1. No category

Imperial College
Kidney and Transplant Centre
Clinical Trials in IgA Nephropathy
Dr Frederick Tam
MBBChir PhD FRCP FHEA
Reader in Renal Medicine/Hon. Consultant Nephrologist
Outline
• Treatment of hypertension
• Blockers of angiotensin system
• Immunosuppressive treatment
– Non-selective immunosuppression
– Blocking SYK (Spleen Tyrosine Kinase)
Angiotensin system
Inhibitors of the angiotensin system is useful
for treatment of hypertension and proteinuria
in IgA Nephropathy:
• Angiotensin converting enzyme inhibitor
(ACE-I)
e.g. ramipril, perindopril, lisinopril
• Angiotensin receptor blocker (ARB)
e.g. irbesartan, losartan
Clinical Trials of corticosteroid (1)
• Randomised control trial (RCT)
– Corticosteroid reduced proteinuria and long
term progression to end stage renal failure
(Pozzi et al 1999, 2004)
– ACE-I vs ACE-I+corticosteroid
(Manno et al 2009, Lv et al 2009)
– Limitation of older trials: angiotensin inhibitors
were not optimised before adding
corticosteroid
– Concern of the side-effect of high dose steroid
Clinical Trials of corticosteroid (2)
New clinical trials
Optimised use of ACE-I and ARB, then add
immunosuppressive treatment
– Supportive versus Immunosuppressive therapy of
Progressive (STOP) IgAN trial
– Supportive only vs supportive + immunosuppression
• (eGFR≥60) High dose steroid for 6 months
• (eGFR>30, <60) High dose steroid +
cyclophosphamide/azathioprine for 3 years
– Therapeutic Evaluation of STeroids in IgA
Nephropathy Global (TESTING) study
• High dose steroid vs Placebo for 6-8 months
Mycophenolate mofetil (MMF)
• variable outcomes from controlled clinical trials
– Belgian study (34 patients): ACE-I+MMF vs ACE-I
only for 3 years, no benefit (Maes et al 2004)
– North American study (32 patients): MMF vs placebo
for 1 year (follow up at 2 year): no benefit (Frisch et al
2005)
– Chinese study (40 patients): 6 months of MMF vs
Placebo, initially improvement in proteinuria (1.4
year), improved renal survival up to 6 years follow up
(Tang 2005, 2010)
• Kidney Disease Improving Global Outcomes (Kdigo)
guideline: the results are too heterogenous to
recommend (Kidney Int 2012)
New development
• A selective immunotherapy
Spleen tyrosine kinase (Syk)
• Intracellular tyrosine kinase
• Present in white blood cells and kidney cells
• Can be activated during immune response or
inflammation
• For example, binding of an antibody to specific
receptors on cell surface
Hypothesis: IgA complex activates Syk and
results in kidney inflammation
Receptor for IgA1-IC
Human kidney cells
SFK
P
Syk
Mediators of inflammation
e.g. cytokines MCP-1, IL-6
Fostamatinib: inhibit SYK
•Fostamatinib (R788) is an oral prodrug
(Provided by Rigel Pharmaceuticals & AstraZeneca)
•R406 is the active metabolite
•R406 – occupying ATP binding pocket of Syk
•Selective for Syk
•Off target effect: also inhibit Flt-3 with 5 fold less
potency in cell based assays
Ref: Braselmann 2006 JPET 319:998-1008
Clinical Translation
• Does SYK increase in the pathogenesis of
clinical IgA nephropathy?
• What is the evidence that patients‘ IgA will
activate SYK?
• What is the consequence of blocker SYK in
kidney cells?
Study of Kidney Biopsies from patients
Increase in SYK (brown staining) in IgA nephropathy
IgAN
Crescentic IgAN
Minimal change disease
a
b
c
d
e
f
totalSYK
activated
-SYK
Kim MJ et al J Immunol 2012;189:3751-8
Clinical Translation
• Does SYK increase in the pathogenesis of
clinical IgA nephropathy?
• What is the evidence that IgA from patients
will activate SYK?
• What is the consequence of blocker SYK in
kidney cells?
Collaboration with Renal Unit, Leicester
• To study the potential role of SYK in IgA1
stimulated mesangial cells
Induction of activated (phosphorylated) SYK
in human kidney cells by patients’ IgA
IgAN-IgA1 (min)
0
2
5
10
30
p-SYK
72 kD
β-actin
42 kD
Relative expression
(p-Syk/ actin)
0.25
0.20
0.15
0.10
0.05
0.00
0
2
5
10
30
Minutes
•IgA1 from patients with IgA nephropathy
•Induce expression of phospho-SYK in human
kidney (mesangial) cells
Clinical Translation
• Does SYK increase in the pathogenesis of
clinical IgA nephropathy?
• What is the evidence that patients‘ IgA will
activate SYK?
• What is the consequence of blocker SYK in
kidney cells?
