US biotechnology company Nektar Therapeutics (Nasdaq:NKTR) announced on Tuesday the start of its Phase 2b clinical trial evaluating rezpegaldesleukin (REZPEG) in patients with severe to very severe alopecia areata.

REZPEG is a novel agonistic T regulatory cell biologic that is designed to both dampen the inflammatory response and simultaneously restore immune balance by directly expanding functional T reg cells and engaging multiple immunoregulatory pathways.

The company's global, randomised, double-blind, placebo-controlled, dose-ranging Phase 2b study will assess the efficacy and safety of REZPEG in 84 participants with severe to very severe alopecia areata over a 36-week induction treatment period. The induction treatment period will compare two different dosing regimens of REZPEG against placebo. Participants will be followed for an additional 24 weeks after the end of this period to evaluate durability.

Initial results from the study are anticipated in the first half of 2025.

The primary efficacy endpoint will evaluate mean percentage improvement in the Severity of Alopecia Tool (SALT) at week 36. Secondary endpoints include proportion of participants with greater than or equal to 50% reduction in SALT at week 36 and other assessed timepoints and mean percentage improvement in SALT at other assessed timepoints.