Antibody Targeted Amanitin Conjugates (ATACs) Expanding the ADC Landscape With a New Payload Targeting RNA Polymerase II

Transcription

1 Antibody Targeted Amanitin Conjugates (ATACs) Expanding the ADC Landscape With a New Payload Targeting RNA Polymerase II ADC Summit 2016 San Diego Andreas Pahl CS Heidelberg Pharma GmbH Ladenburg, Germany Drug Development

2 utline Amanitin & Supply Antibody Targeted Amanitin Conjugates (ATACs) Synthetic Derivative with Superior Stability HDP-101 : ATAC Candidate for Clinical Development ctober 2016, San Diego - confidential - 2

3 utline Amanitin & Supply Antibody Targeted Amanitin Conjugates (ATACs) Synthetic Derivative with Superior Stability HDP-101 : ATAC Candidate for Clinical Development ctober 2016, San Diego - confidential - 3

4 Amatoxins - structure and origin Group of toxins from the poisonous Green Death-Cap (Amanita phalloides) Nine related toxin structures; most frequently studied are -amanitin and -amanitin Bicyclic octapeptide structure Most effective and specific inhibitor of the eukaryotic transcription The mode of action of amanitin is the specific inhibition of RNA polymerase II (RNA pol II). High liver toxicity prevented therapeutic usage so far H CH CH 2 H H 3 C HN CH CH C NH CH C NH CH 2 C C H 2 C NH CH 3 H N S CH 2 N H HC H C CH CH 2 CH 3 C CH NH H 2 C CR C CH NH C CH 2 NH -Amanitin -Amanitin R = NH 2 R = H ctober 2016, San Diego - confidential - 4

5 USPs of Amantin as an ADC Payload Amanitin kills quiescent and dividing cells No resistance Unique MoA - never used in oncology Target with low copy number (1,000 to 10,000 per cell*); 1:1 binding Hydrophilic; no aggregation, aqeous chemistry Low toxicity of free toxin due to low membrane permeability ctober 2016, San Diego - confidential - 5

6 SPPS Amanitin : Total Chemical Synthesis by Solid Phase H PS SPPS, Fmoc Strategy H N Fmoc-HypH Resin, 3 steps FmocAsn(Tri)H FmocCys(Tri)H Fmoc GlyH FmocIleH FmocGlyH Savige-Fontana Tryptathionylation (B-Ring Formation) & Simultaneous Resin Cleavage Macrolactamisation (A-Ring Formation) Deprotection, Linker Introduction H H N + Cl H H DHIL, 10 steps N H H N HPI, 2 steps H H H 3 C HN C N C H 2 C CH CH CH CH C NH CR CH 2 H NH C CH C NH CH 2 C H 2 C S CH 2 N H CH NH C CH 2 NH HC H C NH -Amanitin -Amanitin Tech Transfer to CDM initiated GMP available in 2017 CH CH 3 CH 2 CH 3 R = NH 2 R = H ctober 2016, San Diego - confidential - 6

7 utline Amanitin & Supply Antibody Targeted Amanitin Conjugates (ATACs) Synthetic Derivative with Superior Stability HDP-101 : ATAC Candidate for Clinical Development ctober 2016, San Diego - confidential - 7

8 Generation of ATACs > 100,000 x Hydrophilic Amanitin does not penetrate cells ctober 2016, San Diego - confidential - 8

9 M e a n t u m o r v o lu m e [ m m 3 ] ATACs show Superior Efficacy Efficacy in trastuzumab-resistant JIMT-1 xenograft model Clinical Dose of T-DM1 ineffective (FDA approved Kadcyla ) fold clinical dose of T-DM1 marginally effective 100-fold less dose of Her2-ATAC shows same efficacy Equivalent dose of Her2-ATAC shows complete remission D a y s a fte r firs t in je c tio n ) ) Identical antibody ( ( V e h ic le T -D M m g /k g Ig G T -D M 1 3 x 3 0 m g /k g Ig G H e r m g /k g Ig G H e r m g /k g Ig G Identical random lysine conjugation Identical type of linker Kadcyla could not achieve remission ctober 2016, San Diego - confidential - 9

