Study of ABS-201 Evaluating Single and Multiple Ascending Doses in Adults With and Without Androgenetic Alopecia

September 1, 2026 updated by: Absci Pty Ltd.

A Randomized, Double-Blind, Placebo-Controlled, Phase 1 First-in-Human Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single and Multiple Ascending Doses of ABS-201 in Adult Participants With and Without Androgenetic Alopecia

This is a first-in-human study of ABS-201, a new investigational medicine, in healthy adult men and women. Its main purpose is to find out whether ABS-201 is safe and well tolerated, as well as to understand how the body processes it and how it affects related biological markers. ABS-201 is being developed as a possible treatment for androgenetic alopecia (male- and female-pattern hair loss); its effect on hair growth has not yet been established. The study has two parts: in the single ascending dose (SAD) part, healthy adults receive one intravenous dose of ABS-201 or placebo; and in the multiple ascending dose (MAD) part, participants (including men with androgenetic alopecia) receive several subcutaneous doses of ABS-201 or placebo. The MAD part also evaluates the effect of ABS-201 on hair growth.

The main questions it aims to answer are:

What medical problems, if any, do participants experience when taking a single dose or many doses of ABS-201? How does the medication, ABS-201, compare to placebo (a look alike substance that does not contain any medication).

Participants who qualify for the trial will receive either ABS-201 or a placebo, and visit the study clinic for scheduled checkups and tests for approximately 12 months in the single ascending dose (SAD) part and approximately 18 months in the multiple ascending dose (MAD) part. In the MAD part, participants receive repeated subcutaneous doses.

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.
227

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 2
  • 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

  • Australia
    • New South Wales
      • Sydney, New South Wales, Australia, 2010
        • Recruiting
        • Momentum Darlinghurst
        • Principal Investigator:
          • Juliet Freeborn, MD
    • Queensland
      • Brisbane, Queensland, Australia, 4006
        • Recruiting
        • Nucleus Network Brisbane
        • Contact:
          • Phone Number: +61 (07) 3707 2720
        • Principal Investigator:
          • Emma Trowbridge, MD
    • Victoria
      • Melbourne, Victoria, Australia, 3004
        • Recruiting
        • Nucleus Network
        • Principal Investigator:
          • Ofer M Gonen, MD, PhD
      • Melbourne, Victoria, Australia, 3002
        • Recruiting
        • Sinclair Dermatology
        • Principal Investigator:
          • Rodney Sinclair, Professor

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
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria (Major):

  • Participants must be overtly healthy, as determined by medical evaluation, which includes a review of medical and surgical history, physical examination, and a 12-lead ECG.
  • Must have normal ranges for hematology, clinical chemistry, coagulation tests, and urine analysis parameters
  • Participants, male and female, must be willing to avoid pregnancy for the duration of the trial.
  • Participants must be capable of giving signed informed consent
  • Participants must have no signs or symptoms of active or latent tuberculosis (TB),

Additional Inclusion criteria for patients with AGA:

  • Diagnosis of AGA with a Norwood-Hamilton Scale III vertex to V pattern.
  • Willing to clip target hair area for analysis and avoid scalp pigmentation products.
  • Willingness to maintain approximately the same hair length at each study visit

Exclusion Criteria (Major):

  • History or presence of cancer, except for basal cell carcinoma or cervical dysplasia successfully treated with no recurrence for ≥90 days before screening.
  • History of liver disease, Gilbert's syndrome, or abnormal liver function tests (e.g., ALT, AST, or bilirubin > ULN) at screening
  • Systolic blood pressure ≤90 or ≥140 mmHg, diastolic BP ≤40 or ≥90 mmHg, pulse rate <40 or >100 bpm
  • Positive test for HIV, hepatitis B (HBV), or hepatitis C (HCV).
  • Recent blood donation
  • Any clinically significant psychiatric disorder
  • Pregnant or breastfeeding females or those planning pregnancy during the study.
  • History of postpartum depression, perimenopausal mood instability, or estrogen withdrawal syndrome

