A Phase 1 Study of MM-302, a HER2targeted PEGylated liposomal doxorubicin, in Patients with HER2-positive Metastatic Breast Cancer (MBC) P LoRusso1, I Krop2, K Miller3, C Ma4, BA Siegel4, AF Shields5, I Molnár6, T Wickham6, J Reynolds6, K Campbell6, B Hendriks6, T McClure6, V Moyo6, P Munster7 1Yale Cancer Center, New Haven, CT; 2Dana-Farber Cancer Institute, Boston, MA; 3Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN, 4Washington University School of Medicine, St. Louis, MO; 5Karmanos Cancer Institute, Detroit, MI; 6Merrimack Pharmaceuticals, Cambridge, MA; 7Helen Diller Family Comprehensive Cancer Center, San Francisco, CA Background • HER2-positive breast cancer affects ~20% of all breast cancer and represents a particularly aggressive form of the disease • Despite recently approved agents like pertuzumab and T-DM1, HER2-positive MBC remains a high unmet medical need • Anthracyclines are particularly effective in HER2-positive BC; however use has declined due to several reasons • Microtubule targeting agents are heavily used in all lines 2 MM-302: HER2-targeted PEGylated liposomal doxorubicin anti-HER2 scFv • Targets liposome to HER2-overexpressing cells • Promotes internalization • Binds to a different epitope than trastuzumab • Does not bind to cardiomyocytes Liposome • Extended half-life • Stably encapsulates doxorubicin • Passive accumulation in tumors • Size precludes delivery to cardiac tissue Lipid Membrane PEG 75-110 nm Doxorubicin Crystals • Effective cytotoxic agent in breast cancer • DNA intercalator, TOP2A inhibitor, free radical generator 3 MM-302 Proposed Mechanism of Action HER2-positive tumor capillary SUM190 cells (HER2-positive) Extravasation via leaky vasculature Binding and internalization 22 2 control MM-302 PLD doxorubicin MM-302 Doxorubicin 2 HER2 Cancer Cell Death 4 MM-302 Proposed Mechanism of Action Cardiac tissue Tight vasculature X Does not bind to cardiomyocytes 2 Human stem cell-derived H e a r t C e lls cardiomyocytes 5000 d o x o r u b ic in ( f e m t o g r a m s /c e ll) X t o t a l c e ll a s s o c ia t e d d o x o r u b ic in capillary PLD 4000 M M -3 0 2 3000 2000 1000 0 0 50 100 150 200 In c u b a tio n t im e (m in ) MM-302 Doxorubicin 2 HER2 Reynolds et al., Toxicol Appl Pharmacol. 2012. 5 Preclinical data supporting MM-302 development BT474-M3-breast MM-302 binds to a different epitope than trastuzumab MM-302 T u m o r V o lu m e (m m 3 ) 3000 2500 2000 1500 1000 500 *** * 0 20 trastuzumab HER2 T u m o r V o lu m e (m m 3 ) Control MM-302 3 mg/kg weekly trastuzumab 3.5 mg/kg q3d MM-302 & trastuzumab 30 40 50 60 D a y s a fte r in o c u la tio n NCI-N87-gastric 2000 1500 1000 ** 500 0 30 40 50 60 70 80 D a y s a fte r in o c u la tio n 90 6 Use of Cyclophosphamide Pretreatment to Enhance MM-302 Tumor Deposition (BT474-M3) Nuclear Doxorubicin No Cyclo % D O X P O S N u c le i 60 + Cyclo MM-302 doxorubicin 15 10 5 30 20 10 N o C y c lo 800 p e rc e n t c h a n g e fro m d a y 1 4 % i.d ./g tis s u e 20 40 0 900 Tumor Deposition 50 700 600 + C y c lo (-4 d ) Tumor Shrinkage