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Zastaprazan (JP-1366)

Alias: Zastaprazan; 2133852-18-1; Zastaprazan [INN]; W9S9KZX5MD; Zastaprazan (INN);
Cat No.:V74230 Purity: ≥98%
Zastaprazan (JP-1366) is a proton pump inhibitor (WO2018008929).
Zastaprazan (JP-1366)
Zastaprazan (JP-1366) Chemical Structure CAS No.: 2133852-18-1
Product category: Proton Pump
This product is for research use only, not for human use. We do not sell to patients.
Size Price Stock Qty
1mg
5mg
10mg
Other Sizes

Other Forms of Zastaprazan (JP-1366):

  • Zastaprazan citrate
Official Supplier of:
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Product Description
Zastaprazan (JP-1366) is a proton pump inhibitor (WO2018008929). Zastaprazan is indicated for the study of gastrointestinal inflammation or stomach acid-related disorders.
Zastaprazan (also known as JP-1366) is a novel potassium-competitive acid blocker developed by Onconic Therapeutics for the treatment of gastroesophageal reflux disease, particularly erosive esophagitis. Chemically, it features an imidazopyridine backbone substituted with an azetidine group. As a P-CAB, Zastaprazan reversibly and competitively inhibits gastric H+/K+-ATPase on both active and inactive proton pumps, leading to rapid and sustained acid suppression. Unlike proton pump inhibitors, it does not require acid activation, is acid-stable (eliminating the need for enteric coating), and its metabolism is independent of CYP2C19, allowing for consistent efficacy regardless of CYP2C19 genotype and flexible dosing irrespective of meals. In a phase III study, Zastaprazan 20 mg once daily demonstrated noninferior efficacy to esomeprazole 40 mg in healing EE at 8 weeks (97.92% vs 94.93%), with a significantly higher healing rate at week 4 (95.14% vs 87.68%, P = 0.026), suggesting a faster onset of action. It was well tolerated with a favorable safety profile comparable to esomeprazole. Its pharmacokinetic profile includes an elimination half-life of 8.6 hours and 83% time with intragastric pH > 4 over 24 hours, supporting its potential as a clinically useful candidate for EE treatment. [1]
Biological Activity I Assay Protocols (From Reference)
Targets
Proton pump[1]
Zastaprazan is a potassium-competitive acid blocker (P-CAB) that inhibits the gastric H+/K+-ATPase (proton pump). It binds reversibly and competitively to both active and inactive proton pumps. [1]
ln Vitro
The mechanism of action is described: unlike proton pump inhibitors (PPIs), Zastaprazan does not require acidic activation; it can directly inhibit proton pumps regardless of their activation state. Its metabolism is not dependent on CYP2C19, and it is acid-stable, eliminating the need for an enteric coating. [1]
Zastaprazan is a small molecule therapeutic agent. The presence of the International Nonproprietary Name stem "-prazan" in its nomenclature classifies it as a proton pump inhibitor that operates independently of acid-activated conversion. Currently, Zastaprazan is being evaluated in clinical study NCT05814809, a trial designed to assess its safety profile and pharmacokinetic characteristics in healthy adult participants. The compound possesses a monoisotopic molecular mass of 362.21 Daltons.
ln Vivo
In a phase I study in healthy volunteers (referenced), Zastaprazan demonstrated potent gastric acid suppression, achieving intragastric pH > 4 within 2 hours and sustaining acid suppression for 24 hours in a dose-dependent manner. [1]
In this phase III study in patients with erosive esophagitis (EE), Zastaprazan 20 mg once daily for up to 8 weeks resulted in a cumulative healing rate (full analysis set) of 97.92% (141/144) at week 8 and 95.14% (137/144) at week 4. The week 4 healing rate was significantly higher than that of esomeprazole 40 mg (87.68%, P = 0.026). [1]
In patients with baseline LA classification grade B/C/D, the 4-week and 8-week healing rates with Zastaprazan were numerically higher than with esomeprazole (91.84% vs 78.72% at week 4; 95.92% vs 89.36% at week 8). [1]
