Rezpegaldesleukin Phase 2b data show durable and deepening responses in alopecia areata and atopic dermatitis at EADV 2026.
Written By: Anamika Kosthi, PharmD
Reviewed By: Pharmacally Editorial Team
Nektar Therapeutics presented long-term Phase 2b data for investigational rezpegaldesleukin on October 1, 2026, at the European Academy of Dermatology and Venereology (EADV) Congress in Vienna. The data came from the REZOLVE-AA study (NCT06340360) in alopecia areata (AA) and REZOLVE-AD (NCT06136741) in atopic dermatitis (AD), with both studies evaluating responses through 52 weeks.
A Regulatory T-Cell Approach to Immune Dermatology
Rezpegaldesleukin is an investigational, self-administered biologic designed to stimulate regulatory T cells through the interleukin-2 receptor complex. The approach is intended to restore immune regulation rather than block a single inflammatory cytokine. The U.S. FDA has granted Fast Track designation for rezpegaldesleukin in both AA and AD.
Alopecia Areata: Regrowth That Continues After Treatment Ends
REZOLVE-AA enrolled 92 patients with severe-to-very-severe AA who had not received a JAK inhibitor or other biologic. During the 36-week induction phase, patients received rezpegaldesleukin 18 or 24 µg/kg twice monthly or placebo. Patients with a SALT score above 20 at Week 36 who showed hair growth could enter a blinded 16-week extension. Of the 31 patients who entered the extension, 27 had received rezpegaldesleukin.
Between Weeks 36 and 52, new SALT ≤20 responses, corresponding to at least 80% scalp hair coverage, occurred in 29% of patients receiving the 18 µg/kg dose and 31% receiving 24 µg/kg, compared with none in the placebo group. Response rates were similar in patients whose current AA episode lasted less than four years and those with episodes lasting four years or longer, at 29% and 30%, respectively.
The off-treatment findings provided an additional durability signal. Among eight patients assessed after 52 weeks of treatment, six (75%) maintained a SALT score of 20 or below four months after treatment cessation, while five (63%) maintained the response at six months. Responses at the stricter SALT ≤10 threshold increased from 7% at Week 52 to 19% after six months off treatment.
Why the Durability Signal Needs Careful Reading?
The off-treatment findings are based on only eight patients and an exploratory extension that included patients who had already demonstrated hair growth. There was also no comparator during the off-treatment period. The findings therefore require confirmation in larger controlled studies.
Nektar said the results support evaluation of less frequent monthly (Q4W) or quarterly (Q12W) dosing in patients who achieve a SALT score of 20 or below.
Atopic Dermatitis: Maintaining and Deepening Response with Fewer Injections
REZOLVE-AD enrolled 393 patients with moderate-to-severe AD who had not received a JAK inhibitor or other biologic. Patients were randomized to 24 µg/kg Q2W, 18 µg/kg Q2W, 24 µg/kg Q4W, or placebo. Patients receiving rezpegaldesleukin who achieved at least a 50% EASI reduction were subsequently re-randomized to Q4W or Q12W maintenance dosing through Week 52.
Both maintenance regimens sustained EASI-75, EASI-90, vIGA-AD and itch responses through Week 52, with Q4W and Q12W dosing showing the highest maintenance responses. Some patients also developed deeper responses over time.
The clearest deepening signal was observed for complete skin clearance, measured by EASI-100. Among all re-randomized patients, EASI-100 increased from 4% to 22% with Q4W dosing and from 9% to 18% with Q12W dosing between Weeks 16 and 52. Among patients who had achieved an EASI-75 or vIGA-AD response at the start of maintenance, EASI-100 increased from 6% to 30% with Q4W and from 14% to 27% with Q12W.
Safety Through 52 Weeks
Across both studies, Nektar described the 52-week safety profile as favorable and consistent with earlier reports. The company did not provide detailed adverse-event rates in the EADV update.
From Phase 2b Evidence to Pivotal Trials
ZENITH AD-1 (NCT07690371) and ZENITH AD-2 (NCT07711418) are evaluating rezpegaldesleukin in biologic- and JAK inhibitor-naive patients with AD. Nektar has also initiated ZENITH AD-3 in patients with prior biologic or JAK inhibitor treatment experience. Initial topline data from the AD Phase 3 program are expected in mid-2028, according to the company.
For AA, Nektar plans to initiate the Phase 3 ZENITH AA study in early 2027. The planned study will enroll approximately 850 patients with severe-to-very-severe disease and use SALT ≤20 at Week 52 as the primary endpoint.
What Phase 3 Must Now Confirm?
The one-year Phase 2b data support further evaluation of rezpegaldesleukin for sustained and deepening responses with less frequent dosing. In AA, the off-treatment findings also provide an early signal of continued hair regrowth after treatment cessation.
Larger controlled studies will need to determine whether the durability observed in the small AA follow-up cohort can be reproduced and whether the deeper AD responses translate into clinically meaningful benefits in Phase 3.
Reference
New Rezpegaldesleukin Data Supporting Long-term Durability and Disease Improvement in Patients with Alopecia Areata and Atopic Dermatitis at EADV Congress 2026, Nektar Therapeutics, 01 September 2026
A Phase 2b Study to Evaluate Rezpegaldesleukin (Rezpeg) in the Treatment of Adult Patients with Moderate-to-Severe Atopic Dermatitis (REZOLVE-AD), ClinicalTrials.gov ID NCT06136741
A Phase 2b Study to Evaluate Rezpegaldesleukin (Rezpeg) in the Treatment of Severe to Very Severe Alopecia Areata in Adult Patients (Rezolve AA), ClinicalTrials.gov ID NCT06340360
About the Writer
Anamika Koshti (LinkedIn) is a PharmD professional and healthcare writer with interests in clinical research, pharmacovigilance, and evidence-based medicine. She has authored peer-reviewed publications on Alzheimer’s disease and PCOS, presented research at national conferences, and gained hands-on experience in medical content development and clinical data interpretation. She is committed to translating complex medical research into accurate, accessible content for healthcare professionals and patients.