Nektar's Hair Loss Treatment Breakthrough: 2b Study Validates New IL-2 Pathway Approach

Nektar Therapeutics (NKTR) has unveiled compelling Phase 2b data for Rezpegaldesleukin in treating severe alopecia areata, a condition where the immune system mistakenly attacks hair follicles causing patchy or total baldness. The REZOLVE-AA trial achieved its primary efficacy targets, marking a significant milestone for this first-in-class immunotherapy candidate.

Clinical Data Demonstrates Meaningful Hair Regrowth

The randomized trial assessed 92 participants receiving either of two Rezpegaldesleukin doses or placebo via subcutaneous injection twice monthly over 36 weeks. Measured by the Severity of Alopecia Tool (SALT), the drug substantially outperformed placebo. Treatment groups achieved SALT reductions of 28.2% and 30.3% respectively, more than doubling placebo’s 11.2% reduction. After excluding patients with protocol violations, efficacy strengthened to 29.6% and 30.4% compared to placebo’s 5.7%, reaching statistical significance.

Beyond scalp hair recovery, investigators documented regrowth of eyebrows and eyelashes, suggesting broad follicle regeneration. Secondary metrics reinforced the benefit, with larger percentages of patients reaching SALT thresholds of 30, 20, and 10.

Safety Profile and Market Implications

The safety data proved reassuring. Nearly all adverse events remained mild-to-moderate and resolved independently, with only 1.4% discontinuation—a favorable profile compared to existing JAK inhibitors, which carry safety concerns and higher relapse risks. This positions Rezpegaldesleukin as a potentially durable solution addressing a substantial treatment gap in alopecia management.

Path Forward and Stock Performance

Nektar has secured FDA Fast Track designation and plans to initiate Phase-3 development in 2026. A 16-week extension study will report data in Q2 2026, with full results presented at industry conferences later that year. The company is simultaneously exploring Rezpegaldesleukin across atopic dermatitis and type-1 diabetes, broadening its applicability as a regulatory T-cell stimulator.

Stock-wise, NKTR has fluctuated between $6.45 and $66.92 over the past year. Pre-market trading shows the stock at $58.39, up 9.55%, reflecting investor optimism around these 2b hair loss findings.