CA2 carbonic anhydrase 2
ENSG00000104267 · protein coding · Open Targets profile
Catalyzes the reversible hydration of carbon dioxide (PubMed:11327835, PubMed:11802772, PubMed:11831900, PubMed:12056894, PubMed:12171926, PubMed:1336460, PubMed:14736236, PubMed:15300855, PubMed:15453828, PubMed:15667203, PubMed:15865431, PubMed:16106378, PubMed:16214338, PubMed:16290146, PubMed:16686544, PubMed:16759856, PubMed:16807956, PubMed:17127057, PubMed:17251017, PubMed:17314045, PubMed:17330962, PubMed:17346964, PubMed:17540563, PubMed:17588751, PubMed:17705204, PubMed:18024029, PubMed:18162396, PubMed:18266323, PubMed:18374572, PubMed:18481843, PubMed:18640037, PubMed:18942852, PubMed:1909891, PubMed:1910042, PubMed:19170619, PubMed:19186056, PubMed:19206230, PubMed:19520834, PubMed:19778001, PubMed:7761440, PubMed:7901850, PubMed:8218160, PubMed:8262987, PubMed:8399159, PubMed:8451242, PubMed:8485129, PubMed:8639494, PubMed:9265618, PubMed:9398308, PubMed:4994926). Can also hydrate cyanamide to urea (PubMed:10550681, PubMed:11015219). Stimulates the chloride-bicarbonate exchange activity of SLC26A6 (PubMed:15990874). Essential for bone resorption and osteoclast differentiation (PubMed:15300855). Involved in the regulation of fluid secretion into the anterior chamber of the eye. Contributes to intracellular pH regulation in the duodenal upper villous epithelium during proton-coupled peptide absorption. {ECO:0000269|PubMed:10550681, ECO:0000269|PubMed:11015219, ECO:0000269|PubMed:11327835, ECO:0000269|PubMed:11802772, ECO:0000269|PubMed:11831900, ECO:0000269|PubMed:12056894, ECO:0000269|PubMed:12171926, ECO:0000269|PubMed:1336460, ECO:0000269|PubMed:14736236, ECO:0000269|PubMed:15300855, ECO:0000269|PubMed:15453828, ECO:0000269|PubMed:15667203, ECO:0000269|PubMed:15865431, ECO:0000269|PubMed:15990874, ECO:0000269|PubMed:16106378, ECO:0000269|PubMed:16214338, ECO:0000269|PubMed:16290146, ECO:0000269|PubMed:16686544, ECO:0000269|PubMed:16759856, ECO:0000269|PubMed:16807956, ECO:0000269|PubMed:17127057, ECO:0000269|PubMed:17251017, ECO:0000269|PubMed:17314045, ECO:0000269|PubMed:17330962, ECO:0000269|PubMed:17346964, ECO:0000269|PubMed:17540563, ECO:0000269|PubMed:17588751, ECO:0000269|PubMed:17705204, ECO:0000269|PubMed:18024029, ECO:0000269|PubMed:18162396, ECO:0000269|PubMed:18266323, ECO:0000269|PubMed:18374572, ECO:0000269|PubMed:18481843, ECO:0000269|PubMed:18640037, ECO:0000269|PubMed:18942852, ECO:0000269|PubMed:1909891, ECO:0000269|PubMed:1910042, ECO:0000269|PubMed:19170619, ECO:0000269|PubMed:19186056, ECO:0000269|PubMed:19206230, ECO:0000269|PubMed:19520834, ECO:0000269|PubMed:19778001, ECO:0000269|PubMed:4994926, ECO:0000269|PubMed:7761440, ECO:0000269|PubMed:7901850, ECO:0000269|PubMed:8218160, ECO:0000269|PubMed:8262987, ECO:0000269|PubMed:8399159, ECO:0000269|PubMed:8451242, ECO:0000269|PubMed:8485129, ECO:0000269|PubMed:8639494, ECO:0000269|PubMed:9265618, ECO:0000269|PubMed:9398308}.
