Nektar Therapeutics (NKTR) Study update summary

Study design and objectives

• Phase IIb REZOLVE-AA trial enrolled 92 adults with severe-to-very-severe alopecia areata, randomized to rezpegaldesleukin (24 or 18 μg/kg) or placebo every two weeks for up to 52 weeks.

• Patients with a SALT score ≥50 and stable disease for over 6 months were included; 31 patients with SALT >20 at week 36 entered a 16-week blinded extension, continuing their original dose.

• The study aimed to determine optimal induction interval (36 vs. 52 weeks), dose selection for phase 3, and evaluate long-term safety and efficacy.

• Primary endpoint was mean % SALT reduction at week 36; key secondary and exploratory endpoints included new SALT ≤20 responses, overall SALT 20/30/50 rates, and deepening of response at week 52.

• 94% of patients completed the 52-week treatment period.

Efficacy results

• At week 52, 27.6% (24 μg/kg) and 25.8% (18 μg/kg) achieved SALT ≤20, compared to 6.7% for placebo (p=0.049).

• 29% (18 μg/kg) and 31% (24 μg/kg) of extension patients achieved new SALT ≤20 responses between weeks 36 and 52; none in placebo.

• SALT ≤30 achieved by 35.0% (24 μg/kg) and 30.2% (18 μg/kg) at week 52, versus 8.4% with placebo (p=0.023).

• SALT 50 (≥50% improvement) achieved by 38.8% (24 μg/kg) and 37.7% (18 μg/kg), versus 13.6% with placebo (p=0.032).

• SALT 30 (≥30% improvement) achieved by 47.6% (24 μg/kg) and 45.6% (18 μg/kg), versus 24.2% with placebo.

Safety and tolerability

• Rezpegaldesleukin maintained a favorable safety profile over 52 weeks, with no new safety findings; most adverse events were mild-to-moderate and self-resolving.

• No discontinuations due to adverse events or injection site reactions during the extension; discontinuation rate due to AEs was 1.4%.

• Injection site reactions were mostly mild, decreased over time, and resolved within five days.

• No increased risks for serious infections, malignancy, cardiovascular events, or JAK inhibitor-like lab abnormalities.

• No extensive lab monitoring required, supporting ease of use in clinical practice.