Breaking news in innovative drugs! "T-cell dark horse" Nektar's eczema efficacy explodes, with stock price soaring 150% in a single day

According to the Zhitong Finance APP, during Tuesday's U.S. stock trading session, a significant piece of news emerged in the global innovative drug sector, driving Nektar Therapeutics (NKTR.US) stock price to surge over 180% at one point during trading, closing up 156% at $24.450. Previously, this cash-strapped biotech company announced that its drug Rezpegaldesleukin for the treatment of moderate to severe atopic dermatitis (also known as eczema) achieved unexpectedly positive results in the REZOLVE-AD phase 2b clinical trial, meeting both primary and secondary endpoints, validating the company's novel approach of using regulatory T cell therapy for inflammatory skin diseases.

Nektar Therapeutics, headquartered in San Francisco and founded in 1990, is a leading American biotech company that has long focused on developing immunomodulatory therapies using PEGylation and polymer conjugation technology. However, in recent years, it has faced challenges due to multiple failed collaborations and tight cash flow, but its latest regulatory T cell (Treg) platform has positioned the company as a "dark horse" in T cell therapy.

The innovative drug Rezpegaldesleukin (REZPEG, also known as NKTR-358) is centered on extending the half-life of interleukin-2 (IL-2) through PEG modification and precisely targeting high-affinity IL-2 receptors (CD25), selectively expanding immunosuppressive Treg cells to reduce inflammation without excessively activating effector T cells.

This mechanism is similar to low-dose IL-2 therapy but amplifies Treg responses through molecular engineering, reduces dosing frequency, and minimizes off-target risks. Clinical data to date show good tolerability with no dose-limiting toxicity observed. Rezpegaldesleukin has seen preliminary success in the eczema field, and the company is also conducting research on psoriasis and systemic lupus erythematosus. More importantly, if phase III trials further confirm its efficacy and it receives approval, Rezpegaldesleukin will provide the first Treg cell-targeted therapy for patients with atopic dermatitis, with the potential to replicate this approach for other autoimmune diseases, making it the world's first Treg-directed IL-2 therapy for skin diseases.

The innovative pharmacological mechanism of Rezpegaldesleukin lies in its PEG modification and receptor affinity redesign at the molecular structure level, allowing IL-2 signaling to specifically favor regulatory T cells (Treg), achieving selective expansion of Treg without excessively activating effector T cells. In inflammatory skin diseases like eczema, insufficient Treg function is one of the pathological cores; enhancing Treg can significantly inhibit Th2/Th22 type inflammatory pathways, markedly improving itching and skin lesions.

The large molecule PEG shields the binding site of IL-2 with IL-2Rβ, making it more reliant on high-affinity CD25 (IL-2Rα); at the same time, it extends the plasma half-life, allowing for injections every 2–4 weeks. Additionally, due to the high expression of CD25 on Treg, Rezpegaldesleukin primarily promotes Treg proliferation and functional enhancement in vivo, while being sparse on effector T/NK cells, thus affecting effector T cells NK cells are hardly activated, thereby reducing side effects such as cytokine storms.

Huge Opportunities in the Eczema Market

Atopic dermatitis has considerable market potential in the United States and globally. According to the American Eczema Association, approximately 31.6 million people (about 10% of the total population) suffer from some form of eczema. Among them, over 30 million are patients with atopic dermatitis, a skin condition commonly referred to as eczema. Although the FDA has approved several biologics (such as Dupixent, Ebglyss, Adbry, Nemluvio), there remains a significant number of patients who respond poorly to existing therapies or experience severe side effects, leaving medical needs far from being met.

It is understood that the REZOLVE-AD study included a total of 393 patients with moderate to severe atopic dermatitis, achieving the primary endpoint after 16 weeks of treatment through the Eczema Area and Severity Index (EASI), while also achieving significantly positive improvements in key secondary endpoints such as lesion clearance rates.

The results of the phase 2b clinical study showed that the high-dose group had a 61% improvement in the EASI index, while the control group only saw a 31% improvement, primarily meeting all key secondary endpoints. Following this, the concept of "the first Treg mechanism eczema drug" rapidly gained traction, and investors were very optimistic about its differentiated competition with existing drugs like Dupixent, ultimately leading to a single-day surge of over 150% in Nektar Therapeutics' stock price.

Financial Impact

For Nektar, which currently has a market capitalization of only about $300 million and primarily relies on $87 million in royalty income, this data has profound financial significance.

If Rezpegaldesleukin is ultimately approved, the drug will become a blockbuster treatment comparable in scale to the weight-loss drug semaglutide, with preliminary estimates from institutions suggesting its peak annual sales could exceed $2 billion, enough for Nektar to transition from a royalty-dependent business model to one driven by its own products, becoming one of the leading biotech companies.

Significant Acquisition Potential

The major success of the phase 2b study makes Nektar an ideal acquisition target for large biotech and pharmaceutical giants such as Pfizer, Eli Lilly, Amgen, and Bristol Myers Squibb looking to strengthen their dermatology product lines. The current valuation of less than $300 million starkly contrasts with the multi-billion dollar market potential of Rezpegaldesleukin, making the acquisition economically attractive.

On the day the announcement related to the study results was released, the stock price doubled in a single day, reflecting investors' high recognition of the drug's efficacy and acquisition prospects. Early-stage biotech companies with late-stage pipelines and valuations perceived as low relative to their potential value are often seen as significant acquisition targets by industry giants.

However, analysts view Nektar as a purely high-risk bet: the overall value of the company is highly dependent on the subsequent clinical progress of Rezpegaldesleukin and FDA approval. Although the significant success of the phase 2b study has notably reduced R&D risks, uncertainties still exist in drug development