Sutro Biopharma, Inc. · NASDAQ:STRO
Sutro Biopharma — Investor Day (November 2025)
57 slides from Sutro Biopharma's investor day presentation, Nov 12, 2025
Slide 1: R&D Day 2025
R&D Day 2025 November 12, 2025 NASDAQ: STRO
Slide 2: Welcome & Opening Remarks
Welcome & Opening Remarks Jane Chung Chief Executive Officer
Slide 3: Forward-Looking Statements
Forward-Looking Statements This presentation and the accompanying oral presentation contain “forward-looking” statements that are based on our management’s beliefs and assumptions and on information currently available to management. Forward-looking statements include all statements other than state
Slide 4: Agenda
Agenda Jane Chung, RPh Jonathan Fawcett, Anthony W. Tolcher, Hans-Peter Gerber, Jane Chung, RPh Chief Executive Officer MBBS, DPhil MD, FRCPC, FACP PhD Chief Executive Officer VP, Clinical Development NEXT Oncology, San Antonio TX Chief Scientific Officer Welcome and STRO-004 (TF ADC) Pipeline Overv
Slide 5: Delivering the Next-Generation of ADC Therapeutics
Proprietary Platform Creates Best-in-Class ADCs At the forefront of next-gen ADCs, with improved antibody, linker, and payload for superior safety and efficacy Single-payload ADCs Dual-payload ADCs, with partnered and for complex targets where wholly-owned programs, to overcome competition is limite
Slide 6: Sutro's Platform Designed to Optimize Every Component of the ADC
Sutro’s Platform Designed to Optimize Every Component of the ADC Expanding the therapeutic window to minimize toxicity and maximize efficacy 1 ANTIBODY 1 ▸High throughput screening identifies Ab with ideal attributes ▸Reduced ILD risk enabled by Fc-silent design 2 PAYLOAD ▸High DAR exatecans; stable
Slide 7: Differentiated Pipeline of Single- and Dual-Payload ADCs
Differentiated Pipeline of Single- and Dual-Payload ADCs SINGLE-PAYLOAD ADCs: DUAL-PAYLOAD ADCs: Focused on Complex Targets Overcome Resistance and Expressed Across Many Tumor Types Delay Progression STRO-227: STRO-004: STRO-006: PTK7-Targeting dpADC TF-Targeting ADC ITGB6-Targeting ADC Supercharge
Slide 8: Dual-Payload ADCs: Targeted Combination Therapy to Improve Outcomes
Dual-Payload ADCs: Targeted Combination Therapy to Improve Outcomes Combination treatment approaches have been shown to improve outcomes in oncology vs single agent chemotherapy and remain standard of care in many therapeutic areas Dual-Payload ADCs: Potential to Become Future Standard of Care • Ove
Slide 9: Proprietary Cell-Free Platform Positions Sutro at the Forefront of Dual-Payload Innovation
Proprietary Cell-Free Platform Positions Sutro at the Forefront of Dual-Payload Innovation Topo1 x Tubulin Enables novel drug combinations and ratios with the Multiple Modalities Topo1 x DDRi broadest payload diversity to overcome tumor resistance and improve tolerability Topo1 x IO Tailored Ratios
Slide 10: STRO-004: Potential Best-in-Class Exatecan ADC Targeting Tissue Factor
STRO-004: Potential Best-in-Class Exatecan ADC Targeting Tissue Factor Dr. Jonathan Fawcett Vice President, Clinical Development
Slide 11: Value Proposition for STRO-004
Value Proposition for STRO-004 Tissue Factor (TF) is a very attractive ADC target, but we believe there is opportunity to build on the validation from Tivdak by improving efficacy and mitigating toxicity Tivdak STRO-004 • Antibody High affinity antibody o Affects TF coagulation function; o Selecte
Slide 12: STRO-004: Favorable In Vitro Tolerability Profile vs. Approved TF ADC
STRO-004: Favorable In Vitro Tolerability Profile vs. Approved TF ADC Eye Inflammation Skin Toxicities STRO-004 Human Corneal Epithelial Cells Human Keratinocytes Reduced Bleeding Risk 50% 46% 40% 30% 20% 10% 1% 0% STRO-004 Tisotumab Up to 70% of Tivdak-treated STRO-004 (DAR8-exatecan) Approved TF A
