First-in-human Study of Orally Administered KT-621 in Healthy Adult Participants

A Phase 1, Randomized, Placebo-Controlled, First-in-Human, Single and Multiple Ascending Dose Study Designed to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Orally Administered KT-621 in Healthy Adult Participants

This is a first-in-human study to evaluate safety, pharmacokinetics, and pharmacodynamics of single and multiple dose levels of KT-621 in healthy male and female adult participants.

Study Overview

• Status: Completed
• Conditions: Healthy Participants Study
• Intervention / Treatment: Drug: KT-621; Drug: Placebo

• Study Type: Interventional
• Enrollment (Actual): 118
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Phoenix, Arizona, United States, 85283
      • Celerion
  • Nebraska
    • Lincoln, Nebraska, United States, 68502
      • Celerion

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Participants aged 19 to 55 years (inclusive) at the time of consent, with a weight of at least 50 kg if male or 40 kg if female, and a body mass index (BMI) between 18.0 and 30.0 kg/m² (inclusive) at Screening.
• Evidence of a personally signed and dated informed consent document indicating that the participant has been informed of all pertinent aspects of the study.
• Participants must be willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures.
• Male participants (and their partners of childbearing potential) and female participants must agree to the contraception requirements as specified in the clinical protocol.
• Female participants may not be pregnant, lactating, or breast-feeding or plan to become pregnant (including ova donation) within 30 days of last study drug administration.
• Female participants must have a negative result for pregnancy test at Screening and on admission to the CRU.

Exclusion Criteria:

• Participants who have a clinically relevant history of respiratory, gastrointestinal (GI), renal, hepatic, hematological, lymphatic, endocrinological, neurological, cardiovascular, psychiatric, musculoskeletal, genitourinary, immunological, dermatological, ophthalmological, or connective tissue diseases or disorders.
• Participants who have a clinically relevant surgical history (eg, surgery of the GI tract that could interfere with the PK of the trial medication) Note: prior appendectomy or cholecystectomy is not exclusionary.
• Participants with a history of alcohol or substance abuse within the previous 5 years.
• Participants who have any known factor, condition, or disease that might interfere with treatment compliance, study conduct or interpretation of the results such as drug or alcohol dependence or psychiatric disease.
• Participants who test positive for alcohol and drugs of abuse at Screening and on admission to the CRU.
• Participants who have acute GI symptoms at the time of Screening or admission to the CRU (eg, nausea, vomiting, diarrhea, heartburn).
• Participants whose results from clinical laboratory safety tests are outside the local reference range at Screening and on admission to the CRU.
• Participants who have previously received KT-621 in another cohort in this study.
• Participants who have been dosed with any investigational drug or device in a clinical study within 30 days or 5 half-lives (whichever is longer) of KT-621/placebo administration.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: KT-621; Each participant receives either a single oral dose (SAD) or multiple oral doses (MAD) of KT-621.	Drug: KT-621; Oral drug
Placebo Comparator: Placebo; Each participant receives either a single oral dose (SAD) or multiple oral doses (MAD) of matched placebo.	Drug: Placebo; Oral drug

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of adverse events		From enrollment through the safety follow-up visit on either Day 14 (SAD) or Day 38 (MAD)
Treatment-emergent potentially clinically significant abnormalities in safety laboratory parameters: coagulation	Activated partial thromboplastin time, Prothrombin time, International Normalized Ratio, Fibrinogen	From enrollment through the safety follow-up visit on either Day 14 (SAD) or Day 38 (MAD)
Treatment-emergent potentially clinically significant abnormalities in electrocardiogram values: QTcF (milliseconds)		From enrollment through the safety follow-up visit on either Day 14 (SAD) or Day 38 (MAD)
Treatment-emergent potentially clinically significant abnormalities in vital signs: heart rate (beats per minute)		From enrollment through the safety follow-up visit on either Day 14 (SAD) or Day 38 (MAD)
Treatment-emergent potentially clinically significant abnormalities in vital signs: blood pressure (mmHg)		From enrollment through the safety follow-up visit on either Day 14 (SAD) or Day 38 (MAD)
Treatment-emergent potentially clinically significant abnormalities in vital signs: respiratory rate (breaths per minute)		From enrollment through the safety follow-up visit on either Day 14 (SAD) or Day 38 (MAD)
Treatment-emergent potentially clinically significant abnormalities in vital signs: temperature (degrees Celsius)		From enrollment through the safety follow-up visit on either Day 14 (SAD) or Day 38 (MAD)
Treatment-emergent potentially clinically-significant abnormalities in safety laboratory parameters: hematology	Hemoglobin, Hematocrit, Erythrocytes, Mean corpuscular volume, Platelets, Leukocytes, Eosinophils, Basophils Neutrophils Lymphocytes Monocytes	From enrollment through the safety follow-up visit on either Day 14 (SAD) or Day 38 (MAD)
Treatment-emergent potentially clinically significant abnormalities in safety laboratory parameters: serum chemistry	Glucose, Blood urea nitrogen, Creatinine, Sodium, Potassium, Calcium, Chloride, Magnesium, Bicarbonate, Phosphate, Bilirubin, total and direct, Alkaline phosphatase, Aspartate transaminase (=SGOT), Alanine transaminase (=SGPT), Gamma glutamyl transferase, Total protein, Albumin, Creatine kinase, HbA1c, Lactate dehydrogenase (LDH)	From enrollment through the safety follow-up visit on either Day 14 (SAD) or Day 38 (MAD)

Secondary Outcome Measures

Outcome Measure	Time Frame
Maximum concentration (Cmax): observed maximum concentrations derived from plasma concentration data	Day 1 (SAD); Day 1, Day 7, and Day 14 (MAD)
Time to maximum concentration (Tmax): observed time to achieve maximum concentrations derived from plasma concentration data	Day 1 (SAD); Day 1, Day 7, and Day 14 (MAD)
Area under the curve (AUC0-last): Area under the plasma concentration-time curve calculated using non-compartmental analysis from time zero to the last observed timepoint	Day 1 (SAD); Day 1, Day 7, and Day 14 (MAD)
Area under the curve (AUC0-infinity): Area under the plasma concentration-time curve calculated using non-compartmental analysis from time zero to infinite time	Day 1 (SAD)
Area under the curve (AUC0-tau): Area under the plasma concentration-time curve calculated using non-compartmental analysis from time zero to end of the dosing interval	Day 1, Day 7, and Day 14 (MAD)
Terminal elimination half-life (t1/2): elimination half-life calculated using non-compartmental analysis	Day 1 (SAD) and Day 14 (MAD)
Fraction excreted: Fraction of drug excreted unchanged in urine	Day 14 (MAD)

Other Outcome Measures

Outcome Measure	Time Frame
Change from baseline in STAT6 protein levels in whole blood and peripheral blood mononuclear cells (SAD)	Day 1
Change from baseline in STAT6 protein levels in whole blood, peripheral blood mononuclear cells, and skin (MAD)	Day 1 to Day 14

Collaborators and Investigators

• Sponsor: Kymera Therapeutics, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): October 22, 2024
• Primary Completion (Actual): April 23, 2025
• Study Completion (Actual): April 23, 2025

Study Registration Dates

• First Submitted: October 23, 2024
• First Submitted That Met QC Criteria: November 1, 2024
• First Posted (Actual): November 5, 2024

Study Record Updates

• Last Update Posted (Estimated): October 2, 2025
• Last Update Submitted That Met QC Criteria: September 29, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Phase 1; STAT6; STAT6 degrader; targeted protein degrader
• Other Study ID Numbers: KT621-HV-101

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No