Targeted Approach using Biomarkers, ADC's The Next Frontier

David O’Malley, M.D.

Ovarian Cancer - Clinical Trial Advisor Director, Division of Gyn Oncology GOG Partners Professor, Department of OB/Gyn The Ohio State University James CCC Objectives

• Understanding targeted drug therapy (ADCs) as a treatment for patients with ovarian cancer • Structure • MOA • Effective Delivery Considerations • Targets • Agents Verbal Disclosure (2 years) Consultation and/or Honorarium Institutional Research Support • Abbvie • Abbvie • Agenus • Agenus • Ambry • Amgen • Amgen • AstraZeneca • AstraZeneca • Clovis • Clovis • Immunogen • Elevar • Iovance • Immunogen • Janssen/J&J • Iovance • Merck • Janssen/J&J • Mersana • Merck • Novartis • Mersana • Novocure • Myriad Genetics • Regeneron • Novartis • Roche/ • Novocure • SeaGen • Regeneron • Tesaro/GSK • Roche/Genentech • EMD Serono • SeaGen • Ergomed • Tarveda • Ajinomoto • Tesaro/GSK • GOG Foundation • Serono Inc, FDA-Approved Drugs for Ovarian Cancer 12+ Approvals since Nov 2014 More approvals in the last 6 years than the prior 60 years combined

Pembrolizumab MSI/dMMR ROC (2017) Gemcitabine/Carboplatin PlSOC (2006) Olaparib Carboplatin Maintenance PlSOC (2017) (1989) Niraparib Paclitaxel Maintenance PlSOC (2017) Paclitaxel Full (1998) Accelerated (1992) Niraparib HRD ROC > 3-L (2019) 1960 1970 1980 1990 2000 2010 2020 1960 1970 1980 1990 2000 2010 2020

PLD-Full Rucaparib gBRCAmut/ Etoposide ROC (2005) sBRCAmut ROC > 2-L (2016) (1983) Melphalan Altretamine PLD-Accelerated (1964) Cisplatin Chemo + (1990) ROC (1999)* (1978) PlSOC (2016)

Olaparib Cyclophosphamide (1959) Topotecan Olaparib gBRCAmut 1-L ROC (1996) gBRCAmut ROC > 3-L (2014) Maintenance (2018)

Bevacizumab Docetaxel Chemo + Bevacizumab (2014) PlROC (1996) 1-L + Maintenance (2018) Rucaparib Maintenance PlSOC (2018)

Niraparib 1-L Maintenance (2020)

Olaparib + Bev 1-L Maintenance (2020) https://www.nccn.org/professionals/physician_gls/pdf/ovarian.pdf. Accessed on 7 March 2021 The Era of Targeted Therapy in Ovarian Cancer is Here

Drug Maintenance Later-line Treatment Olaparib 1 SOLO-2 (BRCA mut) Study 42 (BRCA mut) Study 19 (Dec 19, 2014) (Aug 17, 2017)

SOLO-1 (BRCA mut) (Dec 19, 2018)

With Bev PAOLA-1 (HRD) (May 8, 2020)

2,3 ARIEL3 Study 10 (BRCA mut) Rucaparib (April 6, 2018) ARIEL2 (BRCA mut) (Dec 19, 2016) 4 NOVA QUADRA Niraparib (Mar 27, 2017) (Oct 23, 2019)

PRIMA (April 29, 2020)

5 GOG218 AURELIA Bevacizumab (June 13, 2018) (Nov 14, 2014) OCEANS – GOG213 (Dec 6, 2016) 1. Olaparib package insert. AstraZeneca Pharmaceuticals LP; 2020. 2. FDA. Summary Review for Regulatory Action: Olaparib. https://www.accessdata.fda.gov/drugsatfda_docs/nda/2014/206162Orig1s000SumR.pdf. Approval date December 19, 2014. Accessed April 10, 2018. 3. Rucaparib package insert. Clovis Oncology, Inc; April 2018. 4. Niraparib package insert. TESARO, Inc; August 2020. 5. https://www.drugs.com/history/avastin.html Antibody Structure

