A Long-Acting Anti-IL-5 Therapy with Twice-Yearly Dosing

On April 3, 2026, GlaxoSmithKline (GSK) announced that its innovative biologic Depemokimab injection has been approved by the National Medical Products Administration (NMPA) in China for the treatment of Chronic Rhinosinusitis with Nasal Polyps (CRSwNP).

This marks the second approved indication for depemokimab in China, following its March 2026 approval for Severe Eosinophilic Asthma (SEA). More details on the first approval can be found here: NMPA Approves GSK Depemokimab in China for Severe Eosinophilic Asthma with Twice-Yearly Dosing.

As the first ultra-long-acting anti-IL-5 monoclonal antibody designed for twice-yearly administration, depemokimab has demonstrated strong clinical performance in terms of efficacy, safety, and dosing convenience. Its approval also expands the portfolio of innovative medicines available to Chinese pharmaceutical distributor DengYueMed.

1. Chronic Rhinosinusitis with Nasal Polyps: Disease Overview and Treatment Challenges

CRSwNP is a chronic inflammatory disease of the nasal passages and paranasal sinuses, characterized by persistent mucosal inflammation and nasal polyp formation.

Common symptoms include:

● Nasal congestion and obstruction

● Persistent nasal discharge

● Reduced or lost sense of smell

● Recurrent sinus infections

● Decreased quality of life, including sleep disturbance, headache, and chronic fatigue

Epidemiological studies suggest that approximately 2–4% of adults worldwide suffer from CRSwNP. About half of these patients exhibit eosinophilic inflammation, in which eosinophils play a key pathogenic role by releasing inflammatory cytokines and chemokines that promote mucosal inflammation and polyp growth.

Limitations of Current Treatments

1. Corticosteroids

Topical or systemic corticosteroids can provide temporary relief of inflammation. However, long-term use may lead to significant side effects such as:

● Diabetes

● Hypertension

● Osteoporosis

2. Surgical intervention

Functional endoscopic sinus surgery (FESS) is commonly performed for severe disease. However, recurrence rates remain high, ranging from 30% to 50%, and surgical risks cannot be ignored.

3. Disease-modifying therapies

These treatments may provide benefit in some patients but often have limited efficacy in severe or recurrent cases, requiring long-term disease management.

Given these limitations, there is a strong need for effective, durable, and well-tolerated targeted therapies, particularly those that directly address eosinophilic inflammation.

2. Depemokimab: Mechanism of Action and Therapeutic Advantages

Depemokimab is a monoclonal antibody targeting interleukin-5 (IL-5) developed by GSK. By neutralizing IL-5, it blocks the activation, maturation, and survival of eosinophils, thereby suppressing eosinophil-driven inflammatory responses.

Key features include:

1. Ultra-long half-life

Depemokimab is designed for twice-yearly subcutaneous administration, maintaining effective drug concentrations while significantly reducing treatment burden and improving patient adherence.

2. High binding affinity and potency

The antibody demonstrates strong and sustained inhibition of eosinophil-mediated inflammation.

3. Multiple potential indications

Depemokimab is now approved for:

● Severe eosinophilic asthma (SEA)

● Chronic rhinosinusitis with nasal polyps (CRSwNP)

In addition, Phase III clinical trials are ongoing in other eosinophil-driven diseases, including:

● Chronic obstructive pulmonary disease (COPD)

● Eosinophilic granulomatosis with polyangiitis (EGPA)

4. Next-generation IL-5 therapy

Depemokimab can be considered an evolution of Mepolizumab, a monthly anti-IL-5 antibody. By extending the half-life and reducing dosing frequency, depemokimab may represent the next generation of long-acting biologic therapies for respiratory diseases.

3. Phase III ANCHOR-1 and ANCHOR-2 Clinical Trials

Study Design

Two global Phase III randomized, double-blind, placebo-controlled trials evaluated the efficacy and safety of depemokimab in patients with CRSwNP.

ANCHOR-1: N = 271

ANCHOR-2: N = 257

Treatment regimen: Subcutaneous depemokimab administered twice yearly

Primary endpoints:

● Nasal Polyp Score (NPS)

● Nasal Congestion Score (NC)

Secondary endpoints included:

● Nasal discharge score

● Loss of smell score

● Lund-Mackay CT imaging score

● SNOT-22 quality-of-life score

Primary Endpoint Results

Endpoint	Depemokimab	Placebo	P-value
Improvement in nasal polyp size (NPS)	Significant	Minimal	<0.001
Improvement in nasal congestion	Significant	Minimal	<0.001

Secondary Endpoint Results

Depemokimab also demonstrated significant improvements across multiple secondary outcomes:

● Nasal discharge score: significantly improved compared with placebo

● Olfactory function: meaningful improvement in VRS smell scores

● Imaging findings: improved sinus structure based on Lund-Mackay CT scoring

● Quality of life: substantial improvement in SNOT-22 scores

Safety Profile

The safety results were consistent with expectations for anti-IL-5 biologics:

● Overall adverse event rates were similar to placebo

● The most common adverse events were mild to moderate injection-site reactions

● No new safety signals were identified

Overall Clinical Impact

At Week 52, approximately 74% of patients treated with depemokimab required no systemic corticosteroids, surgery, or additional disease-modifying treatments.

When evaluating surgery or disease-modifying drugs alone, 88% of patients avoided further intervention.

These results indicate that depemokimab can:

● Provide durable symptom control

● Reduce the need for invasive procedures

● Improve long-term disease management and patient quality of life

4. Global Anti-IL-5 / IL-5R Antibody Market Landscape

Drug	Company	Indications	Status	Key Feature
Depemokimab	GSK	SEA, CRSwNP	Approved in US & China	Twice-yearly dosing
Mepolizumab	GSK	SEA	Approved	Monthly dosing
Reslizumab	UCB / Schering	SEA	Approved	Standard IL-5 inhibitor
SHR-1703	Hengrui Pharma	SEA	Phase III	In development
SSGJ-610	3SBio	SEA	Phase III	In development
Benralizumab	AstraZeneca	SEA	Approved	IL-5 receptor antibody

Among IL-5-targeted therapies, depemokimab offers a distinct advantage through its twice-yearly dosing schedule, which could position it as a next-generation leader in the biologics market for eosinophilic respiratory diseases.

GSK is also advancing depemokimab in Phase III trials for COPD and EGPA, highlighting the continued expansion potential of its respiratory biologics pipeline.

With two approved indications in China, depemokimab may evolve into a long-acting biologic covering a broad spectrum of eosinophilic inflammatory diseases, addressing diverse clinical needs.

Conclusion

The approval of Exdensur (depemokimab) for chronic rhinosinusitis with nasal polyps in China provides patients with a long-acting and convenient new treatment option, while further enriching the landscape of innovative biologic therapies in the country.

As advanced biologic treatments continue to emerge, Hong Kong DengYue Medicine is focused on supporting the clinical adoption and accessibility of advanced therapies.

Building on its successful launch for severe eosinophilic asthma, depemokimab has the potential to become a new benchmark in respiratory disease treatment in China, advancing the adoption of long-acting immunotherapies in clinical practice.