ATR-107 (Synonyms: PF-05230900)

Cat. No.: HY-P991272 Purity: 99.9%: Data Sheet
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ATR-107 (PF-05230900) is a humanized monoclonal antibody inhibitor that targets the interleukin-21 receptor (IL-21R). The K_a value of ATR-107 is 2-4 nM in cynomolgus monkeys, 16 nM in mice, and 71 nM in rats. ATR-107 can be used in research related to systemic lupus erythematosus and air pouch inflammation.

For research use only. We do not sell to patients.

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1 mg	In-stock	Estimated Time of Arrival: December 31
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10 mg	In-stock	Estimated Time of Arrival: December 31
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IL-1 IL-2 IL-3 IL-4 IL-5 IL-6 IL-8 IL-10 IL-12 IL-13 IL-15 IL-17 IL-23 IL-7 IL-33 IL-22 IL-18

Biological Activity
Purity & Documentation
References
Customer Review

Description

Isotype

Human IgG1 lambda

Recommend Isotype Controls

Human IgG1 lambda1, Isotype Control

Species Reactivity

Human

IC₅₀ & Target

IL21R/CD360

In Vitro

ATR-107 (100 μg/mL; 24 h) induces a significantly higher DC₅₀ internalization index than bevacizumab and a significantly lower index than bococizumab in human monocyte-derived DCs, consistent with its high clinical anti-drug antibody incidence^[2].
ATR-107 (50 μg/mL; 7-day total incubation, with BrdU added for the final 24 h) induces significant CD4⁺ T cell proliferation in human PBMCs, with a positive response rate in ~30% of healthy donors, consistent with its high clinical anti-drug antibody incidence^[2].
ATR-107 (100 μg/mL; 16 h (MAPPs assay)) has 11 in silico-predicted immunogenic T cell epitopes, 9 of which overlap with MHC-II-associated peptides detected via MAPPs, indicating a high potential for T cell-mediated immunogenicity^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Parmacokinetics

Species	Dose	Route	AUC_0-t
Rat^[1]	10 mg/kg	i.v.	1893 μg·h/mL
Rat^[1]	50 mg/kg	i.v.	27203 (M),18633(F) μg·h/mL
Rat^[1]	250 mg/kg	i.v.	101165(M); 132003(F) μg·h/mL
Rat^[1]	250 mg/kg	s.c.	14777(M);7256(F) μg·h/mL

In Vivo

ATR-107 (10-250 mg/kg; i.v., s.c.; weekly; 13 weeks) causes immune-mediated liver injury (necrosis, bridging fibrosis, elevated liver enzymes) in Sprague-Dawley rats only at 10 mg/kg weekly i.v. after ≥3 doses; ADA presence alone is insufficient for liver injury, as 100% ADA incidence occurred with 10 mg/kg s.c. (no liver injury present), indicating the effect is route-dependent^[1].
ATR-107 (1-10 mg/kg; i.v.; weekly; up to 4 doses) induces liver injury in female Sprague-Dawley rats that requires ≥3 weekly i.v. doses, correlates with high ADA titers, and causes transiently elevated liver enzymes with microscopic changes morphologically consistent with the 13-week study findings^[1].
ATR-107 (0.1-10 mg/kg; i.v.; weekly; 3 or 4 doses) does not cause liver injury in female nude rats, indicating that a functional immune system (and resulting ADA formation) is required for the liver effects observed in immunocompetent Sprague-Dawley rats^[1].
ATR-107 (0.1-250 mg/kg; i.v., s.c.; weekly; up to 4 doses) causes dose-dependent anaphylactic mortality in CD-1 mice after ≥2 weekly i.v. doses (bell-shaped curve centered at 1 mg/kg i.v.), correlated with high ADA incidence, with no such effects observed with s.c. administration^[1].
ATR-107 (10-100 mg/kg; i.v., s.c.; weekly; 13 weeks) shows no ATR-107-related mortality, clinical observations, clinical pathology changes, organ weight changes, or macroscopic/microscopic tissue findings at any dose or route in Cynomolgus monkeys, with low ADA incidence at lower doses and 0% at higher doses^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Animal Model:	Sprague-Dawley (Crl:CD[SD]) (male and female, 7 to 9 weeks old, ≥170 g)^[1]
Dosage:	10 mg/kg; 50 mg/kg; 250 mg/kg (i.v.); 10 mg/kg; 250 mg/kg (s.c.)
Administration:	i.v.; weekly; 13 weeks; s.c.; weekly; 13 weeks
Result:	Caused 1 female death on day 16 due to marked midzonal to diffuse bridging liver necrosis at 10 mg/kg i.v. At end of dosing phase, induced moderate to marked diffuse bridging liver fibrosis with parenchymal nodules, single-cell hepatocyte necrosis, vacuolation, pigment-laden macrophages, bile duct hyperplasia/degeneration/necrosis, and eosinophil-rich mixed inflammation in 2 males and 2 females, and elevated ALT (70-109 IU/L), AST (194-383 IU/L), and AP (239-281 IU/L) in 3 males at 10 mg/kg i.v. At end of recovery phase, resulted in minimal to moderate diffuse bridging fibrosis in 1 male and 4 females, and elevated ALT (115 IU/L), AST (251 IU/L), and AP (186 IU/L) in 1 male at 10 mg/kg i.v. Induced 100% ADA incidence (log titers >4.74) at end of dosing and recovery phases at 10 mg/kg i.v. Showed no ATR-107-related liver findings, mortality, or clinical pathology changes at 50 mg/kg, 250 mg/kg i.v., and 10 mg/kg, 250 mg/kg s.c. Resulted in 33.3% ADA incidence at 50 mg/kg i.v., 0% at 250 mg/kg i.v., 100% at 10 mg/kg s.c., and 66.7% at 250 mg/kg s.c. at end of dosing phase. Increased serum ATR-107 exposures with dose at i.v. routes. Had lower serum ATR-107 exposure at 250 mg/kg s.c. than at 50 mg/kg i.v.