• Antigen • Linker • Payload

Hoffmann RM, Coumbe BGT, Josephs DH, Mele S, Ilieva KM, Cheung A, et al. Antibody structure and engineering considerations for the design and function of Antibody Drug Conjugates (ADCs). Oncoimmunology. 2018, VOL. 7, NO. 3, e1395127 Antibody Structure • Antigen Properties • High homogenous expression on tumor cells • Low/no expression on normal cells • Antigen-antibody binding is the first mechanistic step in a cascade of events • The target antigen must be well internalized by receptor mediated endocytosis • Should not be down-regulated by endocytosis or by the effects of repeated stimulation during treatment • Minimum antigen expression threshold is required for ADC efficacy

Hoffmann RM, Coumbe BGT, Josephs DH, Mele S, Ilieva KM, Cheung A, et al. Antibody structure and engineering considerations for the design and function of Antibody Drug Conjugates (ADCs). Oncoimmunology. 2018, VOL. 7, NO. 3, e1395127 Antibody Structure • Payload • Drugs that are suitable for antibody conjugation and deliver an effective cytotoxic dose • The most commonly utilized payloads in ovarian cancer are: • (MMAE/Vedotin) • DM4 (Ravtansine/Soravtansine) • High potency in the picomolar range is key to therapeutic benefit as payload delivery is limited by the drug to antibody ratio (DAR) • Bystander effect: membrane permeable allows for diffusion from targeted tumor cells into neighboring cells

Hoffmann RM, Coumbe BGT, Josephs DH, Mele S, Ilieva KM, Cheung A, et al. Antibody structure and engineering considerations for the design and function of Antibody Drug Conjugates (ADCs). Oncoimmunology. 2018, VOL. 7, NO. 3, e1395127 Antibody Structure • Linker Properties • Forms the chemical connection between the antibody and payload • Main function is to stabilize the cytotoxic payload while in circulation and allowing release of the payload when the ADC is antigen-bound or internalized • A majority of linkers are designed to allow for payload release after internalization of the ADC • Cleavable: releases the active metabolite intracellularly after cleavage via enzymes, hydrolysis, or reduction of disulfide bonds • Non-cleavable: complete degradation of the antibody backbone before the active metabolite is releases

Hoffmann RM, Coumbe BGT, Josephs DH, Mele S, Ilieva KM, Cheung A, et al. Antibody structure and engineering considerations for the design and function of Antibody Drug Conjugates (ADCs). Oncoimmunology. 2018, VOL. 7, NO. 3, e1395127 Antibody Structure • Linker Properties • Forms the chemical connection between the antibody and payload • Main function is to stabilize the cytotoxic payload while in circulation and allowing release of the payload when the ADC is antigen-bound or internalized • A majority of linkers are designed to allow for payload release after internalization of the ADC • Cleavable: releases the active metabolite intracellularly after cleavage via enzymes, hydrolysis, Choice of linker is also a key determinant of or reduction of disulfide bonds biodistribution, therapeutic activity and • Non-cleavable: complete pharmacokinetics and represents a fine degradation of the antibody backbone before the active balance between therapeutic value/toxicity metabolite is releases and distribution

Hoffmann RM, Coumbe BGT, Josephs DH, Mele S, Ilieva KM, Cheung A, et al. Antibody structure and engineering considerations for the design and function of Antibody Drug Conjugates (ADCs). Oncoimmunology. 2018, VOL. 7, NO. 3, e1395127 Drug to antibody ratio (DAR) • Determined by the linker utilized and is an • Position and number of payloads bound to essential factor affecting therapeutic toxicity with the antibody can have profound effects on: an increased DAR resulting in increased toxicity. • the binding to the antigen, • While a high DAR increases the potency of the • the aggregation of the ADC, ADC, it can adversely affect pharmacokinetics • the pharmacokinetic characteristics of and distribution. the antibody construct, • Historically, the DAR has been limited to an • the safety profile of the ADC average range of 2-4 because ADCs with a • Improving the antibody site for linker higher DAR were prone to increased plasma conjugation has been greatly enhanced clearance largely due to hepatic ADC uptake. through advancements in protein engineering

