What Diagonal Therapeutics does

Diagonal Therapeutics is a clinical-stage biotechnology company developing first-in-class clustering antibody therapeutics that address the root cause of genetic diseases caused by impaired receptor signaling. Founded in 2022 and headquartered in Watertown, Massachusetts, the company emerged from stealth in April 2024 with a $128 million Series A financing. Diagonal targets rare diseases — primarily hereditary hemorrhagic telangiectasia (HHT) and pulmonary arterial hypertension (PAH) — for which no disease-modifying therapies currently exist. Its lead asset, DIAG723, is a bispecific clustering antibody in IND-enabling studies that restores ALK1:BMPRII signaling on endothelial cells, with first-in-human trials planned for the first half of 2026.

The company's core innovation is the DIAGONAL Product Engine, a proprietary platform that combines computational and experimental techniques to discover agonist antibodies capable of binding two or more receptors and bringing them together in specific conformations to activate or inhibit downstream signaling. The platform generates immune repertoires of approximately 200,000 distinct antibody sequences per target, computationally evaluates over 10 billion possible multi-specific antibody combinations, and uses shape clustering and binning by complementarity to identify therapeutic candidates. Preclinical data demonstrated that DIAG723 improved survival from 25% to 100% in HHT mouse models and outperformed sildenafil on key hemodynamic parameters in PAH rat models. Beyond DIAG723, the pipeline includes undisclosed preclinical programs in venous malformations, iron overload, and chronic kidney disease.

Diagonal is pre-revenue and operates a clinical-stage biotech business model with no commercial products. Future revenue is expected from sales of proprietary drug products following regulatory approval, initially through specialty pharmacy and hospital channels typical of orphan/rare disease therapeutics. The company has raised over $253 million across two financing rounds from a syndicate that includes Atlas Venture, BVF Partners, Sanofi Ventures, Janus Henderson Investors, RA Capital Management, Frazier Life Sciences, and Viking Global Investors. Strategic partnerships include the HHT IMPACT natural history study with Cure HHT and research collaborations with Massachusetts General Hospital/Harvard Medical School and the Feinstein Institutes for Medical Research. The company has received Orphan Drug Designation from both the U.S. FDA and the EMA for DIAG723 in HHT.

Name

Diagonal Therapeutics

Legal name

Diagonal Therapeutics, Inc.

Website

https://diagonaltx.com

Company type

Private

Founded year

2024

Operating status

Operating

Headcount range

11–50 employees

Short description

Diagonal Therapeutics is a clinical-stage biotechnology company developing first-in-class clustering antibody therapeutics to treat rare genetic diseases including hereditary hemorrhagic telangiectasia and pulmonary arterial hypertension, using its proprietary DIAGONAL Product Engine platform.

Ownership category

akta.pro rank

Product category

Biotechnology Therapeutics — Rare Genetic Disease Antibodies

NAICS

Research and Development in the Physical, Engineering, and Life Sciences (54171)

akta.pro primary industry

Bispecific & Multispecific Antibodies (HLAAAAAF)

akta.pro secondary industries

Antibody Discovery & Engineering Platforms (display tech, bispecifics, Fc engineering) (HLAAAIAB), Target Identification & Validation Platforms (omics-driven, chemoproteomics, genetic validation) (HLAAAIAI)

Keywords

• Clustering antibody therapeutics
• Rare disease drug discovery
• Agonist antibody platform
• Bispecific antibody engineering
• Orphan genetic disease therapy

Headquarters

HQ city

Watertown

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Technology or R&D, Personnel, Operations, Marketing or Sales, Others

Revenue model

1. Pharmaceutical Product Revenue: Diagonal Therapeutics is a pre-revenue clinical-stage biotechnology company developing clustering antibody therapeutics. The company does not yet have approved products or commercial revenue. Revenue is expected to be generated through sales of proprietary drug products following regulatory approval for the treatment of rare diseases such as HHT and PAH.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels5 records

Core offering

Diagonal Therapeutics is a clinical-stage biotechnology company developing clustering (agonist) antibody therapeutics for rare genetic diseases caused by impaired receptor signaling. Its lead candidate DIAG723 is a bispecific clustering antibody designed to restore ALK1:BMPRII signaling for treatment of hereditary hemorrhagic telangiectasia (HHT) and pulmonary arterial hypertension (PAH). Drug discovery is enabled by the proprietary DIAGONAL Product Engine, which combines computational and experimental techniques to identify clustering antibodies from billions of possible receptor-binding combinations.

Product overview

Diagonal Therapeutics is a biotechnology company pioneering a new approach to discovering and developing clustering agonist antibodies that address the root cause of genetic diseases. The company's core offering centers on its proprietary DIAGONAL Product Engine, which combines computational and experimental techniques to identify clustering antibodies that regulate signaling cascades by binding multiple receptors in specific conformations. The lead product is DIAG723, a first-in-class bispecific clustering antibody in IND-enabling stage for hereditary hemorrhagic telangiectasia (HHT) and pulmonary arterial hypertension (PAH). The pipeline spans multiple therapeutic areas including vasculopathy (HHT, PAH, venous malformations), hepatology (iron overload), and nephrology (chronic kidney disease), with programs at preclinical and IND-enabling stages.