CTL M M - 3 0 2 a lo n e M M - 3 0 2 + C y c lo C y c lo 9 6 h r 500 400 300 200 100 0 20 0 N o C y c lo + C y c lo ( - 4 d ) 30 40 D ay 50 7 MM-302 Phase 1 Study Arm 1 8, 16, 30, 40 & 50 mg/m2 MM-302, q4w Patients with locally advanced/unresectable or metastatic HER2-positive breast cancer (N=69) Arm 2 30 & 40 mg/m2 MM-302, q4w + 4 mg/kg trastuzumaba, q2w Arm 3 30 mg/m2 MM-302, q3w + 6 mg/kg trastuzumabb, q3w + 64Cu-MM-302 Arm 4 30 mg/m2 MM-302, q3w + 6 mg/kg trastuzumabb, q3w + 450 mg/m2 cyclophosphamide, q3w + 64Cu-MM-302 a: 6 mg/kg trastuzumab loading dose, b: 8 mg/kg trastuzumab loading dose patients 34 10 12 13 8 Key Study Objectives • Primary Objective: – To assess the safety and tolerability of: • MM-302 alone • MM-302 plus trastuzumab • MM-302 plus trastuzumab and cyclophosphamide – To determine the Phase 2 dose • Key Secondary Objectives: – – – – – – Describe dose limiting toxicities Objective response rate Clinical benefit rate (CR + PR + SD at 24 weeks) Duration of response Median progression free survival Pharmacokinetics 9 Key Inclusion and Exclusion Criteria • Inclusion: – Locally advanced/unresectable or MBC HER2 positive • HER2+ = HER2 IHC 3+ or HER2 ICH 2+ and FISH/CISH-positive – Measurable disease (RECIST v1.1) – ECOG 0 or 1 • Exclusion: – Received 300 mg/mg2 of anthracycline – NYHA Class III or IV CHF or LVEF 50% – History of: • • • • • • Coronary artery disease Myocardial infarction within the last 12 months Severe and/or uncontrolled ventricular arrhythmias Clinically significant valvular heart disease Angina pectoris requiring medication Prolonged QTc interval 10 Demographics TOTAL N Age Median Years (range) Race Asian, n (%) Black or African American, n (%) Caucasian, n (%) 69 55.0 (31-75) 1 (1.4) 4 (5.8) 64 (92.8) Prior Regimens for Metastatic Disease Median (range) 4 (0-11) Prior Exposure to, n (%) Anthracycline Taxane Trastuzumab Ado-trastuzumab emtansine (T-DM1) Pertuzumab Lapatinib Hormonal Therapy 37 (53.6) 64 (92.8) 68 (98.6) 35 (50.7) 17 (24.6) 42 (60.9) 33 (47.8) 11 MM-302 Pharmacokinetics MM-302 Monotherapy 8 mg/m2 16 mg/m2 30 mg/m2 40 mg/m2 50 mg/m2 MM-302 plus trastuzumab 8 mg/m2 16 mg/m2 30 mg/m2 40 mg/m2 50 mg/m2 t1/2= ~2 days in patients receiving 30 mg/m2 MM-302 +/- trastuzumab 12 AEs occurring in ≥20% of population (any grade) MM-302 MM-302 + trastuzumab MM-302 alone + trastuzumab + cyclo Adverse Event1, n (%) TOTAL (N=34) (N=22) (N=13) (N=69) Fatigue 21 (61.8) 10 (45.5) 3 (23.1) 34 (49.3) Nausea 19 (55.9) 9 (40.9) 6 (46.2) 34 (49.3) Constipation 7 (20.6) 9 (40.9) 4 (30.8) 20 (29.0) Decreased Appetite 13 (38.2) 5 (22.7) 2 (15.4) 20 (29.0) Vomiting 9 (26.5) 5 (22.7) 4 (30.8) 18 (26.1) Cough 8 (23.5) 7 (31.8) 2 (15.4) 17 (24.6) Diarrhea 7 (20.6) 5 (22.7) 4 (30.8) 16 (23.2) Neutropenia 9 (26.5) 3 (13.6) 3 (23.1) 15 (21.7) Stomatitis 8 (23.5) 6 (27.3) 1 (7.7) 15 (21.7) Dyspnea 5 (14.7) 5 (22.7) 4 (30.8) 14 (20.3) 1 MedDRA preferred terms 13 Grade 3/4 Treatment Emergent1 AEs (TEAEs) MM-302 MM-302 + trastuzumab MM-302 alone + trastuzumab + cyclo (N=34) TOTAL (N=22) (N=13) (N=69) 