Dott.ssa Pamela Guglielmini Prof. Francesco Boccardo

The dimension of the problem USA – SEER 2008 182,000 new cases of breast cancer 83,000 women would develop metastatic disease 46,000 women would die of metastatic breast cancer

Advanced Breast Cancer: Heterogeneous Population Requires Tailored Treatments Characteristics Treatment Objectives Symptomatic/ poor PS Palliation Elderly/indolent disease/poor PS Improve TTP & QoL Amenable to locoregional control Increase response rate Young/good PS visceral mts Prolong survival 3

Is metastatic breast cancer a curable disease?

Metastatic breast cancer: improved survival over time 1.0 0.8 0.6 1995–2000 Cumulative survival 1990–1994 0.4 1985–1989 0.2 1980–1984 1974–1979 0.0 12 24 36 48 60 Months Giordano, et al. Proc ASCO 2002

Overall survival curves of 1,544 patients (excluding 37 patients with insufficient information to determine response status) with MBC receiving front-line chemotherapy according to response to therapy. Deaths from any cause were included. Greenberg PAC et al, 1996

Which end points can be achieved in all other patients? Symptoms palliation Quality of life improvement Survival prolongation Objective tumor response is correlated with each of the previous one

Proportion of patients with symptom response according to each objective response category: significant results with both CRF and QoL data. , CR/PR; , SD; , PD. Geels P et al, 2000

Proportion of patients with symptom response according to each objective response category: significant results only QoL data. Const, constipation. , CR/PR; , SD; , PD. Geels P et al, 2000

Which treatment options? Hormone therapy Chemotherapy Biologicals Surgery/radiotherapy Analgesics Bisphosphonates Supportive care (eritropoietin)

Which patients are best candidate to hormonetherapy? Patients characteristics: age/menopausal status Tumor characteristics: DFI duration tumor burden dominant site of disease ER/PgR status previous response to endocrine therapy

Hormonetherapy: which drugs? which sequences? Suppressive treatments Premenopause: ovariectomy, LH-RHa Postmenopause: aromatase inhibitors Competitive treatments Pre/postmenopause: antiestrogens (TAM, TOR) steroidal antiestrogen (Faslodex) progestagens antiprogestins

Invasive Breast Cancer by Age (Year 1998) Premenopausal, and HR+ ≈ 60% Li CL et al. J Clin Oncol 2003, 1:28 ER-/PR- ER+/PR+ Other

Sir G.T. BEATSON Dr E. JENSEN

Mechanism of action of LHRHa Figure A - Hypersecretion of LH following acute administration of LHRHa Figure B - Hyposecretion of LH following chronic administration of LHRHa LHRHa Pituitary Cell LH LHRHa Pituitary Cell LH  Administration of LHRHa initially leads to occupation of a very high proportion of LHRH receptors (Figure A) LH release is transiently increased, but the receptors disappear from the surface of the cell (Down-regulation) As newly synthesised receptors appear on the cell surface, they are occupied by LHRHa and disappear As a result, the continuous presence of LHRHa prevents the reappearance of sufficient numbers of LHRH receptors on the pituitary cell for the synthesis and secretion of LH (Figure B)

Treatment response Measurable disease Goserelin (n 29) Ovariectomy (n 30) Response No. % CR 4 14 3 10 PR 5 17 Stable disease 8 28 26 Increased disease 7 24 9 30 Inadequate assessment Taylor CW et al, 1998

PFS by treatment arm OS by treatment arm Taylor CW et al, 1998

Summary of results by treatment group Endpoint LHRH-agonist alone (n=256) LHRH-agonist + tamoxifen (n=250) Hazard Ratio/Odds Ratio (95% CI) Log-rank p value Primary median survival (yrs) 2.5 2.9 0.78 (0.63-0.96) 0.02 Secondary median progression- free survival (mos) 5.4 8.7 0.70 (0.58-0.85) <0.001 Objective response (%) 29.7 38.8 0.67 (0.46-0.96) 0.03 CHAT and EORTC meta-analysis, 1999

primary breast cancer (3). All previously treated with Z+T. Combined use of Goserelin and Anastrozole as second-line endocrine treatment in pre menopausal women with advanced breast cancer. (Cheung et al, 2004) 16 women with M1 (13) or locally advanced primary breast cancer (3). All previously treated with Z+T. Clinical results: 75% OR/SD Endocrine effects: mean E2 (pmol/L) Z+T (pre )= 224 Z+T (6 mos)= 24 Z+A (3 mos)= 6 Z+A (6 mos)= 5