Differentiator

Problem solved

Functional benefit

Products and services

• DIAG723 First-in-class bispecific clustering antibody designed to restore ALK1 signaling by clustering ALK1 and BMPRII receptors on endothelial cells; in IND-enabling studies for treatment of HHT and PAH.
• Undisclosed Venous Malformations Program Preclinical clustering antibody program targeting vascular malformations within the vasculopathy therapeutic area.
• Undisclosed Iron Overload Program Preclinical clustering antibody program in hepatology addressing iron overload conditions caused by impaired receptor signaling.
• Undisclosed Chronic Kidney Disease Program Preclinical clustering antibody program in nephrology addressing chronic kidney disease caused by impaired receptor signaling.

Quantifiable outcome

• In preclinical HHT models (BMP9/10-deficient mice, ENG-deficient mice, haploinsufficient ALK1 mice), DIAG723 prevented and reversed AVM pathology, prevented HHT-associated anemia and heart enlargement, and improved survival from 25% to 100%.
• +3 more outcomes

Segments3 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

AI capability1 record

Feature1 record

Partnerships

Three partnerships are on record, tiered core and supporting.

• Cure HHTcoreStrategic or Co-development Partner · 4 March 2025Diagonal Therapeutics partnered with Cure HHT, the leading international patient advocacy organization for hereditary hemorrhagic telangiectasia, to launch the HHT IMPACT natural history study — a non-interventional, observational, longitudinal evaluation characterizing patient-reported outcomes including epistaxis, hematologic support, and quality of life in adults with HHT. The study enrolled 109 patients and will inform the design of future clinical trials for DIAG723. Cure HHT also hosted Diagonal at its 15th International Scientific Conference in 2024.
• Massachusetts General Hospital / Harvard Medical SchoolcoreStrategic or Co-development PartnerDiagonal collaborated with Dr. Hanny Al-Samkari (Peggy S. Blitz Endowed Chair in Hematology/Oncology at MGH and Associate Professor of Medicine at Harvard Medical School) on health economics and outcomes research characterizing the cost and clinical burden of HHT patients. The study was published in the American Journal of Hematology and leveraged Komodo Health's Healthcare Map claims database covering 330+ million patients.
• Feinstein Institutes for Medical ResearchsupportingStrategic or Co-development PartnerDiagonal collaborated with Philippe Marambaud, Ph.D. (Professor, Institute of Molecular Medicine, Feinstein Institutes for Medical Research) on preclinical research demonstrating the disease-modifying potential of DIAG723's clustering antibody approach in HHT models. Dr. Marambaud presented invited talks at EHA 2025 and Cure HHT's 15th International Scientific Conference.

Scale indicators4 records

Recent moves6 records

Expansion highlights6 records

Direct peers

• Apogee Therapeutics: Clinical-stage biotech developing novel bispecific/multispecific antibodies for atopic dermatitis, asthma, and other inflammatory/rare diseases — directly comparable antibody platform and rare/specialty-disease GTM to Diagonal's lead program focus.
• Scholar Rock: Late-clinical biotech developing monoclonal antibodies for rare neuromuscular diseases (e.g., spinal muscular atrophy), with an antibody platform approach to validated signaling pathways — closely comparable as a rare-disease antibody platform company.
• Compass Therapeutics: Clinical-stage biotech developing bispecific antibodies against novel targets in oncology — directly comparable in its use of bispecific/multispecific antibody engineering to address diseases caused by aberrant receptor signaling.
• Janux Therapeutics: Clinical-stage biotech developing bispecific T cell engagers (TRACTr platform) for cancer, recently acquired by Merck — closely comparable as a bispecific antibody platform biotech with high-multiple pharma acquirer interest.

Broad incumbents

• Genmab: Large established biotech whose proprietary DuoBody and HexaBody platforms are industry-standard bispecific/multispecific antibody technologies; comparable platform-level R&D but as a much larger, established player with approved products.
• Zymeworks: Established clinical-stage biotech commercializing its Azymetric and EffiFunction bispecific/multispecific antibody platforms — directly comparable antibody engineering platform with broader pipeline scope and partnerships across multiple pharma.
• Roivant Sciences: Large, multi-asset biotech platform operator with several subsidiaries (including antibody-focused ones) targeting rare and specialty diseases — comparable platform-company model and rare-disease commercial orientation, but much larger and more diversified.

Emerging players

• Cullinan Oncology: Clinical-stage biotech developing targeted therapeutics for cancer with a focused, asset-centric model — comparable in stage and strategic approach for advancing precision therapeutics in high-unmet-need indications.
• Adagene: Clinical-stage biotech whose PowerCision and NEObody platforms use computational methods to engineer antibodies for oncology — adjacent platform comparison given Diagonal's also-computational approach to multi-specific antibody discovery.

Others

• Krystal Biotech: Commercial-stage biotech with a genetic-disease focus and first-to-market orphan product (Vyjuvek for DEB) — comparable in size and rare-disease commercial focus but uses gene therapy rather than antibody modality.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/diagonal-therapeutics

Compliance2 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles9 records

Funding overview

Funding rounds2 records

Investors17 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Diagonal Therapeutics