Animal Model:	Sprague-Dawley (Crl:CD[SD]) (female, 7 to 9 weeks old, ≥170 g)^[1]
Dosage:	1 mg/kg; 10 mg/kg
Administration:	i.v.; weekly; up to 4 doses
Result:	Caused no mortality, but elevated ALT (189-1329 IU/L) and AST (294-2079 IU/L) first detected on day 15 (after 3rd dose) in 9/20 and 3/20 rats respectively, values returned to control levels by day 20 then re-elevated in 2/10 rats on day 22 (after 4th dose) at 1 mg/kg i.v. Induced liver microscopic findings (hepatocellular degeneration/necrosis, eosinophilic cytoplasmic droplets, mixed cell inflammation with slight bile duct hyperplasia) after 3 or 4 doses, with necrotic areas and cytoplasmic droplets immunopositive for rat IgG, IgM, and C3 at 1 mg/kg i.v. Detected ADAs at low titers prior to 3rd dose, with high titers (2.75 to >4.74 log titer) in all rats after 3 or 4 doses, and sharp drop in serum ATR-107 concentrations after 3rd dose at 1 mg/kg i.v. Led to 1 female elective euthanasia on day 22 after 4 doses, with marked midzonal hepatocellular necrosis and eosinophilic cytoplasmic droplets at 10 mg/kg i.v. Detected elevated ALT (170-220 IU/L) in 2/20 rats on day 15 (after 3rd dose) and 1/10 rats on day 22 (after 4th dose) at 10 mg/kg i.v. Observed liver microscopic findings (hepatocellular degeneration/necrosis, eosinophilic cytoplasmic droplets) after 4 doses in 1/10 rats, with immunopositivity for rat IgG, IgM, and C3 in affected areas at 10 mg/kg i.v. Detected ADAs in 7/10 rats after 3 doses and 9/10 rats after 4 doses, with measurable but lower serum ATR-107 concentrations after 3rd/4th doses compared to earlier doses at 10 mg/kg i.v.

