4-2. SRNS. Rosanna Coppo (eng)

Rosanna CoppoTorino

Steroid resistant nephrotic syndrome:still a therepeutic challenge

minimal changeGN

mesangial proliferative GN

focal segmental glomerulosclerosis

IgMGN

Idiopathic Nephrotic Syndrome

In all these cases steroid resistance is the most strong predictor

of progression

corticosteroids

Nakayama, 2002

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Clinical Practice Guideline for Glomerulonephritis

Kidney Disease: Improving Global Outcomes

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4.1: EVALUATION OF CHILDREN WITH SRNS

4.1.1: We suggest a minimum of 8 weeks treatment with corticosteroids to define steroid resistance. (2D)

4.1.2: The following are required to evaluate the child with SRNS (Not Graded):

• a diagnostic kidney biopsy;

• evaluation of kidney function by GFR or eGFR;

• quantitation of urine protein excretion.

CHAPTER 4: STEROID-RESISTANT NEPHROTIC SYNDROME IN

CHILDREN

Podocytopathies

14 typesGenetically determined

steroid –resistant Idiopathic NS2-5%

of all the cases

Treatment of children and adults with

idiopathic steroid-resistant NS

ALKYLATING AGENTS

Cochrane Database Syst Rev 2010

Alkylating agents in idiopathic steroid-resistant NS in children

9 RCTs involving 449 children: RR of persistent NS• Oral Cyclophosphamide+P

vs Prednisone RR 1.01 (0.74-1.36)

• IV CPA vs oral CPA RR 0.09 (0.01-1.39)• Azathioprine+P

vs Prednisone RR 1.01 (0.77-1.32)

no significant effect of alkylating drugs

on RR of persistent NS

Treatment and outcome of children and adults with

idiopathic steroid-resistant NS

ALKYLATING AGENTS

CYCLOSPORIN


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4.2: TREATMENT RECOMMENDATIONS FOR SRNS

4.2.1: We recommend using a calcineurin inhibitor (CNI) as initial therapy for children with SRNS. (1B)

4.2.1.1: We suggest that CNI therapy be continued for a minimum of 6 months and then stopped if a partial or complete remission of proteinuria is not achieved. (2C)

4.2.1.2: We suggest CNIs be continued for a minimum of 12 months when at least a partial remission is achieved by 6 months. (2C)

4.2.1.3: We suggest that low-dose corticosteroid therapy be combined with CNI therapy. (2D)


CHILDREN

Cyclosporin treatment decreasesglomerular utrafiltration coefficient

2,40

8,60

3,4

2,1

4,2

1,8

0

5

10

15

Saline CyA

Glomerula volume nl Kf (nl/min mmHg)Kl (ul/min mmHg cmH20)

CyA

Meyrier’s hypothesis:CyA is lipophilic and bind sto a lipidic complex associated to the slit diaphragm, limiting the protein leak

Synaptopodin (protein which stabilyzes cytosckeletal actin and is co-localyzes with

calcineurin)

Synaptopodin is instable and undergoes lysis due to cathepsin with disappearance of cytoskeleton

actin stress fibers

F actin

synactopodin

P ser / treo binding protein

The interaction between synaptopodin and serine/treonine binding protein maintains F-actin

stability, normal cytoskeleton structure and absence of proteinuria

Dephosphorylation

synactopodin

ser / treo BP

ser / tre

o protease

PKA, CaMKII

calcineurin

cathepsin

sinsin

sinCyclosporin

Cochrane Database Syst Rev 2010

Cyclosporin in idiopathic steroid-resistant NS in children

3 RCTs: 49 children:

RR of persistent NS

Cyclosporin (CyA) vs PL RR 0.64 (0.47-0.88)

Treatment of steroid-resistant NSCyclosporin A

Evidence-based recommendations

Treatment Level of evidence

Grade Comments

MCGL

Cyclosporin (at least 6 months)

4 D Possible benefit from pooled case series; no

significant benefit in RCT – small numbers

FSGSCyclosporin (at least 6 months)

1 A Beneficial

An example of CyA nephrotoxicity. Francois H, et al Am J Kidney Dis. 2007;49:158-61.

