SCYNEXIS Proprietary and Confidential Information The Discovery and Clinical Evaluation of the Cyclophilin Inhibitor SCY-635 in HCV Infected Subjects Michael Peel 1 , Richard Harris 1 , Zhuhui Huang 2 , Sam Hopkins 1 , Keqiang Li 1 , Thomas E. Richardson 1 , Bernard Scorneaux 1 , Andrew Scribner 1 , Steve Wring 1 . 1 SCYNEXIS INC. and 2 Southern Research Institute. HCV2009.
SCYNEXIS Proprietary and Confidential Information The Discovery and Clinical Evaluation of the Cyclophilin Inhibitor SCY-635 in HCV Infected Subjects Michael.
Mar 26, 2015
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SCYNEXIS Proprietary and Confidential Information
The Discovery and Clinical Evaluation of the Cyclophilin Inhibitor SCY-635 in HCV Infected Subjects
Michael Peel1, Richard Harris1, Zhuhui Huang2, Sam Hopkins1, Keqiang Li1, Thomas E. Richardson1, Bernard Scorneaux1, Andrew Scribner1, Steve Wring1.1SCYNEXIS INC. and 2Southern Research Institute.HCV2009.
SCYNEXIS Proprietary and Confidential Information● Watanabe (2004); Bartenschlager (2006); Tang (2008)
Non-immunosuppressive Cyclosporins Hepatitis-C
N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O
N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O
N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O
Cyclosporin A (IC50)CypA 10 ng/mLCypB 12 ng/mLHCV EC50 ~ 0.3 uMIL-2 inh. 0.006 ug/mL
NIM-811 (IC50)CypA 10 ng/mLCypB 25 ng/mLHCV EC50 0.06 uMIL-2 inh. >10 ug/mL
Debio-025 (IC50)CypA 14 ng/mLCypB 10 ng/mLHCV EC50 0.04 uMIL-2 inh. 2.5 ug/mL
SCYNEXIS Proprietary and Confidential Information
● Cyclosporin:Cyclophilin A complex
Designing non-immunosuppressive Cyclosporins
SCYNEXIS Proprietary and Confidential Information
4-(-OH-Leu) Analogs have HCV Activity and Decreased Immunosuppressive Potential
N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O
OH
N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O
OH
OMe N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O
OH
SMe
CypA 14 ng/mLCypB 20 ng/mLHCV EC50 ~ 0.35 uMIL-2 inh. 0.15 ug/mL
CypA/B 11/30 ng/mLHCV EC50 ~ 0.1 uMIL-2 inh. 0.63 ug/mL
CypA/B 8/5 ng/mLHCV EC50 ~ 0.07 uMIL-2 inh. 0.1 ug/mL
SCYNEXIS Proprietary and Confidential Information
Non-immunosuppressive 4-(-OH-Leu)-3-Sar-Thioethers with Potent HCV Activity
N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O
OH
X
X Cyp A (IC50, ng/mL)
CypB (IC50, ng/mL)
HCV (EC50, uM)
IL-2 (EC50, uM)
CsA 9 12 0.35 0.005 H 14 20 0.35 0.15
SCH3 8 4 0.06 0.06
S
37 29 0.2 0.18
S
12 28 0.15 >10
S
N
12 11 0.06 >10
SN
14 16 0.07 >25
S
N
N
17 18 0.1 >25
S
S
N
16 15 0.1 24
S
N
NNH
147 121 0.58 8
S OMe 6 24 0.06 (MLR 2.3 uM) S NMe2 6 11 0.1 >10
S N(Et)t-Bu 12 6 0.06 >25 S N(Me)t-Bu 17 15 0.07 >25
S NHt-Bu 16 14 0.2 >25
SCY-635
SCYNEXIS Proprietary and Confidential Information
SCY-635 Inhibits Cyclophilin A PPIase Catalytic Activity
[SCY-635] (nM)
0.0001 0.001 0.01 0.1 1 10 100 1000
Res
idua
l act
ivity
(%
)
0
20
40
60
80
100
[CsA] (nM)
0.00001 0.0001 0.001 0.01 0.1 1 10 100 1000
Res
idua
l act
ivity
(%
)
0
20
40
60
80
100
SCY-635 Cyclosporin A
Ki = 1.84 ± 0.33 nM Ki = 2.64 ± 0.56 nM
Cyclophilin:Protease coupled assay using N-Suc-Ala-Ala-Pro-Phe-p-nitroanilide.G. Fischer, Max-Planck
SCYNEXIS Proprietary and Confidential Information
SCY-635 Binds to the Cyclophilin Active Site
Key residues required for PPiase activity are blocked by ligand
SCYNEXIS Proprietary and Confidential Information
Effect of Serum on Anti-Viral Activity in the Replicon Assay
0
20
40
60
80
100
120
0 0.05 0.16 0.50 1.58 5.00
SCY-635 Concentration (mM)
Vira
l Re
plic
atio
n
(% L
uci
fera
se C
on
tro
l)
0% Added Serum
10% Added Serum
20% Added Serum
40% Added Serum
Human serum added to subgenomic replicon system. EC50s determined at 0%10%, 20%, 40% are 0.08 uM, 0.09 uM, 0.11 uM and 0.12 uM respectively.