Hormonetherapy: which drugs? which sequences? Suppressive treatments Premenopause: ovariectomy, LH-RHa Postmenopause: aromatase inhibitors Competitive treatments Pre/postmenopause: antiestrogens (TAM, TOR) steroidal antiestrogen (Faslodex) progestagens antiprogestins

Structures of non-steroidal anti-oestrogens clinically available or in clinical trials. Howell A et al, 1996

Results of studies using newer non-steroidal anti-oestrogens as first-line endocrine therapy for advanced breast cancer Drug Dose (mg/day) No. of patients Response CR/PR (%) Toremifene [Valavaara, 1990] (Phase II trials summarised) 20 60 240 14 93 38 21 52 68 [Stenbygaard et al, 1993] (Phase III trial) 40 31 29 44 [Hayes et al, 1995] 200 221 212 22 Tamoxifen 215 19 Droloxifene [Rauschning et al, 1994] (Randomised phase II trial 100 84 88 96 30 47 TAT-59 [Tominaga, 1995] (Randomised Phase II trail) 10 15 11 13 55 Howell A et al, 1996

Incidence of common side-effects with new NSAEs Hot flushes (%) Lassitude (%) Nausea/vomiting (%) Tamoxifen 30 10 Toremifene 19 8 Droloxifene 29 26 Raloxifene 43 36 14 TAT-59 3 Idoxifene “similar to tamoxifen” Howell A et al, 1996

Hormonetherapy: which drugs? which sequences? Suppressive treatments Premenopause: ovariectomy, LH-RHa Postmenopause: aromatase inhibitors Competitive treatments Pre/postmenopause: antiestrogens (TAM, TOR) steroidal antiestrogen (Faslodex) progestagens antiprogestins

Estrogen Receptor Downregulator Faslodex (fulvestrant) Estrogen Receptor Downregulator OH 7 HO (CH2)9SO(CH2)3CF2CF3 Catena laterale alchilsulfonilica

ER: Interazione con estradiolo estradiolo+ER Attivazione AF1 e AF2 Omodimerizzazione

ER: Interazione con Tamoxifene Tamoxifene Dimerizzazione con solo AF1 attivato Meccanismo d'azione di tamoxifen Tamoxifen (T) si lega all'ER presente nel citoplasma cellulare (fase 1). Il complesso va incontro a omodimerizzazione (fase 2) e si localizza principalmente nel nucleo cellulare. Al contrario di quanto avviene per l'estradiolo, il complesso dimerico possiede una sola funzione di attivazione (AF1; la funzione AF2 non è attiva). Come risultato, un singolo coattivatore viene reclutato da AF1 e ciò implica una ridotta trascrizione ed una altrettanto ridotta divisione cellulare, in confronto a quelle ottenute dall'agonista completo, l'estradiolo. Il risultato dell'azione di tamoxifen è una trascrizione parzialmente inattivata del DNA. Ciò significa che tamoxifen ha ancora un parziale effetto agonista, il quale potrebbe spiegare lo sviluppo della resistenza al farmaco che si osserva in alcune pazienti affette da carcinoma mammario. Tale effetto agonista parziale può anche essere responsabile della nota incidenza di flare tumorale e di effetti tromboembolici registrata con tamoxifen, così come della stimolazione dell'endometrio che può dar luogo ad alterazioni indesiderate a carico di quest'ultimo. Il risultato dell'azione di tamoxifen è un'inattivazione parziale della trascrizione del DNA. Ciò significa che tamoxifen ha ancora un parziale effetto agonista, il quale potrebbe spiegare il noto sviluppo di resistenza al farmaco in alcune pazienti affette da carcinoma mammario Parziale trascrizione e legame con un solo coattivatore Legame con RNA Pol.II e parziale trascrizione con riduzione prolif.cellulare

