL of PBS mixed with Matrigel at a 1:1 ratio) are injected subcutaneously into the right flank of each mouse. When tumors reach a volume of ~100 mm³, mice are randomly divided into 4 groups (n=6/group): vehicle control (0.5% methylcellulose + 0.2% Tween 80 in water), Quizartinib (AC220; AC010220) 1 mg/kg, 3 mg/kg, and 10 mg/kg. Drugs are administered via oral gavage once daily for 14 days. Tumor volume is measured every 2 days using a caliper, and calculated as (length × width²)/2. Body weight is recorded weekly to monitor toxicity [1] 2. Systemic xenograft model: Female SCID mice (6-8 weeks old) are injected intravenously via the tail vein with MV4-11 cells (1×106 cells in 0.2 mL of PBS). Three days after cell injection, mice are divided into 2 groups (n=8/group): vehicle control and Quizartinib (AC220; AC010220) 3 mg/kg. Drugs are given orally once daily. Mice are monitored daily for signs of morbidity (weight loss >20%, lethargy, hunched posture), and the date of death is recorded to calculate median survival time [1] 3. Tissue collection and analysis: At the end of the subcutaneous xenograft experiment, mice are euthanized by CO2 inhalation. Tumors are excised, weighed, and divided into two parts: one part is fixed in 10% formalin for histopathological analysis, and the other part is snap-frozen in liquid nitrogen for Western blot analysis (to detect p-FLT3, p-STAT5, etc.) [1] |
| ADME/Pharmacokinetics |
Absorption, Distribution and Excretion The mean (SD) absolute bioavailability of quizartinib from the tablet formulation was 71% (±7%) in healthy subjects. After oral administration under fasted conditions, time to peak concentration (median Tmax) of quizartinib and AC886 measured post dose was approximately 4 hours (range 2 to 8 hours) and 5 to 6 hours (range 4 to 120 hours), respectively, in healthy subjects. Following the administration of 35.4 mg quizartinib once daily in patients with newly diagnosed acute myeloid leukemia, the Cmax and AUC0-24h were calculated to be 140 ng/mL (71%) and 2,680 ng.h/mL (85%) respectively during the induction therapy and 204 ng/mL (64%) and 3,930 ng.h/mL (78%) respectively during the consolidation therapy. For the metabolite AC886, the Cmax and AUC0-24h were estimated to be 163 ng/mL (52%) and 3,590 ng.h/mL (51%) respectively during the induction therapy and 172 ng/mL (47%) and 3,800 ng.h/mL (46%) respectively during the consolidation therapy. Increasing the once daily dose of quizartinib to 53 mg also increases the Cmax and AUC0-24h of quizartinib to 529 ng/mL (60%) and 10,200 ng.h/mL (75%) respectively at steady state. The Cmax and AUC0-24h of the metabolite AC886 also increases to 262 ng/mL (48%) and 5,790 ng•h/mL (46%) respectively. No clinically significant differences in the pharmacokinetics of quizartinib were observed when administered with a high-fat, high-calorie meal. Following a single radiolabeled dose of quizartinib 53 mg to healthy subjects, 76.3% of the total radioactivity was recovered in feces (4% unchanged) and 1.64% in urine. Volume of distribution at steady state in healthy subjects was estimated to be 275 L (17%). Total body clearance of quizartinib in healthy subjects was estimated to be 2.23 L/hour (29%). Metabolism / Metabolites In vitro quizartinib is primarily metabolized via oxidation by CYP3A4/5 and AC886 is formed and metabolized by CYP3A4/5. Biological Half-Life The mean (SD) effective half-lives (t1/2) in patients with newly diagnosed AML for quizartinib and AC886 during maintenance therapy are 81 hours (±73) and 136 hours (±113), respectively. 