Additional Exclusion criteria for participants with AGA undergoing hair assessments:

•

Prior use of hair loss treatments:

  1. Topical minoxidil within 3 months before screening.
  2. Oral minoxidil other hair growth stimulators within 6 months before screening.
  3. Finasteride within 6 months before screening

  4. Dutasteride within 12 months before screening.

    • Use of GLP-1 receptor agonists (e.g., semaglutide, liraglutide, dulaglutide, exenatide, tirzepatide, or similar agents) within 3 months prior to screening
    • History of hair transplantation or other major scalp procedures or planned procedures during the study.
    • Use of hair extensions, wigs, hairpieces, weaves, or any other artificial hair enhancement methods within 30 days prior to screening and throughout the study.
    • History of clinically significant dermatologic disease of the scalp that could interfere with hair assessments or target area imaging

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: SAD IV Dose 1 - 150mg ABS201 or Placebo
ABS-201 IV Single Dose
Drug: Placebo IV
Matching placebo
Drug: SAD IV Dose 1 - 150mg ABS201 IV Single Dose
ABS-201 is an IgG1 monoclonal antibody developed to specifically target the prolactin receptor (PRLR)
Experimental: SAD IV Dose 2 - 450mg ABS201 or Placebo
Single Intra-venous dose of active study drug or placebo in Healthy Volunteers
Drug: Placebo IV
Matching placebo
Drug: SAD IV Dose 1 - 150mg ABS201 IV Single Dose
ABS-201 is an IgG1 monoclonal antibody developed to specifically target the prolactin receptor (PRLR)
Experimental: SAD IV Dose 3 - 900mg ABS201 or Placebo
Single Intra-venous dose of active study drug or placebo in Healthy Volunteers
Drug: Placebo IV
Matching placebo
Drug: SAD IV Dose 1 - 150mg ABS201 IV Single Dose
ABS-201 is an IgG1 monoclonal antibody developed to specifically target the prolactin receptor (PRLR)
Experimental: SAD IV Dose 4 - 1800mg ABS201 or Placebo
Single Intra-venous dose of active study drug or placebo in Healthy Volunteers
Drug: Placebo IV
Matching placebo
Drug: SAD IV Dose 1 - 150mg ABS201 IV Single Dose
ABS-201 is an IgG1 monoclonal antibody developed to specifically target the prolactin receptor (PRLR)
Experimental: MAD SC Dose 1 - 300mg ABS201 or Placebo
Multiple Ascending Doses of active study drug or placebo delivered subcutaneously in Patients with AGA
Drug: ABS-201 SC Multiple Doses
Multiple doses of ABS-201 for Subcutaneous injection
Drug: Placebo SC Injection
Subcutaneous Placebo injection for MAD arms
Experimental: MAD SC Dose 2 - 600mg ABS201 or Placebo
Multiple Ascending Doses of active study drug or placebo delivered subcutaneously in Patients with AGA
Drug: ABS-201 SC Multiple Doses
Multiple doses of ABS-201 for Subcutaneous injection
Drug: Placebo SC Injection
Subcutaneous Placebo injection for MAD arms
Experimental: MAD SC Dose 2 - 1200mg ABS201 or Placebo
Multiple Ascending Doses of active study drug or placebo delivered subcutaneously in Patients with AGA
Drug: ABS-201 SC Multiple Doses
Multiple doses of ABS-201 for Subcutaneous injection
Drug: Placebo SC Injection
Subcutaneous Placebo injection for MAD arms

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
Incidence rate of treatment-emergent adverse events (TEAEs) and serious TEAEs
Time Frame: From enrollment to the end of the Study (SAD approximately 12 months, MAD approximately 18 months)
Safety assessments based on reporting of Treatment Emergent Adverse Events, together with clinically significant changes in vital signs, 12-lead ECG parameters, physical examination findings and clinical safety laboratory tests, and change in neurobehavioral symptoms (PHQ-9 and GAD-7).
From enrollment to the end of the Study (SAD approximately 12 months, MAD approximately 18 months)