ER: Interazione con Fulvesrant Fulvestrant Fulvestrant+ER AF1 e AF2 inattivi Meccanismo d'azione di 'Faslodex' F si lega inizialmente all'ER presente nel citoplasma (fase 1). Il complesso accelera la degradazione dell'ER (fase 2) e, in seguito a ciò, il tasso di omodimerizzazione e di localizzazione nucleare del complesso risulta notevolmente diminuito (fase 3). Di conseguenza, il legame del complesso all'ERE risulta ridotto ed i coattivatori rimangono inattivi. Come effetto finale, dunque, non si ha nessuna stimolazione della trascrizione dei geni estradiolo-responsivi (cioè, nessuna trascrizione del DNA) né alcuna divisione cellulare estrogeno-dipendente (fase 4). Inoltre, il complesso F-ER si degrada rapidamente, provocando la perdita della proteina ER. Per riassumere, 'Faslodex' possiede un meccanismo d'azione esclusivo, grazie al quale blocca e degrada gli ER, come è dimostrato dalla rapida perdita di proteina ER. Tale meccanismo si differenzia nettamente da quelli delle attuali opzioni terapeutiche per il trattamento delle donne in postmenopausa con carcinoma mammario ormono-responsivo, fra cui gli inibitori dell'aromatasi quali 'Arimidex', che riducono i livelli di estradiolo, e gli antiestrogeni della classe SERM quali tamoxifen, che bloccano gli ER in modo soltanto competitivo.   'Faslodex' blocca e degrada gli ER, come è dimostrato dalla rapida perdita di proteina ER 'Faslodex' è il primo di una nuova classe di farmaci: esso è un downregulator del recettore per gli estrogeni:  I downregulator del recettore per gli estrogeni ed i SERM differiscono nel meccanismo d'azione e negli effetti sulla via di trasduzione dell'ER. Il meccanismo d'azione di 'Faslodex' è unico per il fatto che questo agente non dimostra alcuna attività agonista nei confronti dell'ER, producendo una completa downregulation del recettore. Inattivazione completa della trascrizione e inibizione alla proliferazione cellulare Riduzione Dimerizzazione e stimolazione alla degradazione ER

69% of patients achieved OR or SD  24 weeks ICI 182,780 (‘Faslodex’): Phase II Results Clinical Efficacy - Response Rate Response n % Complete response 0 0 Partial response 7 37 Stable disease 6 32 Progression 6 31 19 100 } 69 69% of patients achieved OR or SD  24 weeks Howell A et al. Lancet 1995; 345: 29–30.

2nd line Phase III Trial Designs Postmenopausal women with advanced breast cancer. Prior HT for early or advanced breast cancer Trial 20 Trial 21 Fulvestrant 250mg i.m. once monthly Trial 20: 1 x 5ml (n=222) Trial 21: 2 x 2.5ml (n=206) Anastrozole 1mg daily orally Trial 20: n=229 Trial 21: n=194 Analysis after 340 events (progression or death prior to progression) Analysis of TTD performed after >75% of patients dead

Follow-up mediano a 15.1 mesi Efficacia clinica Follow-up mediano a 15.1 mesi 0020 0021 Fx Ax Fx Ax Studi Numero pazienti 222 229 206 194 TTP mediano (mesi) 5,5 5,1 5,4 3,4 Risposta Obiettiva* 20,7% 15,7% 17,5% 17,5% Durata mediana della Risposta Obiettiva (mesi) 14,3 14,0 19,3 10,5 Beneficio Clinico Obiettivo** 44,6% 45,0% 42,2% 36,1% Durata mediana del Benefico Clinico Obiettivo (mesi) 11,8 11,4 12,8 10,8 *Risposta Obiettiva = RC + RP **Beneficio Clinico Obiettivo = RC+RP+MS >24 settimane

Hormonetherapy: which drugs? which sequences? Suppressive treatments Premenopause: ovariectomy, LH-RHa Postmenopause: aromatase inhibitors Competitive treatments Pre/postmenopause: antiestrogens (TAM, TOR) steroidal antiestrogen (Faslodex) progestagens antiprogestins

Second-line therapy with aromatase inhibitors Goss PE & Strasser K, 2001

Front-line Therapy With Aromatase Inhibitors ANA vs TAM1 (1 mg) ANA vs TAM2 LTZ vs TAM3 No. of patients 171/182 340/328 453/454 Response rate (CR + PR) % 21/17 33/32 30/20 (0.006) Clinical benefit (CR + PR + SD>24 wks) % 59/45 56/55 49/38 (0.001) Median TTP, mos 11.1/5.6 (0.005) 8.2/8.3 (8.9/7.8) 10.1/6.2 (0.0001) Median TTF, mos 7.6/5.4 7.3/6.3 (6.2/6.0) 10/6.1 (0.001) Median OS, mos -/- Edema (weight gain) 2.9/1.1 1.8/1.8 Hot flashes 36.5/24.2 20.5/20.7 18/15 Thromboembolic disease 4.1/8.2 4.8/7.3 Nausea 30.6/34.1 12.5/13.4 15/16 Vomiting 14.7/12.1 3.9/4.3 Asthenia 31.8/35.5 8.6/4.9 11/10 Pain 25.3/26.4 6.3/6.1 20/18 1Nabholtz JM, 2000; 2Bonneterre J, 2000; 3Mouridsen H, 2001

