1. The Role of PARP inhibitors in Breast Cancer QROC November 5 th, 2010 Rebecca Dent, MD FRCP(C) Sunnybrook Odette Cancer Center Toronto, Canada

2. Potential Conflict of Interest Dr. Rebecca Dent –AstraZeneca, consultant and honorariat (2007-2010) –Roche, consultant and honorariat (2007-2010) –Sanofis-Aventis, consultant and honorariat (2007-2010)

3. Why did the Scientific Committee ask the young investigator from Sunnybrook to talk about PARP inhibitors in breast cancer? Two Reasons: 1.Smallest study evaluating PARP inhibitors (but provocative!) 2.Large clinical practice of TNBC and BRCA mutation carriers

4. Achilles’ Heel: A deadly weakness in spite of overall strength, that can actually lead to downfall

5. Neoadjuvant endocrine responses in ER + disease can be prolonged and gratifying at very little cost! Can we do this for triple negative and BRCA related cancers?

6. PARP inhibitors – Finding the Achilles’ Heel in BRCA related Cancers

7. BRCA2 -/- BRCA2 +/+ BRCA2 +/- Increased sensitivity of BRCA1 -/- and BRCA2 - /- cells to PARP inhibition BRCA1 -/- BRCA1 +/+ BRCA1 +/- No difference in sensitivity between heterozygous and wild-type BRCA cells Farmer et al. Nature 2005; 434:917-21 Targeted inhibition  selective and less toxic therapy

9. Olaparib (AZD2281) Oral AstraZeneca Compound (Formerly KuDOS)

10. Olaparib A novel, orally active PARP inhibitor A phase I trial identified olaparib (AZD2281; KU-0059436) 400 mg bid as the maximum tolerated dose 1 with a signal of efficacy in BRCA-mutated ovarian cancer Most common toxicities: CTCAE grade 1 and 2 nausea and fatigue Significant PARP inhibition and tumor response at olaparib doses 100–400 mg bid 1. Yap T et al. J Clin Oncol 2007;25(18S):abst 3529; 2. Fong P et al. J Clin Oncol 2008;26(15S):abst 5510.

11. Phase II trial of Olaparib in BRCA-deficient advanced breast cancer To assess the efficacy and tolerability of oral olaparib in BRCA1/ BRCA2 mutation carriers with breast cancer Multicenter proof-of-concept phase II study, single-arm sequential cohort design Confirmed BRCA1 or BRCA2 mutation Advanced refractory breast cancer (stage IIIB/IIIC/IV) after failure of ≥1 prior chemotherapy for advanced disease Olaparib 400 mg po bid (MTD) 28-day cycles; n=27 Cohort 1 (enrolled first) Olaparib 100 mg po bid 28-day cycles; n=27 Cohort 2 * * Following an interim review of the emerging efficacy of each cohort, patients ongoing in 100 mg bid cohort were permitted to crossover to receive the 400 mg bid dose Tutt A. et al. Lancet 2010

12. Efficacy Olaparib 100 mg bid (n=27) 6 (22)* 0 6 (22) *An additional 1 patient in the 400 mg cohort and 3 patients in the 100 mg cohort had unconfirmed responses Overall Response Rate, n (%) Complete Response, n (%) Partial Response, n (%) 11 (41)* 1 (4) 10 (37) Olaparib 400 mg bid (n=27) ITT cohort Tutt A. et al. Lancet 2010

13. Progression-free survival Olaparib 400 mg: 5.7 (4.6–7.4) months No. of patients at risk 272617850221361 400 mg: Median PFS (95% CI) PFS (days) 0 Freedom from progression (%) 0 10 20 30 40 50 60 70 80 90 10 0 50150250350450100200300400 Olaparib 100 mg: 3.8 (1.9–5.5) months 27251000017400 100 mg: NB: Non-randomized sequential cohorts Tutt A. et al. Lancet 2010

14. Best % change from baseline in target lesions by prior chemotherapy –100 –80 –60 –40 –20 0 20 40 60 80 100 Previous anthracycline, taxane and capecitabine Increasing tumor shrinkage Olaparib 400 mg bid cohort Best % change from baseline *Prior platinum Tx * * * * * * Tutt A. et al. ASCO 2009

