Nektar Therapeutics shares plunge 7.77% on mixed Phase 2b trial results for alopecia drug

Nektar Therapeutics shares plunged 7.7674% in pre-market trading on December 17, 2025, as mixed results from a Phase 2b trial of its autoimmune drug rezpegaldesleukin for alopecia areata sparked investor caution. While the drug failed to meet statistical significance in the primary endpoint, the company highlighted that excluding four ineligible patients allowed it to achieve the study’s main goal. The data showed a 28-30% reduction in SALT scores compared to 11% for placebo, with improved safety metrics reinforcing its potential in a competitive therapeutic landscape.

The setback follows years of strategic shifts for Nektar, including a terminated partnership with Bristol Myers Squibb and a near-70% workforce reduction. Despite these challenges, the drug’s promising efficacy in eczema earlier this year reignited investor optimism. Analysts like Jefferies’ Roger Song remain bullish, citing unmet medical needs and a favorable safety profile as key differentiators. Nektar plans to advance rezpegaldesleukin into Phase 3 trials in 2026, positioning it to compete in a market where JAK inhibitors face regulatory scrutiny over cardiovascular risks.

Industry experts suggest that the competitive therapeutic landscape could shift dramatically if rezpegaldesleukin demonstrates consistent efficacy in later-stage trials. With the global autoimmune disease market expected to exceed $150 billion by 2030, the need for safer and more effective treatments is growing. Nektar’s pipeline also includes potential applications in oncology, further diversifying its research focus. Clinical trial data transparency and real-world evidence will likely be key factors in determining its long-term market success.