Symptom response, assessed by Reflux Disease Questionnaire (RDQ) and GERD-Health Related Quality of Life (GERD-HRQL) scores, showed significant improvement from baseline with Zastaprazan treatment, comparable to esomeprazole. [1]
Serum gastrin levels increased significantly from baseline to the end of treatment in the Zastaprazan group (from 45.3 ± 87.0 pg/mL to 114.9 ± 116.2 pg/mL, P < 0.0001). The increase was slightly higher than in the esomeprazole group (P = 0.047), but levels returned to baseline 2 weeks after treatment completion. [1]
Animal Protocol
Study Design and Methodology: [1]
This phase III, multicenter, randomized, double-blind, noninferiority trial enrolled 300 participants with endoscopically confirmed erosive esophagitis. Subjects were randomly assigned to receive either 20 mg of zastaprazan or 40 mg of esomeprazole once daily for up to eight weeks. The primary endpoint was the cumulative proportion of patients with endoscopically confirmed healing of EE at week 8. Secondary endpoints included the healing rate at week 4, symptomatic response, and quality of life measures. Additionally, safety profiles and changes in serum gastrin levels were evaluated.
Key Findings [1]
In the full analysis set, the cumulative healing rate at week 8 was 97.92% (141/144) in the zastaprazan group and 94.93% (131/138) in the esomeprazole group (P=0.178). At week 4, the healing rate was significantly higher with zastaprazan compared to esomeprazole (95.14% [137/144] vs. 87.68% [121/138]; P=0.026). No statistically significant differences were observed between the two groups in the per-protocol analysis for healing rates at week 4 or week 8, nor in symptom response, quality of life assessments, or overall safety profiles. Serum gastrin levels increased during treatment in both groups, with a significant between-group difference (P=0.047), but returned to baseline levels after treatment discontinuation.
ADME/Pharmacokinetics
Zastaprazan is acid-stable and does not require an enteric coating. Its metabolism is not dependent on CYP2C19. [1]
It can be dosed irrespective of meals. [1]
From referenced data, the elimination half-life of Zastaprazan at a 20 mg dose is 8.6 hours. [1]
The proportion of time with intragastric pH > 4 over 24 hours after dosing is 83% for the 20 mg dose, which is known to be associated with healing of esophageal erosions. [1]
Onset of action is rapid, with gastric pH rising above 4 within 2 hours after oral administration of 20 mg. [1]
Toxicity/Toxicokinetics
In this phase III study, Zastaprazan was well tolerated. The overall incidence of treatment-emergent adverse events (TEAEs) in the Zastaprazan group was 16.22% (24/148), compared with 22.15% (33/149) in the esomeprazole group. [1]
Drug-related adverse events (ADRs) occurred in 4.73% (7/148) of Zastaprazan-treated subjects, compared with 9.40% (14/149) in the esomeprazole group. No serious adverse events or deaths were reported in either group. [1]
The most frequently reported TEAEs in the Zastaprazan group were gastrointestinal disorders (7.43%), including hiatus hernia (2.70%), infections (2.70%, all COVID-19), and nervous system disorders (2.03%, including headache). [1]
One subject in the Zastaprazan group discontinued treatment due to a TEAE (skin rash from lacquer poisoning), which was not considered drug-related. [1]
No significant changes in vital signs, ECG findings, or laboratory tests (including liver function) were observed during the study period. [1]
Serum gastrin levels increased during treatment but returned to baseline after treatment cessation. [1]
References

[1]. Randomized, Double-Blind, Active-Controlled Phase 3 Study to Evaluate Efficacy and Safety of Zastaprazan Compared With Esomeprazole in Erosive Esophagitis. Am J Gastroenterol. 2025 Feb 1;120(2):353-361.

[2]. WO2018008929.

