NCT07421024Active, not recruitingPhase 2
GRK-Biased Activation Via β2-Adrenergic Receptors in Human Skeletal Muscle
G Protein-Coupled Receptor Kinase (GRK)-Biased Signaling Via β2-Adrenergic Receptors and Downstream Activation and Its Role for Protein Synthesis-Regulating Kinases, Function and Receptor Desensitization in Human Skeletal Muscle
Source: ClinicalTrials.gov · Last updated 14 Oct 2026
Brief summary (registry, in English)
This longitudinal mechanistic physiological study examines biased β2-adrenergic receptor (β2-AR) signaling in human skeletal muscle, with emphasis on G protein-coupled receptor kinase (GRK)-mediated pathways. Participants will receive daily oral dosing of the GRK-selective long-acting β2-agonist ATR-258 for 8 weeks. Muscle biopsies and physiological measurements will quantify GRK-, cAMP/PKA-, and β-arrestin-related up- and downstream signaling, fiber-type specificity, and potential receptor desensitization with repeated stimulation along with functional read-outs, tissue distribution, cardiovascular response and tolerability.
- Status (registry)
- Active, not recruiting
- Phase (registry)
- Phase 2
- Study type
- Interventional
- Enrollment
- 13 (actual)
- First submitted
- 30 Jan 2026
- Start date
- 19 Feb 2026
- Primary completion date
- 31 Dec 2026
- Lead sponsor
- Morten Hostrup, PhD
- Diseases
- Obesity
- NCT number
- NCT07421024
What you commit to
- Study type: Interventional · Phase 2
- Participants enrolled: 13
- From 19 Feb 2026 to the primary completion date, 31 Dec 2026
- 1 site in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Other illness
- Regular use of or allergy to β2-agonists
- Regular use of medication (except OTC allergy or analgesics)
- Hypertension
- Cardiovascular, metabolic, gastrointestinal, renal, or pulmonary disease
- Psychiatric or neurological disorders affecting compliance/safety reporting
- Cancer history within the last 5 years
Lab values
- Reduced kidney function (eGFR \< 90 ml/min/1.73m\^2)
Other
- Serious adverse reactions to β2-agonists
- Current smoker
- Abnormal ECG before or after β2-AR stimulation
- Substance abuse or alcohol intake \>14 units/week
Who the study is looking for
- Healthy men
- Age 21-45 years
- BMI 25-35 kg/m\^2
- Body fat percentage 25-40%
- Lean Mass Index 14-22
Age in the registry: 21 years to 45 years · Sex: Male · Accepts healthy volunteers
Sites (1)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| University of Copenhagen, August Krogh Section for Human & Molecular Physiology Coordinator of this site? Confirm its status | Copenhagen | Denmark | Unknown status |
This page is information, not medical advice. Discuss any trial with your doctor.