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Study on Rezpegaldesleukin for Treating Severe Alopecia Areata in Adults

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a condition called Alopecia Areata, which is a type of hair loss that can be severe or very severe. The study is testing a new treatment called Rezpegaldesleukin, also known by its code name NKTR-358. This treatment is a special form of a protein that is injected under the skin. The trial will compare the effects of Rezpegaldesleukin with a placebo to see how well it works in reducing hair loss.

The purpose of the study is to evaluate the effectiveness and safety of Rezpegaldesleukin in treating severe to very severe Alopecia Areata in adults. Participants in the study will receive either the new treatment or a placebo. The study will last for several weeks, with regular check-ups to monitor progress. The main goal is to see if there is a reduction in hair loss by the 36th week of the study.

Throughout the study, participants will be asked to attend scheduled visits and complete questionnaires about their condition. The study aims to provide valuable information on whether Rezpegaldesleukin can be a helpful treatment for those suffering from severe hair loss due to Alopecia Areata.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, the patient will be informed about the trial's purpose and procedures. Written informed consent is required to participate.

    Eligibility criteria include being an adult aged 18 to 60 years for males and up to 70 years for females, with a diagnosis of severe to very severe alopecia areata, and the ability to complete questionnaires and attend study visits.

  2. Step 2

    Initial assessment

    An initial assessment will be conducted to confirm the diagnosis of alopecia areata and to establish baseline measurements using the Severity of Alopecia Tool (SALT) score.

  3. Step 3

    Treatment phase

    The treatment phase involves receiving either the investigational drug rezpegaldesleukin (NKTR-358) or a placebo. The medication is administered as a subcutaneous injection.

    The frequency and dosage of the injections will be determined by the study protocol and communicated to the patient during the trial.

  4. Step 4

    Follow-up assessments

    Follow-up assessments will occur at regular intervals to monitor changes in the SALT score. These assessments are scheduled for Weeks 12, 16, 20, 24, 28, 32, and 36.

    The primary goal is to evaluate the percent change in the SALT score from baseline at Week 36.

  5. Step 5

    Completion of the study

    Upon completion of the study, a final assessment will be conducted to evaluate the overall effectiveness of the treatment.

    The study is estimated to conclude by August 24, 2026.

Who can join the trial?

10 criteria

  • Adults who are at least 18 years old and no older than 60 years for males, and no older than 70 years for females at the time of giving consent.
  • Must have a diagnosis of Alopecia Areata (AA) with severe to very severe hair loss, meaning at least 50% of the scalp is affected. This is measured using something called the SALT score, which is a way to measure hair loss.
  • Must have a history of this condition for over 6 months without any natural improvement before starting the study.
  • The current episode of severe to very severe AA must have lasted less than 8 years.
  • Women who can have children must have a negative pregnancy test before starting the study and at the beginning of the study.
  • Women who can have children and are participating in activities that could lead to pregnancy must use approved and highly effective birth control methods while taking the study medication and for at least 30 days after the last dose. Male participants with partners who can have children must also agree to use approved and highly effective birth control methods.
  • Must be able to complete questionnaires given during the study.
  • Must be able and willing to attend study visits and follow the study procedures.
  • Must be able and willing to provide written consent to participate in the study.
  • Must be able to communicate, read, and understand the local language.
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Investigated drugs

Rezpegaldesleukin is a medication being studied for its potential to treat severe to very severe alopecia areata, a condition that causes significant hair loss. The trial aims to assess how effective this medication is in reducing hair loss over a period of 36 weeks. Rezpegaldesleukin is administered to patients to see if it can help improve hair growth and reduce the symptoms of alopecia areata.

What is already known about the treatment

Rezpegaldesleukin – Rezpegaldesleukin is administered via injection and is currently being studied in clinical trials for its effectiveness in treating severe to very severe alopecia areata, a condition characterized by significant hair loss. The medication is in the investigational stage, with ongoing research to determine its safety and efficacy. It works by modulating the immune system to potentially reduce inflammation and promote hair regrowth. Rezpegaldesleukin is classified as an immunomodulatory agent, aiming to alter immune responses that contribute to hair loss in alopecia areata.

Investigated diseases

Alopecia Areata – Alopecia Areata is an autoimmune condition where the immune system mistakenly attacks hair follicles, leading to hair loss. This hair loss can occur in small patches on the scalp and may sometimes progress to complete baldness on the scalp or even the entire body. The condition can develop suddenly, and the extent of hair loss varies from person to person. Hair may regrow on its own, but the cycle of hair loss and regrowth can be unpredictable. The disease does not cause physical pain, but it can have significant emotional and psychological effects.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-509981-39-00Protocol code23-358-06Estimated enrolment84 patientsSponsorNektar Therapeutics

sourced from the EU Clinical Trials Register and site verification

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