Download AVR560

AVR560 - A New HCV Inhibitor that blocks early stages of
viral infection
General Properties
IP position: Pat RU 2436786, WO/2012/011847, Priority date: July 2010
AVR560 is substituteg indol, MW 455, LogD (рH=7.4) = 1.789, log Sw (рH=7.4) = –0.98, number of
heteroatoms = 5, number of hydrogen bond acceptors = 1, number of hydrogen bond donors = 1, number of
rotating links = 3, PSA = 42.58. AVR560 is a crystalline powder from nearly white to yellow shade to light
yellow color soluble in water, alcohol, dimethylformamide, insoluble in chloroform, stable under normal
storage conditions.
Antiviral Properties in vitro
Antiviral activity
Table 1. Antiviral activity and cytotoxicity of AVR560 in cultured human
hepatoma cells (sublineage of Huh7), infected with HCV in vitro (JFH-1).
Compound
EC50, µM
CC50, µM
Selectivity index
AVR560
2.12±1.35
110±17.5
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Effect of human plasma on the antiviral activity
Human plasma has a modest inhibitory effect on the antiviral activity of the substance AVR560.
Table 2. Effect of human plasma on the in vitro antiviral activity of AVR560.
Addition of >40% human plasma inhibited HCV infection, making EC50
determination impossible.
Plasma
EC50 / EC50 (human plasma)
10% fetal bovine
1,00
10% human
0,97
20% human
3,17
30% human
3,75
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Mechanism of action studies
The time of drug addition studies and studies of the infection spread in cultured human hepatoma cells
(sublineage of Huh7), infected with HCV in vitro (JFH-1) had revealed the following:
i) AVR560 inhibits in vitro HCV infection, even if added after the virus was adsorbed on the cell surface. If
the drug is added only 2 hours after virus adsorption to the cell surface, its inhibitory activity is largely lost.
These data indicate that AVR560 blocks the early stages of viral infection (internalization), immediately
following the initial step of adsorption of virus to the cell membrane. Thus, AVR560 is an inhibitor of a
new class that differs from all other classed of HCV inhibitors that are currently in active development.
ii) The immunohistochemical analysis (figure below) has demonstrated that AVR560 blocks the spread of
HCV infection in cell culture. Moreover, not only spread through secreted virus is affected, but also viral
spread through tight cell-to-cell contact. Thus, in the presence of AVR560 viral spread in tissue culture
occurs only through cell division (Fig.1C). For comparison, neutralizing antibodies do not have this ability.
This provides a crucial advantage to AVR560, since the spread of viral infection through tight cell-to-cell
contact plays a very important role in the spread of infection in liver of chronic hepatitis C patients.
Animal PK studies
AVR560 has a favorable PK profile and good bioavailability in animals.
Table 3. Main pharmacokinetic parameters of AVR560 in rats and dogs.
Rat
Dogs
Parameters
Administration
IV
PO
IV
PO
Dose, mg/kg/day
10
10
2
10
Kel, 1/h
0.045
0.04
0.57
0.108
T1/2, h
15.5
15.5
1.22
5.57
C0, ng/ml
112.2
Tmax, h
4.00
0.083
2
Cmax (at Tmax=5 min), ng/ml
86.0
31.5
2229
172
AUC(0→t), ng·h/ml
213.4
431.5 379.9
917.7
AUC(0→∞), ng·h/ml
306.8
654.4 418.3 1788.6
MRTlast, h
7.6
9.3
MRTlinf, h
19.4
21.9
Сl, ml/h/kg
108.7
Vd, ml/kg
146125
Vss, ml/kg
126474
2
MAT
Bioavailability
2.5
43%
86%
Safety Pharmacology
Human cytochrome inhibition
AVR560 did not inhibit major human cytochrome P450 isozymes CYP3A4, CYP1A2, CYP2C19 and
CYP2D6 at concentrations up to 10 µM (the highest concentration tested).
Cardiotoxicity in vitro (hERG test)
AVR560 is a weak potassium channel blocker. An inhibition of 18% and 70% was observed at
concentrations of 3 µM and 30 µM, respectively.
Mutagenicity in vitro and in vivo
The mutagenic effect of AVR560 in vitro was studied in the AMES test using histidine-dependent strains of
Salmonella typhimurium (TA98, TA100, TA1535 and TA1537). The effect on the chromosome aberration
frequency was studied in mice upon single and multiple administration of 20 mg/kg and with single
administration of 200 mg/kg AVR560. No mutagenic effects in vitro nor in vivo was observed in these
experiments.
Acute toxicity in rodents
Table. 4. LD values (mg/kg) of AVR560 in mice and rats.
Administration, rodents
LD
Mice (IP)
Rats (IP)
males
females
432±99
315.0±16.7
LD10
122.2
278.0
110.55
LD16
190.3
286.1
LD84
673.4
343.9
LD50 ± SEM
males
Rats (PO)
females
males
females
2 149±333
1 851±333
181.71
1 409
1 111
215.21
214.24
1 571.21
1 274.09
958.11
445.18
2 725.91
2 428.79
586.66±151.65 329.71±66.67
Repeated-dose toxicity studies in animals
Maximum tolerated dose (MTD, mg/kg) in mice
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Intraperitoneal injection of AVR560 in male mice at 10 and 40 mg/kg/day for 5 days did not affect the body
weight dynamics (figure 2). The MTD for AVR560 in these experiments was determined to be >40 mg/kg.
Long-term (1-3 month) toxicity studies in rats and dogs