SCY-635 is ca. 77% protein bound (cf. >99% for CsA)
SCYNEXIS Proprietary and Confidential Information
Synthesis of Cyclosporin Derivatives
● Biotransformation of Cyclosporin
N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O OH
N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O
Sebekia benihana
● Chemical modification of Cyclosporins
N
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O X
RN
N
O
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O X
1) LDA/nBuLi2) Electrophile
X = H or OH
SCYNEXIS Proprietary and Confidential Information
SCY-635 Profile
SCY-635N
N
O
OH
N
NNNN
OHH
NO
N N N
OOOO
O O O
O
O
SNMe2
● Potent inhibitor of HCV RNA replication in con 1b derived replicons; EC50 = 0.1 uM (subgenomic); EC50 = 0.17 uM (full length)
● Additive or synergistic activity with IFN, ribavirin, protease, polymerase. (Data to be presented at AASLD 2009, S. Hopkins)
● No inhibition (IC50 >10 uM) of Cyp450 3A4, 2D6, 2C9, 2C19.
● No induction of Cyps in primary human hepatocytes.
● Weak interaction with Pgp transporter (cf. CsA)
● Low intrinsic clearance rates in microsomal preparations.
SCYNEXIS Proprietary and Confidential Information
0
0.5
1
1.5
2
2.5
3
0 5 10 15 20 25
Time Post Dosing (hr)
Con
cent
ratio
n (µ
g/m
L)
Debio-025
Cyclosporin A
SCY-635
Mouse blood concentrations: Oral delivery (8 mpk) of CsA, Debio-025 and SCY-635
SCY-635 Profile ● Orally bioavailable in multiple animal species.
● Rat: Cl = 110 mL/h/kg; t0.5 = 24 h; F = 22%.
● Monkey: Cl = 45 mL/h/kg; t0.5 = 32 h; F = 13%.
● Improved oral exposure compared to CsA, Debio-025 from simple vehicle.
SCYNEXIS Proprietary and Confidential Information
Clinical Studies
SCYNEXIS Proprietary and Confidential Information
Clinical Proof of Principle Study Design
● 15-day randomized, double blind assessment of safety, pharmacokinetics, and effect of treatment on plasma viremia.
● Entry criteria
● Proof of Principle Study was conducted in two parts:
● Subjects remained in the CRU on Study Days 1, 2, 3, 4, and 14 for intensive PK and viral load sampling.
Cohorts 1-3
(9 active: 3 placebo)
Cohorts 4-6
(6 active: 1 placebo)
Cohort 1: 30 mg q.d. Cohort 4: 100 mg t.i.d.
Cohort 2:100 mg q.d. Cohort 5: 200 mg t.i.d.
Cohort 3: 300 mg q.d. Cohort 6: 300 mg t.i.d.
Adults aged 18 to 65 No co-infections
Genotype 1 infection Plasma viral > 100,000 IU/mL
Enrollment in Cohort 6 restricted to treatment naïve subjects
SCYNEXIS Proprietary and Confidential Information
Safety Summary
●No deaths or serious adverse events occurred.
●No subjects discontinued treatment.
●One Grade 4 laboratory event (elevated triglycerides following consumption of a high fat meal); resolved without interrupting treatment.
●One subject missed one dose of study medication due to transient nausea on Day 3.
●All other treatment-related adverse events resolved without interruption of study medication.
SCYNEXIS Proprietary and Confidential Information
SCY-635-104: Mean and Median HCV RNA Profiles for Cohort 6 vs. Pooled Placebo
-2.50
-2.00
-1.50
-1.00
-0.50
0.00
0.50
1.00
0 2 4 6 8 10 12 14
Study Day
Lo
g10
Ch
an
ge
in H
CV
RN
A f
rom
Ba
se
line
Mean Cohort 6 Response Median Cohort 6 Response
Mean Placebo Response* Median Placebo Response*
* Mean and median placebo responses determined from placebo subjects in Cohorts 4, 5, and 6 (n=3)
Change in HCV RNA for subjects treated with SCY-635 was significant (p<0.05) from Study Days 2 through 15 (Student’s t-test; one-tailed, unequal variance)
SCYNEXIS Proprietary and Confidential Information
Summary● Thioether derivatives of [4-hydroxy-Leu]4-cyclosporin A have potent
activity in the HCV replicon assay and have low immunosuppressive potential.
● SCY-635 is a potent inhibitor of the enzymatic activity of Cyclophilin A.
● The potency of SCY-635 in the replicon system is unaffected by the addition of added serum.
● SCY-635 achieved a mean 2.3 Log(10) reduction of plasma viral RNA when delivered to treatment naïve HCV patients at a dose of 300 mg t.i.d.
● No clinical or laboratory evidence of dose limiting toxicities was observed.
● SCY-635 is a new cyclophilin inhibitor that has robust anti-HCV activity as a single agent and further, dose escalating, clinical studies are planned.
SCYNEXIS Proprietary and Confidential Information
Contributors
ChemistryKeqiang LiAndrew Scribner
BiochemistryRichard HarrisBernard ScorneauxMari VogelSarah Moser
DMPKSteve WringRyan RandolphCraig Smittley
ClinicalSam Hopkins (CSO)Pam RusnakBetty DeMassimo
SCYNEXISYves Ribeill (CEO)
CollaboratorsZhuhui Huang (SRI)Gunther Fischer (Max-Planck)Hengming Ke (UNC)Doug Heuman, M.D. (Maguire MC)Edith Gavis, R.N. (Maguire MC)Jay Lalezari (Quest)Eileen Glutzer, R.N. (Quest)
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