Here are 1-3 brief analogies for Sutro Biopharma (STRO):

1. A platform biotech company, similar to Moderna or Alnylam for their respective technologies, but focused on precisely engineering complex protein therapeutics like advanced Antibody-Drug Conjugates (ADCs).

2. Imagine TSMC (the chip manufacturer) for advanced biologic drugs, specializing in building next-generation Antibody-Drug Conjugates (ADCs) with high precision.

3. Like a next-generation Seagen (a leader in Antibody-Drug Conjugates, now part of Pfizer), but with a proprietary engineering platform to build more precise and effective ADCs.

• STRO-002: An antibody-drug conjugate (ADC) designed to target Folate Receptor-alpha (FRα) positive solid tumors, primarily in ovarian and endometrial cancers.
• STRO-003: An antibody-drug conjugate (ADC) targeting CD74 for the treatment of multiple myeloma and non-Hodgkin lymphoma.
• SP2579: A BCMA and CD47 bispecific antibody being developed in partnership with Bristol Myers Squibb for the treatment of multiple myeloma.
• XpressCF+™ Platform: A proprietary cell-free protein synthesis platform enabling the rapid and precise design and discovery of novel protein-based therapeutics.

Sutro Biopharma (STRO) is a biotechnology company focused on the discovery and development of novel cancer therapeutics using its proprietary cell-free protein synthesis platform. As such, the company's business model primarily involves strategic collaborations, licensing agreements, and research and development partnerships with other pharmaceutical and biotechnology companies rather than selling directly to individuals.

Therefore, Sutro Biopharma primarily sells to other companies. Its major customers, in the form of collaboration partners who contribute to its revenue through upfront payments, milestone payments, and potential royalties, include:

• Bristol Myers Squibb (Symbol: BMY)
• Merck KGaA (Symbol: MKGAF - OTC; Note: This is a German company, distinct from U.S.-based Merck & Co., Inc.)
• Vaxcyte, Inc. (Symbol: PCVX)
• ONO Pharmaceutical Co., Ltd. (No U.S. public symbol; JPX: 4528)

Jane Chung, R.Ph. Chief Executive Officer

Jane Chung has over 20 years of pharmaceutical and biotechnology experience. She became Chief Executive Officer of Sutro Biopharma in March 2025, after serving as President and Chief Operating Officer from 2023 to 2025 and Chief Commercial Officer from 2021 to 2023. Prior to Sutro, Ms. Chung held leadership roles at AstraZeneca, including President and General Manager of AstraZeneca Canada, Vice President of Sales and Marketing of U.S. Immuno-Oncology, and Senior Commercial Business Director. She also served as a Regional Sales Director and Director of Sales Productivity and Effectiveness for Onyx Pharmaceuticals Inc., and in various commercial roles for Genentech, Inc.

Greg Chow, M.B.A. Chief Financial Officer

Greg Chow was appointed Chief Financial Officer of Sutro Biopharma, effective June 2, 2025. He brings over 25 years of executive leadership experience spanning corporate finance, capital markets, investment banking, financial accounting, and drug development operations. Mr. Chow previously served as Executive Vice President and CFO at Aptose Biosciences, where he oversaw the company's dual listing on Nasdaq and the Toronto Stock Exchange and raised over $225 million in capital. His experience also includes roles as Chief Financial and Business Officer at NodThera, and CFO at Freenome Holdings and Frontier Medicines, where he contributed to major financing rounds and collaborations.

William J. Newell Senior Business Advisor

William J. Newell joined Sutro Biopharma as CEO in January 2009 and served in that role until March 2025, and is now a Senior Business Advisor. He has over 20 years of senior management experience in the biotechnology industry. Previously, he was President of Aerovance, Inc., a venture-backed company, and served as Chief Business Officer and Senior Vice President at publicly-traded QLT, Inc. He also held several senior management positions at Axys Pharmaceuticals, Inc., which was acquired by Celera Genomics. Sutro Biopharma was initially financed by private investors, including venture capitalists.

David Pauling, J.D., M.A. Chief Administrative Officer and General Counsel

David Pauling serves as the Chief Administrative Officer and General Counsel for Sutro Biopharma.