Hamblett KJ, Senter PD, Chace DF, Sun MM, Lenox J, Cerveny CG, et al. Effects of drug loading on the antitumor activity of a drug conjugate. Clin Cancer Res. 2004;10:7063-70. Lyon RP, Bovee TD, Doronina SO, Burke PJ, Hunter JH, Neff-LaFord HD, et al. Reducing hydrophobicity of homogeneous antibody-drug conjugates improves pharmacokinetics and therapeutic index. Nat Biotechnol. 2015;33:733-5. Sun X, Ponte JF, Yoder NC, Laleau R, Coccia J, Lanieri L, et al. Effects of Drug-Antibody Ratio on Pharmacokinetics, Biodistribution, Efficacy, and Tolerability of Antibody-Maytansinoid Conjugates. Bioconjug Chem. 2017;28:1371-81. Hamblett, K.J. Effects of Drug Loading on the Antitumor Activity of a Monoclonal Antibody Drug Conjugate. Clin. Cancer Res. 2004, 10, 7063–7070 Mechanism of Action 1. The ADC travels through the systemic circulation to the tumor tissue 2. The antibody binds to the target antigen on the cell surface 3. The ADC complex is then internalized (majority, but not all ADCs) 4. If the ADC has a cleavable linker this is cleaved releasing the cytotoxic payload intracellularly 5. If the linker is non-cleavable, lysosomal degradation of the antibody backbone occurs with release of the cytotoxic payload 6. Microtubule inhibition or other action occurs via binding of the cytotoxic payloads to tubulin (specific to cytotoxic payload utilized) 7. Cell death/apoptosis 8. Bystander Effect - Diffusion of cytotoxic payload across the cell membrane can result in cell death of neighboring cells

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296

Birrer MJ, Moore KN, Betella I, Bates RC. Antibody-Drug Conjugate-Based Therapeutics: State of the Science. J Natl Cancer Inst. 2019;111:538-49. Mechanism of Action 1. The ADC travels through the systemic circulation to the tumor tissue 2. The antibody binds to the target antigen on the cell surface

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296

Birrer MJ, Moore KN, Betella I, Bates RC. Antibody-Drug Conjugate-Based Therapeutics: State of the Science. J Natl Cancer Inst. 2019;111:538-49. Mechanism of Action 1. The ADC travels through the systemic circulation to the tumor tissue 2. The antibody binds to the target antigen on the cell surface 3. The ADC complex is then internalized (majority, but not all ADCs) 4. If the ADC has a cleavable linker this is cleaved releasing the cytotoxic payload intracellularly 5. If the linker is non-cleavable, lysosomal degradation of the antibody backbone occurs with release of the cytotoxic payload 6. Microtubule inhibition or other action occurs via binding of the cytotoxic payloads to tubulin (specific to cytotoxic payload utilized) 7. Cell death/apoptosis 8. Bystander Effect - Diffusion of cytotoxic payload across the cell membrane can result in cell death of neighboring cells

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296

Birrer MJ, Moore KN, Betella I, Bates RC. Antibody-Drug Conjugate-Based Therapeutics: State of the Science. J Natl Cancer Inst. 2019;111:538-49. Mechanism of Action 1. The ADC travels through the systemic circulation to the tumor tissue 2. The antibody binds to the target antigen on the cell surface 3. The ADC complex is then internalized (majority, but not all ADCs) 4. If the ADC has a cleavable linker this is cleaved releasing the cytotoxic payload intracellularly 5. If the linker is non-cleavable, lysosomal degradation of the antibody backbone occurs with release of the cytotoxic payload 6. Microtubule inhibition or other action occurs via binding of the cytotoxic payloads to tubulin (specific to cytotoxic payload utilized) 7. Cell death/apoptosis 8. Bystander Effect - Diffusion of cytotoxic payload across the cell membrane can result in cell death of neighboring cells