9 (26%) 1 (10%) 2 (15%) 12 (17%) 6 (17) 2 (6) 1 (3) 2 (6) 1 (3) 1 (3) 1 (3) 1 (3) 1 (3) 1 (3) 1 (10) 1 (10) - 1 (7) 1 (7) - 7 (10.1) 2 (2.9) 2 (2.9) 2 (2.9) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) Patients with related Grade 3/4 TEAE, n (%) Adverse Events2, n (%) Neutropenia Leukopenia Lymphopenia Mucosal Inflammation Anemia Dyspnea Febrile Neutropenia Hematocrit decreased Neutropenic Infection PPE Thrombocytopenia WBC decreased 1 Events determined by investigator to be “possibly”, “probably” or “definitely” related to study drug treatment preferred terms 2 MedDRA 14 Related1 SAEs and AEs Leading to Treatment Discontinuation # of patients experiencing SAE Individual SAEs2 Febrile Neutropenia Anemia White blood cell count decreased Neutropenia Thrombocytopenia Palmar-plantar erythrodysesthesia Adverse Events2 Leading to Treatment Discontinuation Aphasia/face edema Peripheral neuropathy Cardiac failure Neutropenia Hypoxia Thrombocytopenia N=69 3 (4.3) 6 (8.7) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) 6 (8.7) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) 1 (1.4) There were no treatment related deaths on study 1 Events determined by investigator to be “possibly”, “probably” or “definitely” related to study drug treatment 2 MedDRA preferred terms 15 AEs of Special Interest Adverse Event1 (N=69) Neutropenia 15 (21.7) Stomatitis 15 (21.7) Mucositis 12 (17.4) Alopecia 7 (10.1) Infusion Reaction 6 (8.7) LVEF changes 6 (8.7) PPE 3 (4.3) Cardiac failure 1 (1.4) Neutropenic fever 1 (1.4) PPE: palmar-plantar erthrodysesthesia syndrome There were no severe infusion reactions 1 MedDRA preferred terms 16 Cardiac Safety • No cardiac events with MM-302 monotherapy (34 pts) • Infrequent cardiac events with no SAEs in combination arms – 6 had protocol defined asymptomatic declines in LVEF • 4 Pts reversible declines - consistent with trastuzumab-induced changes • 1 Pt decline to 47% noted at off-study assessment • 1 Pt noted twice to have a range of 45-50% LVEF (off study – unchanged) • One patient described above discontinued treatment due to LVEF changes experienced Grade 1 Heart Failure • 11 patients have cumulative anthracycline exposure >550 mg/m2 – 7 monotherapy pts, 4 in combination with trastuzumab 17 MM-302 Phase 1 Efficacy Patients Receiving ≥30 mg/m2 MM-302 ORR: 11% (7/62) CBR: 21% (13/62) 75 b a s e lin e ) 50 25 fro m 0 -25 (% b e s t c h a n g e in t a r g e t le s io n 100 -50 -75 -100 # prior regimens for metastatic disease Median prior exposure to, n (%) Anthracycline Trastuzumab Lapatinib Taxane Ado-trastuzumab emtansine (T-DM1) Pertuzumab Hormonal therapy 24 (m o n th s ) p r o g r e s s io n fr e e s u r v iv a l 30 18 12 4 mPFS 7.6 months (95% CI) (3.6-10.9) 37 (60) 61 (98) 38 (61) 57 (92) 34 (55) 17 (27) 30 (48) * * 6 * 0 + trastuzumab + cyclophosphamide ● ●●●● ● ● ● ● ● ● ● ● ●● ●●●●●● ● ●●●●● ● ● ● ● *: patients still on study, ORR: Overall Response Rate, CBR: Clinical Benefit Rate (CR, PR and Stable Disease (SD) at 24 weeks) ● ● ● ●● ● ●● ● ●●●●● ●●● 18 Enhanced Efficacy in