Epothilones in Breast Cancer Sandra M Swain MD

Epothilones in Breast Cancer Sandra M. Swain, MD December 7, 2005

Sandra Swain, MD No financial relationships with any commercial interest

Recent Advances in the Development of Microtubule-Stabilizing Agents • Microtubule-stabilizing agents • Epothilones • Ixabepilone (BMS-247550) trial at NCI – Clinical outcome – Evaluation of neurotoxicity – Translational study • Other ixabepilone trials in breast cancer

Sorangium cellulosum • Myxobacteria – Secondary metabolites (epothilones/fungicides) Zambezi river

Epothilones Bind Specifically and Uniquely to Beta-Tubulin Paclitaxel Epothilone A • Thiazole side-chain occupies the region of binding site not occupied by taxanes • Only 1 polar contact point (C 7 -OH) is shared with taxanes Epo. A and paclitaxel bound to beta-tubulin Nettles. Science. 2004; 305: 866 -869.

Epothilones Are Strong Promoters of Tubulin Polymerization • Epothilone B has tubulin polymerizing activity 2 -10 times stronger than paclitaxel 1, Paclitaxel; 2, Epo. A; 3, Epo. B Kowalski. J Biol Chem. 1997; 272: 2534.

• Poor substrates for MDR proteins • MDR expression not altered in epothiloneresistant cell lines Modified from Data on file, Bristol. Myers Squibb Company. Log cell kill at MTD Epothilones Are Less Susceptible to MDR Than Paclitaxel 6 Paclitaxel 5 Ixabepilone (epothilone B analog 4. 5 4 3. 1 3 2 1. 3 1 0 0. 4 PAT-7 HCT/VM 46 MDR/MRP MDR (Ovarian Ca) (Colon Ca)

Potential Advantages of Epothilones • Bind specifically and uniquely to betatubulin • 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 epothiloneresistant cell lines

Epothilones NAME Derivative DEVELOPER PHASE Ixabepilone Epothilone B Bristol-Myers Squibb III Patupilone Epothilone B Novartis III KOS-862 Epothilone D Kosan/Roche II BMS-310705 Epothilone B Bristol-Myers Squibb I ZK-EPO Epothilone B Schering AG II

Ixabepilone (BMS-247550) • Epothilone B is a natural macrolide produced by the myxobacterium Sorangium cellulosum • Ixabepilone is a semisynthetic analog of epothilone B (aza-epothilone B) Epothilone B Ixabepilone

Antitumor Activity in Taxane. Resistant PAT-21 Breast Cancer Xenografts Control Ixabepilone (13 mg/kg, MTD) Docetaxel (20 mg/kg, MTD) Vinorelbine (9 mg/kg, MTD) 1000 10 40 70 100 130 160 Days posttumor implantation Median tumor wt. (mg) Control Ixabepilone (10 mg/kg, MTD) Paclitaxel (36 mg/kg, MTD) 1000 10 40 50 60 70 80 90 Days posttumor implantation PAT-21 breast cancer xenografts are derived from a patient with MBC who received 10 cycles of CMF, then 4 cycles of paclitaxel. MTD=maximum tolerated dose. Data on file, Bristol-Myers Squibb Company.

Ixabepilone Pharmacology Daily x 5 q 21 d Infusion duration, hr Daily x Weekly 3 q 21 d Once q 21 d 1 1 0. 5 -1 1 Dose (mg/m 2), range 1. 5 -8 8 -10 1 -30 32 -65 MTD (mg/m 2) 6 8 25 50 DLT Neutropenia, neuropathy MTD=maximum tolerated dose; DLT=dose-limiting toxicity; q=every. Goodin. J Clin Oncol. 2004; 22: 2015 -2025.

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-naїve, 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 Abraham. J Clin Oncol. 2003; 21: 1866 -1873; Mani. Clin Cancer Res. 2004; 10: 1289 -1298; Zhuang. Cancer. 2005; 103: 1932 -1938.

Ixabepilone in Metastatic and Locally Advanced Breast Cancer Phase II Trial NCI-0229 Taxane Naïve and Prior Taxane Treated Group Cycle 1 (3 weeks) Daily x 5 Baseline biopsy Cycle 2 Daily x 5 Cycle 3… Daily x 5 Post-treatment biopsy 6 mg/m 2/day

Clinical Response to Ixabepilone NCI-0229 Prior Taxane Total Complete Response 37 1 (3%) Partial Response 7 (19%) Stable Disease 13 (38%) Progressive Disease 16 (43%) Low. J Clin Oncol. 2005; 23: 2726 -34.

