The percentage of patients achieving total clearance of eczema lesions in a Phase 2b trial increased with prolonged rezpeg treatment.
Nektar Therapeutics reported that its investigational T cell stimulator rezpegaldesleukin not only maintains but deepens long-term treatment response, results that William Blair analysts said set the asset apart in a crowded atopic dermatitis field.
In the Phase 2b REZOLVE-AD study, Nektar enrolled and dosed 393 patients with moderate-to-severe atopic dermatitis. Three arms received various doses of subcutaneous rezpegaldesleukin—referred to as rezpeg—on different schedules, while a fourth group was given placebo.
Results presented on Tuesday showed that the monthly and quarterly dosing schedules of rezpeg maintained disease control through 52 weeks of follow-up across several efficacy scoring scales used. Study participants on rezpeg also saw improvements in their treatment response over time, with Nektar detecting a two- to five-fold increase in the percentage of patients who achieved total clearance in eczema lesions from baseline.
The durability and deepening response data “showcase differentiation” for rezpeg, William Blair told investors in a note on Tuesday, additionally noting that “there appears to be no meaningful deterioration of response when comparing the monthly dosing to the quarterly dosing.”
The analysts also noted that compared with Dupixent, the current atopic dermatitis leader, the quarterly maintenance dose of rezpeg elicited a “numerically higher” rate of EASI-75, a clinical endpoint that signifies the severity and extent of eczema.
Nektar closed Tuesday trading with its shares up 51% to $56.
The feedback from William Blair marks a reversal from its previous ambivalence over rezpeg. In September 2025, Nektar released more data from REZOLVE-AD, noting that prolonged exposure to rezpeg improves treatment outcomes. The analysts at the time were unconvinced, writing that the results did not “materially alter our view on rezpeg in this setting as questions about rezpeg’s differentiated remain unanswered.”
Tuesday’s mid-stage data for rezpeg “offer compelling efficacy and safety advantages and less frequent maintenance dosing as compared to current mechanisms,” Nektar CEO Howard Robin said in a statement, adding that the company will push the asset into Phase 3 development, with an eye toward submitting an approval application in 2029.
Rezpeg, a T cell stimulator, targets the IL-2 receptor complex to stimulate the multiplication of regulatory T cells, in turn helping correct immune dysregulation. This mechanism gives rezpeg its therapeutic potential for various autoimmune and inflammatory conditions. Aside from atopic dermatitis, Nektar is also developing rezpeg for alopecia areata and type 1 diabetes mellitus.
Elsewhere in the eczema arena, Evommune on Tuesday reported that its therapeutic protein EVO301 cut eczema severity by 33% in a Phase 2a study, which the company now plans to follow up with Phase 2b dose-ranging trial.