Hans-Peter Gerber, Ph.D. Chief Scientific Officer

Hans-Peter Gerber is the Chief Scientific Officer at Sutro Biopharma.

1. Clinical Development and Regulatory Risk: Sutro Biopharma's business is highly dependent on the successful development and regulatory approval of its product candidates, which are primarily in early stages. There is a significant risk that preclinical data may not translate to successful human clinical trials, or that trials may experience failures or delays. The process for obtaining regulatory approval for clinical trials and commercialization is complex, time-consuming, and subject to setbacks that could negatively impact Sutro's timelines and potential for commercialization. The discontinuation of its previous lead program, Luvelta, and the subsequent shift to earlier-stage candidates like STRO-004, underscore this inherent risk in drug development.
2. Funding Requirements and Financial Viability: Advancing multiple preclinical candidates through clinical development demands substantial financial resources. Although Sutro Biopharma has reported a strong cash position, there is a risk that if clinical trials take longer or are more expensive than anticipated, the company may require additional funding. Failure to secure sufficient funding on reasonable terms could force Sutro to delay, limit, or terminate its product development programs, which could dilute existing shareholders. The recent restructuring efforts and workforce reduction, while intended to extend the cash runway, also highlight the financial pressures and the need for prudent resource management.
3. Intense Competition: The antibody-drug conjugate (ADC) market, in which Sutro Biopharma operates, is highly competitive. The company faces competition from established pharmaceutical companies and other biotechnology firms that are developing similar or alternative treatments. To succeed, Sutro must demonstrate clear differentiation and superiority of its product candidates to compete effectively against these numerous existing and emerging players.

The successful and expanding market penetration of ImmunoGen's Elahere (mirvetuximab soravtansine), an FRα-targeted antibody-drug conjugate (ADC) for platinum-resistant ovarian cancer, poses a clear emerging threat. Elahere received full FDA approval in March 2024 and is actively establishing itself as a standard of care in the same patient population that Sutro Biopharma's lead investigational asset, luveltamab tazemetat (luvelta), aims to address. The growing entrenchment and potential label expansion of Elahere could significantly limit luvelta's future market opportunity, pricing power, and ability to differentiate upon potential launch, setting a high competitive bar before luvelta completes its clinical development.

Sutro Biopharma (STRO) is focused on developing precisely designed cancer therapeutics, primarily through its antibody-drug conjugate (ADC) pipeline. The addressable markets for their main products or services are:

• Luveltamab Tazevibulin (STRO-002): Although Sutro Biopharma has deprioritized further investment into luveltamab, they are exploring out-licensing opportunities for its use in platinum-resistant ovarian cancer.
  • The global ovarian cancer drugs market was estimated at approximately USD 3.84 billion in 2024 and is projected to reach around USD 7.34 billion by 2034, growing at a CAGR of 6.7% from 2025 to 2034. The United States alone accounted for the highest market size for platinum-resistant ovarian cancer treatment in 2024 within the leading markets (US, EU4, UK, Japan).
• STRO-004: This is Sutro's novel exatecan Tissue Factor ADC, prioritized as the company's lead program with an initial focus on solid tumors. Tissue Factor is expressed in various solid tumors, including cervical, lung, and breast cancer.
  • The global lung cancer therapeutics market size was estimated at USD 35.1 billion in 2024 and is expected to grow to USD 95.1 billion by 2034. Another estimate places the global lung cancer therapeutics market at USD 41.8 billion in 2025, projected to reach USD 126.5 billion by 2035.
  • The global breast cancer therapeutics market size was estimated at USD 26.23 billion in 2025 and is predicted to increase to approximately USD 38.54 billion by 2034. Another report indicates the breast cancer market size was USD 38.89 billion in 2024, poised to grow to USD 86 billion by 2032.
  • The global cervical cancer treatment market size was estimated at USD 8.16 billion in 2023 and is projected to reach USD 11.74 billion by 2030.
• STRO-006: This differentiated integrin beta-6 ADC is expected to enter clinical development in 2026, aimed at multiple solid tumors. Integrin beta-6 is upregulated in several tumors.
  • The global solid tumor therapeutics market size stood at USD 207.29 billion in 2025 and is forecast to advance to USD 307.41 billion by 2030, reflecting an 8.21% CAGR.
• Dual-Payload Program: Sutro anticipates filing an Investigational New Drug (IND) application for its first wholly-owned dual-payload ADC in 2027. Due to its early preclinical stage, specific addressable market sizing is not yet available for this program beyond the general solid tumor therapeutics market.
  • The global solid tumor therapeutics market size stood at USD 207.29 billion in 2025 and is forecast to advance to USD 307.41 billion by 2030, reflecting an 8.21% CAGR.

