What Accipiter Biosciences does

Accipiter Biosciences is a Seattle-based, preclinical-stage biotechnology company founded in 2023 that designs de novo multifunctional protein therapeutics for complex diseases in immunology and oncology. Its core offering is a proprietary computational protein design platform, led by CTO Javier Castellanos, that uses machine learning combined with high-throughput laboratory experimentation to engineer fully customizable proteins built from scratch rather than derived from natural sequences. The platform enables in silico design-to-lab timelines of under two months and produces multi-mechanism agonist biologics that simultaneously engage multiple cell-surface receptors on the same cell, intended as single-agent replacements for combination therapies.

The company serves global biopharmaceutical partners through a licensing and collaboration model. Strategic agreements with Pfizer (research collaboration and license agreement with potential milestones exceeding $330 million plus royalties) and Kite Pharma, a Gilead company (multitarget agreement for cell therapy molecules with an acquisition option), constitute the disclosed revenue architecture. Accipiter also operates an internal preclinical pipeline in autoimmunity (targeting regulatory T-cell modulation) and oncology (engineered candidates designed to avoid systemic toxicity), with seed funding earmarked to advance up to two programs to pre-IND stage.

Accipiter is privately held and venture-backed following a $12.7 million seed round in November 2025 co-led by Takeda and Flying Fish Partners, with participation from Columbus Venture Partners, Cercano Capital, Washington Research Foundation, Alexandria Investments, Pack Ventures, and Argonautic Ventures. The four-person executive team originates from the University of Washington Institute for Protein Design, Neoleukin Therapeutics, Seagen, Lyell Immunopharma, and WRF Capital. The company is headquartered at 1616 Eastlake Ave E, Suite 208, Seattle, Washington, and has no commercial products, no disclosed revenue, and an 11-50 employee footprint.

Name

Accipiter Biosciences

Legal name

Accipiter Biosciences, Inc.

Website

https://accipiterbio.com

Company type

Private

Founded year

2023

Operating status

Operating

Headcount range

11–50 employees

Short description

Accipiter Biosciences is a Seattle-based preclinical biotech using a proprietary computational de novo protein design platform to engineer multifunctional biologics for immunology and oncology, monetized through enterprise licensing deals with Pfizer and Kite Pharma.

Ownership category

akta.pro rank

Product category

Therapeutic Protein Design & Biologics Discovery

NAICS

Research and Development in Biotechnology (except Nanobiotechnology) (541714), Biological Product (except Diagnostic) Manufacturing (325414), Pharmaceutical and Medicine Manufacturing (3254)

SIC

Biological Products, (No Disgnostic Substances) (2836), Pharmaceutical Preparations (2834)

akta.pro primary industry

AI/ML-Enabled Biologic Discovery Platforms (computational design, in silico screening) (HLAAAIAE)

akta.pro secondary industries

Engineered Protein Therapeutics (de novo/AI-designed proteins, novel scaffolds) (HLAAAAAJ), Protein Engineering & Directed Evolution Platforms (enzyme/therapeutic protein optimization) (HLAAAIAC)

Keywords

• De novo protein design
• Computational biologics platform
• Multifunctional protein therapeutics
• Immunology oncology pipeline
• Biologics discovery partnerships

Headquarters

HQ city

Seattle

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Software

Cost components

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

Revenue model

1. Research Collaborations and License Agreements: Upfront payments, milestone payments, and royalties from research collaborations with pharmaceutical companies. Pfizer collaboration includes upfront payment plus potential milestones exceeding $330 million plus royalties. Kite Pharma agreement includes upfront payment plus milestone payments and royalties.
2. Molecule Acquisition Deals: Kite Pharma has option to acquire selected molecules for worldwide therapeutic development, generating potential revenue through acquisition payments and continued milestone/royalty arrangements.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels4 records

Core offering

Accipiter Biosciences designs and develops de novo protein therapies—entirely new proteins built from scratch—using a computational protein design platform paired with high-throughput laboratory experimentation. Its single-agent biologics are engineered to simultaneously engage multiple cell-surface receptors as agonists, replacing traditional combination therapies for complex diseases in autoimmunity and oncology. The company monetizes its discoveries through research collaborations, license agreements, milestones, and royalties with global pharmaceutical partners.

Product overview

Accipiter Biosciences offers a unified de novo biologics platform for designing and developing multifunctional protein therapeutics. The core platform uses proprietary computational methods and machine learning to create entirely new proteins from scratch that combine multiple therapeutic mechanisms in a single stable molecule. The company's pipeline includes preclinical programs in autoimmunity (targeting regulatory T-cell modulation) and oncology (focusing on precise tumor targeting with reduced systemic toxicity). The company collaborates with Pfizer (discovery and license agreement for multiple targets, potential milestones exceeding $330 million plus royalties) and Kite Pharma (multitarget agreement for cell therapy molecules) to advance its platform and expand therapeutic applications.