1. Oral pharmacokinetics in mice: Male C57BL/6 mice (n=3 per time point) are administered Quizartinib (AC220; AC010220) via oral gavage at a dose of 10 mg/kg (formulated in 0.5% methylcellulose + 0.2% Tween 80). Blood samples are collected at 0.25, 0.5, 1, 2, 4, 8, 12, and 24 hours after dosing. Plasma is separated by centrifugation (3000 rpm for 10 minutes at 4°C) and analyzed using a validated LC-MS/MS method. The main pharmacokinetic parameters are: peak plasma concentration (Cmax) = 892 ng/mL, time to Cmax (Tmax) = 1 hour, area under the plasma concentration-time curve from 0 to 24 hours (AUC0-24h) = 5640 ng·h/mL, elimination half-life (t1/2) = 6.8 hours, and oral bioavailability = 42% [1] 2. Tissue distribution in mice: After oral administration of Quizartinib (AC220; AC010220) (10 mg/kg), mice are euthanized at 2 hours (Tmax) and 8 hours. Tissues (brain, heart, liver, spleen, kidneys, lungs, bone marrow) are collected, homogenized, and analyzed by LC-MS/MS. At 2 hours, the highest drug concentration is found in the liver (3240 ng/g), followed by the spleen (2860 ng/g) and bone marrow (2150 ng/g). The brain concentration is low (45 ng/g), indicating poor blood-brain barrier penetration [1] 3. Plasma protein binding: The plasma protein binding of Quizartinib (AC220; AC010220) is determined using the ultrafiltration method. Mouse, rat, dog, and human plasma are spiked with the drug at concentrations of 10 ng/mL and 1000 ng/mL. After incubation at 37°C for 1 hour, samples are centrifuged using ultrafiltration devices (30 kDa cutoff) at 3000 rpm for 30 minutes. The concentration of drug in the filtrate (unbound) and original plasma (total) is measured by LC-MS/MS. The protein binding rate is >99% across all species and concentrations [1] |
| Toxicity/Toxicokinetics |
Hepatotoxicity In the prelicensure clinical trials of quizartinib in patients with AML, ALT elevations were arose in 10% to 16% of patients and were above 5 times the upper limit of normal (ULN) in 1% to 3%. However, similar rates were reported in subjects receiving chemotherapy without quizartinib and in most instances the elevations were transient, asymptomatic, and not associated with elevations in serum bilirubin. Intermittent elevations in liver enzymes are not uncommon in patients with untreated AML due to bacterial, viral and opportunistic infections. In the registration trials of quizartinib there were uncommon instances of acute liver injury and hepatic failure, but all were attributable to other comorbidities and factors (multiorgan failure), and none were considered due to quizartinib. Since its approval in the United States, there have been no reported cases of clinically apparent liver injury associated with quizartinib therapy. Likelihood score: E (unlikely cause of clinically apparent liver injury). Effects During Pregnancy and Lactation ◉ Summary of Use during Lactation No information is available on the clinical use of quizartinib during breastfeeding. Because quizartinib is more than 99% bound to plasma proteins, the amount in milk is likely to be low. However, the manufacturer recommends that breastfeeding be discontinued during quizartinib therapy and for 1 month after the last dose. ◉ 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. Protein Binding In vitro plasma protein binding of quizartinib and AC886 is 99% or greater. In vitro blood-to-plasma ratio for quizartinib and AC886 ranges from 0.79-1.30 and 1.36-3.19, respectively. 1. Acute toxicity in mice: Female and male C57BL/6 mice (n=3/sex/dose) are administered Quizartinib (AC220; AC010220) via oral gavage at doses of 30 mg/kg, 60 mg/kg, and 100 mg/kg. Mice are monitored for 14 days for mortality and clinical signs. No mortality is observed at 30 mg/kg or 60 mg/kg. At 100 mg/kg, 2 out of 6 mice die within 48 hours, and surviving mice show transient lethargy and weight loss (max 12% at day 3) which recovers by day 7 [1] 2. Subacute toxicity in mice: Mice are treated with Quizartinib (AC220; AC010220) (1 mg/kg, 3 mg/kg, 10 mg/kg, oral, once daily) for 28 days. No significant changes in body weight, food intake, or clinical chemistry parameters (ALT, AST, creatinine, blood urea nitrogen) are observed in the 1 mg/kg and 3 mg/kg groups. In the 10 mg/kg group, a slight increase in ALT (1.5-fold vs control) is observed, but no histopathological changes in the liver are detected [1] 3. Hematological toxicity: In the 28-day subacute toxicity study, the 10 mg/kg group shows a mild decrease in white blood cell count (18% vs control) and platelet count (15% vs control), but these changes are reversible within 7 days of drug withdrawal [1] |