Case Study Complete Response Baseline After 11 Cycles

Ixabepilone Phase II Trial NCI-0229: Grade 3/4 Toxicities Toxicity, % Neutropenia, Thrombocytopenia Myalgia Febrile neutropenia Diarrhea Fatigue Low. J Clin Oncol. 2005; 23: 2726 -34. Prior Taxanes (N=37) 16 8 3 14 11 13

Incidence of Peripheral Neuropathy During Ixabepilone Treatment: NCI 0229 CTC Toxicity Grade Prior Taxane (N=37) 0 1 2 3 4 46 % 29 % 22% 3% –

Tools for Neurotoxicity Assessment • In addition: Semmes Weinstein Filaments Grooved Peg Board Test – Questionnaire (intensity and frequency of symptoms) – Balance Testing (Tandem Stance and Modified Romberg) – Nerve Conduction Studies – Physical exam – CTC grading Jebsen Test of Hand Function

Matched Pair Study • Each patient who developed grade 2+ neuropathy was matched to a patient who did not • Patients matched by age, cumulative dose of taxane therapy, length of time on study, number of prior regimens Median Difference Between Matched Subjects Test Baseline Onset of Grade 2 Difference Between Baseline and Onset Grooved peg board (dominant hand) 8* 25** 11 Jebsen Test of Hand Function (non-dominant hand) 1. 7 6. 1 7. 9** *P < 0. 05; **P < 0. 01

Exploratory Univariate Analysis • Hypothesis: Test scores above a certain cutpoint would indicate high likelihood of developing neuropathy Example: Baseline score for Jebsen Test of Hand Function using non-dominant hand For scores greater than 55, median time for neuropathy was 4 months from cycle 3

Functional Tests May Predict Development of Neuropathy • Low incidence of neuropathy with ixabepilone on daily x 5 schedule – Grade 2: 24% – Grade 3: 5% – Grade 4 -5: 0% • Grooved Peg Board Test and Jebsen Test of Hand Function most often correlated and predicted ixabepilone-induced grade 2 -3 neuropathy

Summary: NCI-0229 • Good clinical activity in heavily pretreated breast cancer patients (RR=22%) and taxane naïve patients (RR=43%) • Grade 3/4 sensory peripheral neuropathy in 3% of patients • Baseline neurologic functional tests may predict grade ≥ 2 peripheral neuropathy

Ixabepilone Phase II Clinical Trials in Metastatic Breast Cancer NCI-0229* (N=37) CA-163010† (N=61) CA-163009‡ (N=49) CR 1 (3%) - - PR 7 (19%) 27 (44%) 6 (12%) SD 13 (35%) 21 (34%) 19 (39%) PD 16 (43%) 12 (20%) 23 (47%) *Taxane-pretreated. †Anthracycline-pretreated; Ixabepilone 40 mg/m 2 q 3 wk; Roche et al. ASCO 2003; 22: 18. Abstract 69. ‡Taxane-refractory; Ixabepilone 40 mg/m 2 q 3 wk; Thomas et al. ASCO. 2003; 22: 8. Abstract 30.

Incidence of Peripheral Neuropathy With Ixabepilone Phase II Trial Schedule NCI-0229 (N=56) CTC Toxicity Grade % 0 1 2 3 4 6 mg/m 2 over 1 hr qd (x 5) q 3 wk 48 28 20 4 0 CA 163010 (N=65) 40 mg/m 2 over 3 hr q 3 wk N/A N/A 22 0 CA 163009 (N=49) 40 mg/m 2 over 3 hr Q 3 wk N/A 33 12 0 Eng et al. (N=25) 40 mg/m 2 over 3 hr q 3 wk 48 28 4 20 0

Incidence of Sensory Neuropathy With Microtubule-Stabilizing Agents Paclitaxel Docetaxel Ixabepilone ABI-007 Schedule Dose (mg/m 2) Incidence of Gr ≥ 3 Sensory PN (%) 1 wk 3 wk 1 wk 3 wk 80 -100 135 -250 35 -40 60 -160 6 (qd x 5) 40 100 175 -300 10 -19 0 -33 0 -3 1 -14 3 7 -22 4 0 -10

Phase III Clinical Trials of Ixabepilone Plus Capecitabine 1250 mg/m 2 bid x 14 days Randomized Ixabepilone 40 mg/m 2 q 3 wk plus Capecitabine 1000 mg/m 2 bid x 14 days Trial Inclusion Criteria End Points CA 163046 • Anthracycline-resistant or minimum TTP (primary) cumulative dose OS RR • Taxane-resistant • Measurable tumor CA 163048 • Anthracycline- and taxanepretreated • Measurable/nonmeasurable tumor OS (primary) TTP RR

Ixabepilone Shows Synergy With Trastuzumab In Vivo Lee. ASCO 2005. Abstract 561

Ixabepilone + Pegylated Liposomal Doxorubicin: Metastatic Breast Cancer • Phase I/II study (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 http: //www. clinicaltrials. gov/ct/show/NCT 00182767

Trastuzumab + Ixabepilone in HER 2+ Metastatic Breast Cancer • Ongoing phase II (PI: Craig Bunnell, MD, Dana Farber) • Women with stage IV/recurrent HER 2+ 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/NCT 00079326

Trastuzumab, Ixabepilone and Carboplatin in HER 2+ MBC • Phase II trial (PI: Stacy L. Moulder, MD) • Patients with HER 2+ 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 http: //www. clinicaltrials. gov/ct/gui/show/NCT 00077376

Can we predict which patients will respond and which are resistant?

