A Phase 2 interventional study of Rezpegaldesleukin and Placebo in Alopecia Areata, sponsored by Nektar Therapeutics. Completed at 26 sites in 3 countries. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-09-18.
Sponsored by Nektar Therapeutics · Phase 2, Interventional, and Treatment
This is an interventional, randomized, double blind, parallel group, placebo-controlled, Phase 2b, 3-arm study to assess the effect of pegylated-recombinant-human interleukin-2 (rezpegaldesleukin) in adult participants with severe to very severe alopecia areata.
The estimated duration includes a screening period of up to 35 days, a 36-week treatment period, an optional 16-week treatment extension period, and a 24-week follow-up period. The maximum study duration is approximately 81 weeks for all participants.
220 studies on the registry are indexed under Alopecia Areata; 61 are open to participants now.
This study's enrollment of 94 is above the median of 50 across 171 interventional studies indexed under Alopecia Areata.
Browse Alopecia Areata studies →Nektar Therapeutics is the lead sponsor of 39 studies on the registry; 2 are open to participants now.
Of its 22 completed or terminated interventional studies of FDA-regulated products, 13 (59%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Diagnosis of Alopecia Areata (AA) severity at screening and baseline:
Exclusion Criteria:
Prior use of any of the following treatments:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Reproductive potential
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Rezpegaldesleukin Low Dose Every 2 weeks
Drug: Rezpegaldesleukin
Rezpegaldesleukin High Dose Every 2 weeks
Drug: Rezpegaldesleukin
Placebo Every 2 weeks
Drug: Placebo
Pharmaceutical form: Injection solution Route of administration: subcutaneous
Also known as: REZPEG, NKTR-358, LY3471851 (formerly)
Pharmaceutical form: Injection solution Route of administration: subcutaneous
Percent change from baseline in Severity of Alopecia Tool (SALT) score at Week 36
The SALT score is the sum of percentage of hair loss in all areas with a maximum score of 100 (higher score indicates greater hair loss).
Time frame: Baseline and Week 36
Percent change from baseline in SALT score
SALT score is the sum of percentage of hair loss in all areas with a maximum score of 100 (higher score indicates greater hair loss).
Time frame: Baseline and Weeks 12, 16, 20, 24, 28, and 32
Proportion of patients achieving improvement in Severity of Alopecia Tool (SALT) ≥ 50%/75%/90%
Proportion of patients achieving improvement of ≥ 50%/75%/90% in Severity of Alopecia Tool (SALT) relative to their baseline score (SALT50/75/90). SALT score is the sum of percentage of hair loss in all areas with a maximum score of 100 (higher score indicates greater hair loss).
Time frame: Baseline and Weeks 12, 16, 20, 24, 28, 32, and 36
Proportion of patients achieving an absolute SALT score ≤ 10/20/30/50
Proportion of patients achieving an absolute SALT score of ≤ 10/20/30/50. SALT score is the sum of percentage of hair loss in all areas (higher score indicates greater hair loss). Total percentage of patients with absolute SALT score of ≤ 10/20/30/50 will be calculated.
Time frame: Baseline and Weeks 12, 16, 20, 24, 28, 32, and 36
Plan to share: No
No publications or documents are linked to this record.
Ran from Apr 2024 to primary completion in Nov 2025, 19 months.
Of 30 phase 2 interventional studies under Alopecia Areata, half reached primary completion within 24 months of starting (the median), counting those still running; a quarter within 15 and three quarters within 35. This study's 19 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Rezpegaldesleukin