OncoSignal
Live from Open Targets Platform, fetched 2026-11-12 08:55 UTC. Every row links to its source record.

CYSLTR1 cysteinyl leukotriene receptor 1

ENSG00000173198 · protein coding · Open Targets profile

Receptor for cysteinyl leukotrienes mediating bronchoconstriction of individuals with and without asthma. Stimulation by LTD4 results in the contraction and proliferation of smooth muscle, edema, eosinophil migration and damage to the mucus layer in the lung. This response is mediated via a G protein that activates a phosphatidylinositol-calcium second messenger system. The rank order of affinities for the leukotrienes is LTD4 >> LTE4 = LTC4 >> LTB4.

4 of the 5 drugs recorded against CYSLTR1 are approved

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.

4 small molecule drugs at Approved: ZAFIRLUKAST, PRANLUKAST, MONTELUKAST, MONTELUKAST SODIUM1 small molecule drug at Phase 1: CR-3465Small molecule 5Approved 4Phase 1 1

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 Withdrawn means the drug was pulled from the market or from development.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.

In 2 of 15 cancers, the evidence for CYSLTR1 comes mainly from mutations found in tumours

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.

Inherited (germline) variantsMutations in tumours (somatic)
00.250.50.751Familial prostate cancerFamilial prostate cancerFamilial prostate cancer: somatic 0.18prostate cancerprostate cancerprostate cancer: somatic 0.18colonic neoplasmcolonic neoplasmmalignant colon neoplasmmalignant colon neoplasmcolorectal carcinomacolorectal carcinomaovarian cancerovarian cancercholangiocarcinomacholangiocarcinomalung carcinomalung carcinomalung cancerlung cancerbreast cancerbreast cancerrenal cell carcinomarenal cell carcinomabreast carcinomabreast carcinomapancreatic ductal adenocarcinomapancreatic ductal adenocarcinomapolyppolypcolorectal cancercolorectal cancer

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, Druggable Family
Antibody
GO CC high conf, UniProt loc med conf, UniProt SigP or TMHMM
PROTAC
Small Molecule Binder

gnomAD loss of function constraint: o/e 0.47982001304626465 (upper bound 2.27620005607605). 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 CYSLTR1 (zafirlukast, pranlukast, montelukast), ranked by Phase 2+ trials. Live from ClinicalTrials.gov.

29 of 54 trials of drugs against CYSLTR1 have sites only in United States

Registry trials of zafirlukast, pranlukast, montelukast 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; 46 of 54 have all sites in one country.

Sites only in this groupSites here and elsewhere
United StatesUnited States: 29 trials with sites only hereUnited States: 7 trials with sites here and elsewhere36ChinaChina: 4 trials with sites only hereChina: 3 trials with sites here and elsewhere7EuropeEurope: 1 trials with sites only hereEurope: 8 trials with sites here and elsewhere9JapanJapan: 0 trials with sites only hereJapan: 3 trials with sites here and elsewhere3OtherOther: 12 trials with sites only hereOther: 6 trials with sites here and elsewhere18

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. 43 trials list no sites and are left out. Source: ClinicalTrials.gov, fetched live.

29 trials of drugs against CYSLTR1 were stopped early; 6 give no reason

Terminated, withdrawn and suspended interventional trials of zafirlukast, pranlukast, montelukast, CR-3465, 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 29.