Slide 13: DAR 8 Demonstrated Superior Anti-tumor Activity to DAR 4 in Preclinical Model
DAR 8 Demonstrated Superior Anti-tumor Activity to DAR 4 in Preclinical Model STRO-004 (DAR8 TF ADC) HCT-116 Growth Improves Anti-Tumor ActivityCurves at a Lower Dose 1500 1250 Tumor Volume (mm3) 1000 750 500 250 0 0 10 20 30 40 50 60 70 Days Post Treatment STRO-004 (DAR8), STRO TF ADC (DAR4), TIVDA
Slide 14: STRO-004 DAR8 Exatecan Achieved Sustained Tumor Regressions in Xenograft Models
STRO-004 DAR8 Exatecan Achieved Sustained Tumor Regressions in Xenograft Models of NSCLC and HNSCC at Low Doses Lung (TF+++) Head and Neck (TF++) H1975 Growth Curves Detroit562 Growth Curves 1500 1500 ) ) 3) 3 3)3 1250 1250 (mm (mm Volume (mm Volume (mm 1000 1000 TumorVolume TumorVolume 750 750 500
Slide 15: STRO-004 Showed Promising Anti-tumor Activity in TF-Positive PDX Models
STRO-004 Showed Promising Anti-tumor Activity in TF-Positive PDX Models of HNSCC, NSCLC, and Pancreatic Cancer STRO-004 % Best Response in PDX Models of Solid Tumors 100 DCR: 28/30 ORR:28/30 DCR: 22/30 (93%) STRO-004 ORR: 22/30 (73%) % tumor volume change 50 ORR CR PR SD from baseline Cancer N (%) 1
Slide 16: STRO-004 Demonstrated Promising Anti-Tumor Activity in NSCLC and PDAC PDX Models
STRO-004 Demonstrated Promising Anti-Tumor Activity in NSCLC and PDAC PDX Models % Best Response in Non-Small Cell Lung Cancer PDX Models % Best Response in Pancreatic Cancer PDX Models % Best Response in Non Small Cell Lung Cancer PDX Models % Best Response in Pancreatic Cancer PDX Models 100 100 %
Slide 17: Single Dose of STRO-004 Greater Than Tivdak in HNSCC PDX Models
Anti-Tumor Activity Following a Single Dose of STRO-004 is Greater Compared to Single Dose of Tivdak in HNSCC PDX Models % Best Response in Head and Neck Squamous Cancer PDX Models 200 DCR: 15/17 STRO-004 DCR:MMAE aTF DAR4 14/17ADC % tumor volume change 150 % ORR: Best DCR: 11/17 15/17 Response in P
Slide 18: Significant Unmet Need Across Large Oncology Patient Populations
Significant Unmet Need Across Large Oncology Patient Populations Incidence (U.S.) and relapsed/refractory ORR and OS benchmarks across select relevant tumor types Incidence (U.S.) and Relapsed/Refractory ORR and Current Standard of Care in R/R OS Benchmarks Across Select Relevant Tumor Types % ORR m
Slide 19: Detailed Monotherapy Development Strategy: Phase 1 Basket Trial Initiated
Detailed Monotherapy Development Strategy: Phase 1 Basket Trial Initiated Dose Escalation Move Forward with Advanced Solid Tumors with Tissue Factor Expression Recommended Dose(s) Tumor type eligibility Selected for TF expression: • Early detection of activity • Early characterisation of safety prof
Slide 20: STRO-004 Clinical Development Plan is Designed for Rapid Initial Market Entry
STRO-004 Clinical Development Plan is Designed for Rapid Initial Market Entry 2025 2026 2027 2028 2H 1H 2H 1H 2H 1H 2H FPI Phase 1 Pre-IND Dose Escalation in Basket of Indications Advanced Solid Tumors RP2D with TF Expression Optimized Dose, Accelerated Approval Opportunity Retrospective Biomarker A
Slide 21: ADC Innovation
ADC Innovation Anthony W. Tolcher, MD, FRCPC, FACP NEXT Oncology, San Antonio TX
Slide 22: ADC: Practical Innovation and What It Looks Like
ADC: Practical Innovation and What It Looks Like Transformative therapies are derived from combinations of drugs • Curative therapy came from MOPP, ABVD, CHOP, TC and others • Combinations of non-overlapping MOA and toxicities • The future of ADCs are combinations of payloads • Validated payloads in
Slide 23: Most ADCs fail due to Safety
Most ADCs fail due to Safety Yet the premise of ADC technology was to improve therapeutic index 23
