ATP4A ATPase H+/K+ transporting subunit alpha
ENSG00000105675 · protein coding · Open Targets profile
The catalytic subunit of the gastric H(+)/K(+) ATPase pump which transports H(+) ions in exchange for K(+) ions across the apical membrane of parietal cells. Uses ATP as an energy source to pump H(+) ions to the gastric lumen while transporting K(+) ion from the lumen into the cell (By similarity). Remarkably generates a million-fold proton gradient across the gastric parietal cell membrane, acidifying the gastric juice down to pH 1 (By similarity). Within a transport cycle, the transfer of a H(+) ion across the membrane is coupled to ATP hydrolysis and is associated with a transient phosphorylation that shifts the pump conformation from inward-facing (E1) to outward-facing state (E2). The release of the H(+) ion in the stomach lumen is followed by binding of K(+) ion converting the pump conformation back to the E1 state (By similarity). {ECO:0000250|UniProtKB:P09626, ECO:0000250|UniProtKB:P19156, ECO:0000250|UniProtKB:Q64436}.
Each band is a group of drugs. It runs from the kind of drug on the left to the furthest stage that drug has reached in any disease on the right. Thicker bands mean more drugs.
Approved bands are highlighted. Withdrawn means the drug was pulled from the market or from development. A combined phase counts as the later one (Phase 1/2 is shown as Phase 2). Hover a band for the drug names. Source: Open Targets Platform, fetched live.
Each row is a cancer, strongest overall evidence first. The two dots show how strong the inherited (germline) and tumour-mutation (somatic) evidence is; the line between them is the gap.
Scores run from 0 (no evidence) to 1 (strongest). A missing dot at 0 means Open Targets holds no evidence of that kind. Source: Open Targets Platform, fetched live.
Tractability
- Small molecule
- Approved Drug, Druggable Family
- Antibody
- UniProt loc high conf, GO CC high conf, UniProt SigP or TMHMM
- PROTAC
- Database Ubiquitination, Small Molecule Binder
gnomAD loss of function constraint: o/e 0.6510999798774719 (upper bound 0.7910799980163574). Low values mean loss of function is poorly tolerated, a safety flag for inhibition.
Who runs trials of these drugs
Principal investigators and study chairs on 400 registry trials, updated in the last three years, of the most advanced drugs against ATP4A (esomeprazole strontium, vonoprazan, abeprazan, pantoprazole, omeprazole, tegoprazan, esomeprazole magnesium, esomeprazole, lansoprazole, rabeprazole, dexlansoprazole, ilaprazole), ranked by Phase 2+ trials. Live from ClinicalTrials.gov.
- Hsiu-Chi ChengNational Cheng-Kung University Hospital · 4 of 4 trials Phase 2+
- Yafen LiangThe University of Texas Health Science Center, Houston · 3 of 3 trials Phase 2+
- Hong GaoFudan University · 2 of 2 trials Phase 2+
- Jyh-Chin YangNational Taiwan University Hospital · 2 of 2 trials Phase 2+
- Pingsheng HuJiangsu Sinorda Biomedicine Co., Ltd · 2 of 2 trials Phase 2+
- Sameh A LashenAlexandria University · 2 of 2 trials Phase 2+
- Yongquan ShiXijing Hosipital of Digestive Disease · 2 of 2 trials Phase 2+
- Wanli LiuNanjing First Hospital, Nanjing Medical University · 1 of 3 trials Phase 2+
- Adrian CanavesiHospital de Clínicas Dr. Manuel Quintela · 1 of 1 trials Phase 2+
- Anders PernerCopenhagen University Hospital, Rigshospitalet · 1 of 1 trials Phase 2+
- Andrew WilsonNorfolk and Norwich University Hospitals NHS Foundation Trust · 1 of 1 trials Phase 2+
- Anne ArmstrongThe Christie NHS Foundation Trust · 1 of 1 trials Phase 2+
- Ansgar W LohseI. Department of Medicine, University Medical Center Hamburg-Eppendorf · 1 of 1 trials Phase 2+
- Antonio HardanStanford University · 1 of 1 trials Phase 2+
- Ari F SyamFakultas Kedokteran Universitas Indonesia · 1 of 1 trials Phase 2+
Registry trials of esomeprazole strontium, vonoprazan, abeprazan, pantoprazole, omeprazole, tegoprazan, esomeprazole magnesium, esomeprazole, lansoprazole, rabeprazole, dexlansoprazole, ilaprazole updated in the last three years, counted by the country group of their listed sites. A trial with sites in several groups counts in each; 336 of 363 have all sites in one country.
Site counts are not patients per country, and trials registered only outside ClinicalTrials.gov are not covered. Where sites are is a fact about the record, not a judgement of its quality. Europe is the EU and EEA, the UK and Switzerland. 37 trials list no sites and are left out. Source: ClinicalTrials.gov, fetched live.