15. Response by BRCA mutation status and hormonal status Cohort: Olaparib 400mg BID BRCA1 (n=18) BRCA2 (n=9) TNBC (n=13) Non-TNBC (n=14) Objective Resposne 9 (50%)2 (22%)7 (54%)4 (29%) Tutt A. et al. Lancet 2010

16. Adverse events* 15 (56) 11 (41) 7 (26) 10 (37) 6 (22) 8 (30) 4 (15) 1 (4) 2 (7) Fatigue Nausea Vomiting Headache Constipation Diarrhea Cough Dyspnea Insomnia Pain in extremity Olaparib 400 mg bid (n=27) Patients, n (%) Grade 1/2 4 (15) 5 (19) 3 (11) 0 Grade 3 Olaparib 100 mg bid (n=27) 15 (56) 6 (22) 5 (19) 8 (30) 4 (15) 8 (30) 10 (37) 7 (26) 6 (22) Grade 1/2 2 (7) 0 1 (4) 0 1 (4) 0 1 (4) Grade 3 *≥25% reported in either cohort; Common Terminology Criteria for Adverse Events

17. Olaparib Phase2 - Conclusions In BRCA mutation carriers: – single agent oral olaparib 400 mg bid has substantial activity with ORR 41% and median PFS 5.7 months – well tolerated Not all patients with BRCA mutations responded – Are there different Homologous Recombination Repair Defects affecting sensitivity to PARP inhibition? – Is there something else that predicts response to PARP inhibition? Likely need functional assay! – Perhaps subtypes of sporadic breast cancer may benefit from PARP inhibitors

18. Veliparib (ABT-888) Oral Abbott Compound

19. Phase II Study of oral Veliparib Plus Temozolomide in Metastatic Breast Cancer Efficacy appears to be restricted to BRCA1/2 mutation carriers. Further evaluation of this combination is ongoing in BRCA1/2-mutated cancers. Total (n = 41) (23 TNBC) BRCA1/2 Mutant (n = 8) BRCA1/2 Normal/Unknown (n = 33) Overall Response Rate7%37.5%0 Clinical Benefit Rate a 17%62.5%6% Median Progression-Free Survival 1.9 months 5.5 months1.8 months P =.0042 Isakoff et al. J Clin Oncol 2010; 28(suppl):118s (abstract 1019). a ORR + stable disease

20. Phase II Study Veliparib (ABT-888) + Temozolamide ORR: 7% – All BRCA1/2+ (RR 38%) Toxicity: – marrow, nausea, electrolyte, fatigue – no gr3-4 after dose change ABT888 * * * * = BRCA carriers % change p-value = 0.0042 Noncarriers: Median PFS = 1.8 Mo Carriers: Median PFS = 5.5 Mo Isakoff et al, ASCO 2010

21. Proof of Concept Phase 2 trials Studies with Olaparib and Veliparib confirm that BRCA related cancers deficient in specific aspects of DNA repair are sensitive to agents that exploit this pathway, unless resistance occurs... Major mechanism of resistance...not in PARP genes but...re-expression of a functional form of BRCA2 and in some cases almost the full-length protein

22. Resistance to PARP inhibitors Reversion of BRCA2 mutations Edwards et al. Nature 451: 1111-1115, 2008 Restoration of the open reading frame of BRCA1 or 2 by intragenic deletion Partial function of BRCA is restored and cells become competent for HR repair

23. Cisplatin Resistance in tumors Ovarian tumors with BRCA2 mutations highly sensitive to cisplatin but resistance develops Analysis of resistant tumor line revealed reversion of BRCA2 mutation as with PARP inhibitors Implications: -Phase 2 Olaparib study showed that pts who progressed on platinum therapy rarely responded to Olaparib =but too soon to conclude cross- resistance Sakai et al. Nature 451:1116-1120,2008

24. What is the Role of PARP inhibitors in Triple Negative Breast Cancer? BRCA and TNBC

25. Theorem: Shared genome-wide expression array patterns between BRCA1-mutant and basal breast cancer may reflect shared defects in DNA repair processes Corollary: Sporadic basal breast cancers may be especially sensitive to DNA-damaging agents 25