Additional Infomation
Background: Zastaprazan (JP-1366) is a novel potassium-competitive acid blocker developed by Onconic Therapeutics for the treatment of gastroesophageal reflux disease (GERD), specifically erosive esophagitis. Chemically, it has an imidazopyridine backbone substituted with an azetidine group. [1]
Mechanism of action: As a P-CAB, Zastaprazan reversibly and competitively inhibits gastric H+/K+-ATPase on both active and inactive proton pumps, leading to rapid and sustained acid suppression. Unlike PPIs, it does not require acid activation, and its efficacy is independent of CYP2C19 genotype. [1]
Clinical efficacy: In this phase III study, Zastaprazan 20 mg once daily demonstrated noninferior efficacy to esomeprazole 40 mg in healing EE at 8 weeks. The 4-week healing rate was numerically higher with Zastaprazan, suggesting a faster onset of action. [1]
Comparison with other P-CABs: The 8-week healing rate of Zastaprazan (97.92%–100%) is comparable to that of other approved P-CABs such as vonoprazan, tegoprazan, fexuprazan, and kevoprazan. The pharmacokinetic profile (half-life 8.6 h, pH > 4 holding time 83%) is favorable. [1]
Safety: Zastaprazan was well tolerated with a low incidence of drug-related adverse events, comparable to esomeprazole and other P-CABs. No new safety signals were identified. [1]
These protocols are for reference only. InvivoChem does not independently validate these methods.
Physicochemical Properties
Molecular Formula
C22H26N4O
Molecular Weight
362.468044757843
Exact Mass
362.21
Elemental Analysis
C, 72.90; H, 7.23; N, 15.46; O, 4.41
CAS #
2133852-18-1
Related CAS #
2936619-43-9 (citrate)
PubChem CID
138622158
Appearance
White to off-white solid powder
LogP
4.4
Hydrogen Bond Donor Count
1
Hydrogen Bond Acceptor Count
3
Rotatable Bond Count
4
Heavy Atom Count
27
Complexity
526
Defined Atom Stereocenter Count
0
SMILES
O=C(C1C=C(C2=NC(C)=C(C)N2C=1)NCC1C(C)=CC=CC=1C)N1CCC1
InChi Key
FEQFUBYYZYQTOJ-UHFFFAOYSA-N
InChi Code
InChI=1S/C22H26N4O/c1-14-7-5-8-15(2)19(14)12-23-20-11-18(22(27)25-9-6-10-25)13-26-17(4)16(3)24-21(20)26/h5,7-8,11,13,23H,6,9-10,12H2,1-4H3
Chemical Name
azetidin-1-yl-[8-[(2,6-dimethylphenyl)methylamino]-2,3-dimethylimidazo[1,2-a]pyridin-6-yl]methanone
Synonyms
Zastaprazan; 2133852-18-1; Zastaprazan [INN]; W9S9KZX5MD; Zastaprazan (INN);
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)
Solubility Data
Solubility (In Vitro)
DMSO: 33.33 mg/mL (91.95 mM)
Solubility (In Vivo)
Solubility in Formulation 1: ≥ 2.5 mg/mL (6.90 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 25.0 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 (6.90 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 2.7588 mL 13.7942 mL 27.5885 mL
5 mM 0.5518 mL 2.7588 mL 5.5177 mL
10 mM 0.2759 mL 1.3794 mL 2.7588 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.

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Working concentration mg/mL;

Method for preparing DMSO stock solution mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.

Method for preparing in vivo formulation:Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O,mix and clarify.

