REZOLVE-AA: 52-Week Data Highlight Positive Alopecia Areata Outcomes with Rezpegaldesleukin

Rezpegaldesleukin (REZPEG) therapy may lead to continued improvements in hair regrowth and Severity of Alopecia Tool (SALT) scores through 52 weeks among individuals with severe-to-very-severe alopecia areata, new data suggest.1,2

These findings, announced on April 20 by Nektar Therapeutics, represent the updated results of a blinded 16-week extension of the phase 2b REZOLVE-AA study assessing rezpegaldesleukin, an investigational interleukin (IL)-2 pathway agonist designed to selectively expand regulatory T cells, in patients with severe-to-very-severe alopecia areata, or hair loss.

“The new SALT≤20 responders in this set of patients treated out to 52 weeks reflect how the T regulatory cell mechanism of REZPEG can have more clinical benefit over time, a phenomenon the investigators observed in the Phase 2 study in atopic dermatitis as well," Jonathan Silverberg, MD, PhD, MPH, professor of dermatology at The George Washington University School of Medicine and Health Sciences, said in a statement.1

92 patients who had been naïve to prior Janus-kinase (JAK) inhibitors or biologic drugs were involved in this global study, with trial investigators randomizing them during a 36-week induction period to be given either 1 of 2 dose regimens of rezpegaldesleukin or placebo. These regimens were administered as twice-monthly subcutaneous injections. Overall, the investigators identified notable baseline disease burden, with mean SALT scores being near 78 in the treatment cohorts and 76.6 in the placebo cohort.

Additionally, there had been a median disease duration of approximately 6 - 7 years. After the study’s induction phase, those who demonstrated some hair regrowth but continued to have significant scalp involvement (SALT >20) were deemed eligible to jin a blinded extension period through Week 52. There were 31 total patients who continued into this phase, including 27 on a rezpegaldesleukin regimen, with a low- (18 µg/kg; n = 14) and high-dose (24 µg/kg; n = 13) cohort. There were 4 remaining on placebo.

In REZOLVE-AA’s extension period, additional clinical responses were observed, with 29% of individuals featured in the low-dose arm and 31% in the high-dose arm attaining new SALT ≤20 responses. This corresponded to ≥80% scalp hair coverage. This was compared with no new responders in the placebo arm of the trial. By the 52-week mark, outcomes across the overall study population continued to favor rezpegaldesleukin therapy.

The proportion of participants with a SALT ≤20 score rose to 25.8% in the low-dose cohort and 27.6% in the high-dose cohort, with only 6.7% in the placebo arm (P = .049). In a similar finding, the investigative team observed rates of SALT ≤30, representing ≥70% scalp hair coverage, attained by 30.2% and 35.0% of those in the low- and high-dose groups, respectively, versus 8.4% with placebo (P = .023).

In the team’s additional efficacy endpoints, findings also demonstrated improvements with active treatment. Such results included SALT50 responses observed in 37.7% and 38.8% of individuals in the low- and high-dose arms, respectively. This was compared with only 13.6% noted among those in the placebo arm. SALT30 responses were seen in 45.6% and 47.6% of participants treated with rezpegaldesleukin, versus 24.2% with placebo.

Collectively, these data were described by Nektar as indicators that continued rezpegaldesleukin use may lead to incremental improvements in hair regrowth over time in those living with severe alopecia areata. The company further noted its plans for the REZOLVE-AA results to be submitted for presentation at a medical meeting in 2026.

"Given the prescribing and safety limitations of JAK inhibitors, these new data point to the potential for rezpegaldesleukin to be the first safe and effective biologic in alopecia areata, which may completely transform the management of the disease,” Silverberg said in his statement.1

References

1. 52-Week Topline Results from 16-Week Blinded Treatment Extension of REZOLVE-AA Demonstrate Deepening of Responses in Severe-to-Very-Severe Alopecia Areata with Rezpegaldesleukin. Nektar Therapeutics. April 20, 2026. https://www.prnewswire.com/news-releases/52-week-topline-results-from-16-week-blinded-treatment-extension-of-rezolve-aa-demonstrate-deepening-of-responses-in-severe-to-very-severe-alopecia-areata-with-rezpegaldesleukin-302746837.html.

2. Chovatiya R. REZOLVE-AD: Rezpegaldesleukin Shows Consistent Efficacy Across Atopic Dermatitis Severity, With Raj Chovatiya, MD, PhD. HCPLive. March 20, 2026. Accessed April 20, 2026. https://www.hcplive.com/view/rezolve-ad-rezpegaldesleukin-consistent-efficacy-across-atopic-dermatitis-severity-chovatiya.