What Sutro Biopharma does

Sutro Biopharma, Inc. (NASDAQ: STRO) is a clinical-stage biopharmaceutical company headquartered in South San Francisco, California, that develops next-generation protein therapeutics for cancer using its proprietary cell-free protein synthesis platform, XpressCF. The platform separates cell-mass production from protein production, enabling rapid parallel evaluation of thousands of protein variants in under 24 hours, efficient site-specific incorporation of non-natural amino acids, and generation of homogeneous single-species antibody-drug conjugates (ADCs) rather than heterogeneous mixtures. Sutro's wholly-owned pipeline comprises tissue factor-targeting exatecan ADC STRO-004 (Phase 1, dosed December 2025), PTK7-targeting STRO-006 (IND planned 2026), and STRO-227 (IND planned late 2026). The company is also advancing immunostimulatory dual-payload ADCs (iADCs) in collaboration with Astellas, with ASP2998 (TROP2-targeted iADC) entering clinical trials in Q2 2026.

Sutro monetizes primarily through strategic collaborations and licensing rather than direct commercialization. Core partnerships include Merck (cytokine derivatives, up to $1.6 billion in potential milestones), Celgene/BMS (BCMA ADC and bispecifics), EMD Serono (up to six ADC targets), Astellas (dual-payload iADCs), and Vaxcyte (exclusive license of XpressCF for pneumococcal conjugate vaccines VAX-31 and VAX-24). A June 2023 royalty financing with Blackstone Life Sciences provided $140 million upfront (with up to $250 million in milestones) in exchange for a 4% royalty interest in Vaxcyte's future product sales. FY2025 collaboration revenue of $102.5 million (65% growth from $62.0 million in 2024) was driven by Astellas and Ipsen milestones, with cumulative collaboration payments reaching approximately $1.016 billion through December 2025.

Following a March 2025 strategic review, Sutro deprioritized luveltamab tazevibulin (STRO-002), reduced its workforce by approximately one third in October 2025, and narrowed focus to three ADC programs. The company operates cGMP manufacturing at a San Carlos facility and benefits from a January 2025 scale-up of XpressCF to 4,500L GMP at Boehringer Ingelheim's Vienna site — the first large-scale third-party CDMO validation of cell-free protein synthesis. As of early 2026, Sutro had a market capitalization of approximately $406 million, ~97% institutional ownership, and a cash position of $141.4 million extended to Q2 2028 following a February 2026 $110 million public offering.

Name

Sutro Biopharma

Legal name

Sutro Biopharma, Inc.

Website

https://sutrobio.com

Company type

Public

Founded year

2018

Operating status

Operating

Headcount range

101–250 employees

Short description

Sutro Biopharma is a clinical-stage biopharmaceutical company developing next-generation antibody-drug conjugates for oncology using its proprietary XpressCF cell-free protein synthesis platform, monetizing through pharma collaborations while advancing a focused internal ADC pipeline.

Ownership category

akta.pro rank

Product category

Biopharmaceutical Oncology Therapeutics

NAICS

Biological Product (except Diagnostic) Manufacturing (325414), Research and Development in Biotechnology (except Nanobiotechnology) (541714), Pharmaceutical Preparation Manufacturing (325412)

SIC

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

akta.pro primary industry

Antibody-Drug Conjugates (ADCs) & Antibody Conjugates (HLAAAAAE)

akta.pro secondary industries

Bispecific & Multispecific Antibodies (HLAAAAAF), Antibody Discovery & Engineering Platforms (display tech, bispecifics, Fc engineering) (HLAAAIAB), Monoclonal Antibody Therapeutics (mAbs) (HLAAAAAA)

Keywords

• Cell-free protein synthesis
• Antibody-drug conjugates
• Oncology therapeutics development
• Biologics manufacturing platform
• Clinical-stage biopharmaceuticals

Headquarters

HQ city

South San Francisco

HQ country

United States

HQ region

North America

Offices2 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations, Supply Chain

Revenue model

1. Collaboration and Partnership Revenue: Revenue from upfront payments, research and development funding, milestone payments, and royalty payments from strategic partnerships with pharmaceutical companies including Merck, Celgene, EMD Serono, and Astellas. FY2025 revenue was $102.5 million, a 65% increase from $62.0 million in 2024, driven by collaboration milestones from Astellas and Ipsen.
2. Royalty Income from Vaxcyte: Blackstone provides $140 million upfront to Sutro in exchange for 4% royalty interest on future sales of Vaxcyte's products, including pneumococcal conjugate vaccine VAX-24. Sutro retains equity interest in Vaxcyte.
3. Equity Financing: Underwritten public offerings of common stock to institutional investors. February 2026 offering raised approximately $110 million through sale of 7,868,383 shares at $13.98 per share.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels9 records