10 utline Amanitin & Supply Antibody Targeted Amanitin Conjugates (ATACs) Synthetic Derivative with Superior Stability HDP-101 : ATAC Candidate for Clinical Development ctober 2016, San Diego - confidential - 10

11 ptimization of Natural Amanitin -amanitin Contains various functional groups which may be modified to gain improved properties without loosing cytotoxic activity Identification of an optimized synthetic derivative ctober 2016, San Diego - confidential - 11

12 Comparison of ptimized Synthetic Derivative with Natural Amanitin HDP Amanitin source: Natural Linker: Protease cleavable Conjugation: thiol reactive maleimide HDP Amanitin source: ptimized synthetic derivative Linker: Protease cleavable Conjugation: thiol reactive maleimide Antibody BCMA-Antibody Cysteine engineered in heavy chain Site-specific conjugation to engineered cysteine ctober 2016, San Diego

13 Increased Stability of Synthetic HDP in Plasma anti-amanitin Western Blotting of ADCs incubated in murine (left) and human (right) plasma for up to 10 days ctober 2016, San Diego - confidential - 13

14 Comparable Cytotoxicity of Synthetic Derivative Increased Stability Leads to Prolonged Cytotoxicity Cytotoxic activity of ATACs after incubation in human plasma for up to 10 days ctober 2016, San Diego - confidential - 14

15 ptimization of Natural Amanitin -amanitin Contains various functional groups which may be modified to gain improved properties without loosing cytotoxic activity Identification of an optimized synthetic derivative with Improved stability Prolonged cytotoxicity New IP (not found in nature) ctober 2016, San Diego - confidential - 15

16 utline Amanitin & Supply Antibody Targeted Amanitin Conjugates (ATACs) Synthetic Derivative with Superior Stability HDP-101 : ATAC Candidate for Clinical Development ctober 2016, San Diego

17 BCMA as a Target for ATACs BCMA is expressed on mature but not on healthy earlier stage plasma cells BCMA is specifically expressed in multiple myeloma (MM), a mature B-cell neoplasm Upside : In CLL and DLBCL approximately 50% of patients have BCMA positive B-cells making them eligible for BCMA-ATAC therapy as well BCMA BCMA ctober 2016, San Diego

18 Humanized Anti-BCMA Antibodies Chimeric and humanized J22.9 variants bind to purified human and cynomolgus BCMA ELISA (human) ELISA (cynomolgus) Flow cytometry Affinity (SPR) (human, n=3) Affinity (SPR) (cyno, n=2) J22.9-xi ± 0.7 x M 2.7 x 10-9 M J22.9-H ++ + nd 1.5 ± 0.3 x 10-8 M 2.7 x 10-7 M J22.9-FSY ± 0.3 x 10-9 M 2.7 x 10-8 M J22.9-ISY ± 0.2 x 10-9 M 2.7 x 10-8 M ctober 2016, San Diego

19 Cellular Cytotoxicity of BCMA-ATACs BCMA-ATACs are highly cytotoxic in BCMA-expressing but not in BCMA-negative cells Cytotoxicity correlates with BCMA levels on cell lines NCI-H929 MM.1S Luc MM.1S U266B1 PM-2 CCRF-CEM (BCMA-negative) J22.9-ISY-D265C J22.9-ISY-D265C EC 50 [M]: NCI-H929 MM.1S Luc MM.1S U266B1 PM-2 J22.9-ISY- D265C J22.9-ISY- D265C x x x x x x x x x x 10-7 ctober 2016, San Diego

20 T u m o r V o lu m e [m m 3 ] Efficacy of BCMA-ATACs in Subcutaneous Xenografts Subcutaneous multiple myeloma xenograft model (NCI-H929) Both compounds show dose-dependent tumor regression Complete remission at 4 mg/kg single injection E ffic a c y o f A T A C s in a s c N C I-H M M X e n o g ra ft P B S [1 0 m L /k g ] J IS Y - D C [ 2 m g /k g ] J IS Y - D C [ 4 m g /k g ] J IS Y - D C [ 2 m g /k g ] J IS Y - D C [ 4 m g /k g ] D a y s A fte r T re a tm e n t (s in g le d o s e iv ) ctober 2016, San Diego

