Nektar Therapeutics stock has rallied 51% after its lead asset, rezpeg (rezpegaldesleukin), demonstrated potential across monthly and quarterly maintenance dosing regimens during a Phase II trial in atopic dermatitis (AD).
At the one-year point in the REZOLVE-AD study (NCT06136741), a 24 µg/kg dose of the T-regulatory (Treg) therapy continued to show disease control across four common measures of AD disease severity. This includes Eczema Area Severity Index 75 and 90 scores (EASI-75; EASI-90), validated Investigator Global Assessment of Atopic Dermatitis (vIGA-AD) response, and Itch Numerical Rating Scale (NRS) response.
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Of the patients on the monthly dosing regimen who had achieved EASI-50 during the 16-week induction, 71% and 80% of patients achieved EASI-75 and EASI-90, respectively, after a year of dosing.
Rezpeg was similarly efficacious in quarterly-dosed patients who met this criterion in induction, with 83% and 78% of the cohort achieving EASI-75 and EASI-90 at the same time point. Meanwhile, 22% given a monthly dose and 18% allocated to a quarterly schedule achieved EASI-100, or total AD clearance, at week 52.
Rezpeg also prompted 85% and 63% of patients, respectively, to achieve vIGA-AD scores of 0 or 1 across the monthly and quarterly dosing schedules at 52 weeks, while improving itch NRS scores in 75% and 77% of patients.
Alongside its activity in responders, rezpeg also offered benefits to previous non-responders during the 36-week, blinded maintenance period – with 33% achieving EASI-90 in the monthly dosing cohort. 26% of patients allocated to the quarterly dosing schedule experienced the same outcome.
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By GlobalDataThe IL-2 receptor (IL-2R) pathway agonist was found to be safe and tolerable. The most common treatment-emergent adverse event (TEAE) was injection site reactions – of which 77% were classed as mild. There were no cases of conjunctivitis, oral ulcers, erythema, cardiovascular adverse events or malignancies observed.
Investors appear to be pleased with the Phase II outcome for rezpeg in AD, as Nektar’s stock value soared 51% after the news debuted – going from $37.07 at market close on 9 February to $56.00 at market open on 10 February. The company’s stock value may have also seen an increase due to the commencement of an underwritten public offering, which will see Nektar offer $3m of its shares in common stock to investors.
This follows the positive outcomes seen in the early stages of the REZOLVE-AD study, which were announced in June and September 2025, respectively. When data was presented at the 2025 European Academy of Dermatology and Venereology (EADV) Congress in Paris, France, in September 2025, Nektar’s stock rose more than 150%.
Next steps for Rezpeg
Based on the outcomes of the REZOLVE-AD study, Nektar plans to initiate a Phase III study to further explore rezpeg’s AD potential in Q2 2026. If the results of this trial mirror those seen in the Phase II trial, the biotech hopes to file a biologics license application (BLA) for the Treg therapy by 2029. The company is also conducting the Phase IIb REZOLVE-AA trial (NCT06340360) on rezpeg in alopecia areata, which is currently ongoing.
In an investor call, David Rosmarin, chair of the department of dermatology at the Indiana University School of Medicine, said he would be inclined to use rezpeg as a first-line treatment in AD, subject to consistent data in Phase III. “There are patients who would love to have Q12-week dosing,” Rosmarin commented.
Rosmarin also pointed out rezpeg’s potential to treat comorbid asthma and alopecia areata, which sees rezpeg “possess some advantages” that other drugs on the AD market do not.
William Blair analyst, Andy Hsieh added: “With respect to durability, there appears to be no meaningful deterioration of response when comparing the monthly dosing and quarterly dosing”.
Despite vIGA-AD values being numerically lower in the quarterly dosing cohort, Hsieh notes that the response range of 59%-65% remains “higher than competitor datasets of about 50%”. This is also true for EASI-75, Hsieh added, with the 74%-92% response rate at a quarterly maintenance dose being “numerically higher than Dupixent’s 72%”.
If rezpeg were to gain approval in AD, it would enter a market that GlobalData forecasts will be worth $22.4 billion by 2033 across the seven major markets (7MM: US, France, Germany, Italy, Spain, UK, and Japan)
