REZOLVE-AD Study: Rezpegaldesleukin Data Presented at ACAAI 2025

SAN FRANCISCO, Nov. 8, 2025 – Nektar Therapeutics (Nasdaq: NKTR) unveiled compelling new data from its Phase 2b REZOLVE-AD study at the American College of Allergy, Asthma & Immunology (ACAAI) 2025 Annual Scientific Meeting. The presentation highlighted the potential of rezpegaldesleukin, a first-in-class IL-2 pathway agonist, to address both atopic dermatitis and comorbid asthma.

Rezpegaldesleukin is currently under investigation in two Phase 2b trials: REZOLVE-AD, focusing on moderate-to-severe atopic dermatitis, and REZOLVE-AA, targeting severe-to-very-severe alopecia areata.

“The interplay between atopic dermatitis and asthma is significant, with approximately one in four atopic dermatitis patients also experiencing asthma,” commented Dr. Jonathan Corren, Associate Clinical Professor of Medicine and Pediatrics at the David Geffen School of Medicine, University of California, Los Angeles. “The data suggest that rezpegaldesleukin, by promoting regulatory T-cell (Treg) activity, may offer benefits beyond the skin, potentially impacting lower airway symptoms. This warrants further exploration.”

The REZOLVE-AD trial, involving 393 patients with moderate-to-severe atopic dermatitis, included a subset of 99 patients with a history of asthma. A pre-planned analysis assessed Asthma Control Questionnaire (ACQ-5) scores at baseline and after the 16-week induction period. Key findings included statistically significant reductions in mean ACQ-5 scores at week 16 in two rezpegaldesleukin dose arms (24 μg/kg q2w and 24 μg/kg q4w) compared to placebo. This is a statistically significant (p<0.05), clinically meaningful change.

Improvements were even more pronounced in patients with poorly controlled asthma. For instance, in patients with a baseline ACQ-5 score of 0.5 or higher, at least half experienced a clinically significant improvement (≥0.5 point reduction) in ACQ-5 at Week 16 across all treatment arms, compared to just 13% in the placebo arm.

• Placebo-adjusted reductions of mean ACQ-5 scores in the subset of patients with baseline ACQ-5 score of 0.5 or higher ranged from 0.7 to 1.0.
• Among the 25 patients with uncontrolled asthma at baseline (≥1.5 ACQ-5 score), all three active doses of rezpegaldesleukin demonstrated a meaningful improvement in mean observed ACQ-5 scores at Week 16 and all dose arms achieved statistical significance (p
• Placebo-adjusted reductions of mean ACQ-5 scores in this subset of patients with uncontrolled asthma at baseline (≥1.5 ACQ-5 score) ranged from 1.0 to 1.4.
• For the 24 μg/kg q2w treatment arm, 75% of patients with uncontrolled asthma at baseline had a clinically significant improvement (≥0.5 points reduction) in ACQ-5 at Week 16.

Dr. Jonathan Zalevsky, Chief Research and Development Officer of Nektar, emphasized, “These improvements in asthma control in REZOLVE-AD reinforce the broad potential of rezpegaldesleukin’s Treg mechanism across various T-cell mediated inflammatory diseases. The data suggest rezpegaldesleukin could become a differentiated treatment option for atopic dermatitis.”

Overall, the 24 μg/kg q2w rezpegaldesleukin dose led to statistically significant improvements in primary and secondary endpoints across all measures of atopic dermatitis disease control compared to placebo, including a statistically significant (p<0.05) improvement of mean percent change in EASI.

Furthermore, data from 42 placebo patients who crossed over at Week 16 to receive high-dose rezpegaldesleukin (24 µg/kg q2w) showed promising results at crossover week 24: EASI-75 response rate was 60%, vIGA-AD 0/1 response rate was 33%, EASI-90 response rate was 37%, and Itch NRS response rate was 50% in patients with a baseline score ≥ 4. These findings support advancing the 24 μg/kg q2w dose regimen with a 24-week induction period into Phase 3 trials.

Nektar anticipates reporting top-line Phase 2b data for rezpegaldesleukin in alopecia areata in December 2025. The company expects data from the long-term maintenance portion of the REZOLVE-AD study, with 52 weeks of treatment, in Q1 2026. The extended dosing with rezpegaldesleukin q2w supports a 24-week induction period for planned Phase 3 studies with improvement across major efficacy endpoints from Week 16 to 24, including EASI-75, EASI-90, and vIGA-AD.

About the REZOLVE-AD Phase 2b Study

REZOLVE-AD (NCT06136741) is a global Phase 2b study enrolling 393 patients with moderate-to-severe atopic dermatitis who hadn’t previously received biologic or JAK inhibitor therapies. Patients were randomized to three different subcutaneous rezpegaldesleukin dose regimens or placebo for a 16-week induction period. After this, rezpegaldesleukin-treated patients achieving >50% EASI score reductions (EASI-50) were re-randomized (1:1) to continue the same dose on a q4w or q12w regimen through week 52 in a blinded maintenance period.