21 T o t a l F l u x [ p / s ] Efficacy of BCMA-ATACs in Disseminating Xenografts Intravenous Multiple Myeloma xenograft model (MM1.S-Luc) Disease progression monitored with bioimaging Both compounds show complete tumor remission at doses of 2 and 4 mg/kg single injection PBS [10mL/kg] J22.9-ISY-D265C [2mg/kg] J22.9-ISY-D265C [4mg/kg] J22.9-ISY-D265C [2mg/kg] J22.9-ISY-D265C [4mg/kg] Background Level * Treatment (single dose iv) Days Post Tumor Cell Inoculation * 9/10 animals: background level ctober 2016, San Diego

22 T o ta l F lu x [p /s ] Efficacy of BCMA-ATACs in Disseminating Xenografts Intravenous Multiple Myeloma xenograft model (MM1.S-Luc) Disease progression monitored with bioimaging Synthetic BCMA-ATAC shows complete remission at doses of 0.1, 0.3, 1 and 2 mg/kg. E ffic a c y o f A T A C s in a d is s e m in a tin g iv M M 1.S -L u c M M X e n o g r a ft P B S [ 1 0 m l/k g ] J IS Y - D C [ 0.1 m g /k g ] J IS Y - D C [ 0.3 m g /k g ] J IS Y - D C [ 1 m g /k g ] J IS Y - D C [ 2 m g /k g ] B a c k g r o u n d L e v e l * * T r e a t m e n t ( s i n g l e d o s e i v ) D a y s P o s t T u m o r C e ll In o c u la tio n * 9 /1 0 a n im a ls : b a c k g r o u n d le v e l ctober 2016, San Diego

23 U /L S e r u m BCMA-ATAC : Non-Human Primate Study Dose Escalation and Repeated Dosing : ALT A L T H D P m g /k g 1 m g /k g 3 m g /k g 3 animals per group week schedule * Scheduled sacrifice D a y s * ---- min/mean/max/ values of untreated animals ctober 2016, San Diego

24 U /L S e r u m BCMA-ATAC : Non-Human Primate Study Dose Escalation and Repeated Dosing : LDH L D H H D P m g /k g 1 m g /k g 3 m g /k g 3 animals per group week schedule D a y s * * Scheduled sacrifice ---- min/mean/max/ values of untreated animals ctober 2016, San Diego

25 HDP-101 : Tolerability in Non-Human Primates Mouse tolerability is not predictive Liver enzymes hardly affected; not dose limiting; No signs of liver toxicity in histopathology LDH most sensitive; transient increase of neutrophils & decrease of monocytes and lymphocytes TI : HNSTD (3mg/kg repeated in NHP) / MED (0.1 mg/kg single in murine disseminating xenograft) Therapeutic index based on BSA : 120 BCMA-ATAC based on synthetic amanitin derivative selected for development : HDP-101 ctober 2016, San Diego

26 Summary Amanitin Highly potent payload Chemical synthesis established. Tech transfer & GMP initiated Synthetic derivative with improved stability Linker & Conjugation technology Comprehensive linker toolbox established Linker & conjugation technology for different conjugation strategies established Favorable therapeutic index demonstrated in non-human primates Biomarker / Companion Diagnostic First biomarker in ADC area, high incidence in advanced tumors Guidance of R&D in target and indication selection Stratification of patients in clinical trials to decrease RR and probability of approval Candidate for Clinical Development HDP-101 (BCMA-ATAC) ctober 2016, San Diego - confidential - 26

27 Acknowledgements Heidelberg Pharma Torsten Hechler Christoph Müller Christian Lutz Michael Kulke Gudrun Schiedner Team of Heidelberg Pharma Thank you for your attention ctober 2016, San Diego - confidential - 27