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Oral KT-621 for adults with moderate to severe eosinophilic asthma

A Phase 2b, Randomized, Double-blind, Placebo-controlled, Parallel-group, Multicenter, Dose-ranging Study Investigating the Efficacy and Safety Profile of KT-621 Administered Orally to Adult Participants With Uncontrolled Moderate to Severe Eosinophilic Asthma

Phase 2 Interventional Kymera Therapeutics, Inc. · NCT07323654

This study will test whether an oral medicine called KT-621 can help adults with uncontrolled moderate to severe eosinophilic asthma and is safe and tolerable.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment264 (estimated)
Ages18 Years to 75 Years
SexAll
SponsorKymera Therapeutics, Inc. Industry-sponsored
Locations17 sites (Redding, California and 16 other locations)
Trial IDNCT07323654 on ClinicalTrials.gov

What this trial studies

This Phase 2b interventional trial compares oral KT-621 to placebo in adults with uncontrolled moderate to severe eosinophilic asthma. Participants remain on a stable medium-to-high dose inhaled corticosteroid plus long-acting beta-agonist regimen and must meet lung function and biomarker criteria (pre-bronchodilator FEV1 40–80% predicted, ACQ-5 ≥1.5, FeNO ≥25 ppb). The study will collect safety, tolerability, efficacy, and pharmacokinetic data during the treatment period. Sites are run by Kymera Therapeutics at investigational sites in California and Florida.

Who should consider this trial

Good fit: Adults 18–75 years old with physician-diagnosed moderate to severe eosinophilic asthma that remains uncontrolled despite stable medium-to-high dose ICS/LABA therapy and who meet the required biomarker and lung function thresholds are ideal candidates.

Not a fit: Patients with well-controlled asthma, non-eosinophilic asthma phenotypes, or those who do not meet the required biomarker or lung function criteria (for example low FeNO or ACQ-5 < 1.5) are unlikely to benefit from this study.

Why it matters

Potential benefit: If successful, KT-621 could reduce symptoms and exacerbations and improve lung function in adults with eosinophilic asthma through a novel STAT6-targeting mechanism.

How similar studies have performed: Targeted STAT6 degradation is a novel approach with limited clinical experience to date, although other eosinophil-targeting therapies such as anti–IL-5 agents have demonstrated benefit in similar populations.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Must be 18 years old (or the legal age of consent in the jurisdiction in which the study is taking place) to 75 years of age, inclusive, at the time of signing the ICF.
* Must have a physician diagnosis of asthma for at least 1 year prior to the Screening visit.
* Must be on a stable regimen of medium- to high- dose inhaled corticosteroid (ICS), in combination with a long-acting β2-agonist (LABA). The regimen may include additional controller medications used for at least 12 weeks, at a stable dose and regimen, with no change in the dose or frequency of administration for at least 4 weeks prior to the Screening visit and between the Screening and Baseline visits.
* Must have a pre-bronchodilator FEV1 40 to 80% of predicted normal at the Screening and Baseline visits, prior to randomization.
* Must have an ACQ-5 score ≥ 1.5 at the Screening and Baseline visits, prior to randomization.
* Must have a FeNO level of ≥ 25 ppb at the Screening and Baseline visits.
* Must have a demonstrated evidence of reversible airway obstruction by post-bronchodilator (albuterol/salbutamol) reversibility of FEV1 ≥12% and ≥200 mL at Screening.
* Must have an absolute blood eosinophil count must be ≥ 0.30 × 10\^9/L at Screening.
* Must have a documented history of at least 1 asthma exacerbation requiring either treatment with systemic corticosteroids (intramuscular, intravenous, or oral) and/or hospitalization or an emergency/urgent medical care visit for acute asthma worsening within the past 52 weeks prior to Screening.
* Must agree to contraceptive requirements in compliance with the clinical study and local requirements.
* Must be willing and able to comply with scheduled visits, treatment plan, laboratory tests, other study-related procedures, and questionnaires, including completing the electronic diary (e-diary), for the duration of the study as required by the study protocol.

Exclusion Criteria:

* Must not have any clinically significant pulmonary disease other than asthma.
* Must not have had an asthma exacerbation, requiring either treatment with systemic corticosteroids (intramuscular, intravenous, or oral) and/or hospitalization or an emergency/urgent medical care visit for acute asthma worsening, at any time from 4 weeks prior to the Screening visit up to and including the Baseline visit.
* Must not have any other clinically significant disease, condition, or medical history that, in the opinion of the Investigator, would interfere with participant safety, study evaluations, and/or study procedures.
* Must not be pregnant or breastfeeding; must not be a woman planning to become pregnant or breastfeed during the study.
* Must not have results from clinical laboratory safety tests that are outside the local reference range at Screening.
* Must not have been dosed with any investigational drug or device in a clinical study within 8 weeks or 5 half-lives (whichever is longer) of KT-621 administration.
* Must not have any known factor, condition, or disease that might interfere with treatment compliance, study conduct or interpretation of the results.
* Must not be a current smoker of nicotine/tobacco as well as non-nicotine products, have a smoking history of ≥ 10 pack years, or use vaping products, including electronic cigarettes. Former smokers with a smoking history of \< 10 pack years and users of vaping or e-cigarette products must have stopped for at least 26 weeks prior to the Screening visit.
* Must not have a known sensitivity to any of the components of KT-621.
* Must not be a member of the investigational team or his/her immediate family.

Where this trial is running

Redding, California and 16 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Eosinophilic Asthmakt-621stat6 degraderstat6targeted protein degraderPhase 2phase 2b
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.