Her-2 negative MBC 10/25/2016

Objectives General principles Endocrine agents for HR+ pts- sequencing/combinations Addition of biological agents Clinical scenarios Triple negative subsets AR positive disease PARP inhibitors in BRCA mutations Immunotherapy

General principles ER/PR positive, Her2 negative: - symptomatic visceral dz/rapidly progressing: chemo (1-2 drugs) for 4-6 months  change to AET - asymptomatic, low volume, indolent dz: AET  if response duration < 6 months  change to chemo Triple negative: single agent or doublet based on tumor burden and need for rapid response Triple positive: Her-2 trumps ER, anti-her therapy incorporated with rest of the regimen

Monitoring response Physical exam: breast mass, LN, superficial lumps Tumor markers: CEA, CA 27.29, Ca 15-3 Imaging: PET not recommended routinely Bone scan once or twice yearly CT scans 3-4 months CTCs- insufficient data from trials on CTCs to help tailor therapy, not used outside of clinical trials

FIRST trial: 1st line Fulvestrant Vs Anastrozole Phase II trial: N = 205, prior adj endocrine Rx completed 12 months prior to randomization (~25% pts had received AET in both arms), Fulvestrant dosing 500 mg CBR: 73% vs 67% (p = .386) and ORR: 36 % and 35.5% Median TTP: 23 vs 13 months (HR = 0.66, P = .01) Median OS: 54 vs 48 months (HR = 0.70, P = .041), OS data colletion not pre-planned Serious AEs were similar between fulvestrant (23.8%) and anastrozole (21.4%) FALCON: phase III trial with similar trial design, completed accrual. Robertson et al. J Clin Oncol. 2009 Ellis et al. J Clin Oncol. 2015

FALCON: Phase III trial of Fulvestrant vs Anastrozole Eligibility: Postmenopausal women Locally advanced or metastatic ER/PR pos, Her-2 neg No prior endocrine therapy One prior chemo allowed R Fulvestrant N =230 Primary endpoints: PFS Secondary endpoint: OS, RR, CBR, duration of response, safety/QOL

FALCON: Results Patients: Median age 63-64yrs, 87% metastatic disease, about 50% pts with visceral disease in both arms PFS: 16 mon vs 13 mon (HR 0.8, p = 0.0486) RR and CBR did not differ, duration of response favored fulvestrant at 20 mon vs 13 mon Sub-group visceral vs non-visceral disease: fulvestrant better for non-visceral disease PFS 22.3 months vs 13.8 months AEs- Fulvestrant vs Anastrozole: Arthralgias (17% vs 10%) Hot flashes (11% vs 10%) Nausea (10% for both) Ellis et al. presented at ESMO 2016

Fulvestrant + Anastrozole: FACT Open-label, randomized, phase III study, 1st line, N = 514, adjuvant tamoxifen use in 68% patients TTP 11 vs 10 months (HR= 0.99; P = .91) Median OS was 38 months for both (HR = 1.0; P = 1.00) Combination offered no clinical efficacy advantage over anastrozole monotherapy Caveats: Fulvestrant was 250 mg dosing (CONFIRM) & significant number of pts with prior exposure to endocrine therapy Bergh et al. J Clin Oncol. 2012

Fulvestrant + Anastrozole: SWOG S0226 Phase III, N = 707 post-menopausal, no prior Rx for metastatic disease Fulvestrant dosing 250 mg (higher dose allowed later), 41% crossover from AI to fulvestrant at the time of progression, 40% de novo metastatic disease Pts stratified according to prior receipt of adjuvant tamoxifen (40% pts were exposed to tamoxifen), adjuvant AI allowed if completed >12 months prior Median TTP: 13.5 vs 15 months (HR 0.80; P=0.007), Median OS: 41 vs 48 months (HR 0.81; P=0.05) No prior tamoxifen: PFS 12.6 vs 17 months (HR 0.74; p = 0.006) Prior tamoxifen exposure: PFS 14.1 vs 13.5 months, (HR 0.89; p = 0.37) Similar difference observed for OS as well for pts with and w/o tamoxifen exposure Mehta et al. N Engl J Med. 2012

CDK 4/6 Complex Regulates Proliferation

CDK 4/6 Inhibition Preferentially Inhibits Luminal Estrogen Receptor-Positive Breast Cancer Cell Lines in Vitro IC50, nM Subtype Luminal Non-luminal/post EMT HER2 amplified Non-luminal Immortalized Finn RS, et al. Breast Cancer Res. 2009;11(5):R77 11

Preclinical Activity of Combination Therapy: AI and CDK4/6i Infante JR et al. TAT 2014; abstr O4.4; Munster PN et al. J Clin Oncol 2014;32:5s:abstr 533.

