1. Activity of Epothilones in Breast Cancer and Other Tumor Types Sandra M. Swain, MD Professor of Medicine Uniformed Services University of Health Sciences Chief, Cancer Therapeutics Branch Center for Cancer Research National Cancer Institute Bethesda, Maryland

2. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Novel Microtubule-Stabilizing Agents Under Evaluation  Ixabepilone (BMS-247550) –Current NCI translational study –Clinical outcome –Evaluation of neurotoxicity –Other ixabepilone trials in breast cancer –Phase I/II trials in other cancer types  Epothilone B (Patupilone, EPO906)  Epothilone D (KOS-862)

3. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Potential Advantages of Epothilones  Bind specifically and uniquely to beta-tubulin  Epothilone B has 2- to 10-fold greater polymerizing activity than paclitaxel  No steroid premedication needed  Less susceptible to multidrug resistance (MDR) –Poor substrates for MDR proteins –MDR expression not altered in epothilone-resistant cell lines

4. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Antitumor Activity: Taxane-Resistant Breast Cancer Xenografts  PAT-21 breast cancer xenografts are derived from a patient with MBC who received 10 cycles of CMF, then 4 cycles of paclitaxel. Modified from data on file, Bristol-Myers Squibb Median Tumor Wt. (mg) Days Post-Tumor Implant Control Ixabepilone (10 mg/kg, MTD) Paclitaxel (36 mg/kg, MTD) Control Ixabepilone (13 mg/kg, MTD) Docetaxel (20 mg/kg, MTD) Vinorelbine (9 mg/kg, MTD) 1000 Days Post-Tumor Implant 10 100 4050607080 90 Median Tumor Wt. (mg) 10 100 1000 407010013016070 100

5. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Ixabepilone (BMS-247550) Epothilone B Ixabepilone  Epothilone B: Natural macrolide produced by myxobacterium Sorangium cellulosum  Ixabepilone: Semisynthetic epothilone B analog (aza- epothilone B)

6. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Abraham J et al. J Clin Oncol. 2003;21:1866-1873. Mani S et al. Clin Cancer Res. 2004;10:1289-1298. Zhuang SH et al. Cancer. 2005;103:1932-1938. Phase I Trials of Ixabepilone  Ixabepilone IV over 1 hr, 5 days every 21 days (N = 27) –Objective responses in patients with cervical, breast, and basal cell cancer  Ixabepilone IV over 1 hr, 1 day every 21 days (N = 25) –Objective PRs in paclitaxel-refractory ovarian cancer (n = 2) and breast cancer (1 taxane-naive, 1 taxane-refractory)  Ixabepilone IV over 1 hr, 3 days every 21 days (N = 26) –DLT: neutropenia –Prolonged SD in patients with mesothelioma, ovarian cancer, and renal cell carcinoma

7. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Ixabepilone in Metastatic and Locally Advanced Breast Cancer (NCI-0229) Post-treatment biopsy Baseline biopsy Cycle 1 (3 weeks)Cycle 2Cycle 3  Phase II trial  Daily x 5 schedule (6 mg/m 2 per day) –Patients previously treated with a taxane –Taxane-naive patients Daily x 5

8. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Phase II Clinical Trial of Ixabepilone in Breast Cancer (NCI-0229) Outcome, n (%) Prior Taxane (n = 37) Complete response 1 (3) Partial response7 (19) Stable disease13 (38) Progressive disease16 (43)  43% partial response in taxane-naive patients Low JA et al. J Clin Oncol. 2005;23:2726-2734.

9. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Baseline After 11 cycles Complete Response: Taxane-Treated Group

10. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Phase II Ixabepilone Trial (NCI-0229): Grade 3/4 Toxicity Toxicity (%) Taxane-Treated (n = 37) Neutropenia16 Thrombocytopenia8 Myalgia3 Febrile neutropenia14 Diarrhea11 Fatigue13 Low JA et al. J Clin Oncol. 2005;23:2726-2734.

11. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Phase II Ixabepilone Trial (NCI-0229): Peripheral Neuropathy  Neurologic function evaluated before ixabepilone treatment Patients CTC Toxicity Grade, % 123 Taxane-treated (n = 37)29223 Low JA et al. J Clin Oncol. 2005;23:2726-2734. CTC, Common Toxicity Criteria.

12. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer  Baseline evaluation prior to treatment  Neurologic function tests included –Balance test –Semmes-Weinstein monofilaments –Jebsen Test of Hand Function (JTH) –Grooved Peg Board Test (PEG) Low JA et al. J Clin Oncol. 2005;23:2726-2734. Phase II Ixabepilone Trial (NCI-0229): Neurologic Function

13. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Microtubule Stability: Acetylated Tubulin At Baseline Cycle 2 Partial Response Progressive Disease Tumor Stromal staining Low JA et al. J Clin Oncol. 2005;23:2726-2734.

14. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Phase II Ixabepilone Trial (NCI-0229): Summary  Good clinical activity in heavily pretreated breast cancer patients (RR = 22%)  Grade 3/4 sensory peripheral neuropathy in 3% of patients  Baseline neurologic function tests may predict grade ≥ 2 peripheral neuropathy  Acetylation of tubulin may predict response

15. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Phase II Ixabepilone Clinical Trials in Metastatic Breast Cancer Outcome, n (%) NCI- 0229* (n = 37) CA-163010 † (n = 61) CA-163009 ‡ (n = 49) CR1 (3%)- - PR 7 (19%)27 (44%) 6 (12%) SD13 (35%)21 (34%) 19 (39%) PD16 (43%)12 (20%) 23 (47%) *Taxane-pretreated. † Anthracycline-pretreated; Ixabepilone 40 mg/m 2 q3wk; Roche et al. ASCO 2003; Abstract 69. ‡ Taxane-refractory; Ixabepilone 40 mg/m 2 q3wk; Thomas et al. ASCO. 2003;22:8. Abstract 30.

16. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Incidence of Peripheral Neuropathy With Ixabepilone Phase II TrialSchedule CTC Toxicity Grade,% 01234 NCI-0229 (N = 56) 6 mg/m 2 over 1 hr qd (x5) q3wk 48282040 CA 163010 (N = 65) 40 mg/m 2 over 3 hr q3wk N/A 220 CA 163009 (N = 49) 40 mg/m 2 over 3 hr Q3wk N/A 33120 Eng et al. (N = 25) 40 mg/m 2 over 3 hr q3wk 48284200

17. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Incidence of Sensory Neuropathy With Microtubule-Stabilizing Agents AgentsSchedule Dose (mg/m 2 ) Incidence of Gr ≥ 3 sensory PN (%) Paclitaxel1 wk80-10010-19 3 wk135-2500-33 Docetaxel1 wk35-400-3 3 wk60-1601-14 Ixabepilone3 wk6 (qd x5)3 3 wk407-22 ABI-0071 wk1004 3 wk175-3000-10

18. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Neoadjuvant Ixabepilone Trial (CA 163080) Llombart Cussac et al. ASCO 2005. Abstract 586  Primary endpoint: pharmacogenomic markers  Eligibility: Stage IIA and IIIB breast cancer  Treatment: 4 cycles 40 mg/m 2 IV over 3 hrs every 3 wks  Preliminary report in 96 patients –19% pathologic CR in breast –13% pathologic CR in breast and nodes

19. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Planned and Ongoing Trials of Ixabepilone in Metastatic Breast Cancer

20. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Phase III Clinical Trials of Ixabepilone + Capecitabine Ixabepilone 40 mg/m 2 every 3 wks plus Capecitabine 1000 mg/m 2 bid x 14 days Capecitabine 1250 mg/m 2 bid x 14 days Patients with metastatic or locally advanced breast cancer TrialInclusion CriteriaEndpoints CA163046Anthracycline-pretreated/resistant Taxane-resistant Measurable tumor TTP (primary) OS RR CA163048Prior anthracycline/taxane Measurable/nonmeasurable tumor OS (primary) TTP RR

21. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Ixabepilone + Pegylated Liposomal Doxorubicin: Metastatic Breast Cancer http://www.clinicaltrials.gov/ct/show/NCT00182767  Phase I/II study, currently enrolling (PI: Ellen Chuang, MD, Weill Cornell)  Previously treated metastatic breast, ovarian epithelial, primary peritoneal cavity, or fallopian tube cancer  Ixabepilone + pegylated doxorubicin (PLD) IV Day 1 every 21 days –Phase I (dose escalation): Ixabepilone over 3 hours + PLD over 30-60 min –Phase II: Ixabepilone at MTD (determined in phase I) plus fixed phase I PLD dose  Endpoints: MTD, safety, efficacy

22. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Trastuzumab + Ixabepilone in HER2+ Metastatic Breast Cancer  Ongoing phase II (PI: Craig Bunnell, MD, Dana Farber)  Women with stage IV/recurrent HER2+ metastatic breast cancer (3+ by IHC or FISH+)  Prior therapy –Cohort 1: No prior treatment for metastatic breast cancer except hormone therapy –Cohort 2: Prior chemotherapy + trastuzumab –Trastuzumab + ixabepilone IV Day 1 every 21 days  Primary objective, response rate http://www.clinicaltrials.gov/ct/gui/show/NCT00079326

23. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Trastuzumab, Ixabepilone, and Carboplatin in HER2+ MBC http://www.clinicaltrials.gov/ct/gui/show/NCT00077376  Phase II trial (Study chair: Stacy L. Moulder, MD)  Patients with HER2+ metastatic breast cancer  No prior chemotherapy for metastatic disease  Primary objective, response rate  Treatment schedule –Trastuzumab IV on Days 1, 8, 15, and 22 –Ixabepilone + carboplatin IV on Days 1, 8, and 15 –Treatment every 28 days for ≤ 6 cycles in the absence of unacceptable toxicity

24. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Phase I/II Ixabepilone Studies: Other Tumor Types

25. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Colorectal + Prostate Cancer Studies  Patients (N = 23) with advanced progressive colorectal cancer after IFL 1 –Ixabepilone 40 mg/m 2 IV over 3 hours every 3 weeks –13 patients (56%) achieved SD after 2 cycles –Grade 3/4 peripheral neuropathy, 20%  Patients (N = 92) with treatment-naive metastatic prostate cancer 2 –Ixabepilone 35 mg/m 2 every 3 weeks +/- oral estramustine –32% PR rate in ixabepilone arm, 48% PR rate in ixabepilone + estramustine arm –Grade 3/4 toxicity in ixabepilone + estramustine arm: neutropenia (29%), febrile neutropenia (9%), fatigue (9%), neuropathy (7%) Eng C et al. Ann Oncol. 2004;15:928-932. Galsky MD et al. J Clin Oncol. 2005;23:1439-1446.

26. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Other Tumor Types  Ixabepilone currently being evaluated in phase I and II clinical trials for: –Advanced cisplatin-refractory germ cell tumors –Endometrial cancer –Metastatic, recurrent, or unresectable kidney cancer –Recurrent glioma –Relapsed/refractory lymphoproliferative disorders –Relapsed/refractory aggressive non-Hodgkin's lymphoma www.clinicaltrials.gov

27. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Other Epothilones Under Development

28. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Epothilone B (Patupilone, EPO906): Phase I Trials  Patupilone + gemcitabine –DLTs included grade 3 diarrhea (n = 3), nausea (n = 1), dizziness (n = 1) –MTD: 2.0 mg/m² –Out of 16 evaluable patients, 1 PR and 7 SD  Patupilone + estramustine –Prior taxane therapy in 13/14 patients –DLT, grade 3 diarrhea (n = 1) –MTD, 2.5 mg/m 2 –Grade 3/4 adverse events: diarrhea, fatigue, vomiting (n = 8) –1 PR and 8 SD (preliminary tumor assessment) Rinehart JJ et al. ASCO 2004. Abstract 3100. Wojtowicz M et al. ASCO 2004. Abstract 4623.

29. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Epothilone D (KOS-862)  Anthracycline- and taxane-pretreated metastatic breast cancer –Antitumor activity in 2/10 evaluable patients –Grade 3 toxicity: peripheral neuropathy and ataxia  Second-line therapy in NSCLC –Toxicity: fatigue, neurosensory (paresthesias), nausea/vomiting –4 of first 35 patients withdrew due to toxicity –1 PR; SD for 16 and 31 weeks seen  Phase II study ongoing in hormone-resistant prostate cancer Overmoyer B et al. ASCO 2005. Abstract 778. Yee L,et al. ASCO 2005. Abstract 7127.

30. Beyond Taxane Therapy: Emerging Role of Epothilones in Metastatic Breast Cancer Summary  Ixabepilone –Novel microtubule-stabilizing agent –Non–cross-resistant with taxanes –May have favorable efficacy and safety vs paclitaxel –Being evaluated alone and in combination in phase II/III trials of breast cancer, other cancers  Patupilone and KOS-862 also under evaluation in phase I trials