Core offering

Sutro Biopharma develops next-generation protein therapeutics for cancer using its proprietary XpressCF and XpressCF+ cell-free protein synthesis platforms. The company creates antibody-drug conjugates (ADCs), bispecific antibodies, and cytokine-based therapeutics through site-specific incorporation of non-natural amino acids, producing homogeneous single-species conjugates. Its clinical pipeline includes STRO-004 (tissue factor ADC in Phase 1), STRO-006, and STRO-227, alongside partnered programs with Astellas (ASP2998 iADC) and Vaxcyte (pneumococcal conjugate vaccines).

Product overview

Sutro Biopharma is a clinical-stage biopharmaceutical company that has developed a proprietary integrated cell-free protein synthesis platform (XpressCF™ and XpressCF+™) to create a broad variety of optimally designed, next-generation protein therapeutics for cancer. The company's product portfolio includes wholly owned ADC programs: STRO-004 (tissue factor-targeting TOP1i ADC in Phase 1), STRO-006, and STRO-227. Sutro also licenses its XpressCF technology to partners including Vaxcyte for vaccine development and has partnered with Astellas Pharma on dual-payload immunostimulatory ADC programs including ASP2998. The company focuses on antibody-drug conjugates for solid tumors and leverages its platform for cytokine-based immuno-oncology therapeutics, ADCs, and bispecific antibodies.

Differentiator

Problem solved

Functional benefit

Products and services

• XpressCF Platform Proprietary cell-free protein synthesis technology that enables rapid, parallel production of protein structures, supports incorporation of non-natural amino acids, and accelerates drug discovery and development for antibody-drug conjugates (ADCs), bispecific antibodies, and cytokine-based therapeutics. The platform is offered to pharmaceutical partners through licensing and collaboration agreements.
• XpressCF+ Platform Enhanced cell-free protein synthesis platform incorporating one or more non-natural amino acids for site-specific conjugation, enabling homogeneous antibody-drug conjugate design and optimized therapeutic candidates. The platform is licensed to partners for use in therapeutic development.
• STRO-004 Next-generation tissue factor-targeting exatecan antibody-drug conjugate with a drug-to-antibody ratio of 8, in Phase 1 clinical trial for tissue factor-expressing solid tumors. Initial clinical data are expected mid-2026.
• STRO-006 Next-generation antibody-drug conjugate candidate targeting PTK7, with IND submission planned for 2026.
• STRO-227 Antibody-drug conjugate candidate with IND submission targeted for late 2026.
• XpressCF Cell-Free Protein Synthesis (Licensed to Vaxcyte) Cell-free protein synthesis technology licensed exclusively to Vaxcyte for use in developing pneumococcal conjugate vaccine candidates, including VAX-31 (which received FDA Breakthrough Therapy designation) and VAX-24.
• ASP2998 (Partnered with Astellas) TROP2-targeted immunostimulatory antibody-drug conjugate developed on Sutro's iADC platform, advanced into clinical trials by Astellas Pharma as a partnered program.

Quantifiable outcome

• 65% revenue growth in FY2025 to $102.5 million
• +1 more outcomes

Named customers1 record

Segments2 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Seven partnerships are on record, tiered core and minor.