Animal Model:	Crl:CD-1 (ICR) (male and female, 7 to 9 weeks old, ~22 g)^[1]
Dosage:	0.1 mg/kg; 1 mg/kg; 10 mg/kg; 250 mg/kg (i.v.); 10 mg/kg; 250 mg/kg (s.c.)
Administration:	i.v.; weekly; up to 4 doses (dosing discontinued after 2 or 3 doses in 1 mg/kg i.v. group); s.c.; weekly; up to 4 doses
Result:	Caused dose-dependent anaphylactic mortality after ≥2 weekly i.v. doses, with a bell-shaped incidence curve centered at 1 mg/kg i.v. (20/76 animals at 1 mg/kg, 5/76 at 0.1 mg/kg, 4/76 at 10 mg/kg, 1/76 at 250 mg/kg). Induced clinical signs (decreased motor activity, convulsions, ataxia, dyspnea, hunched posture, cool to touch, ptosis, tachypnea, bradypnea) within 4 minutes to 1 hour of dosing at all i.v. doses. Observed mild to moderate pulmonary thrombi with increased intravascular neutrophils in some 1 mg/kg i.v. animals that died. Showed no ATR-107-related body weight, food consumption, or macroscopic/microscopic findings in surviving animals (except clinical signs in 0.1 and 1 mg/kg i.v. groups) at i.v. doses. Resulted in 77% (54/70) ADA incidence at 0.1 mg/kg i.v., 73% (41/56) at 1 mg/kg i.v., 7% (5/71) at 10 mg/kg i.v., and 0% (0/74) at 250 mg/kg i.v. Showed no mortality, clinical signs, or ATR-107-related findings at 10 mg/kg and 250 mg/kg s.c. Resulted in 22% (16/74) ADA incidence at 10 mg/kg s.c. and 0% (0/70) at 250 mg/kg s.c.

Animal Model:	Cynomolgus Monkey (male and female, ~3 to 5 years old, ~2 to 6 kg)^[1]
Dosage:	10 mg/kg; 30 mg/kg; 100 mg/kg (i.v.); 10 mg/kg; 100 mg/kg (s.c.)
Administration:	i.v.; weekly; 13 weeks; s.c.; weekly; 13 weeks
Result:	Caused no ATR-107-related mortality, clinical observations, clinical pathology changes, organ weight changes, or macroscopic/microscopic tissue findings at any dose or route. Resulted in 8.3% ADA incidence at 10 mg/kg i.v., 16.7% at 10 mg/kg s.c., and 0% at all higher i.v. and s.c. doses.

Clinical Trial

Gene ID

50615 [NCBI]

Accession

Q9HBE5

Application

ELISA, FACS, Functional assay

Conjugated

Unconjugated

Reconsititution

The product can be reconstituted/diluted with sterile PBS or saline.

Molecular Weight

143.42 kDa

Appearance

Liquid

Color

Colorless to light yellow

SMILES

N/A

Shipping

Shipping with dry ice.

Formulation

Please refer to the lot-specific COA for specific buffer information.

Storage

Please store the product under the recommended conditions in the Certificate of Analysis.

Biological Activity

Immobilized Human IL-21 R Protein, His Tag can bind ATR-107. The EC₅₀ for this effect is 79 ng/mL.
Flow cytometric analysis of 1X10⁶ HepG2 cells labeling CD360 with ATR-107 (HY-P991272, red). Cells were fixed with 4% paraformaldehyde. Then stained with the primary antibody at 1/200 for an hour at 4℃. AF488-conjugated Goat Anti-Human IgG H&L (AF488) (HY-P83776) was used as the secondary antibody at 1/1,000 dilution for 30 minutes at 4℃. Human IgG1 kappa Isotype Control (HY-P99992, blue) was used as the isotype control, cells without incubation with primary antibody were used as the unlabeled control (black).

Purity & Documentation

Purity: 99.9%

Select Batch:

Data Sheet (267 KB) SDS (251 KB)

COA (232 KB) SDS-PAGE (155 KB) SEC-HPLC (334 KB)

Inhibitory Antibodies User Guide (603 KB)

References

[1]. Hu W, et al. Immune-Mediated Liver Effects Associated With Administration of a Human Anti-IL-21 Receptor Antibody (ATR-107) in Rats. Toxicol Pathol. 2024;52(5):232-250. [Content Brief]

[2]. Tsai WK, et al. Nonclinical immunogenicity risk assessment for knobs-into-holes bispecific IgG₁ antibodies. MAbs. 2024;16(1):2362789. [Content Brief]

ATR-107 Related Classifications

Inflammation/Immunology

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Help & FAQs

Do most proteins show cross-species activity?
Species cross-reactivity must be investigated individually for each product. Many human cytokines will produce a nice response in mouse cell lines, and many mouse proteins will show activity on human cells. Other proteins may have a lower specific activity when used in the opposite species.

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