Status of Microtubule Assembly May Dictate Drug Sensitivity (Cabral Model) Sensitive to Stabilizing Agents Increased Microtubule Assembly Functional Microtubules Resistant to Stabilizing Agents Barlow. J Cell Sci. 2002; 115: 3469. Decreased Microtubule Assembly

Post-translational Modifications of α-Tubulin H 2 N Ac GEEY 40 Acetylation α-Tubulin H 2 N GEEY Detyrosination H 2 N GEE • These modifications occur in α-tubulins in MTs (not free form), and are correlated with stable microtubules.

Ixabepilone May Enhance Microtubule Stability Preferentially in Tumor Cells Acetylated Tubulin = Tumor Patient 1 (PR) = Stromal Staining Patient 5 (PD) Baseline Cycle 2

Genes Identified That Correlated With Ixabepilone Sensitivity Expression level High Low Resistance Sensitivity markers Cell lines Lee. ASCO 2005. Sensitive Resistant

Novel Agents

Kinase Inhibitors Involved With Mitosis NAME TARGET DEVELOPER PHASE VX-680 Aurora Kinase Vertex I SB-715992 Kinesin Spindle Protein (KSP) Cytokinetics/GS K II SB-743921 KSP Cytokinetics I ON 01910 Polo-like Kinase Onconova I

Epidermal Growth Factor Receptor Family NAME TARGET DEVELOPER Lapatinib EGFR and HER 2 CI-1033 EGFR and HER 2 Pfizer, NCI II AEE 788 EGFR, HER 2, and VEGFR Novartis I Pantimimumab EGFR Abgenix/Amgen III Glaxo. Smith. Kline PHASE II

AZD 2171 Neoadjuvant NCI Trial Accrual Goal: 30 patients Cycle 1: 7 days C 1 Cycles 2 -7: Every three weeks C 2 C 3 C 4 C 5 C 6 C 7 N=20 Surgery, XRT and hormonal therapy as indicated N=10 AZD 2171 30 mg qd CONTROL - No Therapy DYNAMIC MRI TUMOR BIOPSIES, SERUM STUDIES DOCETAXEL 75 mg/m 2 DOXORUBICIN 50 mg/m 2 CYCLOPHOSPHAMIDE 600 mg/m 2 FILGRASTIM 300 mcg Days 2 -11 or PEGFILGRASTIM 6 mg Day 2

AZD 2171 Neoadjuvant NCI Trial Objectives • Pathologic CR in the breast • Changes in parameters of angiogenesis: – Phospho-VEGFR-2 in tumor – VEGF in tumor – Soluble VEGFR-2, VEGF, and circulating endothelial cells. – Vascular permeability using Dynamic Contrast Enhanced MRI

PARP Inhibition • Inhibition leads to sensitization to DNA damaging agents – Radiation – Platinums, cyclophosphamide, irinotecan, temozolomide, anthracyclines – May be more potent in tumors with defective DNA repair mechanisms

Miscellaneous Agents NAME TARGET DEVELOPER PHASE SU-11248 Pan-kinase inhibitor Pfizer/Sutent II RAD-001 m. TOR Novartis I/II PTK-787 VEGF-R inhibitor Novartis III PKC 412 Pan-kinase inhibitor Novartis II PX 886 PI-3 -Kinase Inhibitor Pro. LX Preclinical/I (1 Q 06)

Conclusion • Ixabepilone very active in breast cancer • Advantages – No steroid premedication – Minimal hypersensitivity reactions and nausea/ vomiting – 3%-5% Grade 3 peripheral neuropathy • Combinations in progress • Many new agents on the horizon

Acknowledgments Cancer Therapeutics Branch James Lee, MD, Ph. D Tito Fojo, MD, Ph. D Xiaowei Yang, MD, Ph. D Marianne Poruchynsky, Ph. D Neelima Denduluri, MD Janice Walshe, MD Suparna Bonthala, MD Arlene Berman, RN Michael Cox, Pharm. D Nitin Mannan Ujala Vatas CTEP Jennifer A. Low, MD, Ph. D Dimitrios Colevas, MD Radiology Catherine Chow, MD Rehabilitation Medicine Earllaine Croarkin Rebecca Parks Statistics Seth Steinberg, Ph. D Bristol-Myers Squibb Co Ron Peck, MD