PR Newswire·Dec 16, 2025, 7:30 AM ET

REZOLVE-AA Phase 2b Study of Rezpegaldesleukin Establishes Proof-of-Concept in Patients with Severe-to-Very-Severe Alopecia Areata

NKTR

Nektar Therapeutics announced topline results from the Phase 2b REZOLVE-AA trial of investigational rezpegaldesleukin for severe-to-very-severe alopecia areata.
The study enrolled 92 patients randomized to receive rezpegaldesleukin (18 µg/kg or 24 µg/kg) or placebo via subcutaneous injection twice-monthly.
The primary endpoint of mean percent SALT score reduction at Week 36 narrowly missed statistical significance in the full analysis, showing 28.2% for the 24 µg/kg arm, 30.3% for the 18 µg/kg arm, vs 11.2% for placebo.
When excluding four patients with major study eligibility violations, both treatment arms achieved statistical significance, with reductions of 29.6% (24 µg/kg) and 30.4% (18 µg/kg) versus 5.7% for placebo (p<0.05).
Both rezpegaldesleukin dose arms demonstrated dose-dependent clinical effects on key secondary endpoints including SALT ≤ 30, SALT ≤ 20, SALT ≤ 10, and SALT 30.
The safety profile showed rezpegaldesleukin was well tolerated with a 1.4% discontinuation rate due to adverse events, no discontinuations due to injection site reactions, and no increased risk of major cardiovascular events or infections compared to placebo.
Study results establish the Phase 3 dose & support the planned advancement of rezpegaldesleukin to Phase 3 development for alopecia areata in 2026.
Rezpegaldesleukin currently holds Fast Track designation from the FDA for both atopic dermatitis (granted Feb 2025) & severe alopecia areata (granted July 2025).
Nektar plans to submit results for presentation at a medical conference in 2026, with data from the 16-week extension period expected in early Q2 2026.