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, High-Quality Pocket, Druggable Family
- Antibody
- UniProt loc high conf, GO CC high conf
- PROTAC
- Database Ubiquitination, Half-life Data, Small Molecule Binder
gnomAD loss of function constraint: o/e 0.8262900114059448 (upper bound 1.170699954032898). 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 160 registry trials, updated in the last three years, of the most advanced drugs against CA2 (dichlorphenamide, acetazolamide, polmacoxib, topiramate, sulthiame, dorzolamide, methazolamide, brinzolamide), 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+
- Bartolome BurgueraThe Cleveland Clinic · 2 of 2 trials Phase 2+
- Christopher SchmicklUniversity of California, San Diego · 2 of 2 trials Phase 2+
- mohamed G. Zeinhomneurology department kafr el-sheikh university · 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+
- Aaron KellyUniversity of Minnesota · 1 of 1 trials Phase 2+
- Aharon AbboRambam Health Care Campus · 1 of 1 trials Phase 2+
- Ali AminaniBariatric Research Medical Director · 1 of 1 trials Phase 2+
- Ali AminianThe Cleveland Clinic · 1 of 1 trials Phase 2+
- BANG-YAN ZHANGNew Taipei Municipal TuCheng Hospital (Built and Operated by Chang Gung Medical Foundation) · 1 of 1 trials Phase 2+
- Bankole A JohnsonUniversity of Virginia · 1 of 1 trials Phase 2+
- Benjamin CanalesUniversity of Florida · 1 of 1 trials Phase 2+
- Benoit ChampigneulleEXALT (Centre d'Expertise sur l'Altitude), Grenoble, France · 1 of 1 trials Phase 2+
Registry trials of dichlorphenamide, acetazolamide, polmacoxib, topiramate, sulthiame, dorzolamide, methazolamide, brinzolamide 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; 142 of 150 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. 10 trials list no sites and are left out. Source: ClinicalTrials.gov, fetched live.
91 trials of drugs against CA2 were stopped early; 8 give no reason
Terminated, withdrawn and suspended interventional trials of dichlorphenamide, acetazolamide, polmacoxib, topiramate, sulthiame, dorzolamide, methazolamide, brinzolamide, 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 91.
- suspended · 2026-10-27 · University of California, Irvine · Topiramate“Enrollment temporarily paused pending IRB continuing review; recruitment expected to resume.”
- terminated · 2026-05-07 · Laboratorios Sophia S.A de C.V. · Dorzolamide-timolol-brimonidine and latanoprost, Dorzolamide-timolol and latanoprost“For interests of sponsor.”
- terminated · 2026-03-12 · University of Iowa · Topiramate“Lack of funding”
- terminated · 2026-01-22 · Supernus Pharmaceuticals, Inc. · matched by the registry's drug synonyms“Difficulty in recruitment”
- withdrawn · 2025-12-18 · Eurofarma Laboratorios S.A. · ADF1 Group Eurofarma drug association of Sibutramine IR 15mg / Topiramate XR 75mg, ADF2 Group Eurofarma drug association of Sibutramine IR 15mg / Topiramate XR 100mg“Strategic change in development priorities”
- terminated · 2025-08-26 · University of Miami · Dorzolamide, Brinzolamide, Acetazolamide, Methazolamide“No patients had abnormal PERG and could not be included in the first two arms from the baseline timepoint.”
- withdrawn · 2025-05-31 · Janey Pratt · Topiramate“No available funding”
- withdrawn · 2025-04-11 · Stanford University · matched by the registry's drug synonyms“Not funded”
- terminated · 2025-04-01 · Universidad Peruana Cayetano Heredia · Acetazolamide“Low recruitment”
- terminated · 2025-03-20 · Mayo Clinic · Acetazolamide“Lack of funding”
- terminated · 2025-03-06 · Laboratorios Sophia S.A de C.V. · Dorzolamide-Timolol Ophthalmic“Sponsor's prerogative since initial purpose for study shifted according to business strategy.”
