A Single- and Multiple-Ascending Dose Study of SRK-439 in Healthy Adults

February 24, 2026 updated by: Scholar Rock, Inc.

A Phase 1 Single- and Multiple-Ascending Dose Study to Assess the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of SRK-439 in Healthy Adults

A phase 1 study to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of SRK-439 in healthy adults

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
76

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Ohio
      • Cincinnati, Ohio, United States, 45227
        • Recruiting
        • Medpace CPU

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Key Inclusion Criteria:

  1. Male or female participants, ≥18 to ≤55 years of age, at the time of informed consent
  2. BMI of ≥18 kg/m2 to ≤35 kg/m2 (inclusive) at screening

Exclusion Criteria:

  1. Previous treatment with SRK-439 or apitegromab, or with other anti-myostatin therapies, including ACTR antagonists.
  2. History of immunosuppressive, chemotherapeutic, or radiation treatment within 12 months prior to screening.
  3. Current or prior use of anabolic steroids, growth hormones, or other substances with known effects on muscle.
  4. Use of therapies with potentially significant muscle effects (eg, insulin-like growth factor, systemic beta-agonist, neurotoxins, or muscle relaxants or muscle-enhancing supplements) in any form within 3 months prior to screening or during the study.
  5. Any history of exposure to a mAb or Fc domain-bearing recombinant protein within 5 years prior to screening with any prior history of hypersensitivity reactions from exposure
  6. Treatment with other investigational drugs or devices in a clinical study or exposure to a biologic therapeutic within 3 months or 5 half-lives, whichever is longer, prior to screening.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Sequential Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Part A
Participants will be treated with a single dose of SRK-439 or matching placebo.
Drug: Placebo
Matching placebo to SRK-439, subcutaneous administration
Drug: SRK-439
Single ascending dose, subcutaneous administration
Drug: SRK-439
Multiple ascending dose, subcutaneous administration
Experimental: Part B
Participants will be treated with multiple doses of SRK-439 or matching placebo.
Drug: Placebo
Matching placebo to SRK-439, subcutaneous administration
Drug: SRK-439
Single ascending dose, subcutaneous administration
Drug: SRK-439
Multiple ascending dose, subcutaneous administration

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
• Incidence of AEs
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
• Incidence of SAEs
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Changes from baseline in clinical safety laboratory tests (serum chemistry)
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Changes from baseline in clinical safety laboratory tests (hematology)
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Changes from baseline in clinical safety laboratory tests (urinalysis)
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Changes from baseline in clinical safety laboratory tests (coagulation assessments)
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Changes from baseline in vital signs (heart rate) measured in bpm
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Changes from baseline in vital signs (blood pressure) measured in mmHg
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Changes from baseline in vital signs (respiratory rate) measured in rpm
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Changes from baseline in vital signs (body temperature) measured in Celsius
Up to 32 weeks
Evaluate the safety and tolerability of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Changes from baseline in ECG measurements
Up to 32 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Evaluate the PK of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
• Maximum observed serum concentration [Cmax]
Up to 32 weeks
Evaluate the PK of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
• Time to maximum observed concentration in serum [Tmax]
Up to 32 weeks
Evaluate the PK of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
• Area under the serum concentration-time curve [AUC]
Up to 32 weeks
Evaluate the PK of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
• Terminal elimination half-life in serum [t1/2]
Up to 32 weeks
Evaluate the PD of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Serum concentrations of total latent myostatin and changes over time
Up to 32 weeks
Evaluate the immunogenicity of single and multiple SRK-439 SC dose administration in healthy adult participants
Time Frame: Up to 32 weeks
Incidence of ADAs against SRK-439 in serum
Up to 32 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Scholar Rock, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 21, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 17, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 9, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 11, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 24, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 2, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 2, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 24, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • SRK-439-001

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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