Slide 24: The Truth(s) About Current ADCs: Target Antigens
The Truth(s) About Current ADCs Target Antigens • There are a finite number of internalizing Target Antigens • Loss of Target Antigens is Not a Mechanism of Resistance One can reduce developmental risk by choosing credentialed antigens, and using new payloads, or combinations of payloads, for POC 24
Slide 25: The Truth(s) About Current ADCs: Antibody Construct
The Truth(s) About Current ADCs Antibody Construct should be designed for an ADC not naked Ab • Fc silent should be the standard (no need for ADCC) • Risk for ILD if intact functional Fc • “Tunable” payload sites • Optimize for Linker Chemistry 25
Slide 26: The Truth(s) About Current ADCs: Linker Technologies
The Truth(s) About Current ADCs Older linker technologies result in off target toxicity Neutropenia, GI issues, and neuropathy limit therapeutic index • Examples: Sacituzumab govitecan, enfortumab vedotin, tisotumab vedotin 26
Slide 27: The Truth(s) About Current ADCs: Chemotherapy Reminders
The Truth(s) About Current ADCs Reminders from the chemotherapy era Every patient with advanced disease will become resistant to a chemo • There are opportunities even with HER2, TROP2, with novel payloads Optimal Ratios of Cytotoxic combinations was required • Foolish to assume 1:1 • Safety drove c
Slide 28: An Approach To Assessing Success
An Approach To Assessing Success Antigen Target (Credentialed or Novel) Antibody Construct (Fc Silent, tunable) Linker Stability (Historical versus Modern) Payload Type (MMAE/F, DM/DM4, TOPO1 Era) (demand Novel soon) Approach to Exposure 28
Slide 29: Pipeline Overview: The Next Revolution in ADCs
Pipeline Overview: The Next Revolution in ADCs Dr. Hans-Peter Gerber Chief Scientific Officer
Slide 30: Topo1 Inhibitor ADC Payloads Demonstrate Improved Efficacy over Tubulin Inhibitors
Topo1 Inhibitor ADC Payloads Demonstrate Improved Efficacy over Tubulin Inhibitors Across Indications and Targets ADC Target Indication Program Payload, DAR ORR (%), ORR Gain (%) PFS Gain (mos) SAR408701 DM4, 3.9 0 31 1.8 5.1 CEA Colorectal M9140 Topo1, 8 31 6.9 Kadcyla DM1, 3.5 21 30 2.7 2.9 HER2+
Slide 31: Overcoming Resistance: Key Criteria for Next-Generation ADCs
Overcoming Resistance: Key Criteria for Next-Generation ADCs Increase ADC exposure 1 • Achieve higher payload delivery while reducing platform and on-target toxicity • Exemplified by STRO-004 and STRO-006 programs Designing ADCs to Delay or Prevent 2 Combine payloads with complementary mechanisms of
Slide 32: Pharmacology Attributes of "Winner" ADCs
Pharmacology Attributes of “Winner” ADCs + + PK Safety Activity Long half-life, High exposure In tumor models predictive low clearance & high MTD/HNSTD for clinical responses at clinically relevant dose levels HNSTD – Highest non-severely toxic dose; MTD: Maximum tolerated dose; PK – Pharmacokinetic
Slide 33: Sutro's Cell-Free Manufacturing Platform Enables Site-Selective ADCs
Sutro’s Cell-Free Manufacturing Platform Enables Site-Selective ADCs with Superior Exposure and Design Flexibility Surface Sites Screened on an IgG DAR16 ADCs during an ADC Campaign Total Ab (ng/mL) Site combo A 100,000 Site combo B Site combo C Site combo D 10,000 1,000 100 0 100 200 300 400 Time p
Slide 34: Sutro's Single- and Dual-Payload ADCs Display Highest Exposure in NHPs
Sutro’s Single- and Dual-Payload ADCs Display Highest Exposure in NHPs Conventional Topo1 ADCs Conventional DAR4 MMAE ADCs 0.300 STRO- aHER2 0.250 dpADC (8+4) per ADC [mg/kg] 0.200 MMAE dose 0.150 0.100 STRO- aHER2 Green: Exatecan 0.050 dpADC (8+2) Blue: DXd Yellow: 0.000 MMAE 0 10000 20000 30000 40
Slide 35: STRO-006: Selective ITGB6-Targeting Exatecan ADC for Leading Tolerability and PK
