Belenos Biosciences is a clinical-stage biotech developing immunotherapies for chronic inflammatory diseases, including asthma, chronic obstructive pulmonary disease, and atopic dermatitis. Founded in 2024, the company concentrates on disease areas where existing biologic therapies often deliver limited or short-lived benefit, particularly among patients with ongoing immune dysregulation.
Within the broader immunology landscape, Belenos is advancing its programs as the bispecific antibody sector undergoes rapid expansion, with industry projections estimating U.S. spending to reach approximately $12 billion by 2025 and exceed $50 billion by 2032. Within this expanding landscape, Belenos is building a pipeline of long-acting bispecific antibodies designed to engage multiple validated inflammatory pathways, with lead programs positioned as “pipeline-in-a-product” candidates capable of supporting development across multiple indications through coordinated dual-pathway inhibition.
Strategic partnerships and licensing structure
Belenos Biosciences was founded by OrbiMed, the company’s lead investor. The New York–based startup was created to develop two bispecific antibodies licensed from Keymed Biosciences, with exclusive rights to CM512 and CM536 outside Greater China. The licensing agreement included a $15 million upfront payment, up to $170 million in milestone payments, and a 30% equity stake for Keymed subsidiary iBridge HK Holdings, alongside a planned $50 million equity financing linked to the transaction.
OrbiMed appointed venture partner Donnie McGrath, as CEO of Belenos. McGrath previously led corporate strategy and business development at Biohaven and later served as CEO of its Shanghai-based spinout, BioShin. His appointment aligns with OrbiMed’s established model of building U.S.-based development companies around China-originated clinical assets.
Under the collaboration framework, Keymed continues to lead clinical development activities for both programs in China, while Belenos is responsible for development, manufacturing, and commercialization outside the region. This structure supports a parallel global development strategy, with clinical studies conducted across multiple geographies to generate data from distinct patient populations and regulatory environments, enabling coordinated advancement toward international regulatory submissions.
Long-acting bispecific antibodies
Belenos’ core technology platform is built around long-acting bispecific antibodies. These are antibodies designed to target two disease-related targets at the same time using a single drug. This dual-pathway approach addresses multiple drivers of disease at once, rather than focusing on just one. This approach is intended to provide broader and more effective control of inflammation than traditional therapies that act on only a single target.
In addition, the antibodies are also engineered with half-life extension, which means it lasts longer in the body, allowing for less frequent dosing. Patients may need fewer injections while still receiving consistent treatment over time. Overall, the goal is to deliver more durable disease control with treatments that are easier for patients to stay on, rather than therapies that offer only short-term symptom suppression.
Lead asset spotlight: BEL512, a dual-pathway biologic for durable type 2 inflammation control
Achieving durable disease control in type 2 inflammatory disorders while limiting treatment burden remains a key challenge, as many existing biologics target a single pathway and require frequent dosing. This has created an unmet need for therapies capable of delivering broader and more sustained inflammatory control with improved patient convenience.
BEL512 (CM512) is designed to address these limitations by combining dual-pathway inhibition within a single therapy. The drug targets thymic stromal lymphopoietin (TSLP), which plays an upstream role in initiating inflammatory responses, and interleukin-13 (IL-13), a downstream mediator involved in airway and tissue inflammation. By acting on both pathways simultaneously, the long-acting bispecific antibody is intended to provide broader inflammatory control than single-target biologics. Early clinical findings suggest that co-inhibition of TSLP and IL-13 may offer advantages over therapies that block either pathway alone.
The program is being developed as a “pipeline-in-a-product,” with potential application across multiple indications, including asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), chronic obstructive pulmonary disease, and atopic dermatitis. Data reported to date indicate rapid and sustained improvements across several efficacy measures, accompanied by broad suppression of inflammatory biomarkers and a favorable safety profile. The drug’s pharmacokinetic characteristics support extended dosing intervals, suggesting the potential to lessen treatment burden while maintaining longer-term disease control.
U.S. Pat. App. Pub. No. 2023/0029835, titled “Development and application of therapeutic agents for tslp-related diseases,” supports BEL512, was filed on November 13, 2020, and was published on February 2, 2023. The application is assigned to Keymed Biosciences and the listed inventors are Jingkun Wang, Gang Xu, and Bo Chen.
Second asset: BEL536 combining immune modulation and anti-inflammatory control
A continuing challenge in the treatment of chronic inflammatory and immune-mediated disorders is balancing rapid symptom relief with durable disease control. Many existing biologics primarily target downstream inflammatory mediators and often require frequent dosing, which can leave upstream immune signaling and costimulatory pathways insufficiently addressed. This dynamic has limited the durability of responses in a range of chronic conditions.
BEL536 is designed to address these gaps as an extension of Belenos’ long-acting bispecific antibody platform. The program is positioned as a first-in-class therapy that simultaneously targets OX40 ligand (OX40L), a key regulator of T-cell activation and immune persistence, and interleukin-13 (IL-13), a central mediator of type 2 inflammation. By combining immune modulation with direct anti-inflammatory activity, the approach is intended to provide both rapid symptom control and more sustained suppression of disease-driving immune processes.
Like BEL512, BEL536 is being developed with the aim of applicability across multiple indications. The program is moving toward early clinical evaluation, with current work focused on assessing safety, pharmacokinetics, and biological activity. BEL536 illustrates the company’s effort to extend its bispecific approach to additional immune pathways beyond its lead program.
WO2025256597, titled “Antibodies targeting ox40l and il-13 and uses thereof”, supports BEL536, was filed on June 12, 2025, and published on December 18, 2025 to Keymed Biosciences. The listed inventors are Bo Chen, Changyu Wang, Gang Xu, and Xinyu Yan.
Clinical and competitive significance
The clinical data reported for BEL512 represent the first publicly disclosed results of a bispecific antibody evaluated in patients with moderate-to-severe atopic dermatitis, marking a significant development in the immunology field. In a Phase 1b study conducted in China and sponsored by Keymed Biosciences, three subcutaneous doses administered over the course of one month were associated with rapid and sustained clinical responses that extended well beyond the final dose.
Patients treated with BEL512 achieved EASI-75 as early as six weeks, with responses maintained through week 24, roughly 20 weeks after the last administration. The study also reported consistent reductions in key inflammatory biomarkers, including TARC, IgE, IL-13, TSLP, and eotaxin-3, alongside a favorable safety profile. Pharmacokinetic data indicated a long half-life, supporting dosing intervals of up to 70 days. The trial is the first to report clinical activity of a bispecific agent in this patient population.
Taken together, the results provide early clinical support for dual-pathway inhibition in type 2 inflammatory disease and distinguish BEL512 from existing monospecific biologics, which often require more frequent dosing and show variable durability of response.
Looking forward
Belenos expects several announcements of findings (clinical readouts) in 2026, including U.S. proof-of-concept data for BEL512 in patients with mild-to-moderate asthma. Phase 2 results from partner-run studies in China across asthma, chronic obstructive pulmonary disease, chronic rhinosinusitis with nasal polyps, chronic spontaneous urticaria, and atopic dermatitis are also expected within the year.
In parallel, the company plans to initiate a Phase 1 study of BEL536 in early 2026, following regulatory filings in Australia. These milestones are expected to inform dose selection, indication prioritization, and decisions around progression toward later-stage development.
Looking beyond 2026, Belenos has indicated that the accumulation of clinical data across multiple indications could support a transition toward pivotal development programs beginning in 2027, while continuing to assess opportunities to expand its bispecific platform into additional inflammatory and immune-mediated diseases.
