Logic Gated FLT3 OR CD33 NOT EMCN CAR-NK Cell Therapy (SENTI-202) for Precise Targeting of AML

DO NOT DISTRIBUTE | SENTI BIOSCIENCES DO NOT DISTRIBUTE | SENTI BIOSCIENCESSENTI-202 FLT3 OR CD33 NOT EMCN CAR-NK Cell Approach for Precise Targeting of AML 1 ASGCT 2022 Wed, May 18, 2022 ™ Brian S. Garrison, PhD Director of Research Senti Biosciences, Inc. DO NOT DISTRIBUTE | SENTI BIOSCIENCES Disclaimer DISCLAIMER 2 o Employee of Senti Biosciences, and receive salary and benefits from the company DO NOT DISTRIBUTE | SENTI BIOSCIENCES WE BELIEVE THAT OUR GENE CIRCUITS SOFTWARE PLATFORM IS BROADLY APPLICABLE 3 CAR OR Gate CAR NOT Gate Combo Effector Calibrated Release SM-regulated Promoter Gene Circuit Logic Gating Cell-type Promoter Cell-state Promoter Multi- Arming Regulator Dial Smart Sensor NK Cells iPSCs AAVs • Oncology • Immunology • Genetic Diseases Diverse Modalities Indications T Cells • Cardiology • Ophthalmology • Neuro • Metabolic Diseases HSCs Gene Circuits Could Potentially Power Multiple Cell and Gene Therapy Modalities for Broad Therapeutic Potential DO NOT DISTRIBUTE | SENTI BIOSCIENCES DUE TO DISEASE RELAPSE DRIVEN BY LEUKEMIC STEM CELLS (LSCs) 41 SEER Cancer Stat Facts: Acute Myeloid Leukemia SENTI-202: Designed to Address Unmet Needs in the Treatment of Acute Myeloid Leukemia (AML) 29.5% 5-Year Survival1 SENTI-202: LOGIC-GATED CAR-NK CELLS FOR PRECISION TARGETING OF AML UNMET NEED IN AMLSENTI’S LOGIC GATES SOLVE KEY DISEASE CHALLENGES IN AML Target heterogeneity Relapse due to incomplete targeting of leukemic stem cells (LSCs) Target heterogeneity Off-tumor toxicity and limited efficacy due to lack of AML-specific targets OR Logic Gate Targets multiple AML tumor associated antigens for improved clearance and lower relapse NOT Logic Gate Enables broad targeting of AML while preserving healthy blood stem cells CHALLENGES SENTI GENE CIRCUIT SOLUTIONS SENTI’S LOGIC-GATED CAR-NK PROGRAM OFFERS POTENTIAL TO DEVELOP A CURE FOR AML PATIENTS IN THE ABSENCE OF A BONE MARROW TRANSPLANT Diseased bone marrow 2020 US Incidence1 ~20K Patients diagnosed with AML this year DO NOT DISTRIBUTE | SENTI BIOSCIENCES Regulat or Dial Smart Sensor Combo Effector SM-regulated Promoter Cell-type Promoter Cell-state Promoter Gene Circuit CAR OR Gate Calibrated Release CAR NOT Gate Combo Effector SENTI-202: LOGIC-GATED CAR-NK CELLS FOR PRECISION TARGETING OF AML SENTI-202: Potential to Develop a Cure Without a Bone Marrow Transplant 5 EMCN iCAR FLT3 OR CD33 aCAR crIL-15 PRODUCT SCHEMATIC Allogeneic SENTI OR+NOT-Gate CAR-NK Cells Logic Gating Multi- Arming DO NOT DISTRIBUTE | SENTI BIOSCIENCES 6 OR/NOT GATE: TARGETING BOTH AML BLAST AND AML LSCs WHILE PRESERVING HEALTHY HSCs RESPOND WITH OUTPUTSCOMPUTE LOGIC SENSE INPUTS AML Blasts AML Stem Cells Healthy HSCs/PCs FLT3, CD33 OR GATE ONLY (FLT3 OR CD33) FLT3, CD33, EMCN OR/NOT GATE (FLT3 OR CD33) NOT EMCN CD33 NO LOGIC SENTI-202 SENTI-202: Logic Gated Gene Circuit May Enable Clearance of AML Blasts & LSCs While Sparing Healthy HSCs CD33 is over-represented on AML