Anthracycline Naïve Patients Patients Receiving ≥30 mg/m2 MM-302 ORR: 11% (7/62) CBR: 21% (13/62) 75 b a s e lin e ) 50 25 fro m 0 -25 (% b e s t c h a n g e in t a r g e t le s io n 100 -50 -75 -100 mPFS 7.6 months (95% CI) (3.6-10.9) Anthracycline naive * Anthracycline exposed 24 (m o n th s ) p r o g r e s s io n fr e e s u r v iv a l 30 18 12 * * 6 0 + trastuzumab + cyclophosphamide ● ●●●● ● ● ● ● ● ● ● ● ●● ●●●●●● ● ●●●●● ● ● ● ● *: patients still on study, ORR: Overall Response Rate, CBR: Clinical Benefit Rate (CR, PR and Stable Disease (SD) at 24 weeks) ● ● ● ●● ● ●● ● ●●●●● ●●● 19 Enhanced Efficacy in Anthracycline Naïve Patients Patients Receiving ≥30 mg/m2 MM-302 Anthracycline naive 100 ORR: 24% (6/25) CBR: 28% (7/25) 75 ORR: 3% (1/37) CBR: 16% (6/37) 50 25 25 0 0 -2 5 -2 5 -5 0 -5 0 -7 5 -7 5 -1 0 0 -1 0 0 30 30 (% fro m b a s e lin e ) 50 24 (m o n th s ) p r o g re s s io n fre e s u rv iv a l b e s t c h a n g e in ta r g e t le s io n 75 Anthracycline exposed 100 * mPFS: 11.0 months (95% CI) (1.8-13.1) 24 18 18 12 12 * 6 20 + cyclophosphamide 5.7 months (3.6-8.7) * 6 0 0 + trastuzumab mPFS: (95% CI) ●●● ●● ●● ● ● ●● ●● ● ●● ● ● ●● ● ●● ● ● ● ●●● ● *: patients still on study, ORR: Overall Response Rate, CBR: Clinical Benefit Rate (CR, PR and Stable Disease (SD) at 24 weeks) ●●● ●●●● ● 20 ●● ● ●●● ● ● ● ● 20 Enhanced PFS in Anthracycline Naïve Patients Patients Receiving ≥30 mg/m2 MM-302 100 anthracycline a n t h r a c y c l i n e naive n a iv e anthracycline a n t h r a c y c l i n e exposed exposed Prior Anthracycline: Naïve n= 25 # of Events, n (%) 16 (64.0) # Censored, n (%) 9 (36.0) Exposed 37 19 (51.4) 18 (48.6) mPFS (months) 11.0 (95% CI) (1.8-13.1) 5.7 (3.6-8.7) P e rc e n t s u rv iv a l 75 median # of prior regimens for MBC 2 5 50 25 0 0 6 12 18 24 30 p r o g re s s io n fre e s u rv iv a l (m o n th s ) 21 PET/CT 64Cu-MM-302 Breast & Skin Localizes to Brain and Bone Metastases Sternal Mass 24 h 45 h Bone 22 Liver Brain 19 h 25 h Brain 44 h 19 h 22 HERMIONE Study Schema (NCT02213744) HER2-positive locally advanced/metastatic BC (N=250) MM-302 1 30 mg/m2, Q3W + trastuzumab 6 mg/kg*, Q3W Anthracycline naive Prior metastatic treatment with pertuzumab and T-DM1 Prior treatment with trastuzumab 1 Chemotherapy of Physician’s Choice (capecitabine, gemcitabine or vinorelbine) + trastuzumab 6mg/kg*, Q3W * 8 mg/kg trastuzumab loading dose • 70 participating sites (46 in the US, 4 in Canada and 20 in Europe) • Study currently open and enrolling patients • Enrollment expected to be completed late 2017 23 Conclusions • Manageable safety profile as monotherapy, and in combination with both T and T + C • Appears to have activity in heavily pretreated MBC • RR - 24% and an 11 mo mPFS was observed in anthracycline-naïve patients • HERMIONE - enrolling anthracycline-naïve patients that progressed on pertuzumab and TDM-1 24 Acknowledgements We would like to thank the patients, their families, caregivers, investigators, and research staff for their participation 25
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