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
Pharmacokinetics (PK)
Time Frame: From enrollment to the end of the Study (SAD up to 12 months, MAD up to 18 months)
To investigate the pharmacokinetics (PK) characteristic of ABS201, Serum trough concentrations at each time point and descriptive statistics.
From enrollment to the end of the Study (SAD up to 12 months, MAD up to 18 months)
Pharmacodynamics (PD)
Time Frame: From enrollment to the end of the Study (SAD up to 12 months, MAD up to 18 months)
Change from baseline in prolactin (PRL).
From enrollment to the end of the Study (SAD up to 12 months, MAD up to 18 months)
Immunogenicity
Time Frame: From enrollment to the end of the Study (SAD up to 12 months, MAD up to 18 months)
Incidence of anti-drug antibodies (ADAs) and, in participants who develop ADAs, neutralizing antibodies (NAbs).
From enrollment to the end of the Study (SAD up to 12 months, MAD up to 18 months)
Target Area Hair Count (TAHC) (MAD; participants with AGA)
Time Frame: Baseline to Week 26
Change from baseline in Total Area Hair Count (TAHC)
Baseline to Week 26
Total Area Hair Width (TAHW) (MAD cohort; participants with AGA)
Time Frame: Baseline to week 26
Change from baseline in Total Area Hair Width (TAHW)
Baseline to week 26

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change from Baseline in Total Area Hair Count (TAHC)
Time Frame: Enrollment and up to End of Study Visit (SAD 12 months, MAD 18 months)
Measures the change from baseline in Total Area Hair Count (TAHC) in healthy adult participants with AGA.
Enrollment and up to End of Study Visit (SAD 12 months, MAD 18 months)
Change from Baseline in Total Area Hair Width (TAHW)
Time Frame: Enrollment to the End of Study (SAD 12 months, MAD 18 months)
Change from baseline in Total Area Hair Width (TAHW) in healthy adult participants with AGA.
Enrollment to the End of Study (SAD 12 months, MAD 18 months)
Change From baseline Participant Self Assessment of Hair Growth
Time Frame: Enrollment up to End of Study (SAD 12 months, MAD 18 months)
Hair Growth Assessment in participants with AGA using central photography images comparing baseline to later visits using a Subject Self-Assessment Scale. This scale is an ordinal scale with 7 options (Very much improved, much improved, minimally improved, no change, minimally worse, much worse, very much worse). Improved scores suggest improved hair growth.
Enrollment up to End of Study (SAD 12 months, MAD 18 months)
Change From baseline Investigator Global Assessment of Hair Growth
Time Frame: Enrollment to End of Study (SAD 12 months, MAD 18 months)
Change from baseline in central photography images comparing baseline to later visits using an Investigator Global Assessment Scale. This scale is an ordinal scale with 7 options (Very much improved, much improved, minimally improved, no change, minimally worse, much worse, very much worse). Improved scores suggest improved hair growth.
Enrollment to End of Study (SAD 12 months, MAD 18 months)
Change from Baseline in Target Area Hair Darkness/Pigmentation (TAHD) by Central Analysis of Macrophotography
Time Frame: Enrollment to End of Study (SAD 12 Months, MAD 18 Months)
Change from baseline in TAHD is calculated using a Central Imaging analysis procedure for quantitatively measuring hair shafts. For each detected and segmented hair shaft, the average darkness is determined by calculating the darkness value of every pixel and then computing the mean. Darkness values range from 0 to 255, where 0 represents the darkest possible value and 255 represents the lightest.
Enrollment to End of Study (SAD 12 Months, MAD 18 Months)

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.
Absci Pty Ltd.

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.
December 3, 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.
July 1, 2028

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.
July 1, 2028

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).
November 19, 2025

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.
December 30, 2025

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.
January 5, 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.
September 3, 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.
September 1, 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.
September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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.
  • ABS-201-101

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The IPD sharing plan is not yet developed. The study team will consider data sharing at a later date.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

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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