blast cells; FLT3 is a marker for AML LSCs; HSCs=hematopoietic stem cells; PCs = progenitor cells DO NOT DISTRIBUTE | SENTI BIOSCIENCES SENTI’S GENE CIRCUITS Toolbox of Gene Circuits 7 Safety AntigenInhibitory CAR (iCAR)Tumor-Associated AntigensActivating CAR (aCAR) HEALTHY CELL SENTI NOT-GATE CAR-NK CELLS SAFETY ANTIGEN ENGAGEMENT ENABLES PROTECTION OF HEALTHY CELLS CANCER CELLSENTI NOT-GATE CAR-NK CELLS TUMOR-ASSOCIATED ANTIGENS (TAA) ENGAGEMENT TRIGGERS CANCER CELL KILLING Fast Logic Gating Enables Highly Specific Therapies by Recognizing Multiple Antigens Logic Gating Multi- Arming Regulator Dial Smart Sensor DO NOT DISTRIBUTE | SENTI BIOSCIENCES SENTI’S GENE CIRCUITS 8 Toolbox of Gene Circuits NOT-GATED CAR-NK CELLS REDUCE KILLING OF HEALTHY CELLS RESULTING IN ENRICHMENT OF HEALTHY CELLS Source: Internal data NOT Logic Gate Functions In Vivo to Specifically Kill Cancer Cells and Spare Healthy Cells Control CAR-NK Cells NOT GATE CAR-NK Cells ** Healthy Cells Cancer Cells **** Control CAR-NK Cells NOT GATE CAR-NK Cells I.V. injection Blood collection NOT-Logic Gated CAR-NK Cells Healthy Cells Cancer Cells Healthy Cells Spared Cancer Cells Killed + + 50:50 Logic Gating Multi- Arming Regulator Dial Smart Sensor DO NOT DISTRIBUTE | SENTI BIOSCIENCES 9 SENTI’S DESIGN-BUILD-TEST-LEARN (DBTL) PROCESS ▪ ML / computational algorithms ▪ Patient disease bioinformatics Alternative Designs ▪ Automated high throughput screening ▪ Analytical testing on process efficiencies and robustness Hit Selection ▪ DNA, vector and cell engineering with GMP-relevant processes Production Efficiency DESIGN BUILD TEST LEARN Centralized Gene Circuit Design Team Disease Indication Teams, in vivo Core, Analytical Core Vector Core, Cell Manufacturing Core, Disease Indication Teams Biological Data Central Knowledge Database Optimized Gene Circuits SENTI’S DESIGN-BUILD-TEST-LEARN ENGINE Powerful and Scalable Engine Optimizes Gene Circuits to Enable Creation of Intelligent Medicines DO NOT DISTRIBUTE | SENTI BIOSCIENCES 10 SENTI-202 GENE CIRCUIT OPTIMIZATION Systematic Gene Circuit Optimization for FLT3 OR CD33 NOT EMCN CAR-NK Cell Development >500 SENTI-202 total constructs tested EMCN iCAR FLT3 OR CD33 aCAR crIL-15 Allogeneic SENTI OR+NOT Gate CAR-NK Cells 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data DO NOT DISTRIBUTE | SENTI BIOSCIENCES 11 SENTI-202 GENE CIRCUIT OPTIMIZATION 1. NK Cell Engineering Platform Optimization Yielded >80% CAR Expression Lentivirus optimization Envelope optimization Vector optimization Various CARs Flow cytometry-based CAR expression assay EMCN iCAR FLT3 OR CD33 aCAR crIL-15 Allogeneic SENTI OR+NOT Gate CAR-NK Cells 1. 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data Source: Internal data Retrovirus optimization DO NOT DISTRIBUTE | SENTI BIOSCIENCES 12 SENTI-202 GENE CIRCUIT OPTIMIZATION 2. Gene Circuit Promoter Design Optimization Enabled >70% CAR expression Promoter 1 Promoter 2 Promoter 3 Flow cytometry-based CAR expression assay EMCN iCAR FLT3 OR CD33 aCAR crIL-15 Allogeneic SENTI OR+NOT Gate CAR-NK Cells 2. 