Belenos Biosciences, Inc. (“Belenos”), a clinical-stage biotechnology company developing long-acting bispecific antibodies for chronic inflammatory diseases, today announced that ‘512 met its primary and all secondary endpoints in a double-blind, placebo-controlled Phase 2 clinical study in adults with inadequately controlled CRSwNP (NCT06930612). ‘512 is known as BEL512 ex-China and CM512 in Greater China.

The study was conducted in China by Belenos’ partner, Keymed Biosciences, and enrolled 120 patients with CRSwNP with a Nasal Polyp Score of ≥5, with at least 2 polyps per nostril and a Nasal Congestion Score of 2-3 at baseline. Patients were randomized to receive either 300 mg ‘512 every 12 weeks, 300 mg ‘512 every 24 weeks, 600 mg ‘512 every 24 weeks, or placebo via subcutaneous injection on top of daily intranasal corticosteroid treatment (mometasone furoate nasal spray [MFNS 200 µg QD]). Treatment lasted 24 weeks, followed by a 12-week safety follow-up.

The primary endpoint was change from baseline at week 24 (W24) in Nasal Polyp Score (NPS). Additional endpoints evaluated throughout the study were:

  • Nasal Congestion Score (NCS)

  • Loss of Smell (LoS) Score

  • Total Symptom Score (TSS)

  • Sinus CT Lund-Mackay (LMK) score

  • Sinonasal Outcome Test-22 (SNOT-22)

The study met its primary and secondary endpoints with statistically significant improvements in the ‘512 treatment groups vs placebo at W24. Improvements were achieved by W4 and durable effects were observed throughout the treatment and follow-up periods.

‘512 was well tolerated across all dosing groups with overall treatment-emergent adverse events (TEAEs) rates similar to placebo, no severe TEAEs, no discontinuations in treatment groups, no serious adverse events (SAEs), and minimal anti-drug antibodies (ADA).

Based on the results of this study, ‘512 was recently included by the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) in its Breakthrough Therapy program for the treatment of CRSwNP.

“These results provide important clinical validation for simultaneously targeting TSLP and IL-13 in treating CRSwNP,” said Donnie McGrath, M.D., CEO of Belenos Biosciences. “The magnitude, speed of onset and durability of improvement across objective measures of nasal polyp disease and the symptoms that matter most to patients, in conjunction with infrequent dosing indicate that BEL512 may offer patients an attractive treatment option. These findings further strengthen our conviction in BEL512 as a potentially best-in-class therapy across multiple respiratory and inflammatory diseases. We congratulate our partners at Keymed Biosciences on a well-executed study.” Keymed is rapidly moving to initiate a Phase 3 study in CRSwNP in China in the near future and Belenos will be initiating a Phase 3 study ex-China in the first half of 2027.

Detailed results are expected to be presented at a scientific meeting and submitted for publication in a peer-reviewed medical journal.

“Patients with CRSwNP experience a significant and profound impact on their quality of life, struggling to breathe through their nose, smell, and sleep normally. A treatment that works quickly and provides lasting benefits for many months after a single injection would substantially improve both the quality of life and treatment experience for my patients,” said Dr. Stella Lee, M.D., Associate Professor of Otolaryngology–Head and Neck Surgery at Harvard Medical School and Director of the Sinus Center at Brigham and Women’s Hospital, who was not involved in the study. “The marked improvements observed across nasal polyp burden, congestion, and sense of smell may translate into meaningful improvements in health-related quality of life, strongly supporting continued development of BEL512 for CRSwNP.”

About Chronic Rhinosinusitis with Nasal Polyps:

Chronic Rhinosinusitis (CRS) affects between 10.9%-13.4% of the Western population, and the more severe subtype of CRSwNP accounts for approximately 18-20% of all CRS cases (Laidlaw TM et al J Allergy Clin Immunology Pract, 2021). CRSwNP is a chronic inflammatory disease of the nasal passages and sinuses characterized by the growth of nasal polyps. The condition is marked by nasal obstruction, congestion, facial pressure, impaired or lost sense of smell, sleep disturbance, and often comorbid asthma. Many patients remain symptomatic despite intranasal corticosteroids, systemic corticosteroids, biologic therapy or endoscopic sinus surgery.

Type 2 inflammation plays an important role in CRSwNP. TSLP is an upstream epithelial cytokine involved in initiating and amplifying inflammatory responses, while IL-13 is a downstream effector associated with mucus production, tissue inflammation, barrier dysfunction and remodeling. BEL512 is designed to inhibit both pathways in a single molecule.

About BEL512:

BEL512, known as CM512 in Greater China, is an investigational, long-acting bispecific antibody designed to inhibit thymic stromal lymphopoietin, or TSLP, and interleukin-13, or IL-13. By targeting an upstream epithelial alarmin and a central downstream effector cytokine, BEL512 is intended to provide broad and durable control of type 2 inflammation.

BEL512 is being developed for chronic inflammatory diseases characterized by epithelial-immune dysregulation, including CRSwNP, asthma, chronic obstructive pulmonary disease, and atopic dermatitis. Belenos holds development and commercialization rights to BEL512 outside Greater China.

About Belenos Biosciences

Founded in 2024, Belenos Biosciences is a clinical-stage biotechnology company developing transformative therapies with the goal to restore immune balance, improving clinical outcomes and achieving disease remission for patients with chronic inflammatory diseases. Belenos licensed all ex-China rights for BEL512 and BEL536 from Keymed Biosciences Ltd. www.belenosbio.com

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