STRO-006: Selective ITGB6-Targeting Exatecan ADC for Leading Tolerability and PK 2-3x higher drug exposure than many conventional ADCs 1 1 ANTIBODY ▸High affinity to ITGB6 without effect on TGFβ signaling ▸Fc-silent to reduce ILD risk 2 PAYLOAD ▸ High stable DAR (8) ▸ Potent anti-tumor activity with
Slide 36: ITGB6: A Compelling Target, with STRO-006 Poised to be Best-in-Class
ITGB6: A Compelling Target, with STRO-006 Poised to be Another Best-in-Class for Sutro ITGB6 is Expressed in Broad Set of Primary Solid Tumor Indications • Broad tumor expression: Expressed across solid tumor indications; highest prevalence in NSCLC, HNSCC, ESCC 300 ITGB6 staining Less Competition
Slide 37: STRO-006 Displays Superior PK and Safety Compared to SGN-B6A
STRO-006 Displays Superior PK and Safety Compared to SGN-B6A (MMAE, Ph3 Trial in Lung) STRO-006 MTD in NHPs is more than 4x higher and the MED is ~10x lower in comparison with competition: widening its therapeutic Index Pfizer/Seagen Sutro 10000 SGN-B6A (MMAE) STRO-006 (Topo1i) 1000 MF Mean Plasma C
Slide 38: STRO-006 Has Shown Superior Activity to Competitor ADCs in Preclinical Models
STRO-006 Has Shown Superior Activity to Competitor ADCs in Preclinical Models Expressing ITGB6 adeno NSCLC PDX (CTG-0743) Non-squamous NSCLC PDX, mut-EGFR Squamous NSCLC PDX, WT-EGFR Bladder CDX, SW780 H score: 136 (Seagen) 2500 1500 SW780 (UCC) 2000 ITGB6-moderate Relative Tumor Volume (%) 2000 Tum
Slide 39: Single Dose of STRO-006 Greater Than aITGB6 MMAE ADC in HNSCC PDX Models
Anti-Tumor Activity Following a Single Dose of STRO-006 is Greater Compared to Single Dose of aITGB6 MMAE ADC in HNSCC PDX Models % Best Response PDX Models of HNSCC 200 % Best Response in PDX Models of HNSCC 150 STRO-006 aITGB6 DAR4 MMAE ADC % tumor volume change DCR: 14/17 DCR: 11/17 ORR: 12/17 *
Slide 40: Duration of Response Greater with STRO-006 vs aITGB6 MMAE ADC
Duration of Response was Greater with STRO-006 Compared to aITGB6 MMAE ADC in HNSCC PDX Models STRO-006 5 mg/kg aITGB6 ADC (DAR4 MMAE) 5 mg/kg 200 200 Change from Baseline (%) Change from Baseline (%) 150 150 100 100 50 50 0 0 20 40 60 20 40 60 -50 Days -50 Days -100 -100 Landmark Response Response
Slide 41: Dual-Payload ADCs: Overcoming ADC Resistance With Payload Diversity
Dual-Payload ADCs: Overcoming ADC Resistance With Payload Diversity
Slide 42: Dual-Payload ADCs have Desirable In Vivo PK and Stability
Dual-Payload ADCs have Desirable In Vivo PK and Stability Mouse Pharmacokinetics ADC Stability Over Three Weeks Time (day) Time (day) DAR Clobs Vss t1/2 Topo1i MMAE (mL⋅d⁻¹/kg) (mL/kg) (days) 8 2 3.3 75.8 16.3 8 4 4.2 81.4 14 DAR – Drug to antibody ratio; MMAE – Monomethyl Auristatin E (tubulin inhi
Slide 43: Dual-Payload ADCs Have Overcome Resistance and Driven Tumor Regression
Dual-Payload ADCs Have Overcome Resistance and Driven Tumor Regression in Preclinical Models Dual-Payload ADC Induces Tumor Dual-Payload ADCs Have Improved In Vivo Regression After Sequential ADC Resistance Efficacy in an MTI-Resistant CRC Xenograft Model HCT-116 Tumor Growth Curves 10 mg/kg Enhertu
Slide 44: PTK7 is a Clinically Validated Pan-Tumor Target
PTK7 is a Clinically Validated Pan-Tumor Target Pan-Tumor Target Enriched Clinically Validated on Tumor-Initiating Cells ADC target • Catalytically inactive receptor tyrosine kinase • Anti-tumor activity of anti-PTK7 ADC demonstrated in involved as a co-receptor in multiple signaling Phase 1b trial
Slide 45: Potential for Greater Efficacy and Tolerability, with Established Development Path
Potential for Greater Efficacy and Tolerability, with Established Development and Regulatory Path Proprietary linker enables efficient delivery of both payloads simultaneously within the tumor cells — minimizing systemic exposure 1 ANTIBODY 1 ▸High affinity antibody with superior internalization ▸Id
