Sutro Biopharma, Inc. (NASDAQ: STRO), a clinical-stage oncology company pioneering the development of site-specific and novel-format antibody-drug conjugates (ADCs), today highlighted its proprietary cell-free platform during an investor webcast. This platform is central to the design and development of next-generation ADCs, intended to expand addressable patient populations across various tumour types. Sutro's pipeline includes several promising preclinical programmes with the potential to deliver transformative therapies in oncology.

The webcast provided an overview of Sutro’s strategic approach, which focuses on enhancing the therapeutic index of ADCs through precise design enabled by its proprietary platform. The Company is on track to file three Investigational New Drug (IND) applications over the next three years, demonstrating its potential to deliver best-in-class therapies.

Key Preclinical Advances
Sutro highlighted data from its preclinical ADC programmes, including STRO-004, a tissue factor-targeting ADC. In preclinical models, STRO-004 has shown superior anti-tumour activity and reduced toxicity compared to a benchmark ADC targeting the same tissue factor. Additionally, Sutro’s dual-payload ADCs (ADC2) and immunostimulatory ADCs (iADCs) have demonstrated potent anti-tumour activity, offering further potential for precision oncology treatments.

Statements from Sutro Leadership
“The precision afforded by our cell-free platform allows us to create ADCs with features not currently achievable using conventional cell-bound methods,” said Hans-Peter Gerber, Ph.D., Chief Scientific Officer at Sutro. “Our platform enables us to safely increase potency and combine different payloads to address key challenges, such as tumour resistance. Today, we are excited to share data that underscores the potential of our platform and the future impact we can have on cancer treatment.”

Presentations from Industry Experts
The webcast featured Sutro’s senior management and Peter Sandor, M.D., Executive Vice President and Head of Corporate Strategy at Astellas Pharma, who previously led the Sutro-Astellas strategic collaboration to advance iADC development. Sutro’s leadership and experts participated in a Q&A session, addressing investors' questions on their next-generation ADCs and future milestones.

Next-Generation ADC Innovations
Sutro’s platform allows for the development of ADCs that can be optimised both inside and outside the tumour:

• Reduced Toxicities: Sutro’s ADCs aim to minimise platform-related toxicities, such as interstitial lung disease and liver, kidney, and skin toxicities, commonly associated with current-generation ADCs.
• Enhanced Tumour Targeting: The Company is exploring innovative approaches, including dual-payload ADCs to overcome tumour resistance and iADCs that integrate immune activation and cytotoxic payloads, resulting in enhanced tumour destruction.

Upcoming Milestones
Sutro is advancing its pipeline and expects to file an IND for STRO-004 with the U.S. Food & Drug Administration in the second half of 2025. Additionally, Sutro aims to deliver two more IND applications over the next three years, advancing its portfolio of preclinical programmes for either internal development or potential external partnerships.