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296

Birrer MJ, Moore KN, Betella I, Bates RC. Antibody-Drug Conjugate-Based Therapeutics: State of the Science. J Natl Cancer Inst. 2019;111:538-49. Mechanism of Action 1. The ADC travels through the systemic circulation to the tumor tissue 2. The antibody binds to the target antigen on the cell surface 3. The ADC complex is then internalized (majority, but not all ADCs) 4. If the ADC has a cleavable linker this is cleaved releasing the cytotoxic payload intracellularly 5. If the linker is non-cleavable, lysosomal degradation of the antibody backbone occurs with release of the cytotoxic payload 6. Microtubule inhibition or other action occurs via binding of the cytotoxic payloads to tubulin (specific to cytotoxic payload utilized) 7. Cell death/apoptosis 8. Bystander Effect - Diffusion of cytotoxic payload across the cell membrane can result in cell death of neighboring cells

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296

Birrer MJ, Moore KN, Betella I, Bates RC. Antibody-Drug Conjugate-Based Therapeutics: State of the Science. J Natl Cancer Inst. 2019;111:538-49. Mechanism of Action 1. The ADC travels through the systemic circulation to the tumor tissue 2. The antibody binds to the target antigen on the cell surface 3. The ADC complex is then internalized (majority, but not all ADCs) 4. If the ADC has a cleavable linker this is cleaved releasing the cytotoxic payload intracellularly 5. If the linker is non-cleavable, lysosomal degradation of the antibody backbone occurs with release of the cytotoxic payload 6. Microtubule inhibition or other action occurs via binding of the cytotoxic payloads to tubulin (specific to cytotoxic payload utilized) 7. Cell death/apoptosis 8. Bystander Effect - Diffusion of cytotoxic payload across the cell membrane can result in cell death of neighboring cells

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296

Birrer MJ, Moore KN, Betella I, Bates RC. Antibody-Drug Conjugate-Based Therapeutics: State of the Science. J Natl Cancer Inst. 2019;111:538-49. Mechanism of Action 1. The ADC travels through the systemic circulation to the tumor tissue 2. The antibody binds to the target antigen on the cell surface 3. The ADC complex is then internalized (majority, but not all ADCs) 4. If the ADC has a cleavable linker this is cleaved releasing the cytotoxic payload intracellularly 5. If the linker is non-cleavable, lysosomal degradation of the antibody backbone occurs with release of the cytotoxic payload 6. Microtubule inhibition or other action occurs via binding of the cytotoxic payloads to tubulin (specific to cytotoxic payload utilized) 7. Cell death/apoptosis 8. Bystander Effect - Diffusion of cytotoxic payload across the cell membrane can result in cell death of neighboring cells

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296

Birrer MJ, Moore KN, Betella I, Bates RC. Antibody-Drug Conjugate-Based Therapeutics: State of the Science. J Natl Cancer Inst. 2019;111:538-49. Mechanism of Action 1. The ADC travels through the systemic circulation to the tumor tissue 2. The antibody binds to the target antigen on the cell surface 3. The ADC complex is then internalized (majority, but not all ADCs) 4. If the ADC has a cleavable linker this is cleaved releasing the cytotoxic payload intracellularly 5. If the linker is non-cleavable, lysosomal degradation of the antibody backbone occurs with release of the cytotoxic payload 6. Microtubule inhibition or other action occurs via binding of the cytotoxic payloads to tubulin (specific to cytotoxic payload utilized) 7. Cell death/apoptosis 8. Bystander Effect - Diffusion of cytotoxic payload across the cell membrane can result in cell death of neighboring cells

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296

Birrer MJ, Moore KN, Betella I, Bates RC. Antibody-Drug Conjugate-Based Therapeutics: State of the Science. J Natl Cancer Inst. 2019;111:538-49. Target Antigens Target antigen Function Expression ADC Folate receptor alpha Transmembrane protein involved in transport of Ovarian: 80-96% Mirvetuximab soravtansine folate into cells necessary for metabolism, DNA STRO-002 synthesis, repair, and proliferation Endometrial: 41% MORAb-202

NaPi2b Sodium-dependent phosphate transport protein Ovarian: 80-100% Lifastuzumab vedotin expressed in epithelial cells. XMT-1536 Tissue Factor Thromboplastin or factor III, involved in extrinsic Ovarian: 96% Tisotumab vedotin coagulation pathway leading to generation of thrombin/clot formation. Endometrial: 15%

Cervical: 34% Mesothelin Hypothesized to be involved in cell adhesion. Ovarian: 60-88% Anetumab ravtansine Expressed on mesothelial cells. DMOT4039A BMS-986148 MUC16 Transmembrane protein with role in Ovarian: 80% DMUC4064A adhesion/peritoneal metastases. CA-125 represents the extracellular, cleaved portion.

