Nektar Therapeutics Surges 140% as Phase 2b Data Validates Efficacy of Rezpegaldesleukin

Shares of Nektar Therapeutics $NKTR soared by 140% after the company reported statistically significant results from a Phase 2b clinical trial of rezpegaldesleukin, its investigational therapy for moderate-to-severe atopic dermatitis. The dramatic rally signals a material shift in investor sentiment, fueled by renewed confidence in the company’s clinical pipeline following a prolonged period of underperformance and strategic uncertainty.

Trial Design and Outcomes: A Clear Signal

The randomized, placebo-controlled Phase 2b trial evaluated three doses of rezpegaldesleukin in patients with moderate to severe atopic dermatitis. All dosing arms achieved statistical significance on the primary endpoint, defined as the mean percentage change from baseline in the Eczema Area and Severity Index (EASI) at week 16 compared to placebo. The treatment also met multiple secondary endpoints, including EASI-75 and EASI-50 scores, as well as meaningful improvements in body surface area (BSA) affected by the disease. The drug demonstrated early onset of efficacy, with clinical benefits observed in both skin clearance and itch relief, two critical dimensions in the management of chronic inflammatory skin conditions.

Implications for Pipeline and Market Position

The positive results mark a critical validation point for Nektar’s immunology-focused development strategy, positioning rezpegaldesleukin as a potential differentiated entrant in a highly competitive space dominated by biologics such as Sanofi’s Dupixent $SNY. Unlike traditional systemic therapies, rezpegaldesleukin targets regulatory T-cell pathways, offering a novel mechanism of action that could appeal to patient segments unresponsive or intolerant to existing treatments. The Phase 2b success is particularly notable given Nektar’s prior setbacks in oncology and its ongoing efforts to reorient toward immuno-dermatology and autoimmune indications.

Study Highlights Supporting the Share Price Reaction

• Primary endpoint met across all three dosing groups with statistical significance;

• Secondary outcomes achieved, including EASI-75 and EASI-50 benchmarks;

• Rapid onset of action in skin clearance and itch reduction;

• BSA improvement indicating broader symptomatic relief;

• No major safety concerns reported at this stage.

Strategic Context: Rebuilding Clinical and Investor Credibility

Nektar has faced significant challenges over the past two years, including the termination of high-profile oncology partnerships and declining investor confidence. The current data offers a rare clinical and reputational boost, potentially opening avenues for licensing, co-development deals, or broader pipeline acceleration.

However, while the market reacted positively to short-term efficacy signals, longer-term outcomes, such as durability of response, safety in extended treatment, and comparative efficacy, remain to be established in Phase 3 trials. Commercial prospects will also depend on regulatory alignment, payer receptivity, and positioning within an increasingly crowded therapeutic landscape.

Conclusion: A Pivotal Milestone With Cautious Optimism

The Phase 2b results validate rezpegaldesleukin’s potential and mark a strategic inflection point for Nektar Therapeutics. While further clinical validation is essential, the trial success materially enhances the asset’s value proposition and may restore the company’s standing in the biotech investment landscape. Execution risk remains, but the trial outcome decisively shifts the narrative from survival to opportunity.