26. CharacteristicsHereditary BRCA1Triple Negative/Basal-Like 1,2,3 ER/PR/HER2 statusNegative TP53 statusMutant BRCA1 statusMutational inactivation*Diminished expression* Gene-expression patternBasal-like Tumor histology Poorly differentiated (high grade) Poorly differentiated (high grade) Chemosensitivity to DNA- damaging agents Highly sensitive TNBC Shares Clinical and Pathologic Features with BRCA-1-Related Breast Cancers 3 Sorlie et al. Proc Natl Acad Sci U S A 2001;98:10869-74 4 Miyoshi et al. Int J Clin Oncol 2008;13:395-400 *BRCA1 dysfunction due to germline mutations, promoter methylation, or overexpression of HMG or ID4 4 1 Perou et al. Nature. 2000; 406:747-752 2 Cleator et al.Lancet Oncol 2007;8:235-44 26

27. RegimenNpCR CMF141 (7%) AC235 (22%) FAC286 (21%) AT252 (8%) Cisplatin1210 (83%) Platinum Sensitivity in BRCA1+/TNBC: Pathologic Response to Neoadjuvant Rx BRCA1+: 102 BRCA1+ patients CDDP 75 mg/m2 x 4 BUT retrospective CDDP cohort – smaller, more node-negative Byrski, JCO 2009 pCR to Cisplatin6 (22%) Clinical CR4 (14%) Clinical PR10 (36%) Stable disease5 (17%) Triple negative: 28 TNBC CDDP also 75 mg/m2 x 4 Prospective trial 2/2 BRCA1+ had pCR Silver, JCO 2010

28. Case LG 51F, known BRCA1 mutation carrier – right sided LABC, TNBC – Treated with Epi/Taxotere x6 on clinical trial – Mastectomy December 2008, with residual 1cm of IDC, 2/19LN + Feb 2010 – Matted ipsilateral supraclavicular, cervical nodes – Brachial plexopathy due to extensive deep axillary recurrence causing severe pain requiring extensive narcotics

29. LG continued Treated as part of TRIO trial with Taxotere +/- IMCLONE antivegf molecule – Radiological Response at 6wk CT scan – However, by clinic visit pt had extensive skin progression and pain requiring Gabapentin 900mg TID and Hydromorphone Contin 12 TID April 2010: Started on Cisplatin 25mg/m2, Gemcitabine 750mg/m2 IV 3 out of 4 weeks After one cycle pt was off all hydromorphone and tapering gabapentin, has just completed cycle 8 with almost complete response!

30. Case CH 49F previously well, BRCA negative – 2cm, grade 3, 8/19LN+ TNBC – Treated with dd AC-paclitaxel – Completed August 2009 November2009 – Acutely unwell, fatigue, jaundice – Abdominal ultrasound confirms diffuse liver metastases with no evidence of obstruction – Started on Cisplatin 25mg/m2 IV 3 out of 4 weeks

31. Pt CH Trend LFT’s Nov 25, 2009 Dec 2, 2009 Feb 25, 2010March 30, 2010 ALP1143952126679 AST4001503398 ALT2481492572 Bilirubin6837721

32. Case CH Why did she respond and so quickly to single agent weekly cisplatin? Why did she unfortunately respond for only four months? Need biopsies!

33. Canadian Study 20 Phase II Trial of Olaparib in BRCA and sporadic breast and ovarian CA Goals – To determine markers of response and resistance to Olaparib in four cohorts of patients – To help inform future studies in terms of patient enrollment – To help determine activity Gelmon K et al ASCO 2010

34. Study Design: 2-stage Simon Screening/e nrolment TNBC with unknown BRCA status (n=15) Known BRCA + breast cancer (n=10) Known BRCA + ovarian cancer (n=10) HGSC with unknown BRCA status (n=15) + 20 patients = (n=35) Olaparib 400 mg bid  1 response + 40 patients = (n=55)  1 response TNBC, Triple-negative breast cancer; HGSC, High grade serous ovarian carcinoma

