Nektar Therapeutics (NASDAQ: NKTR) rezpegaldesleukin shows dual action in skin and asthma — is this a pipeline turning point?

Nektar Therapeutics (NASDAQ: NKTR) has released new clinical data from the ongoing REZOLVE-AD Phase 2b study, offering fresh optimism around its lead candidate rezpegaldesleukin. Presented as a late-breaking oral abstract at the 2025 American College of Allergy, Asthma & Immunology (ACAAI) Annual Scientific Meeting, the findings revealed statistically significant improvements in both skin-related endpoints for atopic dermatitis and respiratory symptoms in patients with comorbid asthma.

Rezpegaldesleukin, a novel interleukin-2 pathway agonist targeting regulatory T cells (Tregs), is emerging as a potential new treatment paradigm across T-cell mediated inflammatory diseases. Nektar Therapeutics now appears poised to move into Phase 3 development, with broader strategic implications for immunology-focused investors tracking the company’s post-oncology repositioning.

What do the latest REZOLVE-AD results reveal about asthma control in atopic dermatitis patients?

Among the 393 patients enrolled in the REZOLVE-AD study, 99 had a documented history of asthma. The trial evaluated changes in Asthma Control Questionnaire (ACQ-5) scores at week 16 for those receiving rezpegaldesleukin compared to placebo. Across all three dosing arms, patients receiving rezpegaldesleukin experienced reductions in ACQ-5 scores, with two doses showing statistically significant improvement over placebo. In contrast, the placebo group reported worsening asthma symptoms.

The benefit was most pronounced in patients with partially controlled or uncontrolled asthma at baseline. Among patients with ACQ-5 scores of 0.5 or higher, at least 50 percent experienced a clinically meaningful improvement of 0.5 points or more. This compared to only 13 percent in the placebo arm. For patients with more severe baseline asthma symptoms (ACQ-5 ≥ 1.5), all rezpegaldesleukin arms delivered statistically significant mean reductions in ACQ-5 scores, ranging from 1.0 to 1.4 points. The highest response rate was observed in the 24 micrograms per kilogram every two weeks arm, where 75 percent of patients with uncontrolled asthma at baseline achieved a clinically relevant reduction.

These findings suggest that beyond addressing skin inflammation, rezpegaldesleukin could play a therapeutic role in managing lower airway inflammation in patients with overlapping atopic disorders. This effect, linked to the drug’s Treg mechanism, distinguishes it from currently approved biologics that target different cytokine pathways.

How did rezpegaldesleukin perform on primary and secondary endpoints in atopic dermatitis?

The 24 micrograms per kilogram every two weeks dose of rezpegaldesleukin showed consistent and statistically significant improvement across all primary and secondary measures of atopic dermatitis severity at week 16. This included significant reductions in Eczema Area and Severity Index (EASI) scores, achievement of EASI-75 and EASI-90 benchmarks, improved scores on the validated Investigator Global Assessment scale (vIGA-AD), and meaningful reductions in pruritus as measured by a four-point drop on the Itch Numeric Rating Scale (NRS).

These effects were observed regardless of asthma status, disease severity, or geographic location, which strengthens the credibility of the findings and provides a strong foundation for Phase 3 planning. The study’s robust design, including global site participation and well-stratified patient cohorts, adds further weight to the results.

Notably, patients who crossed over from placebo to high-dose rezpegaldesleukin after week 16 also demonstrated strong clinical gains by week 24. EASI-75 response was achieved in 60 percent of these patients, while 37 percent reached EASI-90. One-third showed clear or almost clear skin on the vIGA-AD scale, and half of those with significant itch at baseline reported at least a four-point reduction by week 24. These post-crossover results support the continuation of the 24 micrograms per kilogram every two weeks dosing regimen into longer induction periods for Phase 3 trials.

What distinguishes rezpegaldesleukin from other biologics in the atopic dermatitis treatment landscape?

Rezpegaldesleukin’s mechanism of action is based on stimulating the interleukin-2 receptor complex, thereby promoting the proliferation and activity of regulatory T cells. These immune-modulating cells help restore immune balance by suppressing the inflammatory T cells that drive autoimmune and allergic diseases.

This mechanism offers a unique therapeutic strategy compared to other biologics that typically inhibit inflammatory cytokines such as IL-4, IL-13, or IL-31. The dual efficacy observed in both atopic dermatitis and asthma within the same study population is a key differentiator that has not been demonstrated by competing agents to date. According to clinical investigators, this cross-pathway benefit warrants further investigation, especially in light of the high prevalence of comorbid asthma in atopic dermatitis patients.

Nektar Therapeutics has framed rezpegaldesleukin as a resolution therapy, aiming not just to suppress disease symptoms but to recalibrate immune system function over time. If long-term maintenance data replicate the short-term efficacy seen at 16 and 24 weeks, this drug could unlock new clinical positioning within chronic inflammatory disease management.

