The Phase III Study Data of Stapokibart for Seasonal Allergic Rhinitis Published in Nature Medicine

CHENGDU, China, April 5, 2025 /PRNewswire/ -- Keymed Biosciences Inc. (HKEX: 02162) ("Keymed" or the "Company") today announced that the prestigious medical journal Nature Medicine has published the results from the Phase III trial of its independently developed IL-4Rα antibody stapokibart, for the treatment of moderate-to-severe seasonal allergic rhinitis (SAR). The study, led by Professor Luo Zhang of Beijing Tongren Hospital, Capital Medical University, represents the world's first clinical report on an IL-4Rα-targeted biologic for SAR, underscoring Chinese scientists' pioneering role in allergic rhinitis innovation.

The study demonstrated that stapokibart significantly alleviates clinical symptoms and improves quality of life in patients with moderate-to-severe SAR who remained inadequately controlled despite standard therapies. This breakthrough offers a transformative solution to a global health challenge, ushering in a new era of biologic treatments for allergic rhinitis and providing hope to hundreds of millions of patients worldwide. 

Innovative Mechanism Addresses Urgent Clinical Needs

Allergic rhinitis (AR), a chronic inflammatory disease of the nasal mucosa, is triggered by environmental allergens in sensitized individuals. In recent years, its global prevalence has risen significantly. Despite standard therapies, over 50% of patients continue to experience inadequately controlled symptoms, a substantial unmet need that severely impacts quality of life and imposes a heavy socioeconomic burden, positioning AR as a critical public health challenge.

The persistence and exacerbation of AR symptoms are primarily driven by amplified type 2 inflammatory cascades. Stapokibart, targeting the IL-4 receptor alpha subunit (IL-4Rα), dual-blocks both IL-4 and IL-13 signaling pathways. Through a multi-pronged approach—inhibiting T-cell activation and proliferation, suppressing B-cell activation and IgE synthesis, and reducing inflammatory cell infiltration—Stapokibart comprehensively attenuates allergic reactions, providing a novel therapeutic strategy for seasonal allergic rhinitis, and other type 2-mediated allergic diseases.

The First and Only Approved IL-4Rα Antibody Globally with Demonstrated Efficacy and Safety

Results of this phase III trial demonstrated that stapokibart rapidly, significantly, and sustainably controlled both nasal and ocular symptoms in patients with moderate-to-severe SAR, while markedly improving quality of life and maintaining a favorable safety profile.

Rapid, potent and sustained control of nasal symptoms:

Rapid relief of nasal obstruction: Compared to placebo group, patients in stapokibart group achieved significantly greater improvement in nasal congestion symptom at Day 2. By Day 7, 72% of patients reported clear nasal breathing, with the cumulative response rate rising to 86% at Week 2 and 94% at Week 4.

Potent and sustained control of nasal symptoms: Stapokibart demonstrated a 2.7-point reduction in daily reflective total nasal symptom score (rTNSS) from baseline by Day 4, significantly greater than the improvement in the placebo group.

Over the 2-week treatment period, stapokibart achieved a 3.6-point reduction in daily rTNSS from baseline, with a least squares (LS) mean difference of -1.3 points vs. placebo (the primary efficacy endpoint). Additionally, 62% of patients achieved mild or no symptom (defined as rTNSS ≤1 point for each symptom); Over the 4-week treatment period, the stapokibart group showed a 4.9-point reduction in daily rTNSS from baseline, with an LS mean difference of -1.7 points vs. placebo. The proportion of patients achieving mild or no nasal symptoms reached 84%.

Sustained and significant improvement of ocular symptoms:

Stapokibart demonstrated clinically significant reductions in the daily reflective Total Ocular Symptom Score (rTOSS) from baseline, with improvements of 2.6 points at week 2 and 3.7 points at week 4 respectively, both significantly superior to placebo. By Week 2, 62% of patients achieved mild or no ocular symptoms (defined as rTOSS ≤1 point for each symptom), increasing to 94% by Week 4.

Significant reduction in levels of type 2 inflammatory biomarkers

During the 4-week treatment period, the stapokibart group demonstrated significant reductions in total serum IgE levels and allergen-specific IgE (sIgE) levels against pollen allergens.

Additionally, stapokibart reduced type 2 inflammatory biomarker levels in nasal secretions, including cystatin SN (CST1) and eotaxin-3, demonstrating its dual mechanism of action: targeting both the underlying etiology (type 2 inflammation) and symptomatic manifestations of allergic rhinitis.

Safety

Stapokibart demonstrated a favorable safety profile in patients with seasonal allergic rhinitis. The incidence of treatment-emergent adverse events (TEAEs) was comparable to placebo, and no serious adverse events (SAEs) were reported during the trial.

Groundbreaking Research Ushers in a New Era of Biologic Therapy for Allergic Rhinitis

The PHECDA trial pioneered targeted biologic therapy for allergic rhinitis. The results supported the approval of stapokibart—the world's first and only IL-4Rα monoclonal antibody for seasonal allergic rhinitis (SAR)— by China's National Medical Products Administration (NMPA) on February 7, 2025. This breakthrough provides a novel therapeutic option for patients with moderate-to-severe refractory SAR, solidifying Chinese clinical scientists' global leadership in allergic rhinitis research and setting a precedent for future clinical development.

Stapokibart, a Category 1 New Drug independently developed by Keymed, is China's first domestically developed and one of the only two approved IL-4Rα antibody drugs worldwide. Since its initial NMPA approval in September 2024, stapokibart has secured three indications, including moderate-to-severe atopic dermatitis in adults, chronic rhinosinusitis with nasal polyposis(CRSwNP), and SAR,  within six months, addressing critical unmet needs. With spring—the peak season for SAR—approaching, stapokibart offers patients a novel treatment leveraging its precision targeting of type 2 inflammation and robust clinical efficacy.

Keymed focuses on high-value unmet medical needs, delivering high-quality, accessible, and innovative therapies for patients globally. The company has now established a diverse proprietary R&D platform and a differentiated pipeline with industry-leading candidates. With a comprehensive biopharmaceutical industry layout spanning from molecular discovery to commercial-scale production, Keymed is accelerating the availability of transformative medicines.

About Stapokibart

Stapokibart (CM310) is a high-efficient, humanized antibody targeting the interleukin-4 receptor alpha subunit (IL-4Rα), and is the first domestically manufactured IL-4Rα antibody drug granted marketing approval by the NMPA. By targeting IL-4Rα, Stapokibart can block both interleukin-4 (IL-4) and interleukin-13 (IL-13) signaling. IL-4 and IL-13 are two key cytokines trigger type II inflammation. Stapokibart has demonstrated a favorable safety profile and encouraging efficacy across multiple clinical trials and has been approved for marketing for the treatment of moderate to severe atopic dermatitis in adults, chronic rhinosinusitis with nasal polyposis, and Seasonal Allergic Rhinitis in September 2024, December 2024 and February 2025, respectively.

About Keymed Biosciences Inc.

Keymed Biosciences Inc. (HKEX: 02162) focuses on the urgent unmet clinical needs and is committed to providing high-quality, affordable, innovative therapies for patients in China and overseas. Keymed was founded by medical and scientific experts who have strong experience in the transformation of scientific and technological achievements to commercialization at home and abroad.

SOURCE Keymed Biosciences