152 trials of drugs against ATP4A were stopped early; 16 give no reason
Terminated, withdrawn and suspended interventional trials of esomeprazole strontium, vonoprazan, abeprazan, pantoprazole, omeprazole, tegoprazan, esomeprazole magnesium, esomeprazole, lansoprazole, rabeprazole, dexlansoprazole, ilaprazole, newest update first, live from ClinicalTrials.gov. Each reason is quoted exactly as the registry gives it; we do not sort reasons into safety, efficacy or business. Dates are the last registry update. Showing the 25 most recent of 152.
- terminated · 2026-09-09 · Eli Lilly and Company · Rabeprazole“Original scientific question rendered moot by the external scientific community”
- terminated · 2026-08-21 · Genentech, Inc. · Omeprazole“The trial was terminated due to sponsor decision.”
- withdrawn · 2026-08-04 · Shanghai Zhongshan Hospital · Esomeprazole“Unable to complete in vitro culture of Helicobacter pylori in our hospital”
- terminated · 2026-08-03 · Biao Zou · matched by the registry's drug synonyms“The study was terminated early because recruitment of eligible children with refractory functional abdominal pain disorders was slower than anticipated, and enrollment of the planned 50 participants was not feasible within the approved study period.”
- terminated · 2026-06-15 · Pfizer · Full dose Pantoprazole plus matching placebo, Half Dose Pantoprazole plus matching placebo“Pfizer has made an internal business decision to terminate the B1791094 study. This decision was not due to safety concerns or requests from any regulatory authorities.”
- withdrawn · 2026-06-09 · Spital Limmattal Schlieren · matched by the registry's drug synonyms“No participants enrolled.”
- terminated · 2026-06-01 · University of Oklahoma · Omeprazole“Translational scientist left university”
- withdrawn · 2026-05-28 · Cinclus Pharma Holding AB · Lansoprazole - Marketed approved dose“Strategic desicion by Sponsor”
- terminated · 2026-05-06 · Takeda · Dexlansoprazole“Study related”
- withdrawn · 2026-03-12 · Assistance Publique - Hôpitaux de Paris · Pantoprazole“no inclusion”
- withdrawn · 2025-12-08 · The Christie NHS Foundation Trust · Lansoprazole“Unable to open”
- terminated · 2025-08-21 · Janssen Research & Development, LLC · Omeprazole 20 mg“The study was stopped as all post-marketing commitments had been fulfilled or released”
- terminated · 2025-05-31 · Christiana Care Health Services · Esomeprazole“Lost funding”
- terminated · 2025-05-06 · Washington University School of Medicine · Pantoprazole“Investigator and study team chose to end study early.”
- terminated · 2025-04-13 · University of Southern California · Omeprazole“Lack of efficacy”
- withdrawn · 2025-04-01 · Eurofarma Laboratorios S.A. · matched by the registry's drug synonyms“Change company strategy”
- terminated · 2025-01-14 · Pfizer · matched by the registry's drug synonyms“The decision to terminate clinical development of lotiglipron is based on pharmacokinetic data from Phase 1 drug-drug-interaction studies and laboratory measurements of elevated transaminases in these Phase 1 studies as well as a Phase 2 study.”
- terminated · 2024-12-03 · St. Petersburg State Pavlov Medical University · matched by the registry's drug synonyms“Poor recruitment”
- terminated · 2024-04-09 · Pfizer · IV pantoprazole“Study was terminated early due to the infeasibility of enrolling the required number of participants per protocol in the 1 <2 years of age cohort.”
- terminated · 2024-01-31 · Vanderbilt University Medical Center · matched by the registry's drug synonyms“Limitations of the prospective study design revealed that a retrospective study design would be better suited.”
- terminated · 2023-12-26 · Columbia University · Omeprazole (suspension)“Lack of funding”
- terminated · 2023-11-22 · St. Luke's Medical Center, Philippines · Vonoprazan, Omeprazole“Budget for the study was withdrawn and discontinued”
- terminated · 2023-06-22 · Emory University · matched by the registry's drug synonyms“Loss of surgery team member deemed the study procedures impossible to achieve, and no replacement could be found in a timely manner to complete trial as initially planned.”
- withdrawn · 2023-02-23 · University of Chicago · Ibuprofen, Hydrocodone/Acetaminophen, Omeprazole“The study was withdrawn prior to any participants being enrolled.”
