Targeted Therapy in an Era of Genomic Medicine. George W. Sledge MD Stanford University

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1 Targeted Therapy in an Era of Genomic Medicine George W. Sledge MD Stanford University

2 Why Do Women Die of Breast Cancer? Bad biology Avoidable deaths

3 Important subsets of breast cancers defined by molecular markers and by clinical treatment options ER+ All Breast Cancer HER2+ Lesson: Breast cancer is a family of diseases, not one disease. Basaloid

4 2+ 3+

5 Inhibition of Estrogen-Dependent Growth Antiestrogens Estrogen biosynthesis Nucleus Estrogen biosynthesis Aromatase inhibitors Tumor cell Inhibition of cell proliferation

6 Estrogen receptor (ER) is the target of endocrine treatment and is expressed in ~70% of breast cancers EBCTCG, Lancet 2011 Endocrine treatment, is an effective targeted therapy for ER+ patients However, a significant fraction of patients develop resistance Recurrence BC mortality 13% 10% 33% 24%

7 Patients with Disease Progression on One Hormone Therapy May Respond to Another Hormone Therapy 40% 30% 25% 15% 1 st Line 2 nd Line 3 rd Line 4 th Line An optimal sequence of hormone therapies has not been defined R E S I S T A N C E Bavior C et al. Ann Oncol. 2012, Epub Feb 8; Osborne Ck, Schiff R. Ann Res Med.2011;62:

8 Resistance to Hormonal Therapy: Cross-Talk

9 Crosstalk between ER and mtor Signaling mtorc1 activates ER in a ligand-independent fashion 1 Estradiol suppresses apoptosis induced by PI3K/mTOR blockade 2 Hyperactivation of the PI3K/mTOR pathway is observed in endocrineresistant breast cancer cells 3 1. Yamnik, RL. J Biol Chem 2009; 284(10): Crowder, RJ. Cancer Res 2009;69: mtor is a rational target to enhance the efficacy of

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11 Breast Cancers Dividing

12 CDK 4/6 Inhibition: Mechanism of Action

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14 PROLIFERATION Ki-67 STK15 Survivin Cyclin B1 MYBL2 INVASION Stromolysin 3 Cathepsin L2 HER2 GRB7 HER2 Oncotype DX 21 Gene Recurrence Score (RS) Assay 16 Cancer and 5 Reference Genes From 3 Studies ESTROGEN ER PR Bcl2 SCUBE2 GSTM1 BAG1 CD68 REFERENCE Beta-actin GAPDH RPLPO GUS TFRC RS = x HER2 Group Score x ER Group Score x Proliferation Group Score x Invasion Group Score x CD x GSTM x BAG1 Category RS (0 100) Low risk RS < 18 Int risk RS 18 and < 31 High risk RS 31

15 B-20: Absolute % Increase in DRFS at 10 Years Benefit of Chemo Depends on RS Low RS<18 Int RS18-30 n = 353 n = 134 High RS 31 n = % 20% 30% 40% % Increase in DRFS at 10 Yrs (mean ± SE)

16 The HER Family of Receptors Ligands Ligandbinding domain TGF-α EGF Epiregulin Betacellulin HB-EGF Amphiregulin No ligandbinding activity* Heregulin Heregulin (neuregulin-1) Epiregulin HB-EGF Neuregulins-3, -4 Tyrosine kinase Erb-B1 domain HER1 HER2 dimerizes with other members of EGFR the HER family. Roskoski. Biochem Biophys Res Commun. 2004;319:1. Rowinsky. Annu Rev Med. 2004;55:433. Erb-B2 HER2 neu Erb-B3 HER3 Erb-B4 HER4

17 Fluorescence In Situ Hybridization Test Measures HER2 Gene Amplification Chromosome 17 centromere HER2 gene HER2-normal Ratio <2.0 HER2-amplified Ratio 2.0 FISH tests are designed to detect amplification of the PathVysion HER2 PI. Revised gene May 2004.

