CA1 carbonic anhydrase 1
ENSG00000133742 · protein coding · Open Targets profile
Catalyzes the reversible hydration of carbon dioxide (PubMed:10550681, PubMed:16506782, PubMed:16686544, PubMed:16807956, PubMed:17127057, PubMed:17314045, PubMed:17407288, PubMed:19186056, PubMed:19206230, PubMed:4994926). Can hydrate cyanamide to urea (PubMed:10550681). {ECO:0000269|PubMed:10550681, ECO:0000269|PubMed:16506782, ECO:0000269|PubMed:16686544, ECO:0000269|PubMed:16807956, ECO:0000269|PubMed:17127057, ECO:0000269|PubMed:17314045, ECO:0000269|PubMed:17407288, ECO:0000269|PubMed:19186056, ECO:0000269|PubMed:19206230, ECO:0000269|PubMed:4994926}.
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 Withdrawn means the drug was pulled from the market or from development.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, Structure with Ligand, High-Quality Ligand, Med-Quality Pocket, Druggable Family
- PROTAC
- Small Molecule Binder
gnomAD loss of function constraint: o/e 0.9386000037193298 (upper bound 1.2943999767303467). 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 97 registry trials, updated in the last three years, of the most advanced drugs against CA1 (dichlorphenamide, polmacoxib, acetazolamide, methocarbamol, sulthiame, methazolamide), ranked by Phase 2+ trials. Live from ClinicalTrials.gov.
- Michael FurianUniversity of Zurich · 3 of 3 trials Phase 2+
- Talant SooronbaevNational Center of Cardiology and Internal Medicine, Bishkek, Kyrgyzstan · 3 of 3 trials Phase 2+
- Christopher SchmicklUniversity of California, San Diego · 2 of 2 trials Phase 2+
- Olivier VandervekenUniversity Hospital, Antwerp · 2 of 2 trials Phase 2+
- Susmita ChowdhuriJohn D. Dingell VA Medical Center, Detroit, MI · 2 of 2 trials Phase 2+
- Aharon AbboRambam Health Care Campus · 1 of 1 trials Phase 2+
- Andrew BisharaUCSF Department of Anesthesia · 1 of 1 trials Phase 2+
- Benoit ChampigneulleEXALT (Centre d'Expertise sur l'Altitude), Grenoble, France · 1 of 1 trials Phase 2+
- Camiel JF BoonAmsterdam UMC · 1 of 1 trials Phase 2+
- Chief Scientific OfficerApnimed · 1 of 1 trials Phase 2+
- Christopher N SchmicklUniversity of California, San Diego · 1 of 1 trials Phase 2+
- Dalia A GomaaTanta University · 1 of 1 trials Phase 2+
- Dapeng MoBeijing Tiantan Hospital · 1 of 1 trials Phase 2+
- David Z.I CherneyUniversity Health Network, Toronto General Hospital · 1 of 1 trials Phase 2+
- Dillon GilbertsonBrigham and Women's Hospital and Harvard Medical School · 1 of 1 trials Phase 2+
Registry trials of dichlorphenamide, polmacoxib, acetazolamide, methocarbamol, sulthiame, methazolamide 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; 88 of 93 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. 4 trials list no sites and are left out. Source: ClinicalTrials.gov, fetched live.
33 trials of drugs against CA1 were stopped early; 5 give no reason
Terminated, withdrawn and suspended interventional trials of dichlorphenamide, polmacoxib, acetazolamide, methocarbamol, sulthiame, methazolamide, 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 33.
- terminated · 2025-09-24 · AstraZeneca · matched by the registry's drug synonyms“Sponsor Decision”
- terminated · 2025-08-26 · University of Miami · Acetazolamide, Methazolamide“No patients had abnormal PERG and could not be included in the first two arms from the baseline timepoint.”
- terminated · 2025-04-01 · Universidad Peruana Cayetano Heredia · Acetazolamide“Low recruitment”
- terminated · 2025-03-20 · Mayo Clinic · Acetazolamide“Lack of funding”
- terminated · 2025-02-14 · Stadtspital Zürich · Acetazolamide“Low recruitment in both centers”
- terminated · 2025-01-31 · Aziende Chimiche Riunite Angelini Francesco S.p.A · matched by the registry's drug synonyms“The study had to be closed because it was not feasible to reach the estimated sample size.”
- withdrawn · 2024-09-25 · Henry Ford Health System · Methazolamide“Study was never initiated.”
- withdrawn · 2024-03-01 · University of Alabama at Birmingham · Acetazolamide“The investigator decided not to pursue the study.”
- 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 · 2023-04-27 · The University of Texas Health Science Center, Houston · Acetazolamide“Inadequate recruitment; termination of funding”
- terminated · 2023-01-12 · University of Vermont Medical Center · matched by the registry's drug synonyms“Impact of COVID-19 pandemic on COVID precautions and restrictions of research in the clinical setting; challenges with participant engagement and data collection post-discharge.”
- withdrawn · 2022-12-12 · West Virginia University · matched by the registry's drug synonyms“No qualified enrollments; study cancelled due to pandemic”
- terminated · 2022-06-16 · Jaeb Center for Health Research · Acetazolamide“Low enrollment”
- withdrawn · 2021-12-14 · University of Miami · Acetazolamide“No participants were identified per inclusion/exclusion criteria”
- withdrawn · 2020-11-05 · Children's Mercy Hospital Kansas City · Acetazolamide“Determined not feasible”
- terminated · 2020-06-11 · Mayo Clinic · Acetazolamide“Lack of enrollment”
- withdrawn · 2020-04-21 · University of Miami · Acetazolamide“No participants were identified per inclusion/exclusion criteria”
- terminated · 2019-05-10 · Vincent Kan · Acetazolamide“PI was unable to continue to gather data during the trip during to medical illness”
- withdrawn · 2018-12-03 · University of California, Irvine · Methazolamide“This study was closed due to lack of funding.”
- terminated · 2017-04-13 · Rabin Medical Center · Acetazolamide“difficulty in recruiting participants to the study”
- withdrawn · 2017-02-10 · Georgetown University · acetazolamide“poor recruitment”
- withdrawn · 2017-01-24 · NYU Langone Health · AcetazolamideNo reason given
- terminated · 2016-03-14 · VA Office of Research and Development · Acetazolamide“Patient recruitment and Funding inadequate to finish trial”
- withdrawn · 2015-09-24 · University of Florida · Acetazolamide“The PI is leaving the University of Florida.”
- withdrawn · 2015-06-26 · US Department of Veterans Affairs · acetazolamide“This study of the overall grant was not pursued as the aims were changed”
Paediatric incentives and obligations for CA1's drugs
For dichlorphenamide, polmacoxib, acetazolamide, methocarbamol, sulthiame, methazolamide: 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 · CA1 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: no · No EMA paediatric investigation plan decision names dichlorphenamide, polmacoxib, acetazolamide, methocarbamol, sulthiame, methazolamideRule: 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: yes · EU/3/19/2193 positive 21 Aug 2019: Treatment of periodic paralysisRule: 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 EU/3/19/2193, 2026-11-11
- Authorised in the EU: no · EMA lists no centrally authorised medicine of dichlorphenamide, polmacoxib, acetazolamide, methocarbamol, sulthiame, methazolamideRule: 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 dichlorphenamide, polmacoxib, acetazolamide, methocarbamol, sulthiame, methazolamideRule: 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 · 17 interventional studies of dichlorphenamide, polmacoxib, acetazolamide, methocarbamol, sulthiame, methazolamide include patients under 18; 2 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 8 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.