- terminated · 2025-02-28 · VA Office of Research and Development · matched by the registry's drug synonyms“Difficulty recruiting patients”
- terminated · 2025-02-14 · Stadtspital Zürich · Acetazolamide“Low recruitment in both centers”
- withdrawn · 2025-02-14 · University of California, Los Angeles · matched by the registry's drug synonyms“Conducted an interim analysis on similar data”
- suspended · 2025-01-28 · University of Sao Paulo · Topiramate-Implant“We suspended the study for budget issues. It might be resumed in the future.”
- withdrawn · 2024-09-25 · Henry Ford Health System · Methazolamide“Study was never initiated.”
- terminated · 2024-09-19 · The Cleveland Clinic · Phentermine / Topiramate Extended Release Oral Capsule“After an unplanned yet IRB approved interim analysis, it was found that there was not a significant difference between the 3 arms of the study. The study was closed due to futility. All Patients are off study and this study will not resume.”
- terminated · 2024-08-23 · CT Glaucoma Associates · dorzolamide/timolol“The 95% confidence interval for non-inferiority was met before planned enrollment was reached.”
- terminated · 2024-06-11 · Kristin R Hoffman · Topiramate“The study was stopped early due to changes in the UC Davis guidelines on who qualified for therapeutic hypothermia and significant difficulty in recruitment of patients following the COVID19 pandemic.”
- withdrawn · 2024-03-01 · University of Alabama at Birmingham · Acetazolamide“The investigator decided not to pursue the study.”
- terminated · 2023-12-05 · Alcon Research · Travoprost 0.004% + Brinzolamide 1.0%“difficulty of enrolling patients”
- withdrawn · 2023-10-26 · University of Minnesota · matched by the registry's drug synonyms“The project was not funded”
- terminated · 2023-04-27 · The University of Texas Health Science Center, Houston · Acetazolamide“Inadequate recruitment; termination of funding”
- terminated · 2023-03-23 · VA Office of Research and Development · Topiramate“In ability to recruit”
- terminated · 2023-02-14 · Hartford Hospital · Administration of weight loss drug (Metformin or Topiramate)“Difficulty with enrollment and then Covid pandemic”
Paediatric incentives and obligations for CA2's drugs
For dichlorphenamide, acetazolamide, polmacoxib, topiramate, sulthiame, dorzolamide, methazolamide, brinzolamide: 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 · CA2 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-001172-PIP01-11 (brinzolamide;brimonidine tartrate, Treatment of glaucoma): W: decision granting a waiver in all age groups for all conditions or indications, 26 Oct 2011; EMEA-000826-PIP01-09 (phentermine;topiramate, Treatment of obesity): W: decision granting a waiver in all age groups for all conditions or indications, 29 Oct 2010; EMEA-000368-PIP01-08 (travoprost;brinzolamide, Treatment of glaucoma;Treatment of ocular hypertension): W: decision granting a waiver in all age groups for all conditions or indications, 23 Dec 2008Rule: 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/3/24/2932 positive 28 Jun 2024: Treatment of neonatal encephalopathy; 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 data download (dated snapshot), 2026-11-11
- Authorised in the EU: yes · Azopt: authorised since 9 Mar 2000; Azarga: authorised since 25 Nov 2008; Simbrinza: authorised since 18 Jul 2014; Qsiva: refusedRule: 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, acetazolamide, polmacoxib, topiramate, sulthiame, dorzolamide, methazolamide, brinzolamideRule: 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 · 96 interventional studies of dichlorphenamide, acetazolamide, polmacoxib, topiramate, sulthiame, dorzolamide, methazolamide, brinzolamide include patients under 18; 4 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 11 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.