The primary endpoint is mean improvement in EASI score at the end of the 16-week induction. Secondary endpoints include the proportion of patients achieving Validated Investigator Global Assessment (vIGA-AD) of 0 or 1, achieving EASI-75, and achieving ≥4-point improvement in Itch Numeric Rating Scale (NRS). Pre-planned exploratory endpoints included biomarker measurements and change in asthma control questionnaire – 5 (ACQ-5) scores for patients with comorbid asthma.

About Rezpegaldesleukin

Rezpegaldesleukin is a potential first-in-class therapy designed to rebalance the immune system in autoimmune and inflammatory diseases by stimulating regulatory T cells (Tregs). By targeting the interleukin-2 receptor complex, it aims to promote the proliferation of these immune-modulating cells, potentially restoring immune homeostasis.

The FDA has granted Fast Track designation to rezpegaldesleukin for the treatment of moderate-to-severe atopic dermatitis (patients 12+) and severe alopecia areata (adults and patients 12+ weighing ≥40 kg). Nektar Therapeutics wholly owns the self-administered injectable.

About Atopic Dermatitis

Atopic dermatitis, the most common type of eczema, affects approximately 30 million people in the United States. It is characterized by a defective skin barrier that allows allergens and irritants to enter, triggering immune reactions and inflammation.

About Nektar Therapeutics

Nektar Therapeutics is a clinical-stage biotechnology company focused on developing treatments for autoimmune and chronic inflammatory diseases. Their lead candidate, rezpegaldesleukin (REZPEG, or NKTR-358), is under evaluation in Phase 2b trials for atopic dermatitis and alopecia areata, and a Phase 2 trial for Type 1 diabetes mellitus. Nektar’s pipeline includes preclinical bivalent tumor necrosis factor receptor type II (TNFR2) antibody and bispecific programs, NKTR-0165 and NKTR-0166, and a modified hematopoietic colony stimulating factor (CSF) protein, NKTR-422. Nektar and partners are also evaluating NKTR-255, an investigational IL-15 receptor agonist, in ongoing clinical trials. The company is headquartered in San Francisco, California

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements which can be identified by words such as: “could,” “develop,” “potential,” “target,” “address,” “may” and similar references to future periods. Examples of forward-looking statements include, among others, statements regarding the therapeutic potential of, and future development plans for, rezpegaldesleukin, NKTR-0165, NKTR-0166, NKTR-422, and NKTR-255. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based only on our current beliefs, expectations and assumptions regarding the future of our business, future plans and strategies, anticipated events and trends, the economy and other future conditions. Because forward-looking statements relate to the future, they are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements. Therefore, you should not rely on any of these forward-looking statements. Important factors that could cause our actual results to differ materially from those indicated in the forward-looking statements include, among others: (i) our statements regarding the therapeutic potential of rezpegaldesleukin, NKTR-0165, NKTR-0166, NKTR-422 and NKTR-255 are based on preclinical and clinical findings and observations and are subject to change as research and development continue; (ii) rezpegaldesleukin, NKTR-0165, NKTR-0166, NKTR-422 and NKTR-255 are investigational agents and continued research and development for these drug candidates is subject to substantial risks, including negative safety and efficacy findings in future clinical studies (notwithstanding positive findings in earlier preclinical and clinical studies); (iii) rezpegaldesleukin, NKTR-0165, NKTR-0166, NKTR-422 and NKTR-255 are in clinical development and the risk of failure is high and can unexpectedly occur at any stage prior to regulatory approval; (iv) data reported from ongoing clinical trials are necessarily interim data only and the final results will change based on continuing observations; (v) the timing of the commencement or end of clinical trials and the availability of clinical data may be delayed or unsuccessful due to regulatory delays, slower than anticipated patient enrollment, manufacturing challenges, changing standards of care, evolving regulatory requirements, clinical trial design, clinical outcomes, competitive factors, or delay or failure in ultimately obtaining regulatory approval in one or more important markets; (vi) a Fast Track designation does not increase the likelihood that rezpegaldesleukin will receive marketing approval in the United States; (vii) patents may not issue from our patent applications for our drug candidates, patents that have issued may not be enforceable, or additional intellectual property licenses from third parties may be required; and (viii) certain other important risks and uncertainties set forth in our Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 7, 2025. Any forward-looking statement made by us in this press release is based only on information currently available to us and speaks only as of the date on which it is made. We undertake no obligation to update any forward-looking statement, whether written or oral, that may be made from time to time, whether as a result of new information, future developments or otherwise.