Hormonetherapy: which drugs? which sequences? Suppressive treatments Premenopause: ovariectomy, LH-RHa Postmenopause: aromatase inhibitors Competitive treatments Pre/postmenopause: antiestrogens (TAM, TOR) steroidal antiestrogen (Faslodex) progestagens antiprogestins

Many premenopausal and postmenopausal women with hormoneresponsive breast cancer benefit from sequential use of endocrine therapies at the time of disease progression. Therefore, women whose breast cancers respond to an endocrine manouvre with either shrinkage of the tumor or long-term disease stabilization (clinical benefit) should receive additional endocrine therapy at the time of disease progression. 37

Ormonoterapia – Pre-menopausa AIOM 2009

Ormonoterapia – Post-menopausa AIOM 2009

The action and reaction model Dependence on multiple different estrogen independent pathways Normanno et al JNCI 2005

CAUSES OF ENDOCRINE-RESISTANCE AROMATASE INHIBITORS Hypersensitivity Increased cross-talk between the growth factor signalling pathways and ER ER remains an integral part of signalling

Tumor cell adaptation:effects of long-term estrogen deprivation

A Randomized phase 2 trial of Low Dose (6 mg Daily) versus High Dose (30 mg Daily) Estradiol for Patients with Estrogen Receptor Positive AI- Resistant ABC Ellis MJ, SABCS 2008

CAUSES OF ENDOCRINE-RESISTANCE AROMATASE INHIBITORS Hypersensitivity Increased cross-talk between the growth factor signalling pathways and ER ER remains an integral part of signalling

Possible approaches to overcoming endocrine resistance: Maximal blockade of ER signaling Co-targeting ERand HER family signalling Co-targeting IGF-1 system Targeting downstream signalling

FASLODEX EXEMESTANE OR (CR+PR) CBR (CR+PR+SD>24WS) 20/270 [7.4%] 18/270 [6.7%] CBR (CR+PR+SD>24WS) 87/270 [32.2%] 85/270 [31.5%]

Fulvestrant plus letrozole is more active than either agent alone in tumour xenografts Change of mean tumour volume (%) Time (weeks) 100 200 300 400 500 600 700 800 6 12 18 24 30 36 Control Letrozole (10 µg/day) Fulvestrant (1 mg/day) + letrozole (10 µg/day) Fulvestrant (1 mg/day) Jelovac et al. Cancer Res 2005; 65: 5439–5444

Fulvestrant combination trials with AIs SWOG S0226 ‘Faslodex’ + ‘Arimidex’ versus ‘Arimidex’ FACT ‘Faslodex’ and ‘Arimidex’ in Clinical Trial SOFEA Study Of ‘Faslodex’, Exemestane and ‘Arimidex’

CONFIRM Phase III Trial: 500 vs 250 mgs Fulvestrant Nr 362 vs 374 Responders to previuos HT 63.3 vs 66.6 % Median TTP (mos) 500 Vs 250 6.5 5.5 Median Duration CB (mos) 16.6 vs 13.9 Angelo Di Leo, Abs 25

Cross-talk and endocrine resistance Increased EGFR and HER2 signalling is associated with the development of resistance to endocrine agents Targeting both the ER with endocrine agents and the EGFR with anti EGFR agents delays the onset of resistance in pre-clinical models

Possible approaches to overcoming endocrine resistance: Maximal blockade of ER signaling Co-targeting ERand HER family signalling Co-targeting IGF-1 system Targeting downstream signalling

