SUTRO BIOPHARMA, INC.

Sutro Biopharma, Inc. (Nasdaq: STRO) is a clinical-stage oncology company developing site-specific antibody-drug conjugates, or ADCs, enabled by its proprietary integrated cell-free protein synthesis platform, XpressCF®, and site-specific conjugation platform, XpressCF+®. The company designs and develops therapeutics using novel modalities including ADCs, bispecific ADCs, immunostimulatory ADCs, or iADCs, and dual-payload ADCs, or dpADCs, directed primarily against clinically validated targets where current standard of care is suboptimal.

Sutro's lead product candidate is STRO-004, a single homogeneous ADC directed against tissue factor for treatment of solid tumors including non-small cell lung cancer, head and neck squamous cell carcinoma, cervical cancer, colorectal cancer, pancreatic ductal adenocarcinoma, endometrial cancer, and bladder cancer. The company filed an IND and received clearance for STRO-004 in October 2025, initiating a Phase 1 trial in November 2025. Additional wholly-owned preclinical assets include STRO-227, a dual-payload ADC targeting Protein Tyrosine Kinase 7, and STRO-006, an ADC targeting integrin alpha v beta 6.

The company's XpressCF® platform represents a fundamentally different approach to protein synthesis by separating cell mass production from protein production, enabling rapid production of diverse protein structures, incorporation of non-natural amino acids, faster cycle times compared to conventional methods, and scalable manufacturing from research through commercial production. The platform has garnered attention from leading pharmaceutical companies, resulting in multitarget, product-focused collaborations with Astellas Pharma Inc., Merck Sharp & Dohme Corp., Celgene Corporation, and EMD Serono. Through December 31, 2025, these collaborations have provided approximately $1.016 billion in aggregate payments, including approximately $79 million in stock investments.

Sutro's XpressCF® platform has also supported Vaxcyte, Inc., focused on discovery and development of vaccines for infectious disease treatment and prophylaxis. The company's website is www.sutrobiopharma.com.