35. Best % Change in Target Lesion Size by Tumor Type and BRCA status: Breast Cancer TNBC BRCA TNBC non-BRCA Non-TNBC BRCA –100 –20 –40 –60 –80 0 20 100 80 60 40 120 No patient met the criteria for a confirmed RECIST response Best change in target lesion size is maximum reduction from baseline or minimum increase in absence of reduction Best % change from baseline 23 treated patients with target lesions identified at baseline 22 had at least one follow-up assessment 1 patient had no follow-up tumour size assessment – 1 due to missing / incomplete post-baseline assessments

36. Phase I safety cohort: Olaparib plus Paclitaxel for TNBC Olaparib (AZD2281) 200 mg BID po + Paclitaxel weekly iv 90 mg/m 2 (3 of 4 weeks) Olaparib (AZD2281) 200 mg BID po + Paclitaxel weekly iv 90 mg/m 2 (3 of 4 weeks) TN metastatic breast Ca ≤1 prior cytotoxic therapy TN metastatic breast Ca ≤1 prior cytotoxic therapy Primary objective: Safety and tolerability Secondary objectives: Objective response rate (ORR) according to RECIST Safety cohort N=19 Dent R et al. ASCO 2010

37. CTCAE in ≥30% of patients overall CTCAE, Common Terminology Criteria for Adverse Events Cohort 1 (no GCSF) (n=9) Cohort 2 (GCSF) (n=10) Grade 1/2Grade ≥3Grade 1/2Grade ≥3Overall (n=19) Diarrhea Nausea Neutropenia Alopecia Fatigue Anemia Constipation Peripheral neuropathy Rash Vomiting 6 (67) 5 (56) 3 (33) 6 (67) 3 (33) 4 (44) 3 (33) 1 (11) 3 (33) 0 4 (44) 0 2 (22) 0 6 (60) 2 (20) 4 (40) 3 (30) 1 (10) 2 (20) 3 (30) 5 (50) 3 (30) 0 2 (20) 0 1 (10) 0 12 (63) 11 (58) 10 (53) 6 (32) Patients with AEs, n (%)

38. Phase I/II Study of Olaparib Plus Paclitaxel for Triple- Negative Metastatic Breast Cancer Dose modifications: − Median dose intensity (total dose received/total dose planned) of paclitaxel was 57.2% (range 26–100%) in cohort 1 and 73.1% (range 29–100%) in cohort 2 Conclusions: − Olaparib/paclitaxel is active in triple-negative MBC. − Associated neutropenia reduced paclitaxel dose intensity Cohort 1 (No G-CSF) (n = 9) Cohort 2 (G-CSF ) (n = 10) Overall Response Rate 33%40% Stable Disease ≥ 7 Weeks 33%40% Median Progression-Free Survival (95% CI) 6.3 (3.5-8.9) months5.2 (3.5-NC) months Dent et al. J Clin Oncol 2010; 28(suppl):118s Eligibility: ≤ 1 prior cytotoxic regimen Regimen: olaparib 200 mg p.o., b.i.d. paclitaxel 90 mg/m 2 /week 3 of 4 weeks

39. Lessons from Study 11 Other than neutropenia, well tolerated therapy – Little to no neurotoxicity, is this related to other physiological roles of PARP? Other Important Observations – Patients exhibited delayed response to Olaparib (implications for neoadjuvant studies with PARPi) – Differential response to treatment (response in lung, progression lymph nodes) – implications for clinical trials Expansion cohort evaluation different schedules of Olaparib Dent, R et al. ASCO 2010

40. Iniparib: BSI-201 Intravenous BiPar/Sanofi Aventis Compound

41. LBA11 Iniparib Study Design Multi-center, open-label, randomized Phase II Metastatic TNBC - about 70% had prior chemotherapy for early BC Measurable disease -median number of metastatic sites = 3 0-2 prior chemotherapy regimens for metastatic disease - no prior chemo~60% No prior gemcitabine, carboplatin, cisplatin, PARP inhibitor Stable brain metastases allowed ECOG PS 0–1- two thirds PS = 0 Gemcitabine 1000 mg/m 2, IV, d 1, 8 Carboplatin AUC 2, IV, d 1, 8 21 day cycles Iniparib 5.6 mg/kg, IV, d 1, 4, 8, 11 Gemcitabine 1000 mg/m 2, IV, d 1, 8 Carboplatin AUC 2, IV, d 1, 8 21 day cycles PRIMARY ENDPOINTS: CBR = CR + PR + SD ≥6 mo, Safety SECONDARY ENDPOINTS: DFS, ORR, Toxicity * 30 patients randomized to gem/carbo crossed over to receive gem/carbo + Iniparib (BSI-201) at disease progression Randomization (1:1) N=62* N=61 RESTAGING: Every 2 Cycles (RECIST)

