Slide 1: Discovery and preclinical characterization of JAK2V617F mutant selective JH2 inhibitors in MPN
Discovery and preclinical characterization of orally bioavailable JAK2V617F mutant selective JH2 inhibitors with disease modification potential in myeloproliferative neoplasms Neha Bhagwat1, Duanya Liu2, Xiaowei Wu1, Alexander Grego1, Amy Crossan1, Andrew Moore1, Arpita Mondal1, Carly Bachner1, Dani
Slide 2: JAK2V617F is the Primary Driver Mutation in Myeloproliferative Neoplasms
JAK2V617F is the Primary Driver Mutation Leading to Constitutive JAK2 Activation and Hyperproliferation in Patients With Myeloproliferative Neoplasms (MPN) Polycythemia Vera (PV) Essential Thrombocythemia (ET) First generation JAK2 inhibitors Campbell P.J. and Green A.R. N Engl J Med 2006;355:2452-2
Slide 3: First Generation JAK Inhibitors Are Effective but Have Limitations
First Generation JAK Inhibitors Are Effective but Have Limitations First generation JAK2 inhibitors such as ruxolitinib are highly effective in reducing spleen size and symptoms in MPN, but inhibit wild type and mutant JAK2 equally Ruxolitinib 50% pathway inhibition overlaps for WT and VF Achiev
Slide 4: PRT12396 is an Allosteric JAK2V617F-Selective Pseudokinase (JH2) Inhibitor
PRT12396 is an Allosteric JAK2V617F-Selective Pseudokinase (JH2) Inhibitor 100 JAK2 JH2 VF JAK1 JH2 Mean ± SD %Binding 200X TYK2 JH2 50 JAK2 JH1 0 0.001 0.1 10 1000 100000 [PRT12396] nM Tested in kinome binding assay at 100X JAK2VF IC50 Structure-Based Drug Design (SBDD) enabled identification of
Slide 5: PRT12396 Demonstrates Selective Inhibition of Aberrant Signaling in JAK2VF Cells
PRT12396 Demonstrates Selective Inhibition of Aberrant Signaling in JAK2VF Cells Dose-dependent inhibition of pJAK2 and STAT-MAPK signaling Selective modulation of aberrant signaling in JAK2VF cells SET2 (VF) + UT-7 (WT) + 100 nM PRT12396 100 nM PRT12396 120 % Relative to DMSO pSTAT1 (Y701) pSTAT3 (
Slide 6: Selectively Inhibits Mutant JAK2V617F in Cellular Assays with Potent Anti-Proliferative Activity
PRT12396 Selectively Inhibits Mutant JAK2V617F in Cellular Assays Leading to Potent Anti-Proliferative Activity 10x Selectivity in Anti-proliferation 10x 1 10X selective anti-proliferative activity 100 100 SET2 (JAK2VF) in JAK2VF cell lines Log 10 IC50 (μM) UT-7 (JAK2WT) % Cell Viability 0 Selec
Slide 7: Maintains Activity in Models of Ruxolitinib-Persistence
PRT12396 Maintains Activity in Models of Ruxolitinib-Persistence SET2-Naive SET2-Naive SET2-Rux persistent SET2-Rux persistent % Cell viability 100 % Cell Viability 100 (1 μM) (1 μM) 50 50 0 0 0.01 0.1 1 10 0.01 0.1 1 10 Ruxolitinib, µM PRT12396, μM Ruxolitinib persistent cells were generated by cul
Slide 8: Selectively Inhibits Expansion and Proliferation of JAK2VF Primary MPN Cells
PRT12396 Selectively Inhibits Expansion and Proliferation of JAK2VF Primary MPN Cells CFU Assay CD34+ ex vivo Proliferation Assay JAK2 WT Normal (N=3) JAK2WT Normal (N=2) JAK2 VF MPN (N=4) JAK2VF MPN (N=2) 100 100 ✱ No. of colonies (% of control) CD34+ cells (% of control) 50 50 0 0 0.02 0.08 1.25 1