Patients‘ IgA stimulate production of
inflammatory mediators
In human kidney (mesangial) cells in culture
* P < 0.001
Kim MJ et al J Immunol 2012;189:3751-8
Does inhibiting SYK reduce
inflammation?
• Study of human kidney cells (mesangial cells) in
culture
• Stimulations with IgA purified from patients’
serum
• Inhibition with a the active metabolite of SYK
inhibitor (R406)
• Check the specific role of SYK further using
molecular biology method (small interfering
RNA, siRNA)
SYK inhibitor (R406) inhibit production of multiple
inhibitors from kidney cells
MCP-1
*
2500
*
MCP-1 (pg/ ml)
2000
1500
*
1000
500
0
Kim MJ et al J Immunol 2012;189:3751-8
R
40
6
0.
2µ
2µ
M
M
+I
gA
+I
gA
R
R
6
40
40
6
0.
2µ
2µ
on
-Ig
A
-Ig
A
*
1
1
1
MCP-1 (pg/ml)
2500
M
+I
gA
N
M
+I
gA
N
1
ly
N
-Ig
A
m
Ig
A
iu
-Ig
A
1
*
N
-Ig
A
1
N
-Ig
A
1
50
R
6
-Ig
A
1
0
A
N
100
Ig
200
40
NS
ly
RANTES
on
ed
M
+I
gA
N
m
2µ
-Ig
A
1
4000
m
300
PDGF-BB (pg/ml)
6
M
+I
gA
N
*
iu
1
40
2µ
6000
ed
-Ig
A
*
M
+I
gA
N
R
0.
ly
N
-Ig
A
on
IL-8 (pg/ml)
*
m
2µ
-Ig
A
1
400
6
6
m
Ig
A
iu
N
-Ig
A
1
N
-Ig
A
1
*
40
40
ed
M
+I
gA
M
+I
gA
m
2µ
2µ
-Ig
A
1
8000
R
M
+I
gA
N
0
2µ
R
6
0.
ly
0
-Ig
A
1
40
6
Ig
A
N
on
0
N
R
40
m
2000
Ig
A
ly
500
on
NS
RANTES (pg/ml)
1000
m
A
1
A
1
*
iu
gA
N
-Ig
N
-Ig
R
iu
1000
0.
+I
+I
gA
IP-10
ed
M
M
A
1
ly
ed
2000
m
2µ
2µ
-Ig
on
m
3000
6
6
0.
A
N
m
*
40
40
6
Ig
iu
1500
R
40
ed
IL-6 (pg/ml)
4000
R
R
m
IP-10 (pg/ml)
SYK inhibitor inhibit production of multiple inhibitors
from
kidney cells MCP-1
IL-6
IL-8
*
*
*
2000
1500
*
1000
500
0
PDGF-BB
+
*
NS
40
+
30
20
10
0
Kim MJ et al J Immunol 2012;189:3751-8
Sy
k
si
R
N
A
A
N
+
+
Ig
1
1
A
A
- Ig
-Ig
N
N
A
A
Ig
1
0
Sy
k
si
R
A
A
N
N
ls
iR
+
+
Ig
A
1
1
A
A
-Ig
-Ig
A
1
-Ig
N
N
N
Ig
A
Ig
A
1
1
ly
A
A
on
-Ig
- Ig
0
A
nt
ro
N
N
m
A
A
iu
Ig
ed
+
m
A
Ig
0
si
R
co
N
+
-Ig
A
1
500
Ig
A
N
-Ig
R
A
1
1
ly
A
on
- Ig
-Ig
A
50
ol
PDGF-BB (pg/ml)
200
ly
1
100
on
A
200
m
- Ig
*
iu
N
si
N
m
N
N
Ig
A
N
iu
Ig
A
ed
+
m
A
Ig
A
IL-8 (pg/ml)
MCP-1 (pg/ml)
100
ed
Ig
A
1
k
iR
N
+
1
150
m
+
-Ig
A
ol
s
Sy
tr
R
A
-Ig
A
200
nt
r
A
N
co
n
si
N
*
co
N
Ig
A
300
R
+
1000
si
A
1
RANTES
k
N
IP-10
Sy
R
0
-Ig
A
*
RANTES (pg/ml)
k
R
0
Ig
A
N
1
400
ly
A
1
600
on
-Ig
A
Sy
si
Ig
A
N
ly
250
si
N
-Ig
800
m
A
N
ol
on
200
iu
Ig
Ig
A
tr
m
400
ed
+
+
co
n
iu
*
m
A
A
1
ly
ed
IL-6 (pg/ml)
600
ol
N
N
on
N
-Ig
A
m
Ig
A
iu
m
IL-8
tr
R
iR
si
ls
Sy
k
nt
ro
ed
IP-10 (pg/ml)
IL-6
co
n
co
m
Effect of siRNA to SYK in human mesangial cells
MCP-1
2500
*
2000
1500
1000
PDGF-BB
200
*
150
100
50
0
Kim MJ et al
• Is SYK inhibitor likely to be useful in
treating glomerulonephritis (GN),
especially patients will have onset of
symptoms and kidney damage before
meeting the kidney doctors?