Renal tolerability of CyA is reasonably goodwhen the dosage is low

Meyrier A, Expert Opin Pharm 2005

Long Term CyA treatment in SRNSGE-ITALIAN STUDY Adult and Children

Ghiggeri 2004

• 55 steroid –resistant

NS treated with CyA

NS remission (partial or total): 20 patients

Mean follow-up: 81 months

Renal biopsy after 5 years of treatment:no tubular or interstitial fibrosis


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4.2: TREATMENT RECOMMENDATIONS FOR SRNS

4.2.1: We recommend using a calcineurin inhibitor (CNI) as initial therapy for children with SRNS. (1B)

4.2.1.1: We suggest that CNI therapy be continued for a minimum of 6 months and then stopped if a partial or complete remission of proteinuria is not achieved. (2C)

4.2.1.2: We suggest CNIs be continued for a minimum of 12 months when at least a partial remission is achieved by 6 months. (2C)

4.2.1.3: We suggest that low-dose corticosteroid therapy be combined with CNI therapy. (2D)


CHILDREN


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4.2.2: We recommend treatment with ACE-I or ARBs for children with SRNS. (1B)

4.2.3: In children who fail to achieve remission with CNI therapy:

4.2.3.1: We suggest that mycophenolate mofetil (2D), high-dose corticosteroids (2D), or a combination of these agents (2D) be considered in children who fail to achieve complete or partial remission with CNIs and corticosteroids.

4.2.3.2: We suggest that cyclophosphamide not be given to children with SRNS. (2B)


CHILDREN

Steroid therapy : different doses, different forms

Cyclosporin late response late and sustained effect,

cyclosporin dependancy, risk of toxicity Other calcineurin-inhibitors:

Tacrolimus

Steroid-, cytotoxic- and cyclosporin-resistant desperate NS:rescue therapy

22 children with steroid-resistant NS

(9 MCD, 11 FSGS, 2 MP)

TAC 0.1 mg/Kg/day (5-10 μg/ml TL)

TAC is an effective therapeutic modality for SRNS, including children non responsive to CP and CyA

Total remission10/13 resistant also to Cyclophosphamide(CP)

2/4 resistant also to Cyclosporine (CyA)Side effects:diarrhea and hypertension (3 withdrawn)

Mean time to remission : 60 days

Roberti I, Vyas S. Pediatr Nephrol 2010, 25: 1117-24


(10 FSGS, 5 other forms)

Long-term outcome of children with steroid-resistant nephrotic syndrome treated with tacrolimus

Complete remission:11/19 (58%) , partial in 6

Mean time to remission : 8 weeks

Remission sustained during follow-up in 58%.

Among FSGF remission 50% ,

in 40% non responders, ESRF.


TAC 0.1-0.2 mg/Kg or CsA 5-6 mg/Kg for 1 year

Alternative day steroids and ACE-i

(10 FSGS, 5 other forms)

At 6 mo Complete remission:TAC 85%, CsA 80%

RR for relapse after 1 year : OR 4.5 (TAC better)

Cosmetic negative effects in CsA only

Steroid therapy : different doses, different forms Cyclosporin late response late and sustained

effect,

cyclosporin dependancy, risk of toxicity

Other calcineurin-inhibitors:

Tacrolimus

Purine synthesis inhibitors:

Mycophenolate


MMF and prednisone in steroid-dependent NS Bagga A Am J Kidney Dis 2003

19 Children previously treated with P, oral CP, and still cortico-dependent NS:

MMF 30 mg/Kg/day for 2 years associated with low tapering doses of Prednisone. FU: 18 months

75% reduction of relapses

After withdrawal relapse in 68% of the cases

Frequency of relapses from 6.6 to 2 each year p<0.0001:

MMF was effective as steroid-sparing agent

MMF in steroid-resistant NS

Author N cases

Regimen Efficacy

Day CJ (Wolverhampt, UK, NDT 2002)

7 adults

MMF (1 gx2) Complete remission 6/71/7 partial r.