Slide 9: Shows Significant Efficacy, Comparable to Ruxolitinib, in BaF3-EPOR-JAK2VF Model
PRT12396 Shows Significant Efficacy, Comparable to Ruxolitinib, in BaF3-EPOR- JAK2VF Model 0.8 ✱✱✱ Significant reduction in splenomegaly Spleen weight (g) BaF3 EPOR JAK2V617F i.v. 0.6 >70% at well-tolerated doses cells 10-12 days reduction 0.4 Normalization of pathogenic cytokines Treatment 0.2
Slide 10: Demonstrates Significant Tumor Growth Inhibition in JAK2VF SET2 Xenograft Model
PRT12396 Demonstrates Significant Tumor Growth Inhibition in JAK2VF SET2 Xenograft Model 3000 SET2 Significant TGI (>80%), superior to Tumor Volume (mm3) ruxolitinib, observed at well-tolerated doses Mean ± SEM 2000 Vehicle 4-6 hours plasma coverage > VF ✱✱✱ PRT12396 100 mg/kg BID ✱✱✱ PRT12396 2
Slide 11: Exhibits Selective Inhibition of Mutant JAK2V617F In Vivo
PRT12396 Exhibits Selective Inhibition of Mutant JAK2V617F In Vivo 200 Tumor (JAK2VF) % pSTAT5 Relative to Vehicle SET2 tumor- Spleen (JAK2WT) bearing mouse 150 Spleen (JAK2 WT) Drug Tx 100 1 hr Tumor (JAK2 VF) non-selective 50 inhibition 50U EPO (subQ) 30 min prior dosing 0 Vehicle PRT12396 PRT1239
Slide 12: Superior Efficacy to Ruxolitinib in a JAK2V617F Knock In Mouse Model
Superior Efficacy to Ruxolitinib in a JAK2V617F Knock In Mouse Model JAK2WT Vehicle Key features that recapitulate human MPN CD45.1+ 2-week At termination • Elevated blood counts engraftment PRT11758 po 7 weeks - Spleen weights • Iron deficiency 1:1 100 mg/kg BID - Cytokine analysis • Splenomegaly W
Slide 13: Selective Effects on JAK2VF Stem and Progenitor Cells in Knock in Model
Selective Effects on JAK2VF Stem and Progenitor Cells in JAK2VF Knock in Model ✱✱ 20 60 Vehicle LT-HSC-BrdU (%) MEP-BrdU (%) 15 Rux 40 PRT11758 Selective decrease in proliferation 10 of JAK2VF long-term-HSC and megakaryocyte-erythroid 20 5 progenitor populations 0 0 WT VF WT VF Minimal effects o
Slide 14: Demonstrates Significant Therapeutic Window In Vivo
PRT12396 Demonstrates Significant Therapeutic Window In Vivo Reticulocyte Inhibition Only at High Dose, with Full Recovery by Day 15 No evidence of WT JAK2 inhibition in 2-week rat toxicology study at 500 Reticulocytes (109/L) 0 mg/kg low and mid doses that provide 400 50 mg/kg efficacious exposur
Slide 15: Summary: PRT12396 is a JAK2V617F-Selective JH2 Inhibitor with Disease Modifying Potential
Summary: PRT12396 is a JAK2V617F-Selective JH2 Inhibitor with Disease Modifying Potential in Myeloproliferative Neoplasms Selectively inhibits JAK2V617F activity in a cellular context while preserving wild type JAK2-mediated cytokine signaling Demonstrates robust preclinical activity in multiple
Slide 16: Acknowledgements
Acknowledgements Screening, Preclinical Biology, and DMPK INSERM - France Alex Grego Miles Cowart Joy Cote Duanya Liu Andrew Moore Arpita Mondal Joe Rager Diego Elrio Amy Crossan Kirsten Gallagher Stefan Ruepp Yann Loret Sharayu Chandratre Yue Zou Min Wang Prelude headquarters Stephane Giraudier Ste