The FDA has granted a “Fast Track” designation to rezpegaldesleukin (REZPEG) as a treatment for severe-to-very severe alopecia areata, according to a press release from the manufacturer, Nektar Therapeutics.
The indication applies to adults and children aged 12 years or older weighing at least 40 kg.
REZPEG is a novel biologic that targets “the interleukin-2 receptor complex in the body to stimulate proliferation of inhibitory immune cells known as regulatory T cells,” according to the company. The Fast Track designation was created to help bring important new treatments to patients as soon as possible and is granted to investigational therapies that may address unmet medical needs for serious conditions, according to the press release.
REZPEG is being evaluated in the ongoing Rezolve AA phase 2b study in patients with alopecia areata. In the study, 90 patients with severe-to-very severe alopecia areata (defined as scalp involvement of 50% or more) who were not previously treated with a JAK inhibitor or another biologic were randomized to two different doses of REZPEG or placebo. It will be a self-administered injection, the company said.
The primary efficacy endpoint is the mean percent change in the Severity of Alopecia Tool (SALT) score at the end of the 36-week induction period, according to the company. Secondary endpoints include the proportion of participants with reductions in SALT scores of 50% or more at 36 weeks and other timepoints, as well as the mean percent improvement in SALT score at multiple timepoints and the proportion of patients achieving an absolute SALT score ≤ 20.
Data from the trial are scheduled to be reported in December 2025, according to the company.
The designation follows a previous Fast Track designation for the product as a treatment for moderate-to-severe atopic dermatitis in February.