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data Source: Internal data DO NOT DISTRIBUTE | SENTI BIOSCIENCES 13 SENTI-202 GENE CIRCUIT OPTIMIZATION 3. Bivalent Activating CAR (aCAR) Binder Optimization Significantly Improves In Vivo Tumor Suppression and Mouse Survival 3. In Vitro Cytotoxicity activity In Vivo AML (MV4-11) Tumor Suppression Bivalent BBivalent APBS Mouse Survival CurveTumor bioluminescenceAML Killing Assay AML (MV4-11) imagining: Day 87 Treatment (1.) PBS (2.) Bivalent design A CAR-NK (3.) Bivalent design B CAR-NK **** **** ** ** ** P-value (3.) vs. (2.) = 0.0064 (3.) vs.(1.) = 0.0034 EMCN iCAR FLT3 OR CD33 aCAR crIL-15 Allogeneic SENTI OR+NOT Gate CAR-NK Cells 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data Source: Internal data DO NOT DISTRIBUTE | SENTI BIOSCIENCES 14 SENTI-202 GENE CIRCUIT OPTIMIZATION 4. Inhibitory CAR (iCAR) Binder Humanization Process Increased NOT GATE function NOT GATE cell protection assay4.EMCN iCAR FLT3 OR CD33 aCAR crIL-15 Allogeneic SENTI OR+NOT Gate CAR-NK Cells 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data Source: Internal data DO NOT DISTRIBUTE | SENTI BIOSCIENCES Tumor-associate antigen+ Tumor-associate antigen+ and safety antigen+ 15 SENTI-202 GENE CIRCUIT OPTIMIZATION 5. Inhibitory CAR (iCAR) Intracellular Domain Screen Identified Architectures Most Compatible with SENTI-202 Target Antigens In vitro aCAR-mediated killing (gray) and iCAR-mediated protection (teal) assay EMCN iCAR FLT3 OR CD33 aCAR crIL-15 Allogeneic SENTI OR+NOT Gate CAR-NK Cells 5. 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data Source: Internal data DO NOT DISTRIBUTE | SENTI BIOSCIENCES 16 SENTI-202 GENE CIRCUIT OPTIMIZATION 6. Calibrated Release (cr) IL-15 Enabled Optimization for CAR-NK Cells Use of tunable cleavage site enables regulated IL-15 presentation & secretion 3° killing 2° killing 0 (hours) 5 4 3 2 1 Tumor cell abundance (relative) crIL-15 outperforms soluble IL-15 in 2° and 3° serial killing assayEMCN iCAR FLT3 OR CD33 aCAR crIL-15 Allogeneic SENTI OR+NOT Gate CAR-NK Cells crIL-15 enables autocrine & paracrine signaling 6. 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data Source: Internal data DO NOT DISTRIBUTE | SENTI BIOSCIENCES 17 SENTI-202 GENE CIRCUIT OPTIMIZATION Robust Single Gene Circuit Expression of all SENTI-202 Components EMCN iCAR FLT3 OR CD33 aCAR crIL-15 Allogeneic SENTI OR+NOT Gate CAR-NK Cells 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data Source: Internal data DO NOT DISTRIBUTE | SENTI BIOSCIENCES 18 OR GATE: CAR-MEDIATED NK CELL KILLING In Vitro Activity: FLT3 OR CD33 CAR-NK Cells Demonstrate Significant In Vitro Activity Against AML Source: Internal data PRIMARY AML SAMPLES WITH EXPANDED BLAST POPULATIONS SSC CD45 Healthy BMMC AML #857 (M2) AML #847 (M3) AML BLASTS FLT3 OR CD33 CAR-NK CELLS KILL PRIMARY AML CELLS * p < 0.05; ** P ≤ 0.01; *** P ≤ 0.001 Percent Killing 80 60 40 20 0 100 AML #770 (M2) AML #857 (M2) AML #847 (M3) AML #837 (M5) AML #846 (M5) NK