18 Joint Analysis: Long-Term Follow-Up Perez, E et al. J Clin Oncol 2014

19 Post-Trastuzumab Therapeutic Options: 1. Block kinase -lapatinib -neratinib 2. Prevent dimerization -pertuzumab 3. MAb-toxin delivery -T-DM1 4. Downstream blockade -PI3K, mtor

20 HERs Hook Up

21 Pertuzumab Prevents Hook-Ups Herman ten Kate: The Chaperone

22 Targeted Therapies for HER2+ Breast Cancer: Trastuzumab, Lapatinib, and T-DM1 Trastuzumab P P Inhibition of microtubule polymerization P Emtansine release Nucleus Lapatinib HER2 Lysosome T-DM1 Antibody: Trastuzumab Cytotoxic: DM1 Stable linker: MCC Adapted from LoRusso PM, et al. Clin Cancer Res 2011; Spector NL, Blackwell KL. J Clin Oncol 2009; P P P Internalization Emtansine

23 Breast Cancer: Subtypes Reflect Genomic Complexity Genome-wide Circos plots of somatic rearrangements Stephens, PJ et al. Nature 462: , 2009.

24 TNBC: Genomic Chaos Shah, S et al. Nature 2012

25 Single Nucleus Genome Sequencing Triple-Negative Breast Cancer Nature 512; , 2014

26 TNBC Heat Map derived from Single Nucleus Genome Sequencing 374 clonal mutations 154 subclonal mutations Three subpopulations: A1: 66 A2: % damage protein function Nature 512; , 2014

27 Breast Cancer as Whack-a-Mole Rapid emergence of compensatory mechanisms of resistance

28 Chaos Reigns

29 25 Patients with HER2 Somatic Mutations Each blue circle represents a patient. From 8 publications with a total of 1,499 patients. 20% of patients have mutations at amino acids 309 or % of patients have mutations at amino acids San Antonio Breast Cancer Symposium December 4 8, 2012

30 HER2 Somatic mutations Occur in < 2% of breast cancers Activating mutations IHC and FISH negative Sensitive to small moleciles but not trastuzumab in preclinical models

31 Phase II Clinical Trial of Neratinib for HER2 Mutation Positive Breast Cancer HER2 gene amplification negative Stage IV Breast Cancer Mutation Absent Not Eligible for Study Therapy Tumor DNA Sequencing for HER2 Mutation Mutation Present Study Therapy Neratinib 240 mg P.O. daily days 1-28 each cycle* Participating Institutions 1. Washington University School of Medicine 2. Dana-Farber Cancer Institute 3. Memorial Sloan-Kettering Cancer Center 4. Univ. of North Carolina 5. Stanford University * 4-week Cycle Restage every 2 cycles Continue therapy until disease progression, or unacceptable adverse events. San Antonio Breast Cancer Symposium December 4 8, 2012

32 The Mutational Landscape of Breast Cancer 100 breast cancers genomes analyzed Driver mutations found in at least 40 different cancer genes 73 different combinations of driver mutated cancer genes 28 cancers had a single driver mutation, but some had as many as 6 driver mutations Stephens, PJ et al. Nature 486: 400, 2012

33 Combinations are Hard Toxicity increases significantly with each added drug New toxicities occur Cost of regimen increases dramatically --$8-10K/drug/month

34 The Orphan Disease Era A myriad of rare diseases Many genomic drivers IT-driven Complex biology Uncertain therapeutics Phase III trials difficult

35 Cancers Live in Neighborhoods Can We Enlist the Neighborhood Watch?

36 T Cell Attacking a Cancer Cell Why Doesn t the Immune System do it s Job?

37 The Immune System

38 How$to$Turn$Up$a$T$Cell$ Turning up The Activating Blocking the Inhibiting

39 Augmenting Antibody Activity with Anti-CD137 MAb

40 Anti-CD137 agonistic mab enhances anti breast cancer activity of trastuzumab in vivo while retaining HER2 specificity against HER2-overexpressing breast cancer cell lines and a primary breast tumor.

41 Conclusions Segmenting breast cancer has led to real advances via targeted therapies Resistance continues to be a problem Improved understanding of resistance new therapeutic approaches Genomic analyses may help Novel immunotherapeutic approaches

42 42 Thank You