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296 ADC Target Antigen/ Cytotoxic Payload and Linker DAR Phase of Antibody mechanism of action development Mirvetuximab soravtansine Folate receptor α Soravtansine (Maytansinoid Sulfo-PDB 3-4 Phase III (ImmunoGen, Inc) DM4) Humanized IgG1 (M9346A) Microtubule inhibitor STRO-002 (Sutro Folate receptor α Proprietary 3-aminophenyl Proprietary cleavable 4 Phase I dose Biopharma, Inc.) hemiasterlin agent: SC209 linker: SC239 escalation/ Human anti-FRα IgG1 antibody expansion ongoing (SP8166) Proprietary tubulin-targeting payload

MORAb-202 (Eisai Inc.) Folate receptor α Eribulin mesylate Cathepsin B-cleavable 4 Phase I ongoing linker (NCT03386942) Humanized anti-human FRα Microtubule inhibitor

XMT-1536 NaPi2b Proprietary auristatin Proprietary hydrophilic 10-12 Phase I dose (Mersana Therapeutics) derivative (auristatin F-HPA) polymer scaffold escalation/ Humanized monoclonal expansion ongoing (NCT03319628) antibody (SLC34A2) Microtubule inhibitor

Lifastuzumab vedotin NaPi2b MMAE Cleavable 3-4 Randomized phase (LIFA/DNIB0600A) maleimidocaproyl-valyl- II completed; further (Genentech, Inc.) Humanized monoclonal Microtubule inhibitor citrullinyl-p- development antibody (SLC34A2) aminobenzyloxycarbonyl discontinued (mc-val-cit-PABC) Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of print. PMID: 32463296 ADC Target Antigen/ Cytotoxic Payload and Linker DAR Phase of Antibody mechanism of action development Tisotumab vedotin (HuMax- Tissue factor MMAE Protease cleavable Phase II ongoing; TF-ADC; TF011-MMAE) valine-citrulline linker Phase III in cervical (Seattle Genetics, Inc.) Fully human monoclonal Microtubule inhibitor cancer ongoing antibody Anetumab ravtansine (BAY Mesothelin Ravtansine/ Sulfo-PDB 3.2 Phase II ongoing 94-9343) DM4 (Bayer) Fully human IgG1 (MF-T) Microtubule inhibitor DMOT4039A (RG7600) Mesothelin MMAE Protease cleavable 3.5 Phase II (Genentech, Inc.) valine-citrulline linker Humanized IgG1 antibody Microtubule inhibitor (h7D9.v3)

BMS-986148 Mesothelin Duocarmycin-related Protease cleavable 1.4 Phase I/IIa ongoing (Bristol-Myers Squibb) valine-citrulline linker Fully human IgG1 monoclonal DNA alkylation antibody Sofituzumab vedotin MUC16 MMAE Protease cleavable 3.5 Phase I completed; (DMUC5754A) valine-citrulline linker further development (Genentech, Inc.) Humanized IgG1 monoclonal Microtubule inhibitor (maleimidocaproyl- discontinued antibody valine-citrulline-p- aminobenzyloxycarbonyl) Anti-MUC16 TDC MUC16 MMAE Cysteine-engineered 2 Phase I completed (DMUC4064A) THIOMABTM (Genentech, Inc.) Humanized anti-MUC16 IgG1 Microtubule inhibitor

Calo CA, O'Malley DM. Antibody-drug conjugates for the treatment of ovarian cancer. Expert Opin Biol Ther. 2020 Jun 8:1-13. doi: 10.1080/14712598.2020.1776253. Online ahead of NCT02146313 print. PMID: 32463296 Thank you

The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute