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.

Inclusion Criteria:

• Adults who are at least 18 years and ≤60 years for males (≤70 years of age for females) old at the time of informed consent

• Diagnosis of Alopecia Areata (AA) severity at screening and baseline:

  1. severe to very severe AA (≥ 50% scalp involvement) as measured using the SALT score
  2. Documented history over 6 months with no spontaneous improvement prior to baseline
  3. Current episode of severe to very severe AA of less than 8 years

• Women of childbearing potential (WOCBP) must have a negative pregnancy test at screening and baseline.

• While on investigational product and for at least 30 days after taking the last dose of investigational product (IP), WOCBP who engage in activity in which conception is possible must use approved highly effective contraceptive method(s). For male patient with partner that is WOCBP in which conception is possible, male patient must agree to use approved highly effective contraceptive method(s).

• Able to complete patient questionnaires

• Able and willing to comply with requested study visits and procedures

• Able and willing to provide written informed consent

• Able to communicate, read and/or understand the local language

Exclusion Criteria:

• Men and women (of reproductive potential) unwilling to use birth control and women who are pregnant or breastfeeding.

• Patient has primarily "diffuse" type AA (characterized by diffuse hair shedding).

• Presence of another form of alopecia.

• Prior use of any of the following treatments:

  1. aldesleukin
  2. investigational IL-2 analog
  3. oral Janus kinase (JAK) inhibitor for any indication, including, but not limited to, baricitinib, upadacitinib, abrocitinib, tofacitinib, and ruxolitinib, whether marketed or investigational
  4. systemic immune-modulating biologic therapy (including, but not limited to, dupilumab, tralokinumab, lebrikizumab, nemolizumab, rocatinlimab, rituximab, ocrelizumab, ofatumumab, belimumab, daxdilimab, etc.) whether marketed or investigational

• History of cancer or lymphoproliferative disease within 5 years prior to Day 1. Note: Patients with successfully treated nonmetastatic cutaneous squamous cell or basal cell carcinoma with no evidence of metastatic disease for 3 years and/or localized carcinoma in situ of the cervix with no evidence of recurrence within the 3 years prior to Day 1 are not to be excluded.

• Current infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV), or hepatitis C virus (HCV) at screening.

• Other skin conditions that would interfere with study assessments of AA