CAR-NK NK CAR-NK NK CAR-NK NK CAR-NK NK CAR-NK ** *** ** * *** 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data DO NOT DISTRIBUTE | SENTI BIOSCIENCES 19 OR GATE: CAR-MEDIATED NK CELL KILLING In Vivo Activity: FLT3 OR CD33 CAR-NK Cells Significantly Suppressed Tumor Growth, Reduced Tumor Burden and Improved Survival No Cancer Moderate Tumor Load Significant Tumor Load Day 30 p-values (3) vs (2): p < 0.05 (3) vs (1): p < 0.01 0 20 40 60 80 0 25 50 75 100 Time (days) Percent survival P-Values (3) vs (1): p < 0.01 (3) vs (2): p < 0.01 (2) vs (1): p < 0.01 Untreated (1) Unengineered NK Cells (2) SENTI OR Gate CAR-NK (3) SENTI FLT3 OR CD33 CAR-NK cells achieved statistically significantly greater anti-tumor activity compared to untreated control mice (p < 0.01) and mice treated with unengineered NK cells (p < 0.05) 2 Unengineered NK cells 3 SENTI OR Gate CAR-NK 1 Untreated Groups DAY 3020139 MV4-11-BASED AML XENOTRANSPLANTATION MODEL FLT3 OR CD33 CAR-NK cells significantly suppressed tumor growth and increased survival 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data Source: Internal data DO NOT DISTRIBUTE | SENTI BIOSCIENCES NOT GATE DISCRIMINATION STUDY: AML CANCER CELLS VS PRIMARY HEALTHY BLOOD STEM CELLS 20Source: Internal data Protection of Primary Healthy HSCs: SENTI-202 Protects Primary Healthy HSCs While Maintaining On-Target Killing of Cancer Cells EMCN NOT-GATE CAR-NK CELLS EFFECTIVELY KILL AML CANCER CELLS EMCN NOT-GATE CAR-NK CELLS PROTECT HEALTHY HSCs/MPPs ** 47% protection We believe that protecting 10-20% of Healthy HSCs is clinically meaningful. AML Cell AML Cell Experimental Approach: OR+NOT GATE CAR-NK Cell OR GATE CAR-NK Cell Healthy HSC/MP P Healthy HSC/MP P OR+NOT GATE CAR-NK Cell OR GATE CAR-NK Cell 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data DO NOT DISTRIBUTE | SENTI BIOSCIENCES 21 SUMMARY Summary: Progress to Date Paves the Way for SENTI-202 IND Filing in 2023 EMCN iCAR FLT3 OR CD33 aCAR crIL-15 Allogeneic SENTI OR+NOT Gate CAR-NK Cells o >500 total constructs generated and tested o Extensive systematic gene circuit optimization resulted in high CAR expression o SENTI-202 exhibited significant killing activity in vitro against primary AML cells in patient samples o SENTI-202 demonstrated significant AML tumor growth suppression and improved mouse survival in vivo o SENTI-202 NOT GATE protects primary donor HSCs while maintaining on-target killing of cancer cells 1. NK Cell Engineering Platform 2. Gene Circuit Promoter Design 3. Bivalent Activating CAR (aCAR) Binder Design 4. Inhibitory CAR (iCAR) Binder Design 5. Inhibitory CAR (iCAR) Intracellular Domain 6. Calibrated release IL-15 7. Complete circuit 8. POC Data DO NOT DISTRIBUTE | SENTI BIOSCIENCES DO NOT DISTRIBUTE | SENTI BIOSCIENCES Together, We Can Outsmart Complex Diseases With Intelligent Medicines. 2 2 [email protected] DO NOT DISTRIBUTE | SENTI BIOSCIENCES DO NOT DISTRIBUTE | SENTI BIOSCIENCES We’re hiring… https://careers.sentibio.com/

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