Slide 46: Better Together: Dual-Payload ADC Outperforms Single-Payload ADCs
Better Together: Dual-Payload ADC Outperforms Single-Payload ADCs Breast Cancer Xenograft Models – Tumor Growth Tumor Growth 10 mg/kg 10 mg/kg 15 mg/kg 10 mg/kg 10 mg/kg MMAE – Monomethyl auristatin E; Topo1 – Topoisomerase I inhibitor NON-CONFIDENTIAL 46
Slide 47: Sutro Dual-Payload ADC: Preclinical Tolerability Meets Single-Payload Benchmarks
Sutro Dual-Payload ADC: Preclinical Tolerability Meets Single-Payload Benchmarks ADC Target Linker Payload DAR NHP HNSTD Highest Clinical Phase Padcev Nectin-4 Val-cit MMAE 4 3 mg/kga (Q1Wx4) Approved Tivdak TF Val-cit MMAE 4 3 mg/kga (Q3Wx5) Approved SGN-B6A ITGB6 Val-cit MMAE 4 6 mg/kga (Q3Wx2) 3
Slide 48: Sutro Dual-Payload ADC: Preclinical Tolerability Meets Single-Payload Benchmarks
Sutro Dual-Payload ADC: Preclinical Tolerability Meets Single-Payload Benchmarks ADC Target Linker Payload DAR NHP HNSTD Highest Clinical Phase Enhertu HER-2 GGFG Deruxtecan 8 30 mg/kga (Q3Wx3) Approved Datroway Trop-2 GGFG Deruxtecan 4 10 mg/kgb (Q3Wx5) Approved MK-1022 HER-3 GGFG Deruxtecan 8 30 m
Slide 49: Developing Next-Generation Immunostimulatory Dual-Payload ADCs
Developing Next-Generation Immunostimulatory Dual-Payload ADCs
Slide 50: New Modality for Cold Tumors: Immunostimulatory Antibody Drug Conjugate (iADC)
New Modality for Cold Tumors: Immunostimulatory Antibody Drug Conjugate (iADC) • Combining exatecan and immune modulator enabled by Sutro’s dual-payload ADC platform • Sutro and Astellas are co- developing iADC programs. • Sutro retained option to develop iADCs in other targets • The HER2 iADC is wh
Slide 51: HER2 iADC Results in More Complete Responses than Exatecan or STING ADC
HER2 iADC Treatment Results in More Complete Responses than Both Exatecan ADC and STING ADC Treatment in the MC38-hHER2 Tumor Model Relative Tumor Volume (%) Group % TGI (Day 27) CR/Total Relative Tumor Volume (%) Vehicle -- 0/8 2000 Relative tumor volume (%) 1500 Exatecan ADC, 1 mg/kg 40 1/8 1000 S
Slide 52: HER2-iADC Treatment Increases NK Cells and Monocytes Infiltrating the Tumor
HER2-iADC Treatment Increases Proportion of NK Cells and Monocytes Infiltrating the Tumor Tumor weight (Day 5) NK Cells CD8+ T cells Monocytes inflammatory monocytes Tumor weight (Day 5) NK cell % of live CD45+ CD8+ T cell % of live CD45+ % of live CD45+ 500 20 10 50 400 8 40 15 % of CD45+ live cell
Slide 53: HER2-iADC Shows Superior Efficacy Compared to Enhertu
HER2-iADC Treatment Shows Superior Efficacy Compared to Enhertu, Achieving a 100% Complete Response Rate in the MC38-hHER2 Tumor Model Relative Tumor Volume (%) Relative Tumor Volume (%) 2000 Relative tumor volume (%) 1500 Group % TGI (Day 21) CR/Total 1000 Vehicle -- 0/8 500 Enhertu, 20 mg/kg 67 0/
Slide 54: HER2-iADC was Well Tolerated in Exploratory NHP Toxicity Study
HER2-iADC was Well Tolerated in Exploratory NHP Toxicity Study (Q3W x2) Study: Two doses of 12.5 or 25 mg/kg given 10000 8.5 to 1M/1F per group on Days 1 and 22; Day 43 necropsy 1000 Mean MF Plasma Conc. 8.0 100 Findings: Average DAR • Both doses well tolerated with no 10 [nM] 7.5 abnormal clinical
Slide 55: Wrap-up and Q&A
Wrap-up and Q&A Jane Chung Chief Executive Officer
Slide 56: Advancing a High-Value ADC Pipeline Toward Key Clinical Milestones
Advancing a High-Value ADC Pipeline Toward Key Clinical Milestones STRO-004: STRO-006: STRO-227: TF-Targeting ADC ITGB6-Targeting ADC PTK7-Targeting dpADC Wholly-owned: Phase 1 study IND submission 2026- Q4 2025 2026 IND submission ongoing expected 2027 expected Initial data Mid- 2026 expected iADC
Slide 57: R&D Day 2025
R&D Day 2025 November 2025 NASDAQ: STRO