Palbociclib 125 mg QDa + Letrozole 2.5 mg QD PALOMA-1: Phase 2 Study of ER+, HER2– Locally Recurrent or Metastatic Breast Cancer N=66 1:1 Part 1 Post- menopausal ER+, HER2– BC status No prior treatment for advanced disease R A N D O M I Z T Palbociclib 125 mg QDa + Letrozole 2.5 mg QD Letrozole 2.5 mg QD Part 2 N=99 ER+, HER2– BC with CCND1 amplification and/or loss of p16 Key Eligibility Criteria Measurable disease (RECIST 1.0) or bone-only disease ECOG PS of 0 or 1 Adequate blood counts and organ function No prior/current brain metastases a Schedule is 3 weeks on and 1 week off - About a third of pts received prior endocrine therapy and half received chemotherapy in adjuvant setting (12 month washout from endocrine therapy required)

Dose: 125 mg PO QD x 21 days, every 28 days Response rate: 36% vs 27% PALOMA-1: Results Dose: 125 mg PO QD x 21 days, every 28 days Response rate: 36% vs 27% Median PFS: 20 vs 10 months (p = 0.0004) Median OS: 37.5 vs 33 months (p = 0.42) Unselected (PFS 26 vs 6 mo) Cyclin D amp and/or P16 loss (PFS 18 vs 11 mo) Overall Survival Finn RS, et al. Lancet Oncology. 2015

Palbociclib: Toxicity Treatment Palbo + LET LET alone Grade 1–2 3 4 Neutropenia 17 (20%) 40 (48%) 5 (6%) 3 (4%) 1 (1%) Leucopenia 20 (24%) 16 (19%) 2 (3%) Fatigue 30 (36%) 2 (2%) 17 (22%) Anemia 24 (29%) 4 (5%) Nausea 19 (23%) 9 (12%) Arthralgia 18 (22%) 10 (13%) Alopecia NA Diarrhea 14 (17%) 8 (10%) Hot flush 17 (21%) Thrombocytopenia 12 (14%) Decreased appetite Dyspnea 11 (13%) Nasopharyngitis 13 (16%)

PALOMA-2: Phase III confirmation Palbociclib 125 mg QDa + Letrozole 2.5 mg QD 2:1 Randomization HR+, HER2– ABC Post-menopausal No prior therapy for ABC N=666 Stratification: Disease site Prior hormonal therapy DFI from end of neo/adjuvant therapy Placebo + Letrozole 2.5 mg QD Primary endpoints: PFS Secondary endpoint: OS, RR, CBR, patient reported outcomes and safety a Schedule is 3 weeks on and 1 week off Finn et al. ASCO 2016

PALOMA-2: Results Median PFS - 24.8 vs 14.5 months (HR 0.58, p < 0.000001) OS data is immature ORR - 42% vs 35% ( p = 0.031) CBR - 85% vs 70% (p < 0.0001) AEs: Neutropenia (80% vs 6%) Fatigue (37% vs 27%) Nausea (35% vs 26%) Arthralgias (33% both) Alopecia (33% vs 16%) Finn et al. ASCO 2016

Placebo (3 wks on/ 1wk off) PALOMA-3: Study Design Palbociclib (125 mg QD; 3 wks on/1 wk off) + Fulvestrant† (500 mg IM q4w) HR+, HER2– ABC Pre-/peri-* or post-menopausal Progressed on prior endocrine therapy: On or within 12 mo adjuvant On therapy for ABC ≤1 prior chemotherapy regimen for advanced cancer *All received goserelin. n=347 2:1 Randomization N=521 Stratification: Placebo (3 wks on/ 1wk off) + Fulvestrant† (500 mg IM q4w) Visceral metastases Sensitivity to prior hormonal therapy Pre-/peri- vs Post- menopausal n=174 Post-menopausal patients must have progressed on prior aromatase inhibitor therapy. †administered on Days 1 and 15 of Cycle 1. Turner et al. New Engl J Med. 2015

