A Study of STX-1150 in Participants With Elevated Low-Density Lipoprotein Cholesterol (LDL-C) (STX-1150-01)

February 24, 2026 updated by: Stephen Nicholls, Monash University

A Phase 1 Open-Label Single Ascending Dose (Part 1) and Single or Multi-Dose Expansion (Part 2) Study to Evaluate Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of STX-1150 in Participants With Elevated Low-Density Lipoprotein Cholesterol (LDL-C)

STX-1150 is an investigational therapy designed to lower LDL-C by silencing a gene called PCSK9 in the liver. STX-1150 does not edit or permanently change the gene. STX-1150 comprises an mRNA and guide RNA (gRNA) delivered via lipid nanoparticles (LNP) for intravenous infusion. The mRNA produces a protein that switches off the PCSK9 gene expression without altering the DNA sequence. This process leverages natural mechanisms that regulate gene activity.

The study will enroll up to 64 participants with elevated LDL-C across sites in Australia and New Zealand. The follow-up period will be up to 1- year post-treatment.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

STX-1150 is an investigational product designed to epigenetically silence the PCSK9 gene. It comprises an mRNA and a guide RNA (gRNA) delivered in a lipid nanoparticle (LNP) for intravenous (IV) infusion.

STX-1150 epigenetically silences the expression of the PCSK9 gene in the liver, thereby reducing circulating PCSK9 and LDL-C levels. The active components, an mRNA and a gRNA are encapsulated in lipid nanoparticles (LNPs) for targeted hepatic delivery. The gRNA precisely guides the complex to a specific locus within the PCSK9 gene promoter.

By reducing PCSK9 expression, STX-1150 prevents the degradation of LDL receptors (LDL-R), leading to increased LDL-R levels on hepatocytes and enhanced clearance of LDL-C from the bloodstream. This targeted and durable epigenetic silencing represents a promising therapeutic strategy for long-term LDL-C reduction, particularly benefiting patients with elevated LDL-C or a high risk for Atherosclerotic Cardiovascular Disease (ASCVD).

Study Type

Interventional

Enrollment (Estimated)

64

Phase

  • 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 Backup

Study Locations

  • Australia
    • Victoria
      • Clayton, Victoria, Australia, 3168

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Elevated serum LDL-C with or without LDL-C lowering medication
  • Willing and able to give informed consent before initiation of any study-related procedures and willing to comply with all required study procedures

Exclusion Criteria:

  • Patients with history of an ASCVD event </= 6 months.
  • Any uncontrolled or serious disease, or any medical or surgical condition that may interfere with participation
  • Diagnosis of familial hypercholesterolemia
  • Active or history of liver disease
  • Previous treatment with PCSK9-inhibitor or other prior treatment within a specified timeframe
  • Clinically significant abnormal laboratory values

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Arm 1

Part 1: An open-label, single ascending dose will serve to identify the Dose-Limiting Toxicities (DLTs) and Optimal Biological Dose (OBD) of STX-1150.

Part 2: Following Part 1, an open-label, single or multi-dose expansion of the OBD cohort will be conducted to further characterize the effect of STX-1150 and obtain additional safety data at the OBD.
Drug: STX-1150
Drug: STX-1150 is an investigational product designed to epigenetically silence the PCSK9 gene. Epigenome modulation offers a way to silence genes without changing their underlying DNA sequence.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Incidence and Severity of Treatment-Emergent Adverse Events (TEAEs)
Time Frame: Up to Week 52 from administration of STX-1150
Up to Week 52 from administration of STX-1150
Incidence and Severity of Serious Adverse Events (SAEs)
Time Frame: Up to Week 52 from administration of STX-1150
Up to Week 52 from administration of STX-1150
Incidence and Severity of Adverse Events of Special Interest (AESI)
Time Frame: Up to Week 52 from administration of STX-1150
Up to Week 52 from administration of STX-1150

Secondary Outcome Measures

Outcome Measure
Time Frame
Incidence of dose-limiting toxicities (DLTs)
Time Frame: Within 14 days from administration of STX-1150
Within 14 days from administration of STX-1150
Percent Change from Baseline in Plasma PCSK9 Concentration
Time Frame: Up to Week 52
Up to Week 52
Percent Change from Baseline in LDL-C
Time Frame: Up to 52 weeks
Up to 52 weeks
Plasma Concentrations of STX-1150 Lipid Components
Time Frame: Up to 52 weeks
Up to 52 weeks
Number of Participants with Treatment-Induced Immunogenicity
Time Frame: Up to 52 Weeks
Up to 52 Weeks
Absolute Change from Baseline in LDL-C
Time Frame: Up to 52 weeks
Up to 52 weeks
The Absolute Change from Baseline in Plasma PCSK9 Concentration
Time Frame: Up to Week 52
Up to Week 52

Collaborators and Investigators

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

Sponsor

Monash University

Collaborators

Scribe Therapeutics Inc.

Investigators

  • Study Chair: Stephen Nicholls, MBBS, FRACP, PhD, VHI

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 (Estimated)

June 1, 2026

Primary Completion (Estimated)

December 30, 2028

Study Completion (Estimated)

December 30, 2028

Study Registration Dates

First Submitted

February 1, 2026

First Submitted That Met QC Criteria

February 19, 2026

First Posted (Actual)

February 23, 2026

Study Record Updates

Last Update Posted (Actual)

February 27, 2026

Last Update Submitted That Met QC Criteria

February 24, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STX-1150-01

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

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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