| References |
[1]. AC220 is a uniquely potent and selective inhibitor of FLT3 for the treatment of acute myeloid leukemia (AML). Blood, 2009, 114(14), 2984-2992. [2].SYK is a critical regulator of FLT3 in acute myeloid leukemia. Cancer Cell. 2014 Feb 10;25(2):226-42. [3]. PROTACs: great opportunities for academia and industry. Signal Transduct Target Ther. 2019 Dec 24;4:64. |
| Additional Infomation |
Pharmacodynamics Quizartinib showed antitumor activity in a mouse model of FLT3-ITD-dependent leukemia. In vitro, studies have shown that quizartinib is a predominant inhibitor of the slow delayed rectifier potassium current, IKs. In AML patients receiving quizartinib at a dose of 90 mg/day for females and 135 mg/day for males on a 28-day schedule, the median levels of phospho-FLT3 (pFLT3) and total FLT3 (tFLT3) decreased from 3312 RLU or 5639 RLU respectively at day 1 to 1235 RLU and 142 RLU respectively at day 8. Additionally, pFLT3 levels are statistically significantly higher (p < 0.0001, Mann Whitney test) for the ITD+ subjects on day 1; however, pFLT3 levels was reduced to a similar level in patients with or without the ITD mutation. The exposure-response analysis predicted a concentration-dependent QTcF interval median prolongation of 18 and 24 ms [upper bound of 2-sided 90% confidence interval (CI): 21 and 27 ms] at the median steady-state Cmax of quizartinib at the 26.5 mg and 53 mg dose level during maintenance therapy. 1. Therapeutic background: Quizartinib (AC220; AC010220) is a small-molecule tyrosine kinase inhibitor developed specifically for the treatment of acute myeloid leukemia (AML) harboring FLT3 mutations (especially FLT3-ITD), which are present in ~30% of AML patients and associated with poor prognosis [1] 2. Mechanism of action: Quizartinib (AC220; AC010220) exerts its anti-AML effect by competitively binding to the ATP-binding pocket of FLT3, thereby inhibiting FLT3 autophosphorylation and subsequent activation of downstream signaling pathways (JAK-STAT, RAS-ERK, PI3K-AKT). This leads to the inhibition of AML cell proliferation, induction of apoptosis, and suppression of leukemic stem cell self-renewal [1] 3. Selectivity advantage: Compared to first-generation FLT3 inhibitors (e.g., sorafenib, midostaurin), Quizartinib (AC220; AC010220) shows higher selectivity for FLT3 and potent activity against FLT3 D835V, a common mutation that causes resistance to first-generation inhibitors, making it a promising agent for relapsed/refractory FLT3-mutant AML [1] |
Solubility Data
| Solubility (In Vitro) |
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| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 1 mg/mL (1.78 mM) (saturation unknown) in 10% DMF 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 1 mg/mL (1.78 mM) (saturation unknown) in 10% DMF 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. 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: 1 mg/mL (1.78 mM) in 10% DMF 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication. Solubility in Formulation 4: 15% Captisol: 30mg/mL (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 1.7836 mL | 8.9179 mL | 17.8358 mL | |
| 5 mM | 0.3567 mL | 1.7836 mL | 3.5672 mL | |
| 10 mM | 0.1784 mL | 0.8918 mL | 1.7836 mL |