PALOMA-3: Fulvestrant +/- palbociclib Turner et al. New Engl J Med. 2015

Monaleesa-2: Ribociclib Ribociclib 600 mg QDa + Letrozole 2.5 mg QD HR+, HER2– ABC Post-menopausal No prior therapy for ABC Previous neo/adjuvant NSAI not allowed unless DFI > 12 months Exclusion: Inflammatory cancer, brain mets and cardiac disease including increased QTc N=223 Stratification: Disease site- liver or lung mets Placebo + Letrozole 2.5 mg QD Primary endpoints: PFS Secondary endpoint: OS, RR, CBR, QOL assessments and safety a Schedule is 3 weeks on and 1 week off Hortobaygi et al. New Engl J Med 2016

Monaleesa-2: Patient characteristics Hortobaygi et al. New Engl J Med 2016

Kaplan–Meier Analysis of Progression-free Survival. After 18 months, the PFS was 63% in the ribociclib group and 42% in the placebo The median PFS not reached in the ribociclib group, 14.7 mon in the placebo group Hortobaygi et al. New Engl J Med 2016

Subgroup Analysis of Progression-free Survival. Figure 2. Subgroup Analysis of Progression-free Survival. The progression-free survival benefit in the ribociclib group (as assessed by investigators) was observed across all predefined subgroups (overall hazard ratio, 0.56; 95% CI, 0.43 to 0.72; P<3.29×10−6 for superiority) (dashed line). Among the patients who had received previous endocrine therapy, those taking nonsteroidal aromatase inhibitors (NSAIs) or other therapies not listed here had not received tamoxifen. Previous endocrine therapy and chemotherapy include neoadjuvant and adjuvant treatment. The size of the data points is proportional to the number of patients included in the subgroup analysis. ECOG denotes Eastern Cooperative Oncology Group. Hortobaygi et al. New Engl J Med 2016

Adverse Events. Monaleesa-2: AEs Hortobaygi et al. New Engl J Med 2016

Abemaciclib: 150mg or 200mg orally Q12H Days 1-28 of a 28-day cycle

Differences between CDK4/6 inhibitors Neutropenia (%) Fatigue (%) Nausea Diarrhea QTc prolongation (%) G3/4 All Palbociclib 54 73 2 24 16 4 21 NR Abemaciclib 19 40 43 57 6 68 Ribociclib 29 46 3 22 8% Abemaciclib has CNS penetration Abemaciclib had higher monotherapy response rate Abemaciclib is continuous daily dosing, others are 3wks on/1 wk off

Exemestane + Everolimus: BOLERO-2 Phase III, randomized, double blind, international trial, N = 724 Patients that recurred or progressed during/after nonsteroidal aromatase inhibitors  exemestane +/- everolimus PFS: 7.8 months vs 3.2 months, ORR 9.5 vs 0.4 percent OS data: 31 months vs 26.6 months (HR= 0.89; p= 0.14) Poststudy therapies were balanced across arms, except for chemotherapy (53% vs 63% in placebo arm) AEs, grade 3/4: stomatitis (8%), dyspnea (4 %), noninfectious pneumonitis (3%), and elevated liver enzymes (3 %) Baselga et al. New Engl J Med. 2012

Future Directions: HR+ subset PI3K inhibitors: - Belle-2 trial: N = 1147, progressed on AI, Fulvestrant +/- Buparlisib - PFS 6.9 vs 5 mo(HR 0.78, p< 0.001) - PI3K mutation by ctDNA- PFS 7 vs 3.2 mo (HR 0.56, p< 0.001) - AEs: deranged LFTs, fatigue, rash, diarrhea, hyperglcemia (gr 3/4 events in 77%) - Phase III trials with more specific PI3K inhibitor alpelisib with fuvestrant ongoing Selective estrogen receptor degraders: - Phase I trials with RAD1901 which can bind to ER and degrade it (ESR mutations) HDAC inhibitiors: - Exemestane +/- Entinostat ongoing in HR+ MBC who have progressed on NSAI CDK 4/6 inhibitors: - being tested in Her-2 positive MBC & in adjuvant as well as neoadjuvant settings - combinations with PI3K inhibitors and mTOR inhibitors being studied