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Clinical Trial Information
Title:Effect of ZaStaprazan on Platelet Reactivity of Clopidogrel After PercuTaneous CoronAry InteRvention
Status:Recruiting
updateDate:2026-04-24
Ctid:NCT07471867

Link: https://clinicaltrials.gov/ct2/show/NCT07471867

Conditions:Chronic Coronary Syndrome
Interventions:Rabeprazole
Phase:Phase 4
Title:Routine Use of Potassium Competitive Acid Blocker vs. Guideline-Directed Gastrointestinal Protection Strategy in Acute Myocardial Infarction
Status:Not yet recruiting
updateDate:2026-03-12
Ctid:NCT07467213

Link: https://clinicaltrials.gov/ct2/show/NCT07467213

Conditions:Acute Myocardial Infarction (AMI)|Gastrointestinal Bleeding
Interventions:Proton Pump Inhibitors (PPI)
Phase:Phase 4
Title:Heartburn, Gastroesophageal Reflux Disease
Status:Recruiting
updateDate:2025-12-23
Ctid:NCT07268820

Link: https://clinicaltrials.gov/ct2/show/NCT07268820

Conditions:GERD
Interventions:Esomeprazole
Phase:Phase 4
View More

Title:Phase 1 Study of JLP-2302 and JP-1366: PK and Safety in Healthy Volunteers
Status:Completed
updateDate:2025-09-18
Ctid:NCT07181538

Link: https://clinicaltrials.gov/ct2/show/NCT07181538

Conditions:Healthy
Interventions:JP-1366
Phase:Phase 1
Title:Phase 3 Study of JP-1366: Efficacy and Safety of JP-1366 in Patients With Non-erosive Gastroesophageal Reflux Disease
Status:Not yet recruiting
updateDate:2025-09-08
Ctid:NCT07160790

Link: https://clinicaltrials.gov/ct2/show/NCT07160790

Conditions:Non-erosive Gastroesophageal Reflux Disease
Interventions:Placebo + Placebo
Phase:Phase 3
Title:Study to Evaluate the Efficacy and Safety of JP-1366 in the Prevention of NSAIDs-Induced Peptic Ulcers
Status:Recruiting
updateDate:2024-11-01
Ctid:NCT06439563

Link: https://clinicaltrials.gov/ct2/show/NCT06439563

Conditions:Peptic Ulcer
Interventions:Lanston Capsule 15 mg placebo
Phase:Phase 3
Title:JP-1366 20mg Versus Esomeprazole 40mg in Patients With Erosive Esophagitis
Status:Completed
updateDate:2024-08-27
Ctid:NCT05443984

Link: https://clinicaltrials.gov/ct2/show/NCT05443984

Conditions:Erosive Esophagitis
Interventions:Esomeprazole 40mg
Phase:Phase 3
Title:Clinical Trial to Evaluate Food-Effects on Pharmacokinetics and Pharmacodynamics of Oral Single Dose of JP-1366 Tablet in Healthy Volunteers
Status:Completed
updateDate:2024-08-26
Ctid:NCT05712681

Link: https://clinicaltrials.gov/ct2/show/NCT05712681

Conditions:Healthy
Interventions:JP-1366 20mg tablet
Phase:Phase 1
Title:Clinical Trial to Evaluate the Efficacy and Safety of JP-1366 in Patients With Gastric Ulcer
Status:Completed
updateDate:2024-08-26
Ctid:NCT05448001

Link: https://clinicaltrials.gov/ct2/show/NCT05448001

Conditions:Gastric Ulcer
Interventions:Lansoprazole 30mg
Phase:Phase 3
Title:Clinical Trial to Evaluate the Safety and Pharmacokinetics of JP-1366 in Healthy Adult Volunteers
Status:Completed
updateDate:2023-04-20
Ctid:NCT05814809

Link: https://clinicaltrials.gov/ct2/show/NCT05814809

Conditions:Healthy
Interventions:JP-1366 20mg capsule
Phase:Phase 1
Title:Clinical Trial to Evaluate the Safety and Efficacy of JP-1366 in Patients With Erosive Gastroesophageal Reflux Disease
Status:Completed
updateDate:2022-07-13
Ctid:NCT04282954

Link: https://clinicaltrials.gov/ct2/show/NCT04282954

Conditions:GERD
Interventions:Esomeprazole placebo
Phase:Phase 2

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