Clinical Evidence for Co-Targeting Growth Factor Receptors in ER+ MBC Trial Regimen Population No. of patients Median PFS, mo Endocrine therapy alone Endocrine therapy + anti-ErbB TAnDEM 1 Phase III Anastrozole +/- trastuzumab HER2+ 208 2.4 * 4.8 * Osborne et al2 Randomized, placebo-controlled phase II Tamoxifen +/- gefitinib ITT HER2+ subset 206† 37 8.8 5.8 10.9 6.7 Cristofanilli et al3 Anastrozole +/- gefitinib 93 8.2 14.5 TAnDEM trial serves as proof of concept in HER2+ 1Mackey J, et al. Breast Cancer Res Treat. 2006;100. Abstract 3; 2Osborne K, et al. Breast Cancer Res Treat. 2007;106. Abstract 2067; 3Cristofanilli M, et al. J Clin Oncol. 2008;26(No 15S). Abstract 1012. 55 55

In newly diagnosed MBC or had completed adj Tam > 1 yrs: Randomized Phase II study of gefitinib or placebo in combination with tamoxifen in pts with hormone receptor positive metastatic breast cancer Osborne CK,SABCC 2007 In newly diagnosed MBC or had completed adj Tam > 1 yrs: PFS (ITT): T+G= 10.9 mos T+P = 8.8 mos HR: 0.84, 95% CI 0.59-1.18

A phase II multicenter, randomized trial to compare anastrozole plus Gefitinib with anastrozole plus placebo in postmenopausal women with hormone receptor-positive metastatic breast cancer (MBC). 5% 12% PFS: A+G = 14.5 mos A+P = 8.2 mos HR: 0.55, 95% CI 0.32-0.94 Conclusions:”…..A+G well tolerated and associated with a marked advantage in PFS versus A+P in postmenopausal women with newly diagnosed HR+ MBC….” Cristofanilli M et al ASCO 2008

Zac-FasT Trial (Zactima Faslodex Trial): a randomised, double-blind, parallel-group, multicentre, phase II study to evaluate the safety and pharmacological activity of the combination of a new TKI Vandetanib (100 or 300 mg/daily or placebo) with Fulvestrant (loading dose), in postmenopausal advanced breast cancer patients. Primary endpoint:EFS Main Secondary endpoints: Success rate at 6 months - Objective tumor response rate Time to Progression Progression-free survival Overall survival - Safety and tolerability of the combination

All

HER-2+ Median OS 33 m HER-2+

(p=0.019), with an improvement in median PFS from 3.0 to 8.2 months Efficacy Summary In postmenopausal women with HR+, HER2+ MBC the combination of letrozole and lapatinib showed: - 29% reduction in risk of disease progression (p=0.019), with an improvement in median PFS from 3.0 to 8.2 months - Significant improvement in clinical benefit rate (29% to 48%; p=0.003) In postmenopausal women with HR+, HER2- ve MBC: No significant treatment benefit on PFS [HR 0.90 (0.77, 1.05; p=0.188)] 23% reduction in risk of disease progression by preplanned Cox analysis [adjusted treatment HR 0.77 (0.64, 0.94; p=0.010)] Prior tamoxifen exposure was a significant covariate Biomarker studies ongoing

Possible approaches to overcoming endocrine resistance: Maximal blockade of ER signaling Co-targeting ERand HER family signalling Co-targeting IGF-1 system Targeting downstream signalling

TCD 10631 Study: Multicenter, randomized, open label study evaluating an anti Insulin-like Growth Factor-1 Receptor (IGF-1R/CD221) monoclonal antibody, AVE1642, administered every 4 weeks in combination with Faslodex® in postmenopausal patients with advanced hormono-dependent breast cancer (in I or II line) Primary endpoint : Clinical Benefit (CB) Main Secondary endpoints : - Progression Free Survival Rate (PFSR) at 6 months - Progression Free Survival (PFS) - Safety

Possible approaches to overcoming endocrine resistance: Maximal blockade of ER signaling Co-targeting ERand HER family signalling Co-targeting IGF-1 system Targeting downstream signalling

Treatment of postmenopausal women with LABC or MBC with Let alone or in combination with Tensirolimus: a randomized, 3-arm, phase 2 study: “…Combination well tolerated, longer PFS….” Baselga J, et al. Breast Cancer Res Treat, 2005 2. Phase 3 study of tensirolimus plus Let vs Let alone in postmenopausal women with LABC or MBC:”… No improvement in PFS was seen in the overall population..” Chow LWC, et al. Breast Cancer Res Treat, 2006

Tailor treatment according to disease characteristics and patients expectations! A negligible achievement to the physician might be terribly important to the patient (… and viceversa).