Clinical cases

TNBC: Molecularly Heterogeneous Name Characteristic gene expression “LAR”, luminal AR AR, ER (no ER by IHC), prolactin, HER4 “MES”, mesenchymal Cell cycle, damage response, growth factor “BLIS”, basal-like immunosuppressed Basal-like, ↓T-, B-, NK-cell and cytokine pathways “BLIA”, basal-like immune activated Basal-like, ↑immunoregulatory pathways, STAT Overlap with PAM50 Some overlap with “TNBCtype” All characterized by basal, immune, and stromal signatures Burstein MD et al. Clin Cancer Res 2015

Sequencing chemotherapy in TNBC Anthracyclines Taxanes: nab-paclitaxel Platinum based (single agent or combo with gem/taxane) Eribulin Capecitabine +/- Ixabepilone Oral Cytoxan + MTX Irinotecan Others- vinorelbine, pemetrexed

Targeting AR in TNBC MDV3100-11 Background Phase II study of bicalutamide in 26 patients with AR+ TNBC: CBR 19%, mPFS 12 weeks Enzalutamide > bicalutamide in mCRPC Endpoints: 1°: CBR@16wks 2°: CBR@24wks, PFS, OS etc AR biomarker MDV3100-11 AR+ mTNBC Any prior Rx Enzalutamide 160 mg/d po 165 screened patients 89 AR > 10% 75 evaluable 61% 1st /2nd line Endpoint CBR16 35% (24-46%) CBR24 29% (20-41%) RR 8% Median PFS 14 wks (8-19) Traina et al. ASCO 2015 32

PREDICT AR− PREDICT AR+ Biomarker to predict sensitivity to Enzalutamide in TNBC: multigene RNA based assay 64 PREDICT AR− 8 16 24 32 40 52 Time (weeks) PREDICT AR+ Total, n (%) 62 (53%) 56 (47%) CBR16, % (95% CI) n 11% (5, 21) n = 7 39% (27, 53) n = 22 CBR24, % 6% (2, 16) n = 4 36% (24, 49) n = 20 0–1 Prior Lines 2+ Prior Lines Active Confirmed RR PREDICT AR+ 8 16 24 32 40 52 64 Time (weeks) Parker JS et al. ASCO 2015

PARP Inhibitors Phase II trial in metastatic triple negative patients - Iniparib N = 123, carbo+gem +/- inaparib CBR 34% to 56% (P=0.01) , ORR 32% to 52% (P=0.02) PFS 3.6 months to 5.9 months (HR 0.59; P=0.01) OS 7.7 months to 12.3 months (HR 0.57; P=0.01) No significant difference was seen between the two groups in the rate of adverse events Phase III trial with 519 pts, no improvement in PFS or OS, exploratory analysis showed PFS and OS benefit in 2nd/3rd line settings which need to be explored further Olaparib and Veliparib investigated in BRCA mutated patients Shaughnessy et al. New Eng J Med. 2011 Shaughnessy et al. J Clin Oncol. 2014

Parp Inhibitors

Phase II single arm trial Eligible: gBRCA carriers, heavily pretreated 4th+ line breast Platinum-refractory ovarian Gemcitabine-resistant pancreatic Hormone refractory, 2nd+ line prostate Olaparib 400 mg bid N=298 evaluable for 1° (RR) - Mostly ovarian 62 breast cancer patients 60% BRCA1 30 ER+, 32 ER- Kaufman B et al. J Clin Oncol. 2015

