Nektar Digs Into Mid-Stage Data To Establish Alopecia Efficacy of Rezpeg
Nektar Therapeutics reported topline Phase 2b REZOLVE‑AA results of rezpegaldesleukin (Rezpeg) in alopecia areata, showing clinically meaningful hair regrowth but a miss on the primary endpoint in the prespecified intent‑to‑treat analysis.123
In the full study population, patients on Rezpeg achieved about a 28–30% mean reduction in SALT score (hair loss severity) versus 11% with placebo, which did not reach statistical significance on the primary endpoint.1
Nektar attributed the statistical miss to four ineligible patients who were later determined not to have met enrollment criteria; when these four were excluded in a sensitivity analysis, the primary endpoint was met, with Rezpeg arms showing roughly 30% SALT reduction vs. 5.7% for placebo.134
Despite the formal miss, Nektar and collaborating investigators characterized the Phase 2b data as positive and clinically meaningful, emphasizing consistent efficacy signals across multiple endpoints and time points.134
The REZOLVE‑AA data are being used to support advancement of Rezpeg into Phase 3 development in alopecia areata, with Nektar stating that the totality of evidence justifies late‑stage trials.34
Rezpegaldesleukin is a modified IL‑2 pathway agonist being developed for autoimmune diseases; the alopecia areata data position it as a potential competitor to established agents and set up a competitive landscape with former partner Eli Lilly, which is also active in the space.23
The trial focused on patients with severe alopecia areata, and results showed a meaningful proportion of patients achieving substantial hair regrowth, supporting the biological activity of Rezpeg even though the primary endpoint in the ITT population was not statistically met.134
Nektar is now engaging with key stakeholders, including advocacy groups such as the National Alopecia Areata Foundation, to communicate the Phase 2b findings and the planned path toward Phase 3 trials.4
Sources:
1. https://www.biopharmadive.com/news/nektar-rezpegaldesleukin-alopecia-areata-drug-results/808013/
2. https://www.bizjournals.com/sanfrancisco/news/2025/12/16/alopecia-areata-nektar-therapeutics-lilly-rezpeg.html