Alzheimer s Disease: the Discovery of a Novel Phosphodiesterase 5 Inhibitor for its Cure.

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1 Alzheimer s Disease: the Discovery of a ovel Phosphodiesterase 5 Inhibitor for its Cure. Jole Fiorito, Ph.D. U.S. Pat. Appl. Publ. (2012), US A I thought elephants never forgot, I thought elephants never forgot, but according to these results you have Alzheimer s disease.

2 Alzheimer s Disease Alzheimer's disease (AD) is the most common cause of dementia among people aged 65 and older; AD is a progressive neurodegenerative disorder that attacks neurons, resulting in loss of memory, thinking and language skills, and behavioral changes. Itis estimated that as many as 5.1 million Americansmayhavemay Alzheimer's disease.

3 Alzheimer s Treatments FDA approved drugs Cholinesterase Inhibitors: Tacrine (Cognex) Donepezil (Aricept) Rivastigmine (Exelon) Galantamine (Razadyne) MDA Antagonist: Memantine (amenda) Current Targets for Drug Development Mullard A. at Rev Drug Discov. (2012)

4 The cascade in learning and memory STRATEGY To Enhance Cell to Cell Communication A down regulates the /cgmp/creb pathway memory LTP Agents that enhance /cgmp/creb signaling rescue A induced d reduction of synaptic plasticity and memory D. Puzzo, et al, J. eurosci. (2005); D. Puzzo et al, J. eurosci. (2009).

5 PDE5 Inhibitors STRATEGY To Enhance Cell to Cell Communication Phosphodiesterasetype5inhibitors (PDE5Is) increase cgmp level and ameliorate synaptic plasticity and memory D. Puzzo, et al, J. eurosci. 25 (2005); D. Puzzo et al, J. eurosci. 29 (2009).

6 PDE5 Inhibitors PDE5Is for the treatment of Erectile Dysfunction and Pulmonary Arterial Hypertension CIALIS GALS ovel PDE5Is which are optimized for AD: To identify compounds with high affinity and good selectivity for PDE5 To identify new PDE5is with good pharmacokinetic (PK) profile that cross blood brain Barrier (BBB) To identify new PDE5is that rescue synaptic dysfunction and memory loss in y y p y y amousemodelofad

7 Drug Development Approach H H H S S H Sildenafil Vardenafil Tadalafil Me Cl Me Cl Me Cl Me Cl H H R C H R H R H R 6 R 3 R 7 R 8 Pyrazolopyridines Phthalazines Pyrazolopyridopyridazines Quinolines H R Based on the structure activity 2 R 1 relationship (SAR) analysis and given Ar the high potency and selectivity, we CMe CMe H have decided to use the quinoline R R 2 scaffold as a template to develop Me Me Me the next generation of novel PDE5 Isoquinolinones aphthyridinones Pyridopyrazinones inhibitors suitable for AD.

8 Structure Activity Relationship To identify compounds with high affinity and good selectivity for PDE5 Compd R8 PDE5 IC50 (nm) 7a b Me c 7d H H 4.3 Me e H 4.1 7f 0.63 Sildenafil 3.4

9 Structure Activity Relationship To identify compounds with high affinity and good selectivity for PDE5 7a Compd PDE1 PDE2 PDE3 PDE4 PDE5 PDE6 PDE7 PDE8 PDE9 PDE10 PDE11 7a Sildenafil Vardenafil Tadalafil IC50 (nm) >10 4 >10 4 >10 4 > >10 4 >10 4 >10 4 >10 4 >10 4 PDEX/PDE5 >10 4 >10 4 >10 4 > >10 4 >10 4 >10 4 >10 4 >10 4 IC50 (nm) > PDEX/PDE > IC50 (nm) PDEX/PDE IC50 (nm) >10 4 >10 4 > >10 4 > PDEX/PDE5 >10 4 >10 4 > >10 4 >

10 Pharmacokinetics of 7a To identify new PDE5Is with good PK profile that cross BBB Concentration Time curve. 7a PK and BBB penetration capability of 7a was investigated. Plasma and brain concentrations ti were dt determined dby the LC MS/MS. Parameters Compound 7a Brain Plasma Ratio* T max (h) C max (ng/ml or ng/g) AUC 0 t (ng h/ml or ng h/g) AUC 0 (ng h/ml or ng h/g) T 1/2 (h) MRT (h)

11 Long Term Potentiation of 7a fepsp Slop pe (% of ba aseline) 400 WT vehicle n=6 APP/PS1 vehicle n=8 WT YF a n=7 n=7 APP/PS1 YF a n=7 n= month old APP/PS1 mice Time (min) fepsp Slo pe (% of ba aseline) 400 WT WT vehicle n=7 n=7 APP/PS1 vehicle n=8 n=8 WT WT YF a n=11 n=11 APP/PS1 YF a n=8 n= month old APP/PS1 mice Time (min)

12 In Vivo Studies of 7a 3 month old APP/PS1 mice 6 month old APP/PS1 mice

13 Lead Compound ptimization The chemical structure of our lead compound was modified in order to improve potency, selectivity, and PK parameters Compds PDE5A1 IC50 (nm) PDE6C IC50 (nm) Ratio PDE6/PDE5 7a ew PDE5Is JF D JF7 1 D JF D JF JF JF D JF >100 >64.5 JF

14 Ex Vivo & In Vivo Studies of JF14 Errors % Freezing day RAWM Blocks FC 24h Contextual baseline 24h contextual WT Vehicle (n=16) WT JF14 3mg/kg (n=16) APP/PS1 Vehicle (n=15) APP/PS1 JF14 3mg/kg (n=15) WT Vehicle (n=16) WT JF14 3mg/kg (n=16) APP/PS1 Vehicle (n=15) APP/PS1 JF14 3mg/kg (n=15) ne) fepsp slop pe (% of baseli LTP WT + vehicle WT + JF14 APP/PS1 + vehicle APP/PS1 + JF Time (min)

15 CCLUSIS A strategy acting at the downstream level of amyloid β might be beneficial against Alzheimer s disease We developed a lead compound inhibiting PDE5 that is potent, selective, and crosses the BBB rescues defects in synaptic function and memory Based on the structure of our lead compound, we are developing a pipeline of new PDE5Is to counteract Alzheimer s disease.

16 Acknowledgments ttavio Arancio Agnieszka Staniszewski Faisal Saeed Hong Zhang Shijun Yan Q&A Donald W. Landry Deng Shi Xian Yan Feng Andrew Wasmuth I call my invention The Wheel but so far I ve been unable to attract any venture capital This work was supported by Alzheimer s Drug Discovery Foundation and IH IA (U01 AG032973).