Nektar Therapeutics Touts 52-Week ResPEG Data in Atopic Dermatitis, Eyes Phase 3 Launch in Q2

Key Points

• ResPEG showed durable 52‑week efficacy: monthly and quarterly maintenance dosing sustained responses through week 52 (e.g., 74% of patients on 24 mcg/kg monthly maintained EASI‑75), with similar EASI‑90 durability (80% vs. 78%) and conversion of many initial non‑responders to responders, while EASI‑100 rates rose from 6% to 30% by week 52.
• Safety remained favorable over one year: the safety profile was consistent with prior reports, with a 3.5% discontinuation rate for adverse events, mostly mild-to-moderate injection‑site reactions (0.7% discontinuations for ISRs) and no observed imbalance in infections or key serious safety signals.
• Phase 3 program and timeline: Nektar plans a Phase 3 launch in Q2 with two global monotherapy trials (~650 patients each) and maintenance re‑randomization, targeting a possible BLA filing in 2029 and including ACQ‑5 asthma assessments as a differentiator.

Nektar Therapeutics NASDAQ: NKTR used an analyst and investor event to highlight 52-week results from the Phase 2b RESOLVE-AD trial of rezpegaldesleukin (ResPEG) in moderate-to-severe atopic dermatitis, with a focus on the 36-week maintenance period following 16 weeks of induction therapy. Management said the new maintenance data reinforce ResPEG’s “first-in-class” regulatory T cell (Treg) agonist mechanism and support advancing both monthly and quarterly maintenance regimens into Phase 3.

Maintenance study goals and trial design

Chief Medical Officer Dr. Mary Tagliaferri said the maintenance portion was designed to test whether lower-frequency dosing could sustain responses and deepen efficacy through one year, while also expanding long-term safety exposure. Patients who achieved at least an EASI-50 response during induction were re-randomized into monthly or quarterly maintenance dosing at the same dose level received in induction.

Tagliaferri emphasized that the RESOLVE-AD maintenance included a placebo arm only to preserve blinding for monthly and quarterly dosing, consistent with other maintenance-study conventions, and that this placebo-to-placebo maintenance cohort is excluded from efficacy analyses.

Durability of responses through week 52

Tagliaferri presented durability analyses across key endpoints—EASI-75, EASI-90, vIGA 0/1, and itch—among responders at the end of induction who entered the 36-week maintenance period. She said all monthly and quarterly maintenance arms showed “excellent durability” through week 52.

As one example, she reported that 74% of patients on the 24 mcg/kg monthly regimen maintained EASI-75 at week 52. In pooled analyses of EASI-50 responders who received 24 mcg/kg maintenance dosing, Tagliaferri said durability was similar between monthly and quarterly dosing; for EASI-90, she cited 80% maintained response on monthly dosing versus 78% on quarterly dosing.

New and deepening responses, including EASI-100

Beyond maintaining existing responses, the company also evaluated whether continued dosing could convert non-responders at week 16 into responders by week 52. Tagliaferri highlighted that in pooled 24 mcg/kg maintenance cohorts, 41% (monthly) and 40% (quarterly) of patients who were vIGA non-responders at re-randomization converted to vIGA responders by week 52.

She also presented an analysis of EASI-100 (complete clearance). In the planned Phase 3-like subset—patients entering maintenance with EASI-75 and/or vIGA 0/1—Tagliaferri said 6% had achieved EASI-100 at maintenance baseline, rising to 30% by week 52, which she described as a five-fold increase.

Safety findings and injection-site reactions

Over 52 weeks of treatment, Tagliaferri said ResPEG’s safety profile remained consistent with prior reports. She reported a 3.5% discontinuation rate due to adverse events and said there was no imbalance suggesting increased infection risk versus placebo. She also said the company has not observed safety signals for conjunctivitis, facial swelling or erythema, oral ulcers, myocardial infarction, pulmonary embolism, deep vein thrombosis, or malignancy.

The most common adverse events were injection-site reactions (ISRs), described as largely mild to moderate and self-resolving. Tagliaferri said discontinuations due to ISRs were rare (0.7%) and that ISR frequency decreased during the maintenance period compared to induction. In Q&A, the company added that only about six to seven new patients experienced ISRs during maintenance after not having them in induction, and roughly 73% of patients had two or fewer ISRs in maintenance.

Phase 3 plans and upcoming milestones

CEO Howard Robin said the company plans to initiate Phase 3 in atopic dermatitis in the second quarter of this year and, if successful, target a biologics license application filing in 2029.

Tagliaferri outlined the planned registrational program:

• Two global Phase 3 monotherapy trials, each enrolling approximately 650 patients ages 12 and older with moderate-to-severe atopic dermatitis
• Induction: 2:1 randomization to ResPEG 24 mcg/kg every two weeks vs. placebo for 24 weeks
• Maintenance: responders (EASI-75 and/or IGA) re-randomized 2:2:1 to monthly ResPEG, quarterly ResPEG, or placebo withdrawal for 28 additional weeks
• Co-primary endpoints: EASI-75 and an IGA-related endpoint

Management said ACQ-5 (asthma control) will be included in Phase 3, noting that about 25% of atopic dermatitis patients have comorbid asthma and that the company views asthma-related data as a differentiator. The company said it did not evaluate ACQ-5 in the Phase 2b maintenance portion.

Additional milestones discussed included a planned presentation of RESOLVE-AD data, including new translational data, at a medical meeting in the third quarter of this year; Phase 2 alopecia areata 52-week follow-up data expected in the second quarter of this year; and completion of RESOLVE-AD’s 52-week off-treatment follow-up in early 2027 with data anticipated in the first quarter of 2027. Robin also said the company is considering funding approaches for Phase 3 including potential collaborations and synthetic royalty structures, and noted that a Lilly litigation trial date has been set for September, without further comment.

About Nektar Therapeutics NASDAQ: NKTR

Nektar Therapeutics NASDAQ: NKTR is a biopharmaceutical company dedicated to discovering and developing novel drug candidates through its proprietary chemistry and immunology platforms. The company focuses on polymer conjugate technology, which enables the creation of longer-acting versions of existing drugs, and on T-cell modulatory therapies aimed at harnessing the body's immune system to treat cancer and other serious diseases.

Nektar's product portfolio and pipeline include a range of clinical-stage and partnered programs.

This instant news alert was generated by narrative science technology and financial data from MarketBeat in order to provide readers with the fastest reporting and unbiased coverage. Please send any questions or comments about this story to contact@marketbeat.com.