Montané (Miami, US, Ped Nephrol 2003)

9childr.

MP pulses (15 mg/kg/week x 4-8)ACE-i/ARBMMF (250-500 mg/m2)

Proteinuria (6-24 months)72% below baselinep<0.01

Mendizabal S (Spain, Ped Nephrol 2005)

275 SRNS

no response to CP and CyAMMF (1200 mg/m2)

1/5 remissionRelapse after withdrawal.

Ulinski (Lyon, Ped Nephrol 2005)

94SRNS

CyA with GFR impairment:2g/1.73 m2

0/4 remissions

In FSGSMMF should be used for > 6 months,

No RCT is available.

The rate of relapse is high.


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4.2.2: We recommend treatment with ACE-I or ARBs for children with SRNS. (1B)

4.2.3: In children who fail to achieve remission with CNI therapy:

4.2.3.1: We suggest that mycophenolate mofetil (2D), high-dose corticosteroids (2D), or a combination of these agents (2D) be considered in children who fail to achieve complete or partial remission with CNIs and corticosteroids.

4.2.3.2: We suggest that cyclophosphamide not be given to children with SRNS. (2B)


CHILDREN

Plasmapheresis


sporadic case reports

Permeability factor (PF)V.Savin 1993

PF is a small anionic protein that binds to Prot A and has analogies with Immunoglobulins

Plasmapheresis and protein A immunoadsorption

Dantal et al (N Engl, 1994) In native and in recurrent FSGS in grafted kidneys:

• Effect often limited in time, with relapse at withdrawal• High cost / often limited benefits• In cases with antiproteinuric response the

progression to ESRF is only partially limited

Recurrence of FSGS on transplanted kidney

Plasmapheresis orImmunoadsorbanceon A Protein+ cyclophosfamide:70% reduction in proteinuria

Lyon and Miami Protocol

B cellsas new target

for NS treatment?

Steroid-, cytotoxic- and cyclosporin- resistant NS:sporadic case reports of

rescue therapy

Anti-CD 20 chimeric MoAbRituximab

Rituximab is a

Chimeric Monoclonal Ab:

Mouse IgG variable region

directed against CD20 Ag

+

Human IgG1 constant

region

A review of the current use of rituximab in autoimmune diseases

Gurvan HM Int Immunopharmacol 2008 Nov

Pharmacological effects: B lymphocytes depletion

Reduced expression of

activated T cell markers

T lymphocytes and NSHodgkin’s diseaseAllergyViral infectionsIn vitro evidences Shaloub’s hypothesis: permeabilizing T lymphokine

Permeability Factor (Ig part?)B cells activated in relapse

B and T collaboration

Francois H, Daugas E, Bensman A, Ronco P.Unexpected efficacy of rituximab in multirelapsing minimal

change nephrotic syndrome in the adult Am J Kidney Dis. 2007;49:158-61.

Rituximab

375 mg/m2 x4

persistent remission

Results

• Always effective in 15/15 proteinuria-free patients

• Remission was induced in 3/7 NS• In 19/22( 85%) one or more concomitant

immunosuppressive treatment was stopped

RTX was repeated in 12 patients who responded,

when CD19 count was >1% of total lymphocytes

Collaborative study (London, Tokyo, Toronto, Turin)

G1) steroid-dependent NS : (28 cases)Complete remission: 61%

G 2) steroid-resistant NS (27 cases)Complete remission: 22%

G3 post transplant recurrrence (15 cases)Complete remission: 40%

Side effects 26%Skin rash,bronchospasm, hypotension

Rituximab used in > 500.000 subjects

Adverse events:

- Allergic reactions, anti chimeric Antibodies.