• Astellas PharmacoreStrategic or Co-development Partner · 19 April 2026Strategic partnership on dual-payload immunostimulatory ADCs (iADC). Astellas has advanced ASP2998 (TROP2-targeted iADC) into clinical trials, triggering $17.5 million in combined milestone payments. Patient dosing commenced under the partnership in Q2 2026.
• VaxcytecoreTechnology or IntegrationVaxcyte licenses XpressCF cell-free protein synthesis technology exclusively from Sutro for developing pneumococcal conjugate vaccines. Vaxcyte exercises option for XtractCF manufacturing rights totaling $75 million across 2023-2024. Sutro retains equity interest and single digit royalties on net sales.
• Merck (Merck Sharp & Dohme)coreStrategic or Co-development PartnerCytokine derivatives collaboration with rights to develop up to three programs for cancer and autoimmune disorders. Merck paid $60 million upfront plus $20 million in Series E investment and $10 million in common stock at IPO. Sutro eligible for up to $1.6 billion in aggregate milestone payments plus tiered royalties.
• Celgene (Bristol-Myers Squibb)coreStrategic or Co-development PartnerCollaboration on BCMA ADC and up to four bispecific antibodies for immuno-oncology. Sutro received $95 million upfront plus additional payments. Eligible for up to $295-393 million in milestones and tiered royalties on worldwide sales.
• EMD Serono (Merck KGaA)minorStrategic or Co-development PartnerADC collaboration with rights to designate up to six cancer targets against which Sutro discovers and optimizes up to three ADC product candidates per target. EMD Serono selected all six target antigens. Sutro eligible for up to $52.5 million per product in pre-commercial payments plus tiered royalties.
• Boehringer IngelheimcoreTechnology or IntegrationCDMO partnership for GMP manufacturing of XpressCF-produced proteins. Boehringer Ingelheim scaled up the platform to 4,500L GMP manufacturing at Vienna facility in January 2025, marking first large-scale commercial validation of cell-free protein synthesis by a third-party CDMO.
• Stanford UniversitycoreTechnology or IntegrationExclusive license from Stanford for patent rights covering methods related to in vitro protein synthesis used in XpressCF Platform. Includes 15 U.S. issued patents and 44 ex-U.S. patents. Annual license maintenance fees of $75,000 plus low single digit royalties on net sales.

Scale indicators9 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• Mersana Therapeutics: Clinical-stage biopharmaceutical company developing antibody-drug conjugates for cancer, with a similar pipeline-stage profile, platform-based discovery approach, and reliance on partnership revenue. Most directly comparable in terms of size, business model, and clinical focus.
• Pyxis Oncology: Clinical-stage ADC developer with a similar focus on next-generation antibody-drug conjugates for solid tumors. Comparable in company size, clinical pipeline depth, and dependence on capital markets to fund development.
• Bolt Biotherapeutics: Clinical-stage company developing immunostimulatory ADCs (ISACs), which is conceptually adjacent to Sutro's dual-payload immunostimulatory ADC (iADC) platform. Similar size, similar platform technology focus, and similar clinical-stage profile.
• MacroGenics: Clinical-stage biopharmaceutical company developing both antibody-drug conjugates and bispecific antibodies for cancer, directly overlapping with Sutro's ADC and bispecific antibody programs. Similar platform-based discovery model and partnership-driven business model.
• Zymeworks: Clinical-stage biotech developing bispecific antibodies and ADC candidates with proprietary platforms. Similar company size, similar business model reliant on partnerships and licensing, and overlapping therapeutic focus in oncology.

Broad incumbents

• Daiichi Sankyo: Global pharmaceutical company and ADC market leader with approved products Enhertu and Datroway developed in partnership with AstraZeneca. Represents the dominant competitive threat in the ADC space and is also a potential licensor or acquirer of ADC technologies.
• AstraZeneca: Global pharmaceutical company with a major ADC franchise (Enhertu, Datroway) developed in partnership with Daiichi Sankyo. Competes in the same therapeutic areas and could be a potential partner or acquirer for next-generation ADC technologies.
• AbbVie (acquired ImmunoGen): Global pharmaceutical company that acquired ImmunoGen in 2024 to gain the Elahere ADC franchise. ImmunoGen was historically a direct peer, and AbbVie now competes in the ADC space with substantially greater resources and commercial infrastructure.
• Pfizer (acquired Seagen): Global pharmaceutical company that acquired Seagen for $43B in 2023, gaining a leading ADC portfolio (Adcetris, Padcev, Tukysa, Tivdak). Represents one of the largest commercial-stage ADC competitors with significant resources and pipeline breadth.

Emerging players

• Innovent Biologics: Chinese biopharmaceutical company with a growing ADC pipeline and existing approved biologics. Represents an emerging player in the ADC space that is developing competitive products for global markets, particularly in oncology indications overlapping with Sutro's pipeline.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

• Xx.com/sutrobio
• YouTubeyoutube.com/channel/UCvuoGtI2ZLG2M5jtwt0_F5g
• LinkedInlinkedin.com/company/1329898
• Instagramthreads.net/@sutrobio
• Facebookfacebook.com/173892899942119

Compliance1 record

Revenue estimate

Valuation estimate

Number of profiles

Profiles16 records

Funding overview

Funding rounds13 records

Investors26 records

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M&A

Investments

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

Frequently asked questions about Sutro Biopharma