What is the long-term development outlook for rezpegaldesleukin?

Nektar Therapeutics plans to advance the 24 micrograms per kilogram every two weeks regimen into Phase 3 trials with a 24-week induction period. Long-term maintenance data from the REZOLVE-AD trial’s 52-week extension arm are expected in the first quarter of 2026. These data will be instrumental in determining whether rezpegaldesleukin can sustain durable control of atopic dermatitis while maintaining the asthma benefits highlighted in the interim analysis.

Simultaneously, topline results from the REZOLVE-AA Phase 2b trial in severe alopecia areata are anticipated by December 2025. Rezpegaldesleukin has received Fast Track designation from the U.S. Food and Drug Administration for both indications, accelerating the path to regulatory filing if Phase 3 outcomes meet expectations.

The drug is being developed as a self-injectable, enabling at-home administration. This mode of delivery could offer an advantage in patient adherence and convenience, particularly for individuals with chronic autoimmune conditions requiring long-term therapy.

Beyond atopic dermatitis and alopecia areata, Nektar Therapeutics is also evaluating rezpegaldesleukin in type 1 diabetes, signaling broader ambitions for the compound in autoimmune diseases.

How are analysts and institutional investors viewing Nektar Therapeutics in light of this update?

While Nektar Therapeutics previously faced setbacks with its oncology pipeline, particularly the discontinuation of bempegaldesleukin, institutional sentiment toward the company appears to be stabilizing around rezpegaldesleukin as a high-conviction immunology asset. The dual benefit observed in REZOLVE-AD has triggered cautious optimism among analysts, with many watching for the December alopecia data and early 2026 maintenance results as critical catalysts.

The stock performance of Nektar Therapeutics has remained subdued in recent months, reflecting a wait-and-see stance from investors. However, the Phase 2b readout has been interpreted positively in industry circles, with potential implications for partnership activity or strategic interest from larger pharmaceutical firms operating in dermatology or respiratory disease.

The company’s pipeline, while still concentrated around a single advanced-stage asset, benefits from Fast Track designations and clear clinical differentiation. The next 6 to 12 months will determine whether rezpegaldesleukin can generate sufficient momentum to reposition Nektar Therapeutics as a credible immunology-focused biotech contender.

What role could rezpegaldesleukin play in reshaping treatment strategies for inflammatory comorbidities?

As chronic inflammatory conditions increasingly reveal overlapping pathophysiological mechanisms, there is growing interest in drugs capable of addressing multiple indications through shared immune pathways. Rezpegaldesleukin’s ability to influence both skin inflammation and airway responsiveness positions it within this emerging class of immunoregulatory therapies.

The drug’s Treg-targeted approach may also prove relevant for future indications such as inflammatory bowel disease, lupus, or autoimmune arthritis, subject to validation in additional studies. Its design as a resolution therapy, rather than a single-cytokine antagonist, reflects a broader trend toward mechanism-based immunomodulation rather than symptom suppression.

For healthcare providers, the emergence of such agents could simplify treatment regimens for patients with multiple atopic or autoimmune diagnoses, potentially reducing polypharmacy, improving quality of life, and lowering overall healthcare costs.

Key takeaways from the REZOLVE-AD Phase 2b trial of rezpegaldesleukin in atopic dermatitis

• Nektar Therapeutics presented new data from the REZOLVE-AD Phase 2b trial of rezpegaldesleukin at the ACAAI 2025 Annual Scientific Meeting.
• Rezpegaldesleukin showed statistically significant and clinically meaningful improvements in both atopic dermatitis and asthma-related endpoints.
• In patients with a history of asthma, all three doses of rezpegaldesleukin improved ACQ-5 scores by week 16, with the highest benefit seen in the 24 μg/kg q2w arm.
• Among patients with uncontrolled asthma at baseline (ACQ-5 ≥ 1.5), all dosing arms achieved significant improvement in asthma control compared to placebo.
• The 24 μg/kg q2w dose also met all primary and secondary endpoints in atopic dermatitis, including EASI-75, EASI-90, vIGA-AD 0/1, and itch reduction.
• Crossover patients initially on placebo who later received rezpegaldesleukin also showed strong response rates by week 24.
• These results support the progression of rezpegaldesleukin into Phase 3 trials with a 24-week induction regimen.
• Nektar Therapeutics is also evaluating the same candidate in Phase 2b trials for alopecia areata and Phase 2 for type 1 diabetes.
• Rezpegaldesleukin’s Treg mechanism could offer a differentiated advantage in treating overlapping autoimmune and inflammatory conditions.
• Institutional sentiment is cautiously optimistic, with upcoming December and Q1 2026 data expected to drive next-phase investor interest and strategic outlook.