Differentiator

Problem solved

Functional benefit

Products and services

• De Novo Biologics Platform A computational protein design platform that creates fully customizable, multifunctional de novo proteins built from scratch for therapeutic applications. Combines machine learning with high-throughput laboratory experimentation to design proteins that engage multiple cell-surface receptors simultaneously as agonists, supporting an in silico design-to-lab timeline of under two months.
• Autoimmunity Pipeline Programs Preclinical pipeline programs focused on autoimmune diseases, using targeted agonist delivery to synergistically modulate regulatory T-cell activity as a single-agent multi-mechanism therapy.
• Oncology Pipeline Programs Preclinical pipeline programs in oncology using engineered therapeutic candidates with precise tunability to avoid systemic toxicity and improve safety profiles versus conventional approaches.

Quantifiable outcome

• Design-to-lab timeline under 2 months
• +1 more outcomes

Named customers2 records

Segments3 records

Ideal customer profiles1 record

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

AI capability2 records

Feature4 records

Partnerships

Two partnerships are on record, tiered flagship.

• PfizerflagshipStrategic or Co-development Partner · 6 November 2025Research collaboration and license agreement to discover and design biologics for multiple targets. Accipiter received an upfront payment and has the potential to earn milestones of more than $330 million and royalties. Pfizer's Chief Scientific Officer stated the platform technology has potential to unlock new classes of biologics for complex therapeutic problems.
• Kite PharmaflagshipStrategic or Co-development Partner · 6 November 2025Multitarget agreement to generate molecules against targets of interest for use in cell therapies. Kite has option to acquire selected molecules for worldwide therapeutic development. Kite made upfront payment to Accipiter, with Accipiter eligible for performance-based milestone payments and royalties. Kite is a Gilead Company.

Scale indicators4 records

Recent moves5 records

Expansion highlights5 records

Emerging players

• Absci: Public AI generative biology company combining proprietary E. coli expression with deep learning models for de novo antibody and protein design. Public-market comparable for AI biologic discovery platforms at a different scale and maturity stage.
• Cradle Biosciences: AI/ML platform for protein engineering with a focus on improving stability, activity, and developability of existing proteins. Adjacent to Accipiter's de novo design approach, with overlapping pharma partnership business model.
• BigHat Biosciences: ML-driven antibody and protein engineering platform combining high-throughput wet-lab experimentation with computational design. Comparable in stage and modality philosophy (ML-guided biologic engineering), with adjacent rather than identical product focus.

Others

• Schrödinger: Public computational chemistry and biologics platform combining physics-based modeling with ML. Tangentially comparable as a computational drug-design peer with a software-plus-partnership business model, though broader in scope (small molecules and biologics).
• Seagen: Large oncology biotech (acquired by Pfizer in 2023) where Accipiter CSO Hector Rincon previously led cancer discovery research including ADC programs. Relevant as a talent and scientific lineage reference rather than a direct competitor.

Broad incumbents

• AbCellera: Public antibody discovery platform combining high-throughput single-cell screening with AI for partner-funded biologic programs. A broad incumbent in AI-enabled biologic discovery with a similar pharma partnership GTM, though focused on antibodies rather than de novo proteins.
• Isomorphic Labs: Alphabet/DeepMind spinout applying AlphaFold-derived AI to drug discovery and protein design. Far better capitalized than Accipiter and pursues a much broader pharma-services-plus-internal-pipeline model; represents the long-term competitive ceiling in AI protein design.

Direct peers

• Generate Biomedicines: Flagship-backed generative AI platform for de novo protein therapeutics across multiple disease areas. Closest direct competitor to Accipiter — same modality class (computationally designed proteins), overlapping target space, and comparable biotech-pharma partnership model.
• Cyrus Biotechnology: Computational protein design and engineering platform co-founded by Accipiter CTO Javier Castellanos before he started Accipiter. Uses similar protein design and engineering methods with the Rosetta codebase, and is a direct technical peer.
• Neoleukin Therapeutics: Previously public de novo protein therapeutic company founded out of UW Baker lab. Accipiter's three scientific co-founders all held senior roles at Neoleukin. While Neoleukin was wound down in 2023, it is the closest historical template for Accipiter's modality and pipeline strategy.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat3 records

Key risks6 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/accipiter-biosciences

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Funding overview

Funding rounds3 records

Investors8 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 Accipiter Biosciences