- withdrawn · 2023-02-01 · Xijing Hospital of Digestive Diseases · rabeprazole“Lack of funds”
Paediatric incentives and obligations for ATP4A's drugs
For esomeprazole strontium, vonoprazan, abeprazan, pantoprazole, omeprazole, tegoprazan, esomeprazole magnesium, esomeprazole, lansoprazole, rabeprazole, dexlansoprazole, ilaprazole: what EMA and FDA publish about paediatric plans, orphan status and pediatric approvals, and how many registered studies take children. Each line is a yes, no or not published fact from the record linked under it; none of it is a forecast.
- FDA pediatric target list: no · ATP4A is not on the listRule: Target is on FDA's Pediatric Molecular Target List (relevant targets). Source: FDA Pediatric Molecular Target List (Listed as February 2026 on the FDA Pediatric Oncology page; the file served is 9.7.22_the_relevant_molecular_target_list.xlsx, whose Summary of Changes sheet is headed 'SEPTEMBER 2022 UPDATE' (footnote date 2022-09-01)), 2026-11-11
- EU paediatric investigation plan: yes · EMEA-002703-PIP01-19-M01 (vonoprazan, Treatment of gastroesophageal reflux disease;Treatment of Helicobacter pylori infection): PM: decision on the application for modification of an agreed PIP, 14 Aug 2024; EMEA-000055-PIP01-07-M06 (rabeprazole (sodium), Treatment of duodenal ulcer;Treatment of gastric ulcer;Treatment of gastro-oesophageal reflux disease;Treatment of Helicobacter pylori in patients with peptic ulcer disease;Treatment of Zollinger-Ellison syndrome): PM: decision on the application for modification of an agreed PIP, 3 Dec 2018; compliance positive 1 Feb 2019; EMEA-002512-PIP01-18 (pantoprazole, Treatment of Helicobacter spp. infections): W: decision granting a waiver in all age groups for all conditions or indications, 15 May 2019; EMEA-001616-PIP01-13 (pantoprazole, Treatment of Helicobacter spp. infections): W: decision granting a waiver in all age groups for all conditions or indications, 18 Jun 2014; +5 moreRule: An EMA PIP decision (agreement, modification or waiver) lists the drug as its active substance, exact name. Source: EMA data download (dated snapshot), 2026-11-11
- EU orphan designation: no · No EU orphan designation names esomeprazole strontium, vonoprazan, abeprazan, pantoprazole, omeprazole, tegoprazan, esomeprazole magnesium, esomeprazole, lansoprazole, rabeprazole, dexlansoprazole, ilaprazoleRule: An EU orphan designation lists the drug as its active substance (exact name) or belongs to a medicine that does; withdrawn and expired designations are listed with their status. Source: EMA data download (dated snapshot), 2026-11-11
- Authorised in the EU: yes · Nexium Control: authorised since 26 Aug 2013; Pantozol Control: authorised since 11 Jun 2009; Controloc Control: authorised since 11 Jun 2009; Somac Control: authorised since 12 Jun 2009; +2 moreRule: An EMA medicine record lists the drug as its active substance or INN, exact name; national-only authorisations are not in this file. Source: EMA data download (dated snapshot), 2026-11-11
- FDA orphan designation: not published · FDA's orphan designation database turns away automated requests, so this app does not read it; search it by hand at the linkRule: Would be: an FDA orphan designation names the drug. Source: FDA orphan designations search
- FDA pediatric oncology approval: no · FDA's table lists no pediatric approval of esomeprazole strontium, vonoprazan, abeprazan, pantoprazole, omeprazole, tegoprazan, esomeprazole magnesium, esomeprazole, lansoprazole, rabeprazole, dexlansoprazole, ilaprazoleRule: FDA's Pediatric Oncology Drug Approvals table names the drug. Source: FDA Pediatric Oncology Drug Approvals (content current as of 2026-03-03), 2026-11-12
- Registered studies open to children: yes · 165 interventional studies of esomeprazole strontium, vonoprazan, abeprazan, pantoprazole, omeprazole, tegoprazan, esomeprazole magnesium, esomeprazole, lansoprazole, rabeprazole, dexlansoprazole, ilaprazole include patients under 18; 18 are recruiting, not yet recruiting or activeRule: The registry's age group includes Child (birth to 17 years), which also counts studies that set no minimum age. Source: ClinicalTrials.gov search, 2026-11-12
Rare pediatric disease voucher. FDA, content current as of 29 Apr 2026: “As of February 3, 2026, enactment of the Consolidated Appropriations Act, 2026, the rare pediatric disease PRV program will sunset after September 30, 2029. FDA may not award any PRVs under this program after September 30, 2029.” Voucher sale prices are not shown here; they appear only as company-reported news. FDA: Rare Pediatric Disease Designation and Priority Review Voucher Programs
All 17 drugs and clinical candidates as a table
Each drug, stage and indication links to its Open Targets record, where the trials and approvals behind it are listed. Salt forms (for example a mesylate) are listed as Open Targets records them, as separate entries.