Is SYK inhibitor likely to be useful in treating
glomerulonephritis (GN), especially patients will
have onset of symptoms and kidney damage
before meeting the kidney doctors?
• Research project: preclinical models of
antibody mediated GN
– It is challenging to have reproducible
preclinical models of IgA nephropathy
– We have studied two other models of
experimental GN
Pre-clinical development
Antibody mediated glomerulonephritis
• Smith J, McDaid JP, Bhangal G, Chawanasuntorapoj R,
Masuda ES, Cook HT, Pusey CD, Tam FWK. A Spleen
Tyrosine Kinase Inhibitor Reduces the Severity of
Established Glomerulonephritis. J Am Soc Nephrol. 2010
(Feb);21(2):231-6
Pre-clinical development
Antibody mediated glomerulonephritis
(GN)
Is fostamatinib effective in treating established GN?
• Fostamatinib was given orally twice daily
• Groups
– Vehicle
– 40 mg/kg twice daily (day 0-10)
– 40 mg/kg twice daily (day 4-10),
• from onset of proteinuria (day 4)
histology of kidney
Pre-clinical development
**p<0.01
% glomeruli with crescents
**p<0.01
100
75
50
25
0
vehicle
prevention treatment
(D0-D10)
(D4-D10)
Fostamatinib
Pre-clinical development
What is the effect of SYK inhibition on
autoimmunity?
Experimental Autoimmune Glomerulonephritis
(EAG)
• Genuine autoimmune model
• Characterised by ongoing autoantibody
production
– Recapitulates clinical diseases
– Allows study of antibody production
McAdoo et al, J Am Soc Nephrology (accepted for publication)
Pre-clinical development
autommune: Treatment Study
α3
Y
Y
Proteinuria
immunisation
Day
0
McAdoo et al, 2014
9
18
27
Fostamatinib 40mg/kg bd
36
Pre-clinical development: autoimmune model
late treatment with fostamatinib reduced
haematuria and proteinuria
haematuria
proteinuria
McAdoo et al, 2014
Pre-clinical development: autoimmune model
late treatment with fostamatinib :
reverse histology damage of the kidney
**
McAdoo et al, 2014
Pre-clinical development: autoimmune model
late treatment with fostamatinib :
reduced production of autoantibody
Serum antibody
Antibody deposited in kidney
McAdoo et al, 2014
Pre-clinical development: autoimmune model
Summary (preclinical models)
• Fostamatinib is an effective treatment in of
established glomerulonephritis
– Prevents and reverses histology of kidney
damage
– Inhibition of autoantibody production
– Inhibition of inflammation
– Reduction in proteinuria
– Protected kidney function
Smith et al 2010, McAdoo et al, 2014
Clinical applications
Clinical trial of SYK inhibitor in
IgA nephropathy
• approved industrial funding from the drug
inventor (Rigel Pharmaceuticals)
• in collaboration with Kidney Research UK
• Collaborating countries:
Austria, Germany, Switzerland, Singapore,
Taiwan, UK
Clinical applications
Proof of Principle (Phase 2)
Clinical Trial
• Recent diagnosis of IgA nephropathy by kidney
biopsy and has signficant proteinuria
• Initial period (3-6 months) optimise treatment of
blood pressure and proteinuria with angiotensin
converting enzyme inhibitor or receptor blocker
• If still has significant proteinuria, then enter
randomised controlled trial with the SYK
inhibitor, Fostamatinib, or placebo for 24 weeks
Clinical applications
End points for clinical trial
• Improvement in proteinuria?
• Improvement in histology of kidney
damage (kidney biopsy after 24 weeks of
treatment)?
• Safety and tolerability assessment
• To ascertain what are the renal histology
features predicting response to SYK
inhibitor
Conclusions (selective SYK inhibition)
• Increase p-SYK in the renal biopsies of
patients with IgA nephropathy
• Both pharmacological inhibition of SYK and
molecular knockout of SYK reduced
production of inflammatory mediators from
kidney cells in culture
• SYK inhibitor was shown to be effective in
reducing autoantibody production and kidney
damage in preclinical models of
glomerulonephritis
• Developing a proof of principle clinical trials of
fostamatinib for treatment patients with IgA
nephropathy
Imperial College London
• Jennifer Smith
• John McDaid
• Steve McAdoo
• Min Jeong Kim
• Gurjeet Bhangal
• Karen Yu
• Ratana Chawanasuntorapoj
• Theresa Page
• Prof. Terry Cook
• Prof. Charles Pusey
Rigel Pharmaceuticals,
South San Francisco
• Esteban Masuda
• Daniel Magilavy
AstraZeneca
• Martin Braddock
University of Leicester
• Tricia Higgins
• Jonathan Barratt
• Karen Molyneux
• Prof. John Feehally
patients
Diamond Fund, Imperial
College Healthcare
Charity
MRC