30-day PO study in rats

Full histopathological anlysis

40, 80 and 160 mg/kg/day safe

Generally well-tolerated
90-day PO study in rats

Full histopathological anlysis

40 and 80 mg/kg/day

In progress
30-day PO study in dogs

Full histopathological anlysis

12 and 40 mg/kg/day safe

Generally well-tolerated
Allergenicity and immunotoxicity
These experiments were performed on CBA mice, white rats and guinea pigs of both sexes.
The PO administration of AVR560 to rodents did not reveal any allergenic properties of the drug.
The macroscopic evaluation upon PO drug administration at sub-acute did not reveal any weight changes in
the main organs of the immune system.
Comparison of the data obtained shows that the product AVR560 has no stimulatory or inhibitory effect on
delayed type hypersensitivity reactions in female CBA mice.
Clinical Studies
Phase I clinical study ongoing (started in Q3 2013).

Phase I clinical study is a double-blind, randomized, placebo-controlled study of the safety and
tolerability of STS-560 after a single oral administration in healthy volunteers Single ascending dose
(50, 100 and 150 mg) in healthy volunteers.

10 subjects per dose cohort (8 drug + 2 placebo), 30 subjects per study.

Objectives:
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

safety,

tolerability,

PK
Interim results

50 mg and 100 dose safe (no serious adverse events reported)

150 mg cohort in progress
Fig. 1A. Immunohistochemical staining of cultured human hepatoma cells (sublineage of Huh7),
infected with HCV (JFH-1) in vitro. The control untreated monolayer (no AVR560). HCV-infected cell foci
are clearly visible.
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Fig. 1B: AVR560 (10 µM) was added after the infection step at 4°C and prior to shifting the
temperature to 37°C (time 0 h). Essentially no infected cells are observed.
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Fig. 1C: AVR560 (10 µM) was added 1 hour after the temperature shift to 37 ° C (time +1 h).
Infected cells are observed, but instead of large foci (Fig. 1A), only single or double cells are
present. This observation suggests that in the presence of AVR560 viral spread occurs only
through cell division.
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Body weight change
(% to Day 1), +/- Conf.Int
140,0
130,0
120,0
110,0
100,0
90,0
80,0
0
1
2
3
4
5
6
Days
Vehicle
10 mg/kg
40 mg/kg
Fig. 2. Change (%) of body weight in male mice after intraperitoneal injections of AVR560 (Mean 
SEM).
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