FDA Grants Fast Track Designation to Rezpegaldesleukin for Atopic Dermatitis

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The US FDA has granted Fast Track designation to Nektar Therapeutics’ rezpegaldesleukin for the treatment of moderate-to-severe atopic dermatitis (AD) in patients aged 12 years and older whose disease is not adequately controlled with topical prescription therapies or for whom such therapies are not advisable.¹

The investigational biologic therapy is designed to target the interleukin-2 receptor complex and stimulate regulatory T cells, which play a role in modulating immune response.¹ Proof of concept efficacy and data on safety from a phase 1b study of rezpegaldesleukin in AD were presented in October 2023 at the Congress of the European Academy of Dermatology and Venereology. Results showed that the therapy showed measurable improvements in disease outcomes during a 12-week induction treatment phase, with effects lasting at least 36 weeks after cessation of treatment.²

"Rezpegaldesleukin has the potential to address a significant unmet need for the millions of patients living with moderate-to-severe atopic dermatitis. We remain on track to announce topline data from the induction period of our Phase 2b REZOLVE-AD study in the second quarter of this year. This designation will now allow us to collaborate closely with the agency on the design of the registrational program for rezpegaldesleukin once we've completed Phase 2," Jonathan Zalevsky, PhD, senior vice president, chief research & development officer, Nektar Therapeutics, said in a February 10, 2025, press release.¹

In January 2025, Nektar Therapeutics announced that they reached target enrollment for the 398-patient phase 2b REZOLVE-AD study (NCT06136741).³ The ongoing study is evaluating rezpegaldesleukin in participants across multiple global sites. The primary endpoint is the mean improvement in the Eczema Area and Severity Index (EASI) score at 16 weeks. Secondary endpoints include achieving a Validated Investigator Global Assessment (vIGA-AD) score of 0 or 1, EASI-75 response, and a 4-point or greater improvement in Itch Numeric Rating Scale (NRS).¹

Rezpegaldesleukin is also being investigated for the treatment of alopecia areata in the REZOLVE-AA study (NCT06340360), according to Nektar.¹

References:

1. Nektar Therapeutics receives fast track designation for rezpegaldesleukin for the treatment of moderate-to-severe atopic dermatitis. News release. Nektar Therapeutics. February 10, 2025. Accessed February 10, 2025. https://ir.nektar.com/news-releases/news-release-details/nektar-therapeutics-receives-fast-track-designation
2. Silverberg, JI, Rosmarin D, Chovatiya R, et al. The regulatory T cell-selective interleukin-2 receptor agonist rezpegaldesleukin in the treatment of inflammatory skin diseases: Two randomized, double-blind, placebo-controlled phase 1b trials. Nat Commun. 2024;15:9230. doi:10.1038/s41467-024-53384-1
3. Halsey G. Phase 2b clinical trial of rezpegaldesleukin in atopic dermatitis achieves target enrollment. Patient Care Online. January 13, 2025. https://www.patientcareonline.com/view/phase-2b-clinical-trial-of-rezpegaldesleukin-in-atopic-dermatitis-achieves-target-enrollment