0

5

10

15

20

25

30

35

% HA

CA po

sitive

0 3 6 9 12

Rituximab toxicity and adverse events:

progressive multifocal leukoencephalopathy (PML)

in 2 cases of SLE and one of RA

treated with multiple drugs , including Rituximab

2 SLE, 1 RA, 2 autoimmune pancytopenia/thrombocytopenia7 stem cells Tx, 26 purine analogues, 39 alkylating agents

52 lymphoproliferative disorders

The emerging role of podocytes

F actin

synactopodin

P ser / treo binding protein

The interaction between synaptopodin and serine/treonine binding protein maintains F-actin

stability, normal cytoskeleton structure and absence of proteinuria

Dephosphorylation

synactopodin

ser / treo BP

ser / tre

o protease

PKA, CaMKII

calcineurin

cathepsin

sinsin

sin

protease inhibitors?

New treatments forNephrotic syndrome

transcription

viral proteins

viral capsids PROTEASE INHIBITORS

PROTEASE INHIBITORS

ANTI-RETROVIRAL DRUGSHIV

• 6 males, 2 females• Previous history of NS: 7.2 ± 4.2 years

3 primary SRNS, 3 secondary SRNS2 SDNS

• Previous treatments: – Steroids, ACTH (8/8)– Cyclophosphamide (4/8)– Cyclosporine A (7/8), Tacrolimus (5/8), MMF (3/8)– Plasma exchange (3/8)– Rituximab (4/8)

• Median age at SAQ start-up : 13.5 (7-38) years• Median duration of treatment: 14.7 (6-68) months

8 patients in treatment with saquinavir 30 mg/Kg/day

Increase in Cyclosporine A and tacrolimus blood levels

CyP450pGpMDR2/3

SAQ is metabolyzed by isoenzyme CYP3A4: modifies CyA and TAC metabolism

SAQ is substrate and inhibitor

Pharmacokinetic interactions

drug interaction between saquinavir and calcineurin inhibitors

• Cyclosporine A: 2 mg/kg/day(vs 5 mg/kg/day before SAQ)to maintain a blood levels of 100 ng/ml

• Tacrolimus: 0.01-0.06 (median 0.018) mg/kg/day(vs 0.1 mg/kg/day before SAQ)to maintain a blood levels of 3-5

Medium dosage of calcineurin inhibitors administered together with saquinavir

Pre-SAQ Post-SAQ0

25

50

75

100

meanreductionof 56%

%

12 months before SAQ Last 12 months with SAQ0

5

10

15

20

25

30

35

p=0.03

Pre-saquinavir Post-saquinavir

Pre

dn

iso

ne

mg

/kg

/mo

nth

Medium dosage of prednisone:

8.4mg/kg/month

Significant decrease in cumulative steroid dosage

Medium dosage of prednisone:

25.2 mg/kg/monthMean

reduction of 63%

Nuclear binding of NF-kB p50- p65 in immortalized human podocytes activated by LPS without or with addition of SAQ 10 and 20 µM.

Nuclear binding of NF-kB p50, p65 in immortalized human podocytes activated by TNFα with or without additionof SAQ10 and 20 µM.

• The protease inhibitor SAQUINAVIR

provided with proteasome inhibitor activity:

1/2 primary SRNS

5/5 SDNS or secondary SRNS

• This drug was active when associated with calcineurin inhibitors, which had to be reduced to less than one third of the original dose to obtain safe blood levels.

Conclusions

Infrequent relapsers

saquinavir benefits:hypotheses

Proteasome-inhibitor activity:

NF-kB hyperactivity inhibition of in circulating mononuclear cells with decrease synthesis of a permeability factor (IPS downregulation)

Proteasome-inhibitor activity:

NF-kB hyperactivity inhibition in podocytes with foot process rearrangement.

Direct impact on podocyte protein synthesis


Combined effect with low doses of CNI and prednisone

NF-kB target forSaquinavir (protease inhibitor)

Glucocorticoids (GCR binding to p65)CNI (non competitive inhibitors of proteasome

& ubiquitinylation)


anti retroviral drug:antiviral beneficial effect in NS?

A rescue therapy may be triedeven in steroid resistant NS

CsA, TAC (MMF)PERituximab

new approaches :Protease inhibitorsAntifibrotic drugs?

Thank you Grazie

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Health & Medicine

4-2. SRNS. Rosanna Coppo (eng)