Belenos Bio’s Six-Month Shot Aims to Reshape Chronic Sinusitis Treatment

SARASOTA, FL – August 11, 2026 – In a significant development for the millions who suffer from chronic inflammatory conditions, biotech newcomer Belenos Biosciences has unveiled promising results that could redefine treatment for a debilitating respiratory disease. The company announced that its investigational drug, BEL512, met all primary and secondary goals in a Phase 2 trial for Chronic Rhinosinusitis with Nasal Polyps (CRSwNP), a severe condition that obstructs breathing and robs patients of their sense of smell.

The findings, which demonstrate not only rapid and significant symptom improvement but also a remarkable durability of effect, position BEL512 as a potential best-in-class therapy. More than just another incremental advance, the drug’s unique dual-action mechanism and potential for a six-month dosing schedule represent a strategic convergence of scientific innovation and patient-centric design, signaling a potential paradigm shift in the management of chronic inflammation.

A New Horizon for Chronic Sinus Sufferers

For individuals living with CRSwNP, daily life is a constant struggle against nasal congestion, facial pressure, and the profound loss of smell and taste. The condition, characterized by the growth of non-cancerous polyps in the nasal passages, affects up to 20% of the 13% of the Western population suffering from chronic rhinosinusitis. Current treatments, including corticosteroids, surgery, and existing biologics, often provide incomplete or temporary relief, leaving a significant unmet need.

The Phase 2 study, conducted in China by Belenos's partner Keymed Biosciences, provides a beacon of hope. The trial enrolled 120 patients with moderate-to-severe disease who were inadequately controlled by standard care. The results were compelling: patients receiving BEL512 showed statistically significant improvements across a battery of endpoints compared to placebo. The primary measure, a reduction in the Nasal Polyp Score (NPS), was met, indicating a physical reduction in the size of the blockages. Critically, improvements began as early as four weeks and were sustained throughout the 24-week treatment period and a subsequent 12-week follow-up.

Beyond the primary goal, the study demonstrated marked improvements in the metrics that matter most to patients. Scores for nasal congestion (NCS), loss of smell (LoS), and the comprehensive Total Symptom Score (TSS) all improved significantly. Furthermore, objective measures like the Sinus CT Lund-Mackay (LMK) score confirmed a reduction in sinus inflammation, while the Sinonasal Outcome Test-22 (SNOT-22), a key quality-of-life questionnaire, showed patients felt substantially better. The drug was also well-tolerated, with an adverse event profile similar to placebo and minimal development of anti-drug antibodies, a crucial factor for long-term therapy.

“Patients with CRSwNP experience a significant and profound impact on their quality of life, struggling to breathe through their nose, smell, and sleep normally,” noted Dr. Stella Lee, M.D., Associate Professor of Otolaryngology–Head and Neck Surgery at Harvard Medical School, who was not involved in the study. “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.”

The Science of Dual Inhibition: A Strategic Bet on Broader Control

What sets BEL512 apart from the current generation of biologics is its innovative design as a bispecific antibody. It is engineered to simultaneously inhibit two key drivers of Type 2 inflammation: thymic stromal lymphopoietin (TSLP) and interleukin-13 (IL-13). This dual-targeting strategy represents a sophisticated evolution in immunology.

TSLP is considered an “upstream” alarmin—an initial trigger released by epithelial cells in response to damage or allergens. It orchestrates a broad inflammatory cascade. IL-13, conversely, is a “downstream” effector cytokine that directly causes many of the disease's hallmarks, including mucus production and tissue inflammation. While existing blockbuster drugs like Dupixent target the IL-13 pathway, and others are emerging to target TSLP, BEL512 is designed to block both simultaneously. The strategic rationale is that by cutting the inflammatory signal at both its root and its most active branches, the therapy can achieve a more profound, comprehensive, and durable suppression of the disease.

“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. He emphasized the drug's potential to be a “best-in-class therapy across multiple respiratory and inflammatory diseases,” signaling the company's broader ambitions for the platform, which includes asthma, atopic dermatitis, and COPD.

A Global Strategy Forged in China

The story of BEL512 is also a case study in modern global biotech strategy. Belenos, founded in 2024, licensed the ex-China rights for the molecule from its developer, Keymed Biosciences. Keymed conducted the successful Phase 2 trial in China, where the drug is known as CM512. This cross-border partnership allowed for efficient and high-quality clinical execution, culminating in a major regulatory win.

Based on the strength of the Phase 2 data, China’s National Medical Products Administration (NMPA) granted CM512 a Breakthrough Therapy designation. This designation is reserved for drugs showing significant advantages over existing options and is designed to accelerate the development and review process. It provides Keymed a clear and expedited path to market in one of the world's largest pharmaceutical markets and serves as a powerful external validation of the drug's potential.

For Belenos, this de-risks its own development pathway significantly. The positive data and regulatory endorsement provide a robust foundation as it prepares for a global Phase 3 study, planned for the first half of 2027. The chosen Phase 3 dose regimen—300 mg administered just once every 24 weeks—highlights the drug's most powerful market differentiator: convenience. A twice-yearly injection would represent a monumental leap in treatment adherence and quality of life compared to the more frequent injections required by current therapies.

With Keymed preparing to launch its own Phase 3 trial in China and Belenos planning its global counterpart, the stage is set for BEL512 to challenge the established leaders in the multi-billion-dollar market for inflammatory diseases. The successful partnership demonstrates a nimble and capital-efficient model for bringing cutting-edge Chinese innovation to the global stage, a trend that is reshaping the landscape of drug development.