Expected Drivers of Future Revenue Growth for Sutro Biopharma (STRO)

• Advancement of Wholly-Owned Next-Generation ADC Pipeline: Sutro Biopharma has strategically prioritized its wholly-owned next-generation Antibody-Drug Conjugate (ADC) programs: STRO-004, STRO-006, and a dual-payload ADC. The company plans to submit three Investigational New Drug (IND) applications over the next three years, starting with STRO-004 in the second half of 2025, STRO-006 in 2026, and a dual-payload ADC in 2027. Successful progression through clinical development and potential regulatory approvals for these candidates are expected to be significant revenue drivers.
• Milestone and Collaboration Payments from Partnerships: Sutro continues to generate revenue from existing collaborations, such as with Astellas, through milestone payments and other agreement payments. The company actively seeks to maximize the value of its proprietary cell-free platform by working with partners across various disease areas and geographies.
• Out-licensing of Luveltamab Tazevibulin (Luvelta): Despite deprioritizing further internal investment into luveltamab tazevibulin (luvelta) development, Sutro is actively exploring global out-licensing opportunities for this program. Securing a partnership for luvelta is intended to provide financial resources and expertise for its multi-indication development and commercialization, which could lead to significant collaboration and license revenue.
• Potential Commercialization of Prioritized ADC Programs: The ultimate driver of substantial future revenue growth for Sutro Biopharma lies in the successful clinical development and eventual market commercialization of its prioritized next-generation ADCs, particularly STRO-004. STRO-004, a Tissue Factor ADC, received IND clearance ahead of projections and is on track to enter the clinic in 2025, with initial clinical data expected in 2026.

Share Issuance

• In December 2020, Sutro Biopharma closed an upsized public offering of 6,900,000 shares of its common stock at a price of $21.00 per share, generating gross proceeds of $144.9 million.
• In April 2024, the company announced the pricing of an underwritten offering of 14,478,764 shares of its common stock at $5.18 per share, with expected gross proceeds of approximately $75.0 million.
• As part of a licensing agreement with Ipsen, Sutro Biopharma received $75 million in upfront payments in April 2024, which included an equity investment by Ipsen USA of $25 million for 4,827,373 shares of common stock.

Inbound Investments

• In June 2023, Sutro Biopharma entered into a royalty financing collaboration with Blackstone Life Sciences, receiving $140 million upfront cash in exchange for its 4% royalty interest in potential future sales of Vaxcyte's products. This agreement also includes up to an additional $250 million in future milestone payments.
• In June 2022, Sutro Biopharma announced a strategic partnership and licensing agreement with Astellas Pharma for immunostimulatory antibody-drug conjugates (iADCs), which included an upfront payment of $90 million and eligibility for up to $422.5 million in development, regulatory, and commercial milestone payments per product candidate.
• In April 2024, Sutro Biopharma secured a global licensing agreement for STRO-003 with Ipsen, making the company eligible for up to $899 million in upfront and potential milestone payments, of which $75 million (including an equity investment) was received in April 2024.

Capital Expenditures

• Sutro Biopharma's Capex to Revenue was reported as 3.0% for the last 12 months as of October 2025.
• In March 2025, Sutro Biopharma announced a strategic decision to exit its internal GMP manufacturing facility by year-end 2025, transitioning to an external manufacturing strategy.
• The company's restructuring efforts in 2025, which include the decommissioning of its manufacturing facility, are estimated to incur costs between $40 million and $45 million.