42. Iniparib: Response and Clinical Benefit Rates (ITT Population) Gem-Carbo N = 62 Iniparib + Gem-Carbo N=61 P-value* Overall response rate20 (32.3%)32 (52.5%)0.023 Complete response1 (1.6%)2 (3.3%) Partial response19 (30.6%)30 (49.2%) Stable disease13 (21.0%)11 (18.0%) Progressive disease18 (29.0%)10 (16.4%) SD ≥ 6 months1 (1.6%)2 (3.3%) Clinical benefit rate (CBR)21 (33.9%)34 (55.7%)0.015 *P-values were not adjusted for multiple interim analyses.

43. Iniparib: Progression-Free and Overall Survival(ITT Population) Gem-Carbo N=62 Iniparib + Gem-Carbo N=61 Median PFS, months (95% CI) 3.6 (2.6, 5.2) 5.9 (4.5, 7.2) HR (95% CI) 0.59 (0.39, 0.9) P-value*0.012 *P-values were not adjusted for multiple interim analyses. Gem-Carbo N = 62 Iniparib + Gem-Carbo N=61 Median OS, months (95% CI) 7.7 (6.5, 13.3) 12.3 (9.8, 21.5) HR (95% CI) 0.57 (0.36, 0.90) P-value*0.014 OS + 4.6 months PFS + 2.3 months Progression Free SurvivalOverall Survival-Exploratory

44. Safety: Hematologic Toxicity Adverse event No. of patients (%) Gem-Carbo (N=59)Iniparib + Gem-Carbo (N=57) AllGrade 3Grade 4AllGrade 3Grade 4 Neutropenia48 (81)21 (36)16 (27)46 (81)25 (44)13 (23) Anemia40 (68)9 (15)038 (67)13 (23)0 Thrombocytopenia30 (51)6 (10)10 (17)36 (63)10 (18)11 (19) Leukopenia13 (22)6 (10)016 (28)7 (12)0

45. Summary Proof of Concept that triple negative breast cancers may be susceptible to PARP inhibition – Impressive improvement in ORR, CBR, PFS and overall survival BSI-201 + gemcitabine/carboplatin was well tolerated and did not potentiate chemotherapy-related toxicities

46. Questions Are the platinum and PARP inhibitor effects additional or synergistic? What is the activity of single agent BSI-201 in pts with TNBC? Why does BSI-201 not show significant myelosuppresion compared to oral PARP inhibitors?

47. Development in PARP inhibitors in TN Breast Cancer Challenges Triple Negative Breast Cancer Defining Triple Negative Breast Cancers Identifying Subset with Homologous Recombination Deficiency What are the Standards of Care for Treatment? What should be the comparators? PARP inhibitors Dosing: IV vs. PO Schedule: Intermittent vs. Continuous Timing: Delivery before, during or after chemotherapy Are they best combined with DNA damaging agent? Role of Resistance

48. Acknowledgements and Collaborators CANADA Maureen Trudeau Steven Narod Karen Gelmon Mark Clemons Wedad Hanna Janet Dancey Kathy Pritchard UK Andy Tutt Alan Ashworth AstraZeneca Lynn Douglas Mark Zarenda Ursula Lotz Jim Carmicahel

49. 2011 Triple Negative Breast Cancer Conference, March 9-11, London UK Scientific programme committee – Alan Ashworth, Jorge Reis-Filho, Rebecca Dent and Andy Tutt Speakers Charles Perou Will Foulkes Jos Jonkers Gabriella Dontu Matt Ellis Speakers cont.. Judy Garber Steven Narod MikeStratton Lajos Pusztai Anne Vincent-Salomon, Andrea Richardson Max Parmar