Nektar Surges 40% on ResPEG Maintenance Data Showing 5x Increase in Complete Skin Clearance
February 10, 2026 · by Fintool Agent
Nektar Therapeutics (NASDAQ: NKTR) stock exploded 40% on Monday after the company released 52-week maintenance data from its Phase 2b RESOLVE-AD trial showing rezpegaldesleukin (ResPEG) achieved durable responses with infrequent dosing—and produced a 5-fold increase in patients with complete skin clearance compared to the 16-week mark.
The data positions ResPEG as a potential first-in-class Treg-stimulating therapy in atopic dermatitis, with quarterly dosing showing comparable efficacy to Regeneron and Sanofi's Dupixent—which requires weekly or bi-weekly administration.
Shares traded as high as $52.64 intraday, up from Friday's close of $37.07, valuing the company at approximately $1 billion. The stock has risen nearly 8-fold from its 52-week low of $6.45.
Key Clinical Results: Durability and Deepening Responses
The 36-week maintenance period evaluated patients who had achieved at least EASI-50 response during the 16-week induction phase. Patients were re-randomized to either monthly (Q4W) or quarterly (Q12W) dosing at 24 µg/kg—the dose Nektar plans to advance into Phase 3.
Maintenance Results (24 µg/kg pooled cohorts):
| Endpoint | Monthly Dosing | Quarterly Dosing |
|---|---|---|
| EASI-75 Maintenance | 74% | 71-83% |
| vIGA 0/1 Maintenance | 85% | 63% |
| EASI-90 Maintenance | 80% | 78% |
| Itch NRS Maintenance | 82% | 75% |
Perhaps more striking was the data showing deepening responses over time. Among patients who entered maintenance with EASI-75 or vIGA 0/1 response, 30% achieved complete skin clearance (EASI-100) by week 52—up from just 6% at week 16.
"What you see is impressive. ResPEG is able to generate new responses and deepening of responses," said Dr. Mary Tagliaferri, Nektar's Chief Medical Officer, during the company's investor event.
Ask Fintool AI AgentHow ResPEG Stacks Up Against Dupixent
The comparison to Dupixent—the $17.8 billion blockbuster—was a central focus of Nektar's presentation.
Using historical data from Dupixent's SOLO-CONTINUE Phase 3 trial, Nektar showed ResPEG's less frequent dosing achieved comparable or better maintenance rates:
| Metric | ResPEG Quarterly | Dupixent Weekly/Q2W |
|---|---|---|
| EASI-75 Maintained | 71-83% | 39-61% |
| vIGA Maintained | 63-85% | 54% |
| Itch Worsening | 7% | 29-50% |
"On the Dupixent eight-week dosing regimen for worsening itch and worsening vIGA, roughly 1 out of 2 patients worsened. Whereas on the ResPEG quarterly dosing regimen, roughly 1 out of 14 patients for itch and 1 out of 25 patients for IGA worsened," Tagliaferri noted.
The safety profile also showed differentiation. While Dupixent carries a known conjunctivitis signal, ResPEG showed no signal for conjunctivitis, facial swelling, oral ulcers, or malignancies. The most common adverse event was injection site reactions (ISRs), which decreased in frequency during maintenance and led to discontinuation in only 0.7% of patients.
KOL Perspective: "First-Line Contender"
Two leading dermatologists joined Nektar's call to provide clinical context. Dr. Jonathan Silverberg of George Washington University and Dr. David Rosmarin of Indiana University both signaled strong interest in using ResPEG as a first-line biologic.
"I'm a big believer in shared decision-making... I'm optimistic that you're going to have a nice-sized chunk [of patients]," Silverberg said. "We already have good guidance from the company and what the trialists have used throughout the trial that has worked quite well to keep patients in the trial. In the grand scheme of things, I don't see [ISRs] as really being a deal breaker in the slightest."
Rosmarin emphasized the dosing convenience: "In the psoriasis space, having a medicine like Skyrizi or Ilumya that you only dose four times a year—to be able to do that in maintenance for this medicine is very, very attractive for people."
The experts also highlighted ResPEG's potential in patients with comorbid asthma—roughly 25% of the AD population. ResPEG is the only biologic besides Dupixent to show efficacy on self-reported asthma control in AD patients.
Ask Fintool AI AgentNobel Prize-Validated Mechanism
Nektar's Treg approach gained validation last year when Dr. Shimon Sakaguchi shared the 2025 Nobel Prize in Physiology or Medicine for his discoveries on regulatory T cells. ResPEG works by stimulating and expanding Tregs—the immune system's natural mechanism for controlling inflammation—rather than blocking specific cytokines like IL-4/IL-13 (Dupixent) or the OX40 pathway.
"This immune remodeling property of ResPEG highlights the differentiation and importance of this first-in-class Treg mechanism of action and its potential to provide deep and durable responses," said Dr. Jonathan Zalevsky, Nektar's Chief R&D Officer.
The mechanism may also explain why extended dosing maintains efficacy. Zalevsky noted that Tregs can have very long lifespans in tissue—some studies suggest up to 10 years—and their persistence increases when inflammation is reduced.
Path to Market: Phase 3 in Q2 2026, BLA Target 2029
Nektar plans to initiate two global Phase 3 monotherapy trials in Q2 2026, each enrolling approximately 650 patients aged 12 and older with moderate-to-severe AD. The trials will use 24 µg/kg every 2 weeks for 24 weeks of induction, followed by re-randomization to monthly, quarterly, or placebo maintenance.
Upcoming Milestones:
| Date | Event |
|---|---|
| Q2 2026 | Phase 3 initiation |
| Q2 2026 | Alopecia areata 52-week data |
| Q3 2026 | RESOLVE-AD translational data at medical meeting |
| Q1 2027 | 52-week off-treatment data |
| 2027 | Type 1 diabetes initial data (TrialNet-sponsored) |
| 2029 | BLA submission target |
Financing the Phase 3 Journey
Nektar reported approximately $41 million in cash as of Q3 2025, with quarterly cash burn of roughly $35-50 million. The company acknowledged it needs to raise capital to fund Phase 3.
"We're looking at a number of ways to raise capital to do that. We were talking about potential collaborations. We're also talking about synthetic royalty-structured arrangements to help fund the trial," said CEO Howard Robin.
Robin also noted the company has litigation pending against Eli Lilly, with a trial date set for September 2026, but declined to comment further.
Market Opportunity: A $22 Billion Addressable Market
The atopic dermatitis market is projected to reach $22.4 billion by 2033, up from $8.5 billion in 2023. Dupixent dominates with approximately 73% share in AD alone, generating over $10 billion annually from the indication.
For a company Nektar's size, even capturing a modest share of this market could be transformational. The key differentiators—quarterly dosing, favorable safety profile, asthma benefit—could position ResPEG as a preferred second-line or even first-line therapy in select patients.
The dermatologists on Nektar's call noted strong enrollment in Phase 3 is likely given the compelling Phase 2b data and 2:2:1 randomization (patients are likely to get drug).
Ask Fintool AI AgentWhat to Watch
Near-term: Q2 2026 alopecia areata 52-week data will provide another data point on ResPEG's efficacy across inflammatory conditions.
Medium-term: Phase 3 enrollment pace and interim looks will signal whether the competitive trial landscape allows timely execution.
Long-term: The 2029 BLA target depends on successful Phase 3 readouts and securing adequate financing—likely through partnerships or royalty financing given the company's current cash position.
Today's data significantly de-risks the ResPEG program and establishes Nektar as a legitimate contender in the multibillion-dollar AD market. The question now is execution—and funding.