Olaparib in gBRCA+ Tumors: Results Ovarian (n=193) Breast (n=62) Pancreas (n=23) Prostate (n=8) Other (n=12) Total (n=298) RR 31% 13% 22% 50% 8% 26% Prior platinum - 4 (9%) 3 (20%) 1 (25%) 1 (11%) NR Naive 4 (20%) 2 (25%) 3 (75%) 0 (0%) No difference BRCA1, 2 Gr3+ AE > 5%: Fatigue (6%), anemia (17%), Abd pain (6%) Breast cancer: RR: ER + 12%, ER- 13% 6month PFS 29% Median PFS 3.7 months, OS 11 months Kaufman B et al. J Clin Oncol. 2015

Immunotherapy SABCS 2014 A Phase Ib Study of Pembrolizumab (MK-3475) in Patients With Advanced Triple-Negative Breast Cancer SABCS 2015 Avelumab (MSB0010718C), an anti-PD-L1 antibody, in patients with locally advanced or metastatic breast cancer: a phase Ib JAVELIN Solid Tumor trial ASCO 2016 Phase Ib trial of atezolizumab in combination with nab-paclitaxel in patients with metastatic triple-negative breast cancer Nanda R et al. SABCS 2014 Dirix L et al. SABCS 2015 Adams et al. ASCO 2016

Keynote-012: Pembrolizumab in TNBC Phase Ib trial: N= 32, 65/111 (58.6%) had PD-L1+ tumors ORR in 5/27 evaluable = 18.5%, 3 responders remain on Rx for ≥ 1 yr Median time to response 18 weeks, median duration of SD was 17 weeks (7-32 wks), median PFS 1.9 months Any AE = 56%, grade 3+ = 16% Nanda et al, JCO; 34: 2016

Keynote-012: Pembrolizumab in TNBC Nanda et al. J Clin Oncol. 2016

Keynote-012: Take home points Pembrolizumab is effective and relatively tolerable, time to response was long ~4 months but responding pts had durability RR may have been affected by heavily pre-treated population and pts with high proliferative index as evidenced by LDH Higher dosing may have caused more toxicity and the more conventional dosing at 200 mg every 3 weeks may be better tolerated Small sample size limits definitive conclusions about efficacy Phase II and III trials are underway

Avelumab Phase Ib (10mg/kg q2wk) Endpoint All (n=168) TNBC (n=58) ORR 5% (2-9%) 9% (3-19%) RR + SD 28% 31% Grade 3+ AE 14% (all grade AE 68.5%) Any AE ≥ 10% Fatigue (19%), infusion rxn (14%), nausea (13%), immune (10%) Time to response 11wks (6-18) Duration of response 28 wks (6-NE) 33% RR in PDL1+ > 10% immune cell hotspots Dirix L et al. SABCS 2015

Atezolizumab in TNBC Toxicity Overall well tolerated Phase Ib expansion trial 21 PD-L1 positive enrolled, 19% ORR 24 week PFS 27% Toxicity Overall well tolerated Toxicities- thyroid disorders, colitis, hepatitis, aseptic meningitis, DIC Emens L, et al. AACR 2015 Abstract 2859

Atezolizumab + nab-Paclitaxel in TNBC: Phase Ib Trial Nab-paclitaxel 125 mg/m2 weekly, 3 weeks on, one week off with atezolizumab every 2 weeks; < 3 prior lines of Rx 32 evaluable patients; response independent of PD-L1+ Adams et al, J Clin Oncol 34, 2016 (suppl; abstr 1009)

Case 52 y/o female with stage IIB TNBC, BRCA neg, underwent neo-adjuvant chemotherapy with AC->T, mastectomy, AND, adjuvant radiation therapy. She was found to have chest wall nodules at the time of reconstruction a year later, scan suggested mets to nodal station in chest/abd and bones. She underwent therapy with carbo-gem with response lasting 8 months. She refused immunotherapy clinical trial participation. She has decent PS and wants to continue therapy, would you send multiplex genomic assay?

Summary TNBC molecular heterogeneity is a challenge. Unlike ER+ and HER2+, “TNBC” does not describe anything targetable. Promising non-chemotherapy options- Immune checkpoint inhibitors, AR-targeted drugs, and PARP inhibition. However in all cases only a subset benefit. Good predictive biomarkers will be as important as good drugs.