  • terminated · 2025-09-17 · Sanofi · Montelukast or equivalent
    “Terminated due to non-safety reasons”
  • terminated · 2025-05-30 · University of Colorado, Denver · Montelukast
    “Funding not available”
  • terminated · 2024-11-26 · Chia Tai Tianqing Pharmaceutical Group Co., Ltd. · TQC3564 tablets, montelukast sodium tablets, Placebo tablets, montelukast sodium tablets
    “This study was closed per sponsor request. Premature closure was not prompted by any safety or efficacy concerns.”
  • withdrawn · 2024-11-18 · Vanderbilt University Medical Center · Montelukast Oral Granules
    “Unfunded”
  • terminated · 2024-07-03 · Fundacio d'Investigacio en Atencio Primaria Jordi Gol i Gurina · Montelukast
    “The incidence of respiratory Long COVID has decreased in the new waves, thus made impossible to achieve the required study sample.”
  • suspended · 2022-09-21 · Benha University · montelukast 10 mg(tab) oral/24hs/ 7 days dydrgesterone 10 mg( tab) oral/12hs/14 days
    “no fund”
  • suspended · 2022-07-22 · Beijing Chao Yang Hospital · Montelukast
    “There are difficulties in recruiting patients”
  • withdrawn · 2022-02-16 · Organon and Co · Montelukast tablets 5 mg (4 mg for children 5 years of age)
    No reason given
  • withdrawn · 2022-02-14 · Organon and Co · Montelukast sodium, Placebo to montelukast
    “Based on input from regulatory agencies, it is not necessary to conduct this study. An ongoing study was sufficient for regulatory purposes.”
  • terminated · 2021-10-20 · Maisonneuve-Rosemont Hospital · Montelukast
    “Not meeting recruitment targets”
  • terminated · 2021-02-17 · University Hospital, Grenoble · Montelukast 10mg
    “lack of recruitment”
  • terminated · 2020-10-30 · Children's Mercy Hospital Kansas City · Montelukast, 5 mg Montelukast
    “Inability to complete enrollment due to difficulty in finding subjects”
  • terminated · 2020-08-28 · Symphogen A/S · matched by the registry's drug synonyms
    “Business reasons”
  • terminated · 2019-12-18 · Brighton and Sussex University Hospitals NHS Trust · Montelukast or Salmeterol or Theophylline or Steroid
    “Change to Primary Endpoint resulted in development of new protocol”
  • terminated · 2019-10-01 · University of California, San Francisco · zafirlukast
    “Low accrual.”
  • withdrawn · 2019-08-28 · Medical College of Wisconsin · Montelukast
    No reason given
  • terminated · 2019-05-03 · University of Chicago · Montelukast
    “Poor accrual”
  • terminated · 2018-09-13 · Merck Sharp & Dohme LLC · Montelukast 10 mg
    No reason given
  • withdrawn · 2017-04-10 · University of Louisville · Montelukast
    “Principal Investigator has transferred to another Institution”
  • terminated · 2016-07-29 · National Heart, Lung, and Blood Institute (NHLBI) · Budesonide + Salmeterol + Montelukast
    “The CARE Network DSMB recommended to the NHLBI that the MARS trial be terminated, based on a futility analysis with 55 randomized children.”
  • withdrawn · 2016-06-16 · Creighton University · matched by the registry's drug synonyms
    No reason given
  • withdrawn · 2016-01-07 · Indiana University · Administration of montelukast or placebo
    No reason given
  • terminated · 2014-12-03 · University of Calgary · Montelukast Sodium
    “Diffic;ulty recruiting”
  • terminated · 2014-11-17 · Duke University · Montelukast
    “Unable to enroll enough study subjects. Study has been terminated”
  • terminated · 2014-10-23 · Universitaire Ziekenhuizen KU Leuven · Montelukast
    “A lot of patients recruited in our center were already on montelukast treatment. It was not possible to recruit sufficient patients for the study.”
Paediatric incentives and obligations for CYSLTR1's drugs

For zafirlukast, pranlukast, montelukast, CR-3465: 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.

  • EU paediatric investigation plan: yes · EMEA-003629-PIP01-24 (montelukast sodium;rupatadine fumarate, Treatment of allergic rhinitis): RW: decision refers to a refusal on a request for waiver in all age groups for the listed condition(s), 13 Sept 2024; EMEA-002646-PIP01-19 (levocetirizine;montelukast, Treatment of allergic rhinitis): W: decision granting a waiver in all age groups for all conditions or indications, 10 Feb 2020; EMEA-001908-PIP01-15 (levocetirizine (dihydrochloride);montelukast sodium, Treatment of asthma): W: decision granting a waiver in all age groups for all conditions or indications, 15 Apr 2016; EMEA-000012-PIP01-07-M01 (montelukast sodium, Asthma): PM: decision on the application for modification of an agreed PIP, 1 Oct 2009; compliance positive 15 Jan 2010
    Rule: 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 zafirlukast, pranlukast, montelukast, cr-3465
    Rule: 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: no · EMA lists no centrally authorised medicine of zafirlukast, pranlukast, montelukast, cr-3465
    Rule: 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 link
    Rule: 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 zafirlukast, pranlukast, montelukast, cr-3465
    Rule: 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 · 168 interventional studies of zafirlukast, pranlukast, montelukast, cr-3465 include patients under 18; 4 are recruiting, not yet recruiting or active
    Rule: 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 5 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.

DrugTypeHighest stageIndicationsSource records
ZAFIRLUKASTSmall moleculeapprovalasthma, Airway obstruction, COVID-19, ovarian cancerOpen Targets · ChEMBL
PRANLUKASTSmall moleculeapprovalasthma, Airway obstruction, sinusitisOpen Targets · ChEMBL
MONTELUKASTSmall moleculephase 4asthma, allergic rhinitis, seasonal allergic rhinitis, Airway obstruction, perennial allergic rhinitis, Nasal congestion, obstructive sleep apnea syndrome, Wheezing, +47 moreOpen Targets · ChEMBL
MONTELUKAST SODIUMSmall moleculephase 4asthma, allergic rhinitis, seasonal allergic rhinitis, perennial allergic rhinitis, bronchiolitis, chronic obstructive pulmonary disease, bronchiolitis obliterans syndromeOpen Targets